Final published version

Transcription

Downloaded from orbit.dtu.dk on: Oct 13, 2016
Comparison of procedures for determination of acoustic nonlinearity of some
inhomogeneous materials
Jensen, Leif Bjørnø
Published in:
Acoustical Society of America. Journal
DOI:
10.1121/1.2020879
Publication date:
1983
Document Version
Publisher's PDF, also known as Version of record
Link to publication
Citation (APA):
Jensen, L. B. (1983). Comparison of procedures for determination of acoustic nonlinearity of some
inhomogeneous materials. Acoustical Society of America. Journal, 74(S1), S27-S27. DOI: 10.1121/1.2020879
General rights
Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners
and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.
• Users may download and print one copy of any publication from the public portal for the purpose of private study or research.
• You may not further distribute the material or use it for any profit-making activity or commercial gain
• You may freely distribute the URL identifying the publication in the public portal ?
If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately
and investigate your claim.
PROGRAM
OF
The 106thMeetingof the AcousticalSocietyof America
Town and CountryHotel © San Diego,California © 7-11 November1983
TUESDAY MORNING,
8 NOVEMBER 1983
SENATE/COMMITTEEROOMS,8:30A.M. TO 12:10P.M.
Session A. Underwater Acoustics: Arctic Acoustics I
William Mosely,Chairman
Naval Research
Laboratory,Washington,
DC 20375
Chairman's Introductions8:30
Invited Papers
8:35
A1. Bottom-interacting
acousticsignaisin theArcticchannel:Long-rangepropagation.
Henry W. Kutschale
andTai Lee(Lamont-DohertyGeologicalObservatory
of ColumbiaUniversity,Palisades,
NY 10964)
Hydroacoustic
signalsfrom underwaterexplosions
that havepropagated
overthe Arctic abyssalplains
commonlydisplaymarkedfrequencydispersion
in pulsesthat arebottom-interacting
andthat arriveafterthe
$OFAR signal.In theinfrasonic
bandof 2 to 20 Hz, thetemporaldispersion
foreachpulsethathasinteracted
withthefiatbottomoftheplaincanbenearlyasstrongasthatobserved
in the$OFAR signalforthefirstmode.
However,the bottom-interacting
pulsescorrespond
to a coherentsummationof manyhigher-order
normal
modesin a channelbounded
abovebytheoceansurfaceandbelowbytheupper400mofthebottomsediments,
wherethe velocityincreases
with depth.Usingnormal-mode
theoryandthe MultipleScattering
PulseFast
Field Program(MSPFFP),we haveanalyzedthedispersion
andpulseshapes
andhavederivedtheacoustic
properties
of thebottomin thePole,Barents,andMendeleyev
AbyssalPlains.The principalproperties
of the
bottomcontrollingthe propagationare compressional
velocity,density,and attenuation.In contrast,the ice
layerhasa negligibleeffecton the dispersion
of the observedwaves.The effecton pulsecompression
of this
frequency
dispersion
of the bottom-interacting
signalswassimulatednumerically,usingpredistorted
waveformsmatchedto thedispersion
of theSOFAR channelat specified
ranges.
9:00
A2. Ambientnoi•ein thecentralArcticOcean.Ira Dyer (Department
ofOceanEngineering,
Massachusetts
Instituteof Technology,Cambridge,MA 02139)
Underwater
ambientnoisehasbeenmeasured
in thecentralArcticOceanonthreeseparate
occasions
with
theuseofa horizontal
anda verticalarray.Thesedatahelptoidentifyvariousnoisemechanisms.
Of principal
interestisnoisecaused
byvariousicecrackingeventswhichdependuponstress
levelsin theiceandwhichseem
to havevaryingtemporalandspectralcharacteristics.
I reviewthesemechanisms
andshowhowthedatarelate
to them.Whilespatialanalyses
havebeencarriedoutonlyat verylowfrequencies,
spectralanalyses
coverthe
rangefrom I to 10000 Hz. In this frequencyrangenoisemechanisms
otherthan packice are sometimes
important,suchaswind-generated
noiseandearthquakenoise.[Work supportedby ONR.]
9:25
A3. Seismic/acoustic
propagationin the Arctic Ocean.Arthur H Baggeroerand GregoryL. Duckworth
(Departments
of Oceanand ElectricalEngineering,
Massachusetts
Instituteof Technology,Cambridge,MA
02139}
During the FRAM II and FRAM IV experimentsin the PoleAbyssalPlain and the BarentsAbyssalPlain
of theArctic Ocean24 channelhydrophone
arraysapproximatelyI km X I km in extentwereusedto record
digitallybothseismic
refractionandlong-range
acoustic
propagation
data.Fromthesedatathevelocityversus
depthfunctionfortheseismic
structure
alongtheFRAM II andFRAM IV drift trackswereestimated
byhighresolutionvelocityspectralanalysisand tau-slowness
migrationmethods.Theseindicateoceaniclayers2 and
3, but they are relatively thin. These techniqueswere also usedto identify internal and surface-reflected
Sl
J. Acoust.Soc.Am.Suppl.1, Vol. 74, Fall 1983
108thMeeting:AcousticalSocietyof America
multipaths
aswellasconverted
shearpathsto obtaina detailed
characterization
of theseismic
propagation.
Thelong-range
acoustic
signals
contained
strongmodalcomponents
andbottominteracting
ones.Velocity
spectra
andautoregressive
algorithms
resolved
thedispersive
properties
ofthephase
andgroup
velocity
ofeach
mode.Thesewereusedto estimatethe watercolumnsoundvelocityprofilewith an inversionalgorithm.
DuringFRAM II thebottominteractions
lastedupto 80slongandcontained
asmuchenergyasthelow-order
modesat low frequencies.
Thesesignalswereusedto estimatethe shallowvelocityversusdepthstructure.
DuringFRAM IV thedispersion
characteristics
ofthelow-order
modes
changed
slightly.
In contrast,
virtually
nobottom-interacting
energywasobserved
suggesting
strongscattering
of thedeeppathsby an intervening
midoceanic
ridge.[Worksupported
by ONR ArcticProgramOffice.]
A4. TRISTEN/FRAM IV ew spatial eoberenceand temporalstability. F. R. DiNspoll, R. Nielsen,
D. Potter(Naval UnderwaterSystemsCenter,New London,CT 06320),and P. L. Stocklin(Analysisand
Technology,Inc., N. Stonington,CT 06359)
The TRISTEN-82/FRAM IV experimentwas a multifacetedexperimentinvestigatingacousticsin the
Arctic. This paper focuseson the spatialcoherenceand temporal (frequency)stability of acousticsignals
transmittedandreceivedbetweenfixedicecampsseparated
by approximately130nmi. A high-powered,
lowfrequency(NUSC HLF-3 Arctic)hydroaroustic
sourcetransmittedstablecw tonesof I h or moreat various
frequencies
from5 to 200Hz duringApril 1982.Thesesignals
werereceivedonan X-shapedarrayhavingan
apertureof 1200m oneachleg.ThearmywasoperatedbytheMassachusetts
Instituteof Technology
andthe
Wood Hole Oceanographic
Institute.The spatialcoherence,
both broadsideand end-fireto the sourcewere
foundfrom normalizedsensorpaircrosscorrelation,correctedfor signal-to-noise
ratio.Total and3-rib down
receivedsignalbandwidthswerefoundusingcomplexdemodulationandFFF with a resolutionto a fractionof
mHz, followedby cumulativeenergyanalysisin the frequencydomain.The experimental
setupdata,analysis
procedures,
and resultswill be presented.
[Work sponsored
by the Officeof Naval Research,Code425-AR.]
10:15
AS.Arcticdatacollectiontheeasyway--Data buoys.BeanmontM. Buck(PolarResearch
Laboratory,Inc.,
123SantaBarbaraStreet,SantaBarbara,CA 93101)
This paperpresents
a reviewof developmental
and operationaluseof Arctic data buoys.Thereare many
problemsinvolvedwith aircraftand icebreakerlogisticsfor scientificsupportin the Arctic. Mannedresearch
stationson seaice are expensive,
self-contaminating
in termsof acousticand electromagnetic
noise,and
generallylimitedtoa 40- to 50-dayperiodin thespringtime.Autonomous
databuoys,ontheotherhand,donot
sufferthoselimitations.Thesedevicescan be installedby parsdrop,aircraft ice-landing,submarine,or icebreakerin almostanygeographic
areaof theArcticOcean,peripheralseas,andmarginalseaicezonesto collect
andreportdataoverall seasons.
Therearerestrictions,
ofcourse,
astowhatcanbeaccomplished
automatically
withina smallbuoyhull, andalmostall Arcticbuoys,sofar, havebeenmechanically
passive.
Recentadvances
in low-powermicroprocessors
andmemories
enableconsiderable
increases
in theextensive
in-buoyprocessing
needed
fordatacompression
toaceomodate
thelimitedcapacities
ofpolarorbitingscientific
satellites.
[Work
supported
by U.S. NavyandNOAA.]
ContributedPapers
10:40
A6. Normal mode and ray equivalencein the Arctic sound channel.
RobertH. Mellen {B-K Dynamics,Inc., 247 ShawStreet,New London,
• 06320)
Effectsof upwardrefractioncombined
with scattering
by the rough
iceinterfaceresultin a dispersive
soundchannelcapableof propagating
only very low frequencies
to longrange.Because
only a few modesare
involved,normalmodetheoryis appropriate.However,surface-scatter
modelsare usuallybasedon plane-waveapproximations
for which ray
theoryis mostuseful.The two approaches
are simplycombinedin the
impulse-response
method.Applicationof thismethodto thepropagation
of transients
andcontinuous
wavesignalsisdiscussed.
Removalof dispersiveeffectsby deconvolution
to increasedata rate is alsoconsideredin
viewoftheextremetemporalstabilityofthechannel.[Worksupported
by
ONR and NUSC.]
A my-theoreticmodelis advancedto describethe averagereverberation intensitieswithin an Arctic channelboundedby a pack-icesurface
and an upward-refractingsound-speed
profilein the presence
of pressure
ridgescattering.
The surfaceisassumed
randomanda phenomenological
modelbasedon Kirchoffassumptions
in the high-frequency
limit is de-
rived.Relevantparameters
areestimated
fromdatasupplied
byChapman
andScottusinga curve-fitroutine.Ridgesaremodeledasinvertedcones,
thesurfaces
of whicharealsoassumed
random.This simplifyinggeometric assumption
allowsfor a highlytractabletechnique.Forwardaswellas
backscattered
geometriesare treated with no assumptionsregarding
source/receiverrangeor depth and ridge location or draft. Applications
to sonarreceiverperformancewill be discussed
in a companionpaper.
[Worksupported
by ONR.]
11:10
Ag. Sonar receiver performance models for the arctic channel in the
10:55
A7. Reverberationmodel of the arctic channelin the presenceof ridge
scattering.Garry M. Jacynaand Alan 1. Friedman{PlanningSystems
Inc., McLean, VA 22102}
S2
J. Acoust.Soc. Am. Suppl.1, Vol. 74, Fall 1983
presenceof ridge scattering.Garry M. Jacynaand Alan J. Friedman
(PlanningSystemsInc., McLean,VA 22102)
A genericclassof sonarreceiversare modeledin an attemptto describeaveragereceiverperformance
in the Arctic channel.A ray-theoretic model,discussed
in a companionpaper,describes
theaveragereverber-
106th Meeting:AcousticalSocietyof America
S2
ationintensities
withinanArcticchannel
in thepresence
ofpressure
ridge
scattering.
Receiver
performance
isevaluated
intermsofsignaldetectabilityasa function
ofrange,ridgelocation,
andsource/receiver
depth.The
modelsareextremelygeneralin that arbitrarypulseshapes
andsensor
campswerenegligibleduringthe transmission
periodsand hencethe resultsapplyto transmission
betweenessentially
fixedstations.
locations
areallowed.
As an illustration,
twopulseshapes
areconsid-
11:40
ered--a transientand a CTFM pulse.Their effecton receiverperformanceisdependent
onthesource/receiver
geometry
aswellasridgelocation. In general,however,the longerCTFM pulseoften leadsto a
reverberation-limited
conditionasa resultof surfaceaswell aspressure
A10. Ultrasonicreflectionmeasurements
of floatingice.Neal G. Brower
(AppliedPhysicsLaboratory,JohnsHopkinsUniversity,Laurel, MD
20702), Kin W. Ng, and Walter G. Mayer (Departmentof Physics,
GeorgetownUniversity, Washington,DC 20057)
ridgescattering.[Work supportedby ONR.]
An experimentalinvestigationof reflectionof ultrasonic,bounded
beamsfromfloatingicehasbeenconducted.
Ultrasonicfrequencies
and
icethicknesses
corresponding
to frequencythicknesses
of between2 and5
mm.MHz are considered.Nonspecularreflectionprofilesare obtained
usingschlierentechniques.
Thesenonspecular
profilesare comparedto
theoreticalprofilescalculatedfor water/iceplate/airsystems.
[Work supportedby ONR.]
11:25
A9.Depthdependence
ofthetemporai
characteristics
ofcw propagation
in theArcticOcean.G. R. Giellis,T. C. Yang,andC. W. Votaw(Code
5123,NavalResearch
Laboratory,
Washington,
DC 20375I
Previous
workbyP. Mikhalevsky[J.Acoust.Sec.Am. 70, 1717-1722
(1981)]
investigated
thetemporal
characteristics
ofcwsignals
propagating
intheArcticOcean.Theprevious
workwaslimitedtoreceivers
ata depth
of 91 m. In thispaper,thetemporalcharacteristics
will beextended
to 28
hydrophones
in a verticalarraywith depthsfrom30 to 960 m. The data
weretakenduringthe FRAM IV experiment
in April 1982.The signals
11:55
All. Acousticscatteringfrom Arctic sea-iceridgesusinghigh-angiePE.
RobertR. Greene(ScienceApplications,Inc., 8400 WestparkDrive,
McLean VA 22101)
weregeneratedat the Tristenicecampand receivedat the FRAM IV ice
camplocatednorthof Spitzbergen.
The rangeof approximately
275km
wasovertheMid-OceanRidge;theaverage
waterdepthalongthepath
was3000m. Mostof thedataexamined
areat a highsignal-to-noise
ratio
Long-rangepropagation
lossrunswith thehigh-anglePE modelindicatethat scattering
of soundintotheoceanbottomby sea-iceroughness
can accountfor the frequencydependence
of transmission
lossin the
Arctic.Butdifferences
between
theslopes
of thedataandpredicted
transmission
losscurvessuggest
thepresence
of anadditional
lossmechanism
(> 10 dB• whichmakesit possible
to studythe temporalfluctuationand
thestatistics
of the cw signalsat differentdepths.By employing
a mode
filteringtechnique,
thetemporaldependence
of theamplitude
andphase
of thelowestordermodehasbeeninvestigated.
The drift ratesof theice
TUESDAY
MORNING,
8 NOVEMBER
1983
in the ice.
CALIFORNIA
ROOM,
9:00 A.M. TO 12:00 NOON
Session B. Noise I: Use and Misuse of the FFF
John C. Burgess,Chairman
Departmentof MechanicalEngineering,Universityof Hawaii, 2540 DoleStreet,Honolulu,Hawaii 96822
Chairman's
Introduction--9:00
Invited Papers
9:05
B1. Digital signalprocessing
for soundand vibrationanalysis:A tutorial. JohnC. Burgess(Departmentof
MechanicalEngineering,Universityof Hawaii, 2540Dole Street,Honolulu,HI 96822)
The literature on digital signalprocessingis basedon four kinds of transform:Fourier transform(leT),
z-transform,Fourierseries,anddiscreteFouriertransform(Dl:q•).Digital implementationusesonly the DI:rT,
usuallyin theformofanFFT algorithm.Somepopulartextsattemptto describe
digitalresultsbyusinganalog
(usuallyFT) analysis.Somehavepresented
analyticalresultsfor infinitelengthrandomsignalsandthenused
illustrationsbasedon finitelengthperiodicsignals.What "windows"do and their differenteffectson random
andperiodicsignalsseldomare clearlyidentified.Thereare two implementations
of the DFT that differby a
constantfactor.Fastconvolutionandcorrelationanalyses
requirespecialhandlingto avoid"circular"effects.
The DIeT treatseachfinitelengthsamplefrom a randomsignalas if it werea samplefrom a deterministic
signal.The purposeof this tutorialis to illuminatetheseand otherpotentiallytroublesome
aspectsof digital
signalprocessing
pertinentto applications
in soundand vibrationanalysis.
9:35
B2. Noise source identification by coherence and acoustical methods using FF'Y analyzers. Thomas
H. Hodgson(Centerfor Soundand Vibration, North Carolina StateUniversity,Raleigh,NC 27650)
The practicalunderstanding
of thetwo-channelFFT spectrumanalyzerasusedin noisesourceidentification will beaddressed.
In particular,the measurement
of the coherencefunctionandthe acousticintensity,the
$3
d. Acoust.Sec. Am. Suppl. 1, VoL 74, Fall 1983
S3
latterby bothtwo-microphone
andsurfacemethods,
will be described.
Problemsrelatedto amplitudeand
phaseinformation
andthedesign
of mostanalyzers
astheyrelateto Fouriertransform
theoryor electrical
networkpracticewill be discussed.
Severalcasestudiesof noisesource.
identification
measurement
will be
presented
in ordertodemonstrate
someof thepointsrelatedto FFT analyzerusedescribed
in thepaper.Both
steady-state
andimpactnoiseproblems
will beconsidered
withreference
to causes
of possible
errors.
9:55
B3. Field experiencewith soundand vibrationmeasurements
usingan FF'Y analyzer.Frank H. Brittsin
{BechtelResearch
andEngineering,
P.O. Box3965,SanFrancisco,
CA 94119}
ThetheoryuponwhichFFT analyzers
arebasedpromises
a verypowerfulandusefulmeasurement
tool.In
thefield,a varietyof practicaldifficulties
oftenaffecttheabilityto obtainvalidresultsusingan FFT analyzer.
Thesedifficulties
fall into fivccategories:
{!) inadequate
knowledge
on the part of the user,{2}detailsof the
analyzeras implemented
by the manufacturers,
{3)bugsin the hardwareand softwareof the analyzer,{4)
conditionsunderwhichmeasurements
are made{includingthe individualcharacteristics
of the equipment
testedandthebackground
vibration),and{5)abilityof thc userto interpretdatafrom theanalyzer.Eachof
thesefivecategories
isdiscussed,
withemphasis
ontwo-channel
measurement
applications.
Practical
cxamplcs
of fieldproblemsencountered
andmethodsusedto overcomethemare discussed.
10:15
B4. Statusof standardson digitalsystemsfor soundandv•ration analysis.Tony F.W. EmbletonIDivisionof
Physics,NationalResearchCouncil,Ottawa,OntarioKIA OSI, Canada)
ExistingANSI lAmericanNationalStandards
Institute)standards
dealprimarilywith analogacoustical
instruments
andtheiruse--following
traditionalthinkingandprocedures
of acousticians.
Theyarerelevantto
theanalogpartsof a digitalsignalprocessing
systemsuchasthesignalitselfItimeandfrequency
characteristics),transduction(directionality,linearity,frequencyresponse
of microphones
or vibrationpick-ups),and
output(preferredfrequencies,
referencequantifies).They are alsorelevantto digitalcomponents
that mimic
closelythe behaviorof analogdevices,e.g.,filtersthat receivesignalscontinuously.
The nextrevisionof S1.1I
will explicitlyincludespecifications
for theperformance
of bothanaloganddigitalfilters.The IEC 0nternational ElectrotechnicalCommission•
acousticalstandardssimilarlyrelateto analoginstrumentsand their use.
The nextseveralyearsshouldseeprogress
in thedevelopment
of standardsfor digitalacousticaliustrumentation, but beforethiscan happenacousticians
mustrecognizeand widelydiscussthe technicalproblemsthat
exist.Generalconsensus
shouldbe reachedon many factors,one of the most fundamentalis the possible
methodsof achievinga desireddegreeof accuracyfor a givenkind of acoustical
signal.Standardswritten
prematurelyrisk biasingmeasurement
procedures,
and instrumentation
to meettheseneeds,in what may be
less-than-optimum
directions.
10'.35 to 11:00
Panel Discussion
ContributedPapers
11:00
Bfi. Amplitudecalibration of an FFT analyzer. JosephPope {Bruel &
Kjaer Instruments,
Inc., 185ForestStreet,Marlborough,MA 01752}
When usedfor frequencyanalysis,an FFT analyzerproducesa line
spectrumon the amplitude-frequency
plane.Eachspectrumline representsthe outputof a filter centeredat the frequencyassociated
with the
line,theshapeof the filterbeingdeterminedby theeffectivetime window
appliedto thedatabeinganalyzed.While it is generallyrecognized
that
theuseof an explicitwindowfunctionisoftendesirablese.g.,to control
spectral"!eakage"--manyFFT usersseemunawarethatuseofa windom
impliesa compensatory
calibrationadjustment
thatisdependent
uponthe
characterof thedataand theobjective
of theanalysis.Effectivefiltershapes
for rectangular,Harming,flat top, and Kaiser-Bessel
windowsare discussedalong with the conceptof filter amplituderesponseand effective
noisebandwidth.
ApprOpriate
calibration
forrms,power,powerspectral
density,andenergyspectraldensityspectraisexplained.
11:15
B6. Acoustic impedancemeasurementv'a FF'r. Werner G. Richarz
(Institute for AerospaceStudies,University of Toronto, 4925 DufFerin
Street,Downsview,Ontario, Canada)
The measurement
of acousticimpedanceof acousticmaterialsand
networksoftenrequiresa ratherlaboriousimpedancetubemeasurement.
84
d. Acoust.So(:.Am. Suppl.1, VoL 74, Fall 1983
Other methodshave beenevolved,but theseusuallyrely on two micro-
phonemeasurements.
Thesinglemicrophone
system
reportedhereutilizes
theincidentand reflectedpulsein a circularimpedancetube.The pulseis
generated
by a suitablydampedloudspeaker
drivenby a low-frequency
squarewave.A two-channelFast FourierTransform.analyzercaptures
the pressure-timehistory.The signalis then conditionedleavingonly
replicates
of theincidentandthereflectedpulsessuitablyshiftedin timeto
simulateconditionsat the samplesurface.Usingthe variousfeaturesof
modernFFT analyzers,the reflection(absorption)
coefiieientas well as
the complexvaluedimpedance
are readilyavailablefrom a singlemeasurement.
At present
theusablefrequency
rangeis5 kHz. [Worksupportedby theNaturalScience
andEngineering
Council,Canada.]
11:30
BY. Use and mistmeof an FFT analyzer for octave-bandand one-third
octave-bandanalysis.Richard C. Sohaney(Bruel& Kjaer Instruments,
Inc., ! 85 ForestStreet,Marlborough,MA 01752)
An FFT analyzeris oftenusedas a "real time analyzer"to perform
octave-bandand one-thirdoctave-bandanalyses.The limitationsand as-
sumptionswhichthe filter synthesizing
techniqueimposeson the data
signalare discussed.
A methodfor synthesizing
ANSI ClassII octavebandand ClassIII one-thirdoctave-bandfiltersusingan FFT analyzeris
explainedwith emphasis
on the shortcomings
of synthesized
filters.
ampleanalyses
of varioussignalsareperformed
withconventional
ANSI
106th Meeting:AcouslicalSocietyof America
S4,
ClassIII one-thirdoctave-bandfiltersand an FI• analyzerto demonstratecorrectandincorrectuseof thesynthesized
filtermethod.
FFT devicesoftenincludea data smoothingcapabilitythat is based
uponaveraging
overa selected
numberof adjacentpointsin a dataarray.
Averaging
timedomaindatain thiswayisequivalent
tolow-pass
filtering
the data. The resultinginaccuracies
associated
with frequencydomain
representations
of theaveraged
dataareexamined.
Predicted
andexperimentalresultsarepresented
for theFF"r'sof averagedsinusoidal,
period-
11:45
ic, and filtered random waveforms.The effectsof sampleinterval and
1•. Dam averagingand FFr devices.David K. Holger(Departmentof
EngineeringScienceand Mechanics, 214 ERI Bldg., Iowa State
University,Amm, IA 50011)
TUESDAY
MORNING,
8 NOVEMBER
1983
numberof averaging
pointson theequivalent
filtercharacteristics
of the
averagingprocess
are discussed.
COUNCIL/CHAMBER
ROOMS, 9:00 TO 10:40 A.M.
SessionC. Engineering AcousticsI and Architectural AcousticsI: Teleconferencing
James E. West, Chairman
Bell Laboratories,
Murray Hill, New Jersey07974
Chairman's
Introduction--9:00
Invited Papers
9:05
CI. Acoustics
ofteleconferencing.
Chris Stockbridge
(AmericanBellInc.,E.D.&D., Room4G-514,Holmdel,
NJ 07733)
Room acousticsis an elementof teleconferencing
too often neglected.Ideally, the room shouldnot be
symmetrical
andthewallsshould
benonparallel,
covered
irregularly
withsoundscattering
andnoiseabsorbing
panels.
At theveryleast,a placeforteleconferencing
mustbequietandnotreverberant.
Technical
specification
of varioussizesof desirable
acoustical
spaces
whichmatchbothpeople's
behaviorandequipment
constraints
will besetforthin thistalk. Equipmentandtechniques
will bediscussed
whichselectacoustics
for a naturalfeel
withintheroomwhilegenerating
signals
thatcreateclearandrecognizable
voicesounds
whenheardat remote
location(s).
Theseincludephasedarraydirectionalmicrophones,
carefullypositioned
loudspeakers,
simple
acoustic
absorption,
andforthemoresophisticated,
nonparallel
wallsandirregularceilingclouds.
Thereal
challenge
is to implement
thistechnology
in an aesthetically
pleasing
fashion,tailoredandmatchedto the
cultureoftheexpected
userpopulation.
A varietyofteleconferencing
roomswillbepresented
in photographs,
showing
evolution
in thedesign
of roomsfor audio,audiographic,
andfull motionvideoteleconferencing.
9:30
C2. The humanengineering
of a newteleconferencing
service.Daryl J. Eigen(BellLaboratories,
NapervilleWheatonRoad, Naperville,IL 60566I
TheBellSystemisdeveloping
a newnetworkteleconferencing
service.
Thisserviceenables
thecustomer
to
setup a conference
with or withoutan operator,andit incorporates
state-of-the-art
signalprocessing
technologyto enhance
audioquality.Thehumanengineering
ofthisnewservice
concentrated
oncharacterizing
the
customer,
optimizing
theperceived
audioquality,andmakingtheconference
setupprocedures
easytouseand
errorfree.A coordinated
seriesof interviews,
surveys,laboratorystudies,andfieldstudieswasimplemented
to
increase
customer
satisfaction,
performance,
andusage.
Thissequence
oftesting
isculminated
ina Controlled
ProductTest,whichis a dressrehearsal
of a newservice,usingBellSystememployees
asthefirstcustomers.
The CPT startedon 7 February1983in selectedsitesin SanDiego,LosAngeles,andSanFranciscowith two
bridges
located
inLosAngeles.
TheCPThassince
beenexpanded
toadditional
sitesin 12states
withfourmore
bridges,
twoin WhitePlains,NewYorkandtwoin Chicago,
Illinois.Thisgeographic
diversity
provides
the
opportunity
forlargecallingvolumes
anda widerangeofconference
configurations.
Over2000callshavebeen
placedthusfar,allowingtheconference
setupprocedures
to besimplified
andperceived
audioqualityto be
improved.
ContributedPapers
9:55
C.3. The Quorum TM teleconferencingmicrophone.James H. Snyder
(AmericanBell, Holmdel,NJ 07733)
Arraysof microphones
havelongbeenusedin underwater
acoustics,
$S
J. Acoust.Soc.Am.Suppl.1, VoL74, Fall 1983
but only recently has it been appreciatedthat the directivity of micro-
phonearraysmakesthemsuperiorto conventional
microphones
in many
audioapplications
aswell. In this paperwe describea particularmicrophonearray,theQuorumTM teleconferencing
microphone,
whosedirectivity is achievedby the nonuniformspacingof the transducers.
We pres-
$5
10:2S
entequations
for thearraysensitivity
assuming
planeandspherical
wave
radiation,andcomparetheseresultswith measurements.
CS.An sentratio
directionfinder.C.H. Coker(BellLaboratories,
Murray
Hill, NJ 07974) and D. R. Fiseheli(Bell Laboratories,Holmdel, NJ
07733)
10:10
CA. Conferencemicrophonewith adjustabledirectivity. J. L. Flanagan
and R. A. Kubli (AcousticsResearchDepartment, Bell Laboratories,
Murray Hill, NJ 07974)
Designs
aregivenforfixed-steered
line-arraymicrophones
suitablefor
teleconferenee
applications.,The
steering
isarranged
sothatthearraycan
be locatedout of line-of-sightof the conferees.
The directivitypatternof
the transducercanbeselectedto giveeffectivespatialcoveragefor a variety of conference
conditions.Additionally,the designsutilize acoustic
summationandanti-aliasing
filtering.They requireonly an inexpensive
electretelementas the transducer.Theoreticalresponses
are calculated
and plottedon an Apple II computer.A prototypemodel is fabricated,
and experimentalmeasurements,
made under free-fieldconditions,are
shownto comparesatisfactorily
with thetheoreticalresponses.
A simpleprocedureisdescribed
for findingthedirectionto thesource
of an acousticsignal--primarilythe humanvoice.The method,in effect,
constructs
the crosscorrelationof severelydistortedsignalsfrom two
microphones.
The distortion,a combination
of time-domain
processing
anddigitallogic,is suchto givestrongpreference
to direct-pathearly
arrivalsover reflections
that follow,and to producestreamsof pulses
whosecrosscorrelations
canbecomputed
verysimply.The methodhas
beenimplemented
as a combination
of customhardware,and a simple
microprocessor.
The implementation
operates
in realtime(with •0.2-s
delay}andproduces
outputstoindicateeithertheazimuthangle,or intermicrophone
delay.Possible
usesincludeself-aiming
directionalmicrophones,automaticaiming or switchingof videocameras,and remote
identification
of talkersin nonvideo
teleconferencing.
SessionD. ArchitecturalAcousticsII: The TechnicalCommitteeon ArchitecturalAcoustics
V. O. KnudsenDistinguishedLecture
SessionD movedto Thursday Afternoon, 10 November 1983 at 1:30 P.M.
TUESDAY MORNING,
8 NOVEMBER
1983
SUNRISE ROOM, 9:00 A.M. TO 12:05 P.M.
SessionE. PhysiologicalAcousticsI: Peripheral Systems
JosephE. Hind, Chairman
Departmentof Neurophysiology,
Medical ScienceBuilding, Universityof Wisconsin,
Madison, Wisconsin
53706
Chairman's IntFoductio•9:00
ContributedPapers
9.'05
El. Comparativecochlear morphologyin echolocatingeetaeeans.D.
R. Ketten,F. L. Starr,'• andD. Wartzok(Department
of Immunology
and InfectiousDisease,JohnHopkinsMedical Institute,615 N. Wolfe
Street,Baltimore,M D 21205)
S6
J. Acoust.Soc.Am.Suppl.1, Vol.74, Fall 1983
The anatomyof the cochleaof six species
of odontocetes,
or toothed
whales(Ph•,setercatadon,Grampusgriseus,Lagenorhynchus
albirostris,
Phocoenaphocoena,Tursiopstruncatus,and Stene!!a!ongirostris)
was
comparedusingconventional
micrographyand radiographictechniques
includingedgeenhancementx-ray, CT scan,magnificationradiography,
anddigitalsubtraction.Thesespecies
wereselectedfor differences
in fre-
106thMeeting:Acoustical
Societyof America
S6
quencyand patterningof normal and ultrasonicvocalizationsin their
naturalenvironments.
The cochleawereextractedpost-mortem
andpreservedby injection.Wholecochleawerefirstexaminedradiographically
for species-specific
differences
in grossmorphologyand topology,particularlyfor angularchangeof the scalaeand torsionof membranaland
neuralcomponents.
Specimens
were then decaltitledand processed
for
SEM or thin sectionmicroscopy.
Measurements
obtainedby bothmethodsare presented
andthe advantages
of the radiographic
techniques
discussed.The resultsare comparedwith the cetaceancochlearmodelsof
Wcvcr[Weveret al., Proc.Natl. Acad. Sci.68, 2381-2385(1971)]and
Fleischer[G. Fleischer,J, Paleon.$0 •1), 133-152(1976)]andanalyzed
accordingto the dimension-frequency
correlationtechniques
of Greenwood[D. D. Greenwood,
J. Acoust.Soc.Am. 33, 1344-1356(1961)]and
Hinchcliffeand Pye JR. Hinchcliffeand A. Pye, Int. Audiol. 7, 259-288
(1968}].[Worksupported
byNSF.]alAlsoat Radiology
Research
Labora-
linearmodulationof this activity,allowingoneto definesmall-signallinear transferratiosand to observetuning curvesfor suchaxons.Each
tuningcurveto datereflectsmultipleresonances,
sometimes
coalescing
with no intervening
antiresonances,
sometimes
separated
by simpleantiresonances.
The latter typicallyare muchsharperthanthe resonances
on
eitherside,indicatingthat theyare not simplyconcomitants
of additive
parallelresonances.
Phaselag typicallyincreases
by two cyclesor more
with increasingfrequencythrough the tuning range(roughly l0 to 200
Hz), with abrupthalf-cycledeclinesthroughthe antiresonances.
Reso-
nantandantiresonant
frequencies
varyfromaxonto axon,usuallylying
between.20and 120Hz. The amplitudesof peaktransferratiosvary ap-
proximately
from50to200spikes/s
percm/s2.At 100Hz,where
it occasionallyis found, the latter corresponds
to approximatelyone spike/s
response
for whole-animal
displacement
of 10 pro. [Supported
by NSF
Grant BNS-8005834.]
tory, JohnsHopkinsHospital,Baltimore,MD 21205.
10:05
9:20
E2.
Three-dimensional
directionalisensitivity
ofgoldfish
8th
nerve
fibers.
E5. Filter characteristics of low-frequency cochlear nerve fibers as
determinedby synchronyresponsepntterns to two-componentsignals.
Richard Fay, Sberyl Coombs,and JosephBaumann(ParrelyHearing
Institute, Loyola University of Chicago, 6525 N. Sheridan Road,
Chicago,IL 60626)
StevenGreenberg,C. Daniel Geisler, and L. Deng (Departmentof
Neurophysiology,
Universityof Wisconsin,1300 UniversityAvenue,
Madison,WI 53706)
Three-dimensional
mapsof directionalsensitivitywereconstructed
for singlefibersof thesaccular,
lagenar,andutricularnervesby measuringacceleration
thresholds
tosinusoidal
motionoriented
along40 axesin
threeorthogonal
planes.
Stimuliweregenerated
byaddingthreemutually
perpendicular
vibrationinputsto a rigidcylindercontainingwater(and
the fish}.The phasesand amplitudesof the inputswere computedto
achievelinearmotionvectorswithparticularorientations,
asdetermined
byanaceelerometer
array.Phase-locking
wasusedto definea cell'saccelerationsensitivity,
andthe po10rity
of theresponse
{theexcitatorydirectionof motion).In general,the3-D directional
sensitivity
ofcells(indB}is
described
by a solidcomposed
of two tangentspheroids,
with an axisof
greatestsensitivitypassingthroughtheir centers.In the saccule,these
axesareoriented
primarilydorsal-ventrally
withdeviations
fromvertical
of up to 40'. Lagenarfibersshowsimilarpatternsbutwithgreatervariationoforientation
in themid-saggital
plane.Utricularunitsshowgreater
variationin all planes.
Anygivenaxisof particlemotionisrepresented
in
theprofileof response
across
arraysof fibersof differentorientation,
and
is bestdefinedby fibersorientedwith a null planeparallelto the axisof
motion.[Supported
by theNSF.]
The tuningandfiltercharacteristics
of cochlearnervefibers,asconventiallydeterminedby stimulationwith single-component
signals,are
usuallyintensitylevel-dependent.
Shiftsin characteristic
frequencyand
significant
deterioration
of frequency
selectivity
areoftenobserved
at supra-rate-saturation
intensities.
In thepresentstudyrelativelylevel-invariant estimatesof characteristicfrequency(CF) and frequencyselectivity
wereobtainedfor low-frequency
( < 3 kHz) cochlearfibersin the cat via
stimulationwith two (equi-amplitude)-component
signals.Characteristic
9:35
frequency
wasestimated
by on-lineanalysis
of the fiber'ssynchrony
response
patterntoa two-component
signalwhose
bandwidth
wasapproximately10%-20% of theunit'sCF. Estimates
of fiberCF remainedrelatively constantover a 60 to 80 dB range of intensities.Frequency
selectivity
(fora two-tonecomplex)
wasdetermined
by settingeitherthe
upperor thelowersignalcomponent
equaltotheunitCF andvaryingthe
frequencyof the secondcomponentoveran octaverange.Two-compo-
nentsignals
providea considerably
higherestimate
of a fiber'sfrequency
selectivitythan is commonlyobservedusingsingle-component
stimuli.
[Researchsupportedby NIH.]
10:20
E3. Whole-nerveresponse
to toneburstsin the alligatorlizard. Robert
G. Turner, Nell T. Shepard,and Donald W. Nielsen (Otological
ResearchLaboratories,
Henry Ford Hospital,Detroit,MI 48202)
E6. Behaviorof theI•ulse-number
distributionfor theneuralspiketrain in
the cat's auditory nerve.Malvin Carl Teich and ShyamM. Khanna
{Departments
of ElectricalEngineering
andOtolaryngology,
Columbia
University,New York, NY 10027)
The peripheral
auditorysystemof the alligatorlizard(Gerrhonotus
multicarinatus)
hasbeenstudiedextensively;
however,limiteddata are
availablefor the whole-nerve(AP) response.
Could the AP serveas a
Pulse-number
distributions
(PNDs)wererecordedfrom primaryafferentfibersin the auditorynerveof the cat, usingstandardmicroelec-
convenientmonitorof the conditionof the ear during experimentation?
AP responses
to toneburstacoustic
stimuliof variousfrequencies
were
recordedfrom the alligatorlizardand threemeasures
usingthe AP response
wereobtained.(1) Averagedsuprathreshold
AP responses
were
relatedto primaryauditorynervefiberactivity.(2) AP thresholds
were
compared
to single-unit
thresholds.
(3)AP excitatorytuningcurveswere
compared
to single-unit
tuningcurves.
Thegoodagreement
between
AP
responses
andsingle-unit
dataindicatethat the AP is a usefultoolfor
measuring
thephysiology
of theperipheralauditorysystemin thealligator lizard.
9:50
trodetechniques.
Pure-tone
andbroadband-noise
stimuliwereused.The
numberof neuralspikes(pulses)
n wasmeasured
in a setof contiguous
intervals,eachof duration T seconds.The quantity.n variesfrom one
interval to another. These data were then used to determine the PND,
whichis the probabilityp(n,T) of occurrence
of n spikesin the time T,
versusthe numbern. The estimatedmean and varianceofp(n,T} were
obtained. Two different values of Twere used. We observe that the count
mean-to-variance
ratio R is relativelyconstantand independentof the
stimulusintensity.The PND readilyexhibitsthe existence
of spikepairs
in the underlyingpointprocess
for someunits.A studyof thescaledand
unscaled
pulse-interval
distributions
{PIDs),underconditions
of spontaneousfiring,demonstrates
thattheoccurrences
of neuraleventsaresometimesnot describable
by a renewalprocess.[Work supportedby NIH
Grant 2-R01-NS03654.]
FA. Linear gain and phasein seismicneurons.Edwin R. Lewis
•Electronics
Research
Laboratory,
University
ofCalifornia,
Berkeley,
CA
10:35
94720 I
In nearlyquiescent
seismic
environments,
manybullfrog(Ranacates-
beiana}
saccular
afferent
axons
exhibitongoing
activity,typicallyranging
from 10to 80 spikes/s.Low-levelvibrationof thewholeanimal[seeH.
Koyamaet al., BrainRes.2S0, 168-172(19821for methods]produces
_e7
J.Acoust.
Soc.Am.Suppl.
1,Vol.74,Fall1983
E7. Acoustic responsepropertiesof units in dorsal cochlearnucleusof
unanesthetized,decerebrategerbil. Herbert F. Voigt (Departmentsof
BiomedicalEngineeringand Otolaryngology,BostonUniversity, 110
CummingtonStreet,Boston,MA 02215)
106th
Meeting:
Acoustical
Society
ofAmerica
S7
Singleunit recordings
were madein the dorsalcochlcarnucleus
(DCN}of unanesthetized,
decerebrate
Mongolian
gerbils.
Access
to the
gerbilDCN wasobtained
using
a newlydescribed
approach
[Frisina
etaL,
HearingRes.6, 259(1982}].Singleunits,recorded
with3M NaCI filled
micropipette
electrodes
(20 Mohm typical},were classified
into three
types{II, III, or IV} basedon theirresponses
to bestfrequency
(BF}tone
bumtsandtheirratesof spontaneous
discharges.
TypeII unitshavelittle
or nospontaneous
activityandareexcitedby BF tonesat all levelsabove
threshold.Type III unitsare alsoexcitedby BF tonesat all levelsabove
Electrophysiological
andpsychophysical
measures
of thresholdasa
functionofsinusoidal
stimulusfrequency
deviatefromthosepredicted
by
Hill's excitationmodel.Severalmembranemodels(e.g.,the Frankenhauser-HuxleymodelandtheHodgkin-Huxleymodel)suggest
possible
mechanisms
responsible
for thedeviations.
For example,byusinga modifiedHodgkin-Huxleymodelmoreaccuratethreshold"predictions"were
obtainedover the 50-500-Hz frequencyrange.The Hodgkin-Huxlcy
threshold,but havespontaneous
activityratesthat exceed2.5 spikes/s.
modelwasmodifiedby increasingthe sodiuminactivationrate constant,
beta-h,by a factor of 4. This modificationcausedthe hyperpolarizing
phaseof thestimulusto becomemoreeffectiveat increasing
thesimulated
TypeIV unitsareexcitedovera narrowrangeof soundlevelsnearBF
threshold,but arestronglyinhibitedat higherlevels.Thusall unit types
membrane's
excitabilityto thesubsequent
depolarizing
phase,particularly whenthehyperpolarizing
phasewason the orderof l0 msin duration.
foundin theunanestbetized,
decerebrate
cat DCN [YoungandBrownell,
1. Neurophysiol.
39, 282 {1976};Youngand Voigt,HearingRes.6, 153
0982}]arealsofoundin gerbil.[Worksupported
byNIH.]
Consistentwith thismodel,recordingsin the AVCN of eat indicatethat a
hyperpolarizing
electricalstimulusappliedto theauditorynervesignificantly increases
the excitabilityof the nerveto a depolarizingstimulus
that follows.[Work supported
by NIH.]
10:50
E8. Temporal-neural-responsecorrelates of pitch-intensity effects and
diplacusis. K. Jones, A. Tubis (Department of Physics, Purdue
University,WestLafayette,IN 47907},andE. M. Burns(Departmentof
Audiologyand SpeechSciences,
PurdueUniversity,WestLafayette,IN
47907)
Pure-tonepitchanomaliessuchaspitch-intensity
effectsanddiplacusishavebeentraditionallyconsideredasevidenceagainsttemporaltheoriesof pitch.Thesephenomena,however,mayat leastin part,becorrelated
with stochasticmodel calculationsof VIIIth nerve firing probabilities.
Thesecalculationspredictshiftsin the peaksof the I$I histogramas a
functionof theintensityof acousticstimulationwhichareconsistent
with
averagehumanpitch-intensity
data.Thesamemodelssuggest
a temporal
basisfor somefeaturesof central-processor-type
algorithmsin complextonepitchperception.They alsoaccountqualitativelyfor the frequencydependent
deviationfromunityof theratioof thefirstISI histogrampeak
to the stimulusperiod,as seenin ISI measurements.
Physiological
and
psyehophysical
measurements,
and detailedneuralmodelstudieswhich
are designedto checkthe validity of thesepreliminaryresults,will be
described.[Work supportedby NIH Grant NS 15405and NSF Grant
BNS 8021529.]
11:05
E9. Implications of ear canal geometry for various acoustical
measurements.Michael R. Stinson (Division of Physics, National
ResearchCouncil,Ottawa, CanadaKIA 0R6}
Recentwork hasdemonstrated
that the geometry(size,shape}of the
humancar canalleadsto a soundfield,at high frequencies,
that varies
within the canal in a complicatedfashion.In particular,the eardrum
terminatesthe ear canalat a rathersharpangle,and significantvariations
of soundpressure(over 15 dB} ariseoverthe eardrumsurfaceabove10
kHz. The implicationsof theseobservations,
as they apply to several
aspects
of hearingresearch,
will bediscussed,
utilizinga three-dimensional horn equationapproachthat hasbeendeveloped.Knowledgeof the
soundpressuredistributionwithin the ear canalis importantin the extensionof audiometryto highfrequencies,
and for guidingthe development
of hearingaids.Studiesof auditoryprocesses
that usea referencemicrophonein thecarcanalbecomeincreasingly
sensitive
to microphone
locationashigherfrequencies
areused;estimates
of theerrorsof reproducibility aregiven.Presentacousticnetworkmodelsof themiddleearassumea
uniformsoundpressure
at the eardrum;possible
waysof handlinga nonuniform pressuredistributionare discussed.
11:20
El0. Electrical stimulation of the auditory nerve: Membrane models
appliedto the interpretationof electrophysiological
and psychophysical
responses.M. White (Department of Otolaryngology, UCSF, San
Francisco,CA 94143)
S8
J. Acoust.Soc.Am.Suppl.1, Vol.74, Fall1983
11:35
E11. Directional sensitivityof auditory neuronsin the superiorcolliculus
of the bat (Myotis !ucifugus}.Donald Wong (Departmentof Biology,
WashingtonUniversity,St. Louis,MO 63130}
The directionalsensitivityof auditoryneuronsin thedeeplayersof the
superiorcolliculuswasexaminedin unanesthetized
batsstimulatedin the
freefieldwithfrequency-modulated
(FM}sounds
(100to40kHz}mimick' ing their naturalorientationsounds.The minimumthresholdof a unit
wasfirstmeasuredwhenthe soundwaspresented
directlyin front of the
animal. Sounds 10, 30, and 50 dB above threshold were then delivered at
every 10. azimuthfrom a hoop-mounted
speakerthat rotatedalongthe
horizontalplanefrom 80' ipsilateralto 80' contralateral.Many unitsexhinted spatialselectivityto a soundsourcethat wasrestrictedbetween10'
ipsilateralto 20' contralateraland hadan intensityI 0 dB abovethreshold.
Soundof higherintensitywaseffectivethroughoutthe contralateralside
in driving theseneurons,althoughthe relative responsemagnitudedifferedat the individualangles.Mappingexperimentsdid not revealany
systematicrepresentation
ofbestazimuthin thismidbrainstructure.Nevertheless,faint echoesreturningfrom a targetalonga line nearthe bags
flightpathprovidedirectional
cuesnecessary
foraccuratetargetlocalization. [Work supportedby NIH.]
11:50
El2. Suseeptibilityto intenseimpulses.G. Richard Price (U.S. Army
HumanEngineering
Laboratory,AberdeenProvingGround,MD 21005}
and David J. Lim {Departmentof Otolaryngology,Ohio StateUniversity
Collegeof Medicine,Columbus,OH 43210}
Pricehasadvancedthe viewthat susceptibility
to intenseimpulsesof
thetypeproducedby weapons
isa functionof a spectrallyrelated"critical
level"in theear[J. AeoustSoc.Am. 73, 556-566(1983};I. Acoust,Soc.
Am. Suppl.1 62, S95.(1977}].
Thisviewresultsin a majordisagreement
with all damagerisk criteriain usein the world by predictingthat for
equalpeakpressures,
rifle impulsesare morehazardousthancannonimpulses.A crucial experimentwasrun usingboth earsof 57 catsto testthis
hypothesis
[G. R. Price,J. Acoust.Soc.Am. Suppl.! 71, S79(I 982}].Two
monthspostexposure,
finalelectrophysiological
measures
weremadeand
the earswereperfusedfor histologicalprocessing.
Histologicalmeasures
involvingboth scanningelectronmicroscopyand serial sectioningand
lightmicroscopy
(opposite
earsof eachcat}cannowbecomparedwith the
earlier electrophysiological
measures.The two setsof histologicalmeasuresshowthe samepictureand they in turn correlatewell with the elec-
trophysiological
measures.
Societyof America
S8
TUESDAY MORNING, 8 NOVEMBER 1983
GOLDEN WEST ROOM, 9:00 TO 11:35A.M.
Session
F.PsychologiCal
Acoustics
I: Pattern
Processing
inSpace
andTime
Lois L. Elliott, Chairman
NorthwesternUniversity,2299 SheridanRoad, Evanston,Illinois 60201
Chairman's Introduction---9:00
ContributedPapers
9.-O5
Fl. Behavioralevidencefor central codingof azimuth as a functionof
stimulusfrequency.Alan D. Musicant
'j (Departmentsof Behavioral
Scienceand Surgery,Universityof Chicago,Chicago,IL 60637)
In a previousreportto theSociety[Musicantand Butler,J. Acoust.
Sec.Am. Suppl.! 72, S93 (1982}]we presented
dataon the orderlyprocression
of perceived
azimuthof narrowbandsof noiseasa functionof
stimulusfrequency.
The patternsthatresultedhavebeencalledSpatial
ReferentMaps (SRMs}.A recentexperimentsuggests
that theseSRMs
mustinvolvea centralmechanismfor codinglocationin the horizontal
plane. In this experiment,stimuli consistedof !-kHz-wide noisebands
withcenterfrequency
(CF}rangingfrom4--14kHz. Therewere13loud-
speakers
placed15'apartat locations
from360'to 180• azimuth.Stimuli
werepresented
fromonlythatloudspeaker
locatedat 270ø. Subjects,
listeningmonaurally,responded
with the loudspeaker
positionfrom which
they perceivedthe soundas originating.SRMs werethen constructed.
Subjects
nextperformed
thesametask,but nowlistenedmonaurallywith
the pinnacavity of the opencar filled. The externalmeatuswasopen.
Azimuthaljudgements
of stimuluslocationwerecollected
andcompared
This paperdescribes
a systemfor processing
sohorantregionsof
speech,
motivatedby knowledge
of thehumanauditorysystem.The spectral representation
is intendedto reflecta proposedmodelfor human
auditoryprocessing
of speech,
whichtakesadvantage
of synchrony
in the
nervefiringpatternsto enhanceformantpeaks.The auditorymodelisalso
appliedto pitchextraction,and thusa temporalpitch ptxmessor
is envisioned.The spectrum
is derivedfromtheoutputsof a setof linearfilters
withcriticalbandwidths.
Saturationandadaptationareincorporated
for
eachfilter independently.
Each "spectral"coefficientis determinedby
weightingthe amplituderesponse
at that frequency(corresponding
to
meanfiringrate}by a measureof synchrony
to thecenterfrequencyof the
filter. Pitchisderivedfroma waveformgenerated
by addingtheIweighted) rectifiedfilter outputsacrossthe frequencydimension.The system
performance
is evaluatedby processing
of a varietyof signals,including
natural and syntheticspeech,and resultsare comparedwith other processing
methodsandwith knownpsychoacoustical
datafromthesetypes
ofstimuli.[Worksupported
in partbyNINCDS andtheSystemDevelopmentFoundation.]
9:50
to the data collected earlier. Correlations between the means of the azi-
muthaljudgements
at eachfrequencyfor the two conditions
rangedfrom
0.81-0.97for sevensubjects.
The highdegreeof correlationsuggests
that,
at least for narrow bands of noise, a central mechanism must exist that
codesazimuthalsoundsourcelocationasa functionof stimulusfrequen-
cy. '•Prcsentaddress:
Department
of Neurophysioiogy,
University
of
Wisconsin,Madison, Wl 53706.
F4. Effect of amplitudemodulationuponfusionof spectralcomponents.
Albert S. Bregman, Jack Abramson {Department of Psychology,
McGill University, 1205 Doctor PenfieldAvenue, Montreal, Quebec,
Canada H3A IBI), and Christopher Darwin (Laboratory of
ExperimentalPsychology,
Sussex
University,Brighton,England}
Westudiedtheperceptual
integration
of twocomplextones,eachsent
9:20
F2. Sidedhessand perceptionfor singleechoof someordinary sounds.
Terry S. Zacconeand Earl D. Schubert(Hearingand SpeechScience,
StanfordUniversity,Stanford,CA 94305}
Ninedifferentsound-sample
sequences
rangingin temporalpredictabilityfromwhitenoiseto Englishspeech
wererecorded
witha singleecho
delayedfrom zeroto 100ms.The soundswererecordedin the presentation modesof menaural,dieboric,and mixedIoriginaito both cars,delayedin one}.Thesinglerepetitionintensitywasequalto, and3 and6 dB
greaterthan, that of the originalsound.Subjectswereaskedto indicate
whenthe echowasperceivedand, in separatetests,on whichsidethey
perceivedthe sound.In general,the abilityof the subjectsto choosethe
sideof theleadingsignaldiminished
astherepetitiondelayincreased
past
20 ms.Theywereexpectedto perceivetemporalorderratherthan sidedhessas the delaybecamelongerthan 20 ms. Even for soundswith pronouncedenvelope,the subjectswere not ableto regainidentificationof
sidedhesS
out to 100-msdelay.Presentation
of differentsoundtypesresoltedin significant
differences
in performance.
Whitenoisepresented
the
mostdifficulttask,asshownby thelow percentage
of identification
of the
leadingcar.The femalesingerand violinyieldedthe highestpercentages
for leading-car
identification.
to both earsand formedby amplitudemodulation{AM) of a carrier frequencyCF bya sinusold
with modulationfrequency
MF. Onetonealways
had CF = ! 500 Hz and MF = 1(30Hz. The other had CFs around 500 Hz
and MFs around 1(30Hz. Bothharmonicand inharmonicpartials,producedby AM, wereemployed.The methodinvolvedstudyingthe competition betweentwo organizations:la} the fusionof the two tones,and (b}
thetendency
of thehigherto bestrippedoutof themixturebya competing
sequentialorganization.Fusionwas bestwhen the both toneshad the
sameMF, evenwhenthe resultingpartialsdid not form part of the same
harmonic
series.
Fusionwasenhanced
whenAM appliedtothetwotones
wasin phase.Resultsrelateto the perceptualseparationof simultaneous
voicesand favor a theoryin which basilarmembraneoutputsthat are
amplitudemodulatedby the sameglottal pulsewill be allocatedto the
same voice.
10:05
FS. Modulation transfer function using temporal-probe tones.
ChristopherAhlstrom and Larry E. Humes (Divisionof Hearing and
Speech,Vanderbilt University, Nashville,TN 37212}
Psychoacoustic
MTFs weremeasuredby embeddinga probetonein
SAM speechnoise.The speechnoisewas 70 dB SPL overall,and the
modulationdepthof lhis noisewas60 dB. The modulationfrequencies
were:0, 2.5, 5, 10,20, and35 Hz. The durationofeachtonepipwas4.7 ms
for frequencies500, 1414, and 4000 Hz. Bandwidths (3 riB} at each of the
F3. Pitch andspectralestimationof speechbasedon auditorysynchrony
model. StephanieScheft {Department of Electrical Engineering&
ComputerScience,Rm. 36-521,Massachusetts
Instituteof Technology,
Cambridge,MA 02139}
$9
J. Acoust.Sec. Am. Suppl. 1, VoL 74, Fall 1983
frequencies
were19,22, and 18Hz. Skirtslopeswerebetween6 and7 dB/
octave.Simplemaskingnearlypredictedchangesin theseMTFs in noise.
A SpeechTransmission
Index{STI}derivedfromthe MTFs in noisewas
nobettercorrelated{r = 0.95}withspeechrecognition
scoresthanwasthe
S9
With monoticburststhe apparentsummationeffecthasa flat maximum
STI calculatedaccordingto H. J. M. Stcenekcn
and T. Houtgast,J.
Acoust.Soc.Am. 67, 318--326(1980}.[Worksupported
by theVe•ran's
around a time interval between the burst onsets of about 60 ms. The
Administration.]
dichoticaswell asthe monoticreflexarc containsat leastonenonlinearity
since the summated effect of the bursts exceeds the arithinetic sum. The
10:20
F6. Temporal effects of vowel productionon listeners'perceptionof
speakerage. HeVoertJ. Oyer and Michael D. Trudeau(Speechand
HearingScienceSection,The Ohio StateUniversity,154 N. Oval Mall,
Columbus,OH 43210}
Twenty-fourspeakers
prolongedthe vowels/a e i o u/and readthe
passage
"My Grandfather."The speakers
weredividedintofourgroups
of six(threemales,threefemales}
basedonchronological
age,41-50 years,
51-60 years,61-70 years,and 71 yearsandover.Naive listenersprovided
perecptual
judgements
of eachspeaker's
agebasedon the firsttwo sentencesfrom "My Grandfather."The speakers'
vowelproductions
were
measured
to determinetimerequiredto initiateandterminateeachvowel.
These ten measuresplus time to articulate the four syllables
/ma I gr•ndfaS•/and speakersexwereregressed
againstspeakerchronologicalandperceived
ages.Thebestsignifibant
modelfor chronological
ageyieldedanR-Squareof only0.428;whilefor thebestsignificant
model
for perceived
ageR-Squarewas0.647.Resultsindicatethatspeakertemporalcontrolof speech
exertsa stronginfluence
on listenerp•rccptionof
speakerage,buthasa relativelyweakerrelationship
with speaker's
chronologicalage.Thesefindingssuggest
that temporalaspects
of speechare
criticalin estimationof speakerage.
10:35
F7. Octave equivalence in the processingof tonal sequences.
Diana Deutsch(Centerfor HumanInformationProcessing.
University
of California,SanDiego,La Jolla,CA 92093)
An issueof considerable
debateconcerns
octaveequivalence
of tones
thatarepresented
in a sequential
setting.In a previous
study,Dentsch
[Perception
Psychophys.
6, 411--412(1972}]showedthata well-known
melodybecameunrecognizable
whenitscomponent
tonesweredisplaced
randomlyto differentoctaves.
It wasconcluded
that,in accordance
with
thetwo-channelmodelfor theabstraction
of pitchrelationships
proposed
byDeutsch[Psychol.
Rev.76,300-307(1969}],octaveequivalence
effects
do notoperatedirectlyin a sequential
setting.It has,however,
beenarguedthatdistortionof melodiccontourwasresponsible
for therecognitionperformance
obtained.To settlethisissue,a newparadigmwasemployed.Musicallytrainedlisteners
werepresented
withnovelsequences
of tones,whichtheyrecorded
in musicalnotation.Whenthetoneswithin
a sequence
werein the sameoctave,a highperformance
levelwasobtained. However, when the toneswithin a sequencewere distributed
acrossoctaves,performance
deteriorated
sharply.This resultconfirms
thehypothesis
thatoctaveequivalence
effects
donotoperatedirectlyin a
sequential
setting.[Worksupported
by NIMH.]
measuredcharacteristics
can be accountedfor quantitativelyby a model
ßcontaininga peripherallinear adaptationstagewith a recoverytime cons•nt on the orderof 50 ms, a linearcentraltemporalintegratorwith a
time constantof about200 ms and a threshold,all connectedin series.All
thenumericalconstants
arcconsistent
withthosefoundin neurophysinlogiealandpsychophysical
experiments.
The inferencethat the threshold
followsthe integratormayproveto beof majorinterest.
11:05
F9. A demonstrationof peripheralconstrainton an auditory duration
diseriminationtask.
GregoryJ. FlectandBrianR. Shelton(Department
of Psychology,
Universityof WesternOntario,London,Ontario,Canada
N6A 5C2}
An earlierstudyinvestigatedthe discriminationof auditorydurations
presented
at a rapidratein a two-alternative
forced-choice
task.The results indicated that a constant Weber fraction was obtained across base
durationsfrom25-1600msifs longinterstimulus
interval(ISI) separated
the two alternativepresentations,
but performance
degradedwith short
basedurationsifa shortISI wasused[B. R. Shelton,J. Acoust.Soc.Am.
Suppl.1 72, S89(1982}].Here,thesamemeasurements
weretakenunder
two presentation
conditions:
(1}a binauralpresentation
of bothintervals,
and (2}a monauralpresentation
of the two intervals,eachto a different
ear. Basedurationsof 25, 50, 100, and 200 ms were used,with ISI valuesof
25, 50, 100,200,400, 800,and 1600ms.The binaurallypresented
condition replicatedthe previousresults,but the presentation
of intervalsto
alternateearsproduceda markedimprovementin performance,
especially with shortISI presentations.
This findingsuggests
that thediscrimination of the durationof rapidly presentedauditorystimuli is restricted
peripherally.
[Worksupported
by NSERC.]
11:20
F10. Auditory time constantsunified. Pierre Divenyi (Speechand
HearingResearch,
VA MedicalCenter,Martinez,CA 94553andINRSTelecommunications,University of Quebec,Verdun, Quebec,Canada
H3E IH6} and RobertV. Shannon(ColemanLab, 863HSE, UCSF, San
Francisco,CA 94143}
bursts.The toneintensitiesweresochosenthat eachburstpresentedsepa-
Psychophysical
measures
of auditorytemporalintegrationtypically
yieldseveraldifferenttimeconstants
depending
on the task.An integrationtimeconstantof 100to 300msisproposed
to explainthe relationship
betweenthresholdandburstdurationJR.Piompand M. A. Bournart,3.
Acoust.Soc.Am. 31, 749-758 {1959}].When click thresholdsare measuredin amplitude-modulated
noisetheresultsareconsistent
witha much
shorterintegrationtimeof 10msor lessIN. F. Viemeister,
in Psychophysicsand Physiology
of Hearing,editedby EvansandWilson(Academic,
New York, 1977,pp. 419-427)].The differencebetweenthesetime constantsis thoughtto be due simplyto the differenttasksinvolved.The
longertime constantis calculatedassuming
a linearintegratoroperating
on the input intensity.Any physiological
integrationmechanism,however,integrates
neuralactivity,whichisa compressire
nonlinearfunction
oftheinputintensity.An integratorwitha 10-mstimeconstant
preeecded
by a compressire
nonlinearitywill produceapparentthresholdintegration timesof 100-300ms,depending
on the magnitudeof the compres-
ratelyevokeda constantresponse.
The resultsshowthat the apparent
sion.Thus a singleintegration mechanismcan account for the apparently
summationof theeffectsof dichoticburstsisgreaterthanthat of monotic
longtimeconstants
for thresholdandtheshortertimcconstants
for temporaldiscrimination.
10:S0
FS. $tapediusreflex:On somefundamentaltemporalcharacteristics.
JozefJ. Zwisiocki(Institutefor Sensory
Research,
Syracuse
University,
Syracuse,NY 13210}
Effects
ofneuraltemporal
summation
andadaptation
onthestapedius
reflexareexamined
with thehelpof monoticanddichoticpairsof tone
burstsanddecays
monotonically
astheinterburst
timeintervalincreases.
S10
J. Acoust.Soc.Am.Suppl.1, Vol.74, Fall1983,
Societyof America
S10
TUESDAY MORNING,
8 NOVEMBER
1983
FORUM ROOM, 8:30 TO 11:45 A.M.
SessionG. Physical AcousticsI: Novel Applications of Macrosonics
RobertE. Apfel, Chairman
Department
of Mechanical
Engineering,
YaleUniversity,
NewHaven,Connecticut
06511
Invited Papers
8:35
G1. Another round with nonlinearacoustics.Robert T. Beyer (PhysicsDepartment,Brown University,
Providence,RI 02912I
Early work in nonlinearacoustics
largelyfollowedthe behaviorof oneor two idealizedbeamsof high
intensity
sound.Morerecentworkhascentered
onattempts
tomakethebeamsmorerealisticin nature,andto
followuponpossible
waysin whichnonlinear
acoustics
canbeappliedtootherproblems
of acoustics.
In the
formercase,suchanalyses
as that of Zabolotskaya-Khokhlov
on a taperedbeam,or the useof truncated
equations,
especially
in thestudyof nonlinear
interaction
of soundwithair bubbles
in watercometo mind.
Therehasalsobeenconsiderable
attentionto thephysicalmeaningof thenonlinearparameter.
On theexperimentalside,muchwork hasbeendoneon the sound-bubble
interaction.In addition,the existence
of higher
harmonics
ina search
beamoffiniteamplitude
means
thatsomeofthelimitations
presented
bythefrequency
of
the fundamentalbeamcanbe favorablymodified.Exampleswill be discussed.
9:00
G2. Newapplications
of nonlinearacoustics
at microwave
frequencies.
Daniel Rugar(EdwardL. Ginzton
Laboratory,StanfordUniversity,Stanford,CA 94305)
Threeimportant
newapplications
havebeenfoundfornonlinear
acoustics
in themicrowave
frequency
regime.
Forthefirstexample,
thegigahertz
frequency
acoustic
microscope
isseentosignificantly
increase
in
resolution
whenoperated
athightransmitted
powerlevels.
Thiseffectisbelieved
tobeduetoenergy
flowfrom
thesecond
andhigherharmonics
backtothefundamental
frequency
afterpassage
throughthefocalregionof
thebeam.Usingthiseffect,resolution
betterthan0.2/.tinhasbeendemonstrated
in waterat 4.3 GHz lB.
Hadimioglu
(tobepublished)].
Thesecond
application
of nonlinear
acoustics
usesthefocused
beamofa liquid
heliumacoustic
microscope
to detectincoherent
phonons
(10 GHz) generated
by a heater[J. S. Foster,D.
Rugar,andC. F. Quate(tobepublished)].
Thistechnique,
whichrelieson scattering
of soundby sound,has
resultedin a newformofacoustic
imaging.The thirdnewapplication
hasprovidedthefirstaccuratemeasure-
rbents
oflow-energy
phonon
dispersion
in liquidheliumat temperatures
lessthan0.1K. Forplanewaves
ina
dispersive,
lossless
fluid,powerin thesecond
harmonic
willperiodically
riseandfallasa function
ofpropagationdistance.
By measuring
theperiodicity,dispersion
canbeaccurately
determined.
This hasrecentlybeen
accomplished
at a fundamental
frequency
of 2 GHz. ]Worksupported
by ONR.]
9:25
G3. Discoveryof a solitary,localized,stationarywater wave.Junru Wu, Robert Keolian,and lsadore
Rudnick(Department
of Physics,
Universityof California,LosAngeles,CA 90024)
When
atrough,
15X1in.,isfilled
with
water
toadepth
of2cmand
driven
parametrically
byoscillating
it
verticallywithanamplitude
ofabout0.06cmat a frequency,
10Hz, wherethehalf-wavelength
of thesurface
waveisequalto thewidthof thetrough,a strikingphenomenon
isobserved.
In a strongly
localized
region,
whichmaybecenteredalmostanywherealongthetrough,a standingwaveof veryhighamplitudeisseento
oscillate
acrossthewidthof thechannel.Surprisingly,
itsamplitudedropsoffexponentially
at itsedgeswitha
I/e lengthof only0.9 era.It oscillates
at subharmonic
frequencies.
Thisenergypackethasparticle-like
behavior. Whenthetroughistiltedthewavepacketmovestowardtheshallowend.Two solitarywavesof opposite
phase,
pair.Thoseof likephase
combine
or formanoscillating
pair.[Worksupported
byONR.]
9:50
G4. Metal fatiguetestingat ultrasonic
frequencies,
historyanduses.WarrenP. Mason(4449Meandering
Way, Tallahassee,FL 32308}
Ultrasonicfrequencies
in therangeof 20 kHz arenowbeingusedto testfatiguein materialson accountof
therapiditywithwhichthetestscanbemade.It appears
thattheoriginalworkwasdoneby thespeaker
as
described
in thepaper.At a recentinternational
conference
"FatigueandCorrosion
Fatigueupto Ultrasonic
Frequencies,"
whichwasdedicated
to meonaccount
of my originalworkin thefield,it is statedthatasa
technique
ultrasonic
fatigueisalmostassophisticated
aspush-pullfatiguetesting.It hasbeenshownthatthe
Sl I
J. Acoust.SoC.Am. Suppl. 1, Vol. 74, Fall 1983
Sl 1
results
obtained
athighfrequencies
areclosely
similartoresults
obtained
at lowfrequencies,
cyclepercycle.
Constant
totalstrainandconstant
displacement
testsarepossible.
Positive
meanload,elevated
temperatures,
andcorrosion
ultrasonic
fatigue
tests
arenowperformed
routinely.
Thefeasibility
andadvantages
ofperform-
ingcrack
propagation
tests
atultrasonic
frequencies
hasbeen
demonstrated.
Hence
ultrasonic
fatigue
testing
is
a verywidelyusedtechnique.
10:15
G5.Spaceapplications
of macrosonics.
TaylorG. Wang(JetPropulsion
Laboratory,
4800OakGroveDrive,
Pasadena,
CA 91109)
(Abstract not available.)
10:40
G6. Recenttrendsin practicalapplications
of macrosonics.
E. A. Neppiras(17 Kinsbourne
Avenue,
Bournemouth,England)
Macrosonics
includes
theareaoftechnology
where
treatment
bysound
orultrasound
produces
permanent
anduseful
changes
inthetreated
medium.
Todate,twotypes
ofapplication
haveachieved
majorimportance
as
viable
commercial
techniques.
These--cleaning
andplastics
welding--are
stillexpanding
inscope
andimportance.
Recent
progress
hasbeenmainly
inthedirection
ofa greater
degree
ofautomation
andcontrol.
Apart
fromthesetwoestablished
areasthereareseveral
applications
thathavealready
beenmore-or-less
fully
developed
butwhich,foronereason
oranother,
havea muchmorelimitedscope.
Examples
are:ultrasonic
machining,
metal-welding,
tinning,andvarious
metaldeformation
processes.
A thirdcategory
consists
of
applications
andideas
thatappear
verypromising
butwhichhavenotyetbeenfullyexplored
ordeveloped.
Examples
are:some
aspects
ofchemical
processing
andvarious
gas-load
applications,
including
theproduction
ofaerosols
•atomization).
Afterbrieflyreviewing
thelatestprogress
in theestablished
areas,
thispaperwill
concentrate
onnewideas
andapplications
thatshow
signs
ofdeveloping
intovaluable
practical
techniques.
11:05
G7. Industrialmachines
employing
resonance
wavesystems
that are inductivelyexcitedby reactivemass
vibrators.
A. G. Bodine
(Bodine
Soundrive
Company,
7877Woodley
Avenue,
VanNuys,CA 91406)
Forthefieldof macrosonics
employing
resonance
technology
witha mechanical
oscillator,
thesystem
is
drivenat a low impedance
regionin orderto haveamplecurrentflow(elasticstroke)at the oscillator.The
oscillatorisanalogous
to a constantvoltagegeneration,
soit hasto functionwithanunconstrained
or variable
amplituderatherthan with a fixedstrokelimitationlike a crankmechanism,for instance.The true mechanical
oscillator
isthusaninductive
coupling
ofadynamic
mass.
Thebestformisanorbiting
mass
describing
itspath
infreespace
except
fortheconstraint
whichconfines
themass
toitsorbit.It istheinductively
phased
reactartec
ofthisconstraint
whichprovides
theconstant
voltage
acdrivefortheresonance
system
frequency.
Thiskindof
oscillator
thusadapts
itscyclicstroketo thefreedom
of theresonance
system.
A veryusefultechnique
isto
determine
andmaintainthefrequency
oftheoscillator
at thatwhichwouldbetheresonance
frequency
ofthe
system
if theworkloadat theoutputregionof thesystem
wereinfinite.MaximumQ thusoccurswith a
"locked"load.Then,for all finiteloads,theoutputamplitude
staysconstant
because
a dropin loadmeans
reduction
in mechanical
amplification
asthefixedfrequency
system
straysfromthe peakresonance
wave
patternenvironment.
ContributedPaper
11:30
sionin the0.5-to10-MHzrangewasaccomplished
by a digitallycon-
G8. TDS measurement of the second harmonic emission from ensonified
trolledsweeping
generatoroperatingat a rate of 500 MHz/s. Second
bubbles.RichardC. Heyset and JamesA. 'Rooney(Jet Propulsion
Laboratory,CaliforniaInstituteof Technology,
Pasadena,
CA 91109)
harmonic
reflection
ofenergy
wasdetected
bya tracking
receiver
whose
sweep
program
wasdrivensynchronously
withthetransmitting
program,
butwitha tracking
rateof 1GHz/sandadelayoffset
corresponding
tothe
The second
harmonicspectrum
of backscattered
soundfromair bubblesin waterhasbeenmeasured
byTDS methods.
Usingthetechnique
of
Miller and Nyborg[D. L. Miller andW. L. Nyborg,J. Acoust.Soc.Am.
73, 1537-1544)],
air wastrappedin theporesof immersed
hydrophobic
Nucleporefilter membranes
to producestablebubbleswhosediameters
lay in the 3-4 •u range.The membranewasinsonifiedwith a wideband
transmitting
crystaldrivenfroma linearamplifier,andthebackscattered
arrival time of backscatteredsound from the membrane. Selectedcombi-
soundwasreceivedby a secondwidebandultrasoundcrystal.Transmis-
soundpassingthroughthe bubble-filledmembrane.
S12
J. Acoust.
Soc.Am.Suppl.1,Vol.74,Fall1983
nationsof transmission
andreception
sweeprateestablished
thattheobservedsecondharmonic signal was due to resonanceof bubblesand not
dueto incidentaltransmitter
or receiverdistortioncomponents.
Themeasuredfrequencyspectrumof secondharmonicbackscatter
from bubbles
corresponds
closely
tothepredicted
spectrum
shape,
showing
a dominant
peakat twicethefrequency
at whicha strongabsorption
dipoccurs
for
106thMeeting:
Acoustical
Society
of America
S12
TUESDAY MORNING, 8 NOVEMBER 1983
CABINET ROOM, 9:00TO 11:40A.M.
Session H. Shock and Vibration h Instrumentation
Ronald L. Bannister, Chairman
Westinghouse
ElectricCorporation,
SteamTurbineDivision,Orlando,Florida32807
Chairman's Introduction--9:0O
Invited Papers
9:05
HI. An overviewof shockandvibratlonmeasurements.
RudolphH. Volin (ShockandVibrationInformation
Center,U.S. Naval ResearchLaboratory,Washington,DC 20375)
Early instruments
limitedour abilityto makeshockand vibrationmeasurements;
however,the development of new instrumentsand measuringtechniqueshasadvancedthe stateof the art in shockand vibration
measurement.
The mostsignificant
developments
werethepiezoelectric
accelerometer
andthe FastFourier
Transformalgorithm.Bothof thesedevelopments,
coupledwith advances
in thedigitalcomputertechnology,
significantly
influencedthe currentstateof the shockand vibrationmeasurement
technology.Piezoelectric
accelerometers
enableus to measurecomplexmotionsof lighterstructuresto higherfrequencies.
The Fast
FourierTransformalgorithminitiallymadeit possible
to analyzeshockandvibrationtestdataon mainframe
digitalcomputers
rapidlyandeconomically;
but,combined
withadvances
in thedigitalcomputertechnology,
it hasbroadenedour ability to conductmanytypesof laboratoryshockand vibrationtests,makemeasurements,and analyzetestdata. Advancesin the digitalcomputertechnology
will continueto influencethe
progress
in shockand vibrationmeasurement.
For example,the microcomputer
hasalreadyprovento be
effective
in certaindataanalysis
applications.
Futureincreases
in theircomputing
powerwill allowthemto be
usedin a widerrangeof measurement
anddataanalyses
applications.
9:30
H2. Array processingto eliminate standingwave effectsin shell radiation measurements.
E. V. Thomas
(DTNSRDC, Code2742,Annapolis,MD 21402)
The spectralmeasurement
of a cylindricalshell'sradiationcharacteristics
in a tidal basinweredesiredto
compare
withdeepoceanfarfieldradiationcharacteristics.
Standing
waveeffects
fromthesurface
andbottom
of thebasinspectrallydistortedthe radiationmeasurements.
The techniques
evaluatedto providerelieffrom
standingwaveeffectswere:large,highlydirectivearrays;line arraysin the nearfieldwith detectionbefore
averaging;
andlinearraysin thesemifarfield
withandwithoutbeamforming.
Detectionmethods
werelinear,
squarelaw,andlogarithmic.
An analyticalevaluation
of thedetection
methods
indicatedlinearor logarithmic
detectionhad a lower standarddeviationthan square-lawdetection.Also, a large, highly directivearray
wrappedaroundthe shell(i.e.,the verynearfield)wasevaluated.The bestsmoothingof the standingwave
effects
of themediumwereachieved
usinga ten-element
linearray(normalto cylinderaxis)in thesemifarfield
usinglogarithmicdetectionbeforeaveraging,Furtherexperimental
work simplifiedthis array to a threeelementslopedline with logarithmicdetection.This systemallowedmeasurement
of the shell'sradiation
characteristics
over2«decades
withoutperturbation
by standing
waves.
9:55
H3. Underwatermodalanalysisof heat exchangertubing usingpressuretransducers.C. D. Powell, C.
P. Dietz,andN.J. Middelburg
(O'Donncll
& Associates,
Inc.,241CurryHollowRoad,Pittsburgh,
PA
15236)
In ordertoperformanaccurate
flow-induced
vibrationanalysis
of heatexchanger
tubing,naturalfrequencies,modeshapes,
anddamping
values
mustbeknown.Thisstudyconcerns
experimental
determination
ofthe
aboveparameters
fortitaniumtubingin anunderwater
environment.
Beinga lightweight
materialwithhigh
stiffness,
it wasanticipatedthat highnaturalfrequencies
with smalldampingvalueswouldbe encountered
whichcouldbeerroneously
alteredbythemountingandcablingof traditionalinstrumentation
suchasaccelerometers.
A l-g microaccelerometer
wasusedto performa preliminarymodalsurveyto determine
system
naturalfrequencies,
modeshapes,
and separation
of tubeand fixturemodes.It wasfoundthat mounted
instrumentation
didindeedcausemassloadingproblems
resultingin erroneous
naturalfrequencies
anddampingvalues.Noncontacting
pressure
transducers
wereusedto confirmtheidenticaltubemodeshapes
andto
thendetermine
truetubenaturalfrequencies
anddampingvaluesusinga varietyof excitationtechniques.
The
studyconcludes
byevaluating
themostapplicable
techniques
to beusedin orderto obtainvaliddata.
10:30
1-14.Applicationof advancedexcitationand analysistechniquesto the Galileo Spacecraftmodalsurvey
program.David L. Hunt (SDRC Inc., 11055RoselieStreet,SanDiego, CA 92121)
S13
J. Acoust.Sec. Am..?,uppl.
1, Vol. 74, Fall 1983
$13
A modaltestof theGalileoSpacecraft
will beusedto tunea finiteelement
modelthatwill servein a
subsequent
loads
analysis.
A partofthetestisbeing
devoted
toapplying
newtechniques
forperforming
modal
tests.
Testing
efforts
willbeapplied
in theareasof multi-shaker
broadband
(MSB)excitation,
timedomain
calculation
ofrational
frequency
response
functions,
andpolyreference
estimation
ofmodalparameters.
These
threetechniques,
having
beendeveloped
andimplemented,
arebeingexamined
asa means
toperform
modal
testsina fractionofthetimepreviously
required,
witha resulting
dataqualitywhichmeets
orexceeds
current
standards.
Thepresentation
willdetailthetechniques,
theirapplication
tothespecific
Galileoprogram,
and
highlightandinterprettheresultsachieved.
10:45
H$. Usingholographle
interferometryin vibrationmenmurements.
R. Page(ApolloLasers,Inc., 9201
Independence
Avenue,Chatsworth,CA 91311)
Thispaper
willreview
principles
ofholographic
interferometry
andprovide
examples
ofcurrent
applicationsinvibration
analysis.
Specific
techniques
discussed
willinclude
double
exposure
(frozen
fringe),
realtime,
andstroboscopic
andtime-average
holographic
interferometry.
ContributedPapers
11:10
11:25
H6. The NBS conical transducer. T. M. Proctor, Jr. (National
Engineering
Laboratory,NationalBureauof Standards,
Washington,DC
H7. Transient waves in an elastic plate. T. M. Proctor, Jr., and F.
R. Breckenridge
(NationalEngineeringLaboratory,NationalBureauof
Standards,Washington,DC 20234),and Y-H. Pao IComeliUniversity,
Ithaca,NY 14853}
20234)
The NBS conicaltransducerwas first reportedon in 1980 [T. M.
Proctor,Jr.,I. Acoust.Sac.Am. Suppl.I 6•, S68(1980)].A numberof
RecentlyPaoetal. [Y-H. Pao,R. R. Gajewski,andA. N. Cevanoglu,
changeshavebeenmadein thistransducerthat improveits usefulness
and
its frequencyresponsefor acousticemissionwork. A designfor useas a
secondarystandardin the calibrationof other acousticemissiontransdueeraisdiscussed.
A smallerversionhasbeenconstructed
with virtually
J. Acoust.Sac.Am. 65, 96-105 (1979}]haveobtainedtheoreticalsolutions
for wavepropagationin an elasticplateby usinggeneralizedray theory.
Thesesolutions
givethedynamicdisplacement
at locations
on thesurface
thesamefrequencyresponse
astheoriginalversion.Electrodeproblems
of a platedueto a pointforcestepfunctioninput.UsingtheNBS conical
transducer,
a broadbanddisplacement
transducer,
experimentalverifica-
are discussed and solutions indicated.
tion of the motion has been obtained.
TUESDAY MORNING,
8 NOVEMBER 1983
TOWN AND COUNTRY
ROOM, 9:00 A.M. to 12:31 P.M.
SessionI. SpeechCommunication
I: SpeechRecognitionAlgorithms
Janet M. Baker, Chairman
DragonSystems;
Inc., 173HighlandStreet,WestNewton,Massachusetts
02165
Chairman's
Introduction-9.q}O
ContributedPapers
9.•5
11. An acousticanalysisof •rticulatory phenomena
in connected
digit
strings.MarciaA. Bush(FairchildLaboratoryfor ArtificialIntelligence
Research,4001 Miranda Avenue, MS 30-888, Palo Alto, CA 94304),
Marie Hamilton, and Kazue Hata (Department of Linguistics,
Universityof Californiaat Berkeley,Berkeley,CA 947201
S14
J. Acoust.Sac.Am.Suppl.1, Vol.74, Fall1983
To date,relativelyfew attemptshavebeenmadeto explicitlyincorporate enarticulatoryinformationin the designof automaticsystemsfor
connected
digit recognition.
One reasonfor the limitedprogress
in this
areahasbeenthelackof a convenient
description
of therelevantcoarticuiatoryphenomena,
culledfrom systematic
analyses
of largeamountsof
realspeech
data.This paperdescribes
theinitialstageof an ongoingproject aimedat remedyingthissituation.The paperis basedon computer-
Societyof America
$14
aidedanalyses
of waveforms
andspectrograms
of I 180isolateddigitsand
connected
digitstrings,asproducedby two maleandtwofemalespeakers
ofAmericanEnglish.Theacoustic
dataweresupplemented
withphonetic
transcriptions
by trainedlinguists.
Coarticulatoryphenomena
arecategorized accordingto: (1) word-boundaryeffects(e.g.,phonemeinsertions
anddeletions);
(2)within-wordeffects(e.g.,context-dependent
changes
in
vowelformantfrequencies);
and (3) consistent
speaker-dependent
effects
(e.g.,allophonicvariationsof/r/). Implicationsof the acousticdata for
systemdesignarealsodiscussed.
In particular,theviewisadvanced
that
certaincoartieulatoryphenomena
may serveas importantsourcesof informationin identifying"difficult"digit sequences
(e.g.,thosecontaining
thedigit "oh").
9:17
12.Exploring
phonot•ctic
lexical
constraints
inwordrecognition.
Daniel
P. Huttenlocher
and VictorW. Zue (Room36-549,Department
of
ElectricalEngineering
andComputerScience,
Massachusetts
Instituteof
Technology,Cambridge,MA 02139)
Phonotactic
constraints
limit thepermissible
wordinternalconsonant
sequences
in English.In somecases,
knowledge
of thephoneme
sequence
uniquelyspecifies
thelocationof thewordboundary,
whilein othercases,
phonological
rulesbasedon allowableconsonant
sequences
are not sufficient. For example,the word boundarycan be uniquelyplacedin the
sequence/...mgl.../,asin the wordpair "someglass,"whereasthe word
boundarylocationis ambiguousin the phonemesequence/...str.../without further acousticinformation. The/...str.../may
have a word bound-
ary in one of threeplacesas in "last rain", "race trials", and "may
stretch."Studieswere conductedto determinethe utility of phonotactic
constraints
to predictwordboundaries.
The databasesincludedthe Merriam-WebsterPocketDictionary,a phonemicallybalancedset of sentences,and samples
of unrestricted
text. Resultsindicatethat:{1}word
internalconsonant
sequences
represent
a verysmallsubset
ofall permissibleconsonant
sequences
acrosswordboundaries;
and(2}acoustic-phonetic knowledge
isneededwhenthewordboundaryisambiguous.
Resultson
thedifferences
betweenwordandsyllableboundaries
will alsobepresented. [Work supportedby the Officeof Naval Researchundercontract
N00014-82-k-0727andthe SystemDevelopmentFoundation.]
In a previousmeetingof theSociety,Zue andShipmandemonstrated
thattheconstraints
imposed
by theallowable
soundsequences
of a languageareextremely
powerful.
Evenat a broadphonetic
levelofrepresentation,sequential
constraints
severely
limit thenumberof possible
word
candidates
[$. Acoust.Soc.Am. Suppl.1 71, S7(1982)].Thisprovides
an
attractivemodelfor lexicalaccess
basedon partialphoneticinformation.
However,Zue andShipman's
resultsdid not takeintoaccountthe fact
that the acousticrealizations
of phoneticsegments
are highlyvariable,
andthisvariabilityintroduces
a gooddealof recognition
ambiguityin the
initial classification
of the signal.We haveconducteda setof studies
investigating
the robustness
of sequential
phoneticconstraints
with respectto variabilityand error in broadphoneticclassification.
In these
9:53
I5. Recognitionof a smallvocabularyspokenby two dialectgroups.R.
W. Bossemeyer
and M. LaferrierelAmericanBell, inc., 2220 Asbury
Ave., Neptune,NJ 07753)
studiessegment
misclassifications
or deletionsarepermitted.In onestudy
it wasfoundthatthephonetically
variablepartsof words(aroundreduced
A majordifference
amongAmericanEnglishdialectsliesin thevariety of phoneticcharacteristics
of vowels(H. Kurath,Studiesin Area
Linguistics,1972}.SinceLPC-basedspeechrecognition
systems
depend
heavilyonthevowelportionof an utterance,
dialectdifferences
notrepresentedin a templateinventorycouldaffectrecognition
accuracyin a
speaker-independent,
LPC-basedisolatedword recognitionsystem.
Eighty-five
speakers
fromeachof twodialectgroups,EasternNewEng-
syllablesl
providemuchlesslexicalconstraint
thanthephonetically
invariantparts.Thus,by utilizingtheinformationfromrobustpartsof a word,
a largelexiconcanstillbepartitioned
intosmallequivalence
classes.
Detailedresultsof the studieswill be presented.
[Work supportedby the
paredwhenreference
templates
werefromI l) theotherdialectgroup;(2)
thesamedialectgroup;and(3)a combination
ofthetwogroups.
Compari-
Office of Naval Researchunder contract N00014-82-K-0727 and by the
SystemDevelopment
Foundation.]
land and Southeastern,
recordedthe digitsand two commandwords.
Word recognition
scoresfor speakers
in eachdialectgroupwerecom-
sonsare madeon a word-by-wordbasisto determinewhat typesof phoneticdialectvariationaffectrecognitionaccuracy.
9:29
10:05
13.Exploringailophonic
andlexicalconstraints
in a continuous
speech
recognitionsystem.FrancineR. Chen and Victor W. Zue IRoom 36545, Departmentof ElectricalEngineeringand ComputerScience,
Massachusetts
Instituteof Technology,Cambridge,MA 02139}
Recentresearch
[ZueandShipman,J. Acoust.Soc.Am. Suppl.I 71,
S7 (1982);Huttenlocher
andZue,thismeeting]hasshownthat a broad
phonetic
representation
of speech
provides
strongconstraints
for lexical
accessof isolatedwords.In addition,Church(Ph.D. thesis,MIT, 1983)
hasdemonstrated
theutilityof detailedallophonicconstraints
for parsing
a sentence
froma phonetician's
transcription.
Thisgivesreason
tobelieve
thatthecoupling
of lexicalandallophonic
constraints
canbea powerful
tool in continuous
speechrecognition.
The presentstudyexploreshow
broadphoneticconstraints
can be appliedto a restrictedcontinuous
speech
task.Usinga broadphonetic
representation
derivedfroman ideal
transcription,
it wasfoundthatontheaverage,
70%ofthewordboundariesin thedigitvocabulary
canbe identified.
Extendingthisapproach
to
speech
data,wehaveimplemented
a classifier
whichderivesa broadphoneticrepresentation
fromthespeech
signal.Preliminaryresultsindicate
that allophonic
and lexicalconstraints
canbe effective
in reducingthe
numberof stringcandidates,
basedupontheoutputfromthisclassifier.
[Work supportedby the Officeof Naval Researchunder contract
N00014-82-K-0727
andby theSystemDevelopment
Foundation.]
9:41
I4. Theuaeof phonotactic
constraints
to determinewordboundaries.
Lori
F. Lamei IRoom 36-545, Departmentof ElectricalEngineeringand
ComputerScience,
Massachusetts
Cambridge,
MA 02139
S15
J. Acoust.Soc. Am. Suppl.1, VoL74, Fall 1983
I6. An improved
worddetection
algorithmfortelephone
qualityspeech.
J.
G. Wilpon, L. R. Rabiner, and T. Martin (AcousticsResearch
Department,Bell Laboratories,
Accuratelocationof the endpointsof spokenwordsand phrasesis
importantfor reliableandrobustspeech
recognition.
Theendpointdetectionproblemisfairlystraightforward
forhigh-level
speech
signals
in lowlevelstationarynoiseenvironments
(e.g.,signal-to-noise
ratiosgreater
than30 dB).However,thisproblembecomes
considerably
moredifficult
wheneitherthe speechsignalsare too low in level(relativeto the backgroundnoise),or whenthebackground
noisebecomes
highlynonstationary. Suchconditions
are oftenencountered
in the switchedtelephone
networkwhenthe limitationon usinglocaldialed-uplinesare removed.
In suchcasesthebackground
noiseisoftenhighlyvariablein bothlevel
andspectral
contentdueto transmission
linedistortions,
transients,
and
tonesfrom the line and/or from signalgenerators,
etc. Conventional
speech
endpointdetectors
havebeenshowntoperformverypoorly(onthe
orderof 50% worddetection)overtheseconditions.In thistalk we presentanimprovedworddetection
algorithmwhichincorporates
bothvocabularyandtaskinformation,
leadingtoworddetection
accuracies
closeto
100%forisolated
digitdetection
overa widerangeoftelephone
transmission conditions.
10:17
17. A pretty goodformanttracker. Ronald A. Cole (Departmentof
ComputerScience,
Carnegie-Mellon
University,Pittsburgh,
PA 15213)
and Robert A. Brennan (Department of Electrical Engineering,
Carnegie-Mellon
University,Pittsburgh,PA 152131
S15
This paperdescribes
two newmethodsby whicha feature-based
isolatedletter recognitionsystem,FEATURE [Coleel aL, Prae. ICASSP1983,pp. 731-733],canlearntheacoustical
characteristics
of individual
speakers
withoutfeedback
fromtheuser.Theoriginaltuningalgorithmof
FEATURE madeuseof labeledobservations
froma givenspeaker,andof
thea prioricovarianees
of thefeaturemeanvalueswithintheacrossdecisionclasses,
to optimallyadjustthe expectedfeaturevaluesof all the
decisionclasses.In the first newprocedurethe systemassumesa correct
decisioneverytime it classifies
a soundwith a highconfidence
level.The
class-conditional
meanvectorsand covariancematricesare thencomput-
Algorithms
weredeveloped
for estimating
formantfrequencies
on a
timeframeby timeframebasis.Thealgorithms
incorporate
acoustic
phoneticknowledge
aboutformants.
The algorithms
arebasedonknowledge
ofacoustic
phonetics,
anddonotmerelyrelyonspectralpeaks.Thustwo
formantswill beidentifiedevenwhenthe firstandsecondformantsmerge
or whenthesecondandthird formantsmergeto forma singlepeak.The
algorithms
wereevaluated
by comparing
formantsdrawnon a speech
spectrogram
bya trainedphonetician
to thosedrawnautomatically.
The
databaseconsisted
ofbothmaleandfemalespeakers
speaking
phonetically balancedsentences.
In addition,synthesis
derivedfrom the formant
frequencies
andamplitudes
wastestedfor intelligibility.Resultswill be
edin the•amewayasin thetuning-with-feedback
procedure.
In thesec-
presented
for thesetwoprocedures.
[Supported
byNSF andDARPA.]
ondnewprocedurethesystemrecordsthe averageobservedfeaturevalues
overall possible
classes
on a feature-by-feature
basis.The a priori covarlances between the mean values of a feature for each decision class with its
meanvaluesover all possibleclasses
are then usedto updatethe classconditionalmeansandcovariances.
Experiments
wereconducted
onconfusablesetsof lettersusingbothspeakeradaptationprocedures.
A significantimprovementin letterrecognitionperformanceusingbothanalyses
wasobserved
aftera smallnumberof iterations.[Supported
by NSF and
DARPA.]
10:29
18. Unsupervisedspeaker adaptation in fenture-ba•ed isolated letter
reengnition.Mosh6 J. Lasry and Richard M. Stern (Departmentsof
Electrical Engineering and Computer Science, Carnegie-Mellon
University,Pittsburgh,PA 15213)
10:41-10:55
Break
ContributedPapers
10:55
I9. On the use of hidden Markov models for speaker-independent
reengnitionof isolated words from n medium size vocabulary.L.
R. Rabiner, S. E. Levinson,and M. M. Sondhi (AcousticsResearch
Department,BellLaboratories,
MurrayHill, NJ 07974I
Recent work at Bell Laboratories has shown how the theories of LPC
VectorQuantization{VQ}and hiddenMarkov modeling(HMM} canbe
appliedto therecognition
of isolatedwordvocabularies.
Our firstexperimentswith HMM basedrecognizers
wererestrictedto a vocabulary
of the
tendigits.For thissimplevocabulary
wefoundthat a highperformance
recognizer
{wordaccuracyon theorderof 97%) couldbe implemented,
andthattbeperformance
was,forthemostpart,insensitive
to parameters
of boththeMarkovmodelandthevectorquantizer.In thistalk weextend
ourinvestigations
to therecognition
of isolatedwordsfroma mediumsize
vocabulary,
(129words),asusedin theBellLaboratories
airlinereservationand informationsystem.For thismoderatelycomplexvocabularywe
havefoundthat recognitionaccuracyis indeeda functionof the HMM
parameter{i.e.,the numberof statesand the numberof symbolsin the
vectorquantizer}.
We havealsofoundthata vectorquantizerwhichuses
energyinformationgivesbetterperformance
than a conventional
LPC
shapevectorquantizerof thesamesize(i.e.,numberof codebook
entries}.
11.-07
I10. Stop identificationusinghiddenMarkov models.Gary E. Kopec
(FairchildLaboratoryfor ArtificialIntelligenceResearch,4001Miranda
Avenue,MS 30-888,Palo Alto, CA 94304)
A seriesof experiments
hasbeenundertaken
to assess
thepowerof
discretespectralslicesfor automaticallydiscriminatingbetweenthe
voiceless
plosives/p,t,k/in CV syllables.
Theseexperiments
involvea
936-tokendatabaseconsisting
of 52 instances
of eachof the 18 syllables
/p,t,k/x/i,e,ae,a,ow, u/spokenby 13maleand 13femaletalkers.In one
The applicationof finite-stateparsingtechniques
is proposedfor the
purposeof assigning
syllablestructureto a phonetictranscription,
subject
to allophonicand phonotactic
constraints.
In thisway,a speechrecognition devicecan exploit contextuallyVARIANT cuesin order to distinguishminimalpairssuchas "a Tease/aTease,""night Rate/niTRate,"
and "great Wine/gray TWine." Our parsingsuggestion
providesan elegant implementationframeworkfor exploitingthe importantinteraction
betweensegmentalvariationand.syllable/wordcontext.Otherexamples
will bediscussed,
includingKlatt's "Did you hit it to Tom?"Finally,the
frameworkwill be extendedto accountfor "featurespreading"{agreement and coarticulation}in a natural way, by reformulatingparsingin
termsof four matrix operations:
addition,multiplication,transitiveclosure, and element-wiseintersection.
11:31
112. A cornpar'sonof dynamictime warp algorithmsfor connectedword
recognition.Stephen C. Olinski (Bell Laboratories,600 Mountain
Avenue,Rm. 7C-427,Murray Hill, NJ 07974)
The applicationof dynamictimewarpingto theproblemofconueeted
wordrecognition
hasrecentlyreceivedmuchattention.Severalsuccessful
approaches
haveappearedin the literatureincludingthe levelbuilding
algorithm[C. MyersandL. Rabiner,IEEE Trans.Acoust.Speech
Signal
Process.
ASSP-29,284-297(1981)]andthesinglepassalgorithm[J. Bridle,M. Brown,andR. Chamberlain,Proc.1982IEEE ICASSP].A single
mathematicaldescriptionof dynamictime warpingis presentedthat unitiestheseand otherapproaches,
and highlightstheir similaritiesand differences.
By testingthe algorithmswith a databaseof connected
digits,it
isfoundthatin general,theuseof additionallevelsof computationresults
in a relativelysmalldecrease
in recognitionerror.
11:43
experiment,identificationwasattemptedusinga singlei 2-poleLPC onset
113. Reclaiming tealrural information after dynamic time warping. Hollis
spectrum.
Theonsetspectrafromeachtalkerwerecompared,
usinga log-
L. Fitch (Institute for DefenseAnalyses,Thanet Road, Princeton,NJ
08540)
likelihood distancemeasure,with the 900 onsetspectraof the remaining
25 talkers.An overallclassification
accuracyof 92% wasachievedusinga
k-nearest-neighbor
decision
strategy.
A second
experiment
involves
classifterswhichusea seriesof LPC spectracomputedduringthefirst50 ms
of the stoprelease.Each CV syllableis modeledas a hiddenMarkov
processwhichgenerates
a spectrumevery5 ms. Classification
is performedusingeithera Viterbi or forward-backwarddecodingstrategy.
11:19
I11. A finite state perser for use in speechrecognition. Kenneth
W. Church (Bell Laboratories,Murray Hill, NJ 07974)
$16
J. Acoust.Soc.Am.Suppl.1, VoL74, Fall1983
Templatematchingmethodsusedynamictime warpingto eliminate
differences
in durationbetweenthe templateand the unknownspeech.
Thesedifferences
may belinguisticallyrelevant.It hasbeendemonstrated
for one test word that the relative durationsof certain segmentsin that
wordcanbeusedto distinguish
it frommost"falsealarms"---stretches
of
speechother than the test word that scorewell on the spectrally-based
templatematch[H. L. Fitch,Proc.ICASSP 82, 1247-1250{1982}].Here,
a moregeneralprocedureis described
for segmenting,
and testingthe
relativedurationsof the segments.This procedurehasnow beenapplied
to ten words,and showspromisingresults.
Societyof Amedca
S16
11:S5
pensation
andfrequency
warping,andparticularlytheintegrationof the
I14. Vowel-space normalization procedures and phone-preserving
transformations
of syntheticvowels.T. M. Nearey (Departmentof
Linguistics,Universityof Alberta,Edmonton,CanadaT6G 2H 1}
A varietyof speaker-normalization
procedures
havebeenproposed
for the recognitionof vowelsof differentspeakers
and/or the cross-languagecomparison
of vowelsystems.
Many suchprocedures
are special
cases
of affinetransformations
of coordinates
in a two-{ormorelformant
space.Resultsof perceptualexperiments
are presented
indicatingthat
onlya limitedsubset
ofaffinetransformations
preserve
thephonetic
identity of a setof syntheticvowels.From a perceptualpointof view, many
vowel normalizationproceduresappearto be too powerfulin the sense
that theycan"over-normalize"vowelswhicharephoneticallydistinct.In
particular,rotations
ofa two-formant
spaceand/orindependent
multiplicatirescalingof the F I and F2 axesleadto markedchangein phonetic
quality.On the other hand,resultsindicatethat uniformmultiplicative
sealingoff I andF2 by a singleconstantis"almostphone-preserving"
in
therangeof male/femalevoweldifferences.
For larger{e.g.,male/child}
differences,
a specificnonuniformscalingsimilarto thatproposed
by Fant
seemsto be requiredto maintain"perceptualconstancy."
02159.
12:19
116. A study of correlation methods for phonemeidentification. A.
Maynard Engebretsonand John P. Tadlock ICentral Institute for the
Deaf, St. Louis, MO 63110}
I15. Speaker normalizing transforms for automatic recognition.
VladimirSejnoha*;{Departmentof ElectricalEngineering,
McGill
University,Montreal, Quebec,Canada}and Paul Mermelstein{McGill
University, Bell-Northern Researchand INRS Telecommunications
{Universityof Quebec},Verdun,Quebec,CanadaH3E I H6}
A methodfor the reductionof inter-speakerdifferencesby spectral
transformationwill bedescribed.Transformsweredesignedfor the addi-
tivecompensation
andfrequency
scalingof spcechspectrabasedon the
logof theenergies
of 20 channelsspacedon the mel-scale.
The frequency
scalingwasimplementedas eithera linearscaling,or as a nonlinearfrequencywarpfoundby dynamicprogramming.
The transformswerethen
combinedsothat theadditivecomponent
principallyaddressed
thediffercncesinthetilt ofthespectrum
whilethefrequency
scalingmainlytreated
the dissimilaritiesin spectrumresonancelocations.The transformswere
appliedto a databaseof averagespectraof tensteady-state
voiced-speech
segments
for sevenmaleandsixfemalespeakers.
Boththeadditivecom-
MORNING,
errorrate in recognition
experiments
on the segmentdata basewasreducedby 50% across
sex,60% withinthefemalespeaker
group,andby
20% for the malespeakergroup.The bestfrequencywarppathswere
foundto be nonlinearand stronglydependent
on the speechsegment.
Parameters
for a single,speaker-dependent,
combinedtransformwere
alsoderivedandtheglobaltransformwasobserved
to beaseffective
asthe
equivalentspeech-segment-dependent
transform.The globaltransform
parameters
derivedfrom asfew asthreesegments
yieldeda performance
levelclosetothatattainedwith parameters
extractedfromthewholesetof
segments
for onespeaker.[Research
supported
by NSERC,Canada.]
'•Presentaddress:
KurzweilAlphaSystems
Inc.,57WellsAve.,Newton,
MA
12:07
TUESDAY
two, wasusefulfor bothwithin- andacross-sex
normalization.The overall
With currentavailabilityof high-speed
digitalsignalprocessors
and
inexpensive
memory,c•rrelationmethodsof real-timespeechrecognition
maybepractical.In themethodspresented
here,speechissegmented
into
overlapping
25.6-mswindows.A spectrumiscalculatedfor eachwindow
and correlatedwith speaker-independent
referencepatterns.Each windowedspeechfragmentis identifiedwith the reference
patternyielding
the highestcorrelation.Averagespectralpatternsare createdautomaticallyfrom "stable"segments
of speech.A highcorrelationbetweenspectra of adjacentwindowsis usedas a measureof stability.The average
patternsarecategorizedacrossspeakersandaveragedwithincategories
to
createthe referencepatterns.We havestudiedstandardand Mellin Iscale
invarient}correlationsin combinationwith linear magnitudeand eepstral-smoothedlog magnitudespectra. Mellin correlation normalizes
spectrathat are scaledwith respectto frequency.Cepstral-smoothing
reducesthenumberof coefficients
requiredto representthespectrum.Also
cepstralcoefficients
canbe normalizedwith regardto transmission
characteristics.Resultswill be presentedfor vowelsrecordedfrom six male
and six femalespeakers.[Work supportedin part by N[H Grant NS038561.
8 NOVEMBER 1983
DEL MAR/HELIX/SANTA
FE ROOMS, 9:00 A.M. TO 12:05 P.M.
SessionJ. Musical AcousticsI: Computer-BasedAnalysisand Synthesisof Music
Linda A. Seltzer, Co-Chairman
Department'of
Music,University
ofCalifornia,
SanDiego,
La Jolla,California
92093
Max V. Mathews, Co-Chairman
Bell Laboratories.Murray Hill, New Jersey07974
Chairman's
Introduction--9:00
Invited Papers
9:05
Jl. Digital processingof instrumentalsounds.Roger Reynolds{Music Department, University of California,
SanDiego; La Jolla,CA 920931
In work at IRCAM IParis},digitvlprocessing
techniques
weredevelopedto alter pre-recordedinstrumental
materialsin perceptuallynovel ways.The goal of this processingwas to createsoundmaterialsthat were
S17
J. Acoust. Soc. Am. Suppl. 1, Vol. 74, Fall 1983
106th Meeting: AcousticalSociety of America
S1 ?
fundamentally
unfamiliar
butcouldcoexistwithnaturalinstruments
in muscially
satisfying
ways.(1)Because
sounds
arerepresented
numerically
fordigitalpurposes,
thepotentialforsoundeditingischanged
qualitatively. Musicalphrases
wereextended
andtransformed
byreplicating
segments
ofthemin orderedpatterns
whose
structuralproperties
dominatedthoseof theoriginalwithouteclipsingits identity.{2}Phasevocodingtechniqueswereusedto analyzeinstrumental
sounds.
Resultingdatawereappropriately
reducedto formthebasis
of resynthesis
throughthe MUSIC X program.In thisway, independent
accessto arbitrarygroupsof partial
components
wasattained.Oddandevenpartialswerepresented
overspatiallydistinctspeakerchannels
and
subjected
to dynamically
changing
vibratofunctions
withdifferingratesanddepths.Additionaldistinctauditory imagesarosein the stereofieldwhilethesonicimageof theoriginalinstrumentremained.Examplesof
instrumental
recordings
andtheirdigitaltransformations
arepresented
in isolationandin musicalcontexts.
9-.35
J2. Changing
conceptions
of pitchstructureandtimbre:A modestproposal.
GeraldJ. Balzano(Department
of
Music,Universityof Californiaat SanDiego,La Jolla,CA 92093)
Two areasof musicalexploration
of interestto composers
for whichthecomputerisunnsuallywell-suited
aremicrotonalsystems
and "new"timbres.Notionsabouthow to achievethesemusicalextensions
aredouhly
theory-dependent
in that theydependonbothour theoryof perception
andour theoryof thestimulus.Most
extantattemptsto do microtonalmusichaveusedsmall-integer
ratiosasthe fundamental
description
of the
musicalelementsinvolvedandthe basicentitiesto whichhumanperceiversarepresumedsensitive.For timbre,
the universeof possibilities
hastraditionallybeencharacterized
in termsof spectralvariables{possibly
timevarying},andmorerecentlyin termsof projections
on axesin a "subjective"
multidimensional
space.In the
presentpaper,alternatives
to prevailing
conceptions
of bothpitchandtimbreareconsidered.
A symmetryorientedgronp-theoretic
approach
to pitchstructurethateschews
ratioswill bedescribed;
theresulting
viewof
pitchsystems
leadsto somenovelideasabouthow to do microtonalmusicon a computer.For timbre,an
approach
thatfocuses
onthedynamics
ofthesound-producing
activityratherthanontheresultingspectrawill
be described.
This leadsnaturallyto an interestingalternativeto currentlypopularmethodsfor generating
timbresand "timbre transformations"on a computer.
10.-05
J3. Someexperimentswith enmpusitional
algorithms.Charles Wuorinen{670West End Avenue,New York,
NY} and Mark Lieherman{BellLaboratories,Murray Hill, NJ 07974}
(Abstractnot received)
10:35
J4. Shakuhachipitchand intonat'on:Applicationto computermusiccomposition.
Linda A. Seltzer(M/ACOM LinkabitCorporation,3033 SciencePark Road, SanDiego, CA 92121and Departmentof Music,
Universityof California,SanDiego,La Jolla,CA 92093}
The musicfor theJapanese
bambooflute,shakuhachi,
containsmicrotonalityaswellascontinuous
change
of pitchin thecourseoflongnotes.Shakuhachi
pitchandintonation
maybestudiedbymeansof pitchdetection
analysis
of thewaveform.Or, altcruatively,
thepitchof a notemaybe described
astheresultof thefollowing
parameters:
fingering,
vocaltractshape,
distance
ofthelipsfromthemouthpiece,
anddirection
ofbreath.The
melodictechnique
of the shakuhachi
maybe appliedto computermusiccomposition
in the continuous
frequencydomain,withoutrestriction
to a scaleconsisting
of discrete
frequencies
11:05
JS.Digital
sound
synthesis
forunderwater
music
perception.
MichelRedolfi
andLeeRay(Computer
Audio
ResearchLaboratory, Center for Music Experiment, University of California at .ganDiego, La Jolla. CA
92123}
A pieceoforiginalelectro-acoustic
music,SonicWatersII, wascreated.Software"instruments"
and "note
lists,"descriptions
of thebehaviorof thoseinstruments
in themusicaltimeof a sequence,
werespecified
for the
cmusicsynthesis
programto produce,by frequencymodulation,amplitudemodulation,andlocalizationand
motionwithina synthesized
space,morphological
transformations
of severalharp recordings.
Meansof(l)
transductionof this wide-bandmusicalwork (20 Hz to 16 kHz) for humanlistenersimmersedin waterand
compensating
for changesof suchmusicallysignificantpsychoacoustic
cuesasdepthperceptionand relative
amplitudes
of overtones
occasioned
by theprominence
of boneconduction
in underwater
listeningwereinvestigated.Onepressure-loaded
diaphragmandfourpiezoelectric
transducers
werepositioned
to broadcast
the
computer-processed
sound.The wavelength
of somebassnotesexceeded
thedimensions
of thepool,limiting
musicallyusefulpropagationof low frequencies
due to cancellationand reinforcementof standingwaves.
[Worksupported
bytheCME, System
Development
Foundation
andtheFrenchgovernment.]
S18
$18
ContributedPapers
11:35
J6. Use of data reductionin computermusic.JamesW. Beauchamp
(2136 Music Bldg., 1114W. Nevada,Universityof Illinois at UrbanaChampaign,Urbana,IL 61801}
Two competingmethodsof digital soundproductionare "instantre-
play"and"synthesis
by algorithm,"If fidelityto an originalsoundwere
theparamountconsideration,
replaywouldbethe moredesireable
method. However,replayrequiresmassiveamountsof memoryand is inflexible with respectto contextualmodification,
an importantconceptfor
composers.
On theOtherhand,algorithmic
synthesis
methods
generally
aredesigned
to minimizememoryrequirements
andemploya few,wellchosen,
perceptually
significant
parameters
whicharevariedin anadhoe
fashion.Data reduction,wheresynthesis
algorithmparameters
areautomaticallyextractedfromtheoriginalsound,offersa link betweeninstant
replayandalgorithmicsynthesis.
It isparticularlyusefulif theextracted
parameters
areperceptually
meaningful
andtherefore
canbeintelligently
modifiedby the composer.Variousmethodsof data reductionwill be
discussed
togetherwith theirassociated
synthesis
algorithms(including
constantwaveform,additive,filter, nonlinear/filter, and waveforminter-
polationsynthesis},
andsoundexampleswill beplayed.
S19
11:50
J7. Modification of musical soundsby means of the phase vocoder.
Mark Dolson(ComputerAudioResearch
Laboratory,Centerfor Music
Experiment,Q-037, Universityof California,SanDiego,CA 92093}
The usefulness
of thephasevocoderfor performingtime-scale
modificationof speechsignalsis well established.
However,the applicationof
thephasevocoderto musicalsignalsisfar lesscommon.Musicalapplicationsof the phasevocoderdiffer from speechapplicationsin severalimportantrespects:
( 1}Musicalsamplingratesaremuchhigher;hence,minimizationofcomputation
andstorage
requirements
isfar moreimportant.
(2}Musicalfidelityrequirements
are alsomuchhigher;thiscounteracts
attemptsto minimizecomputation
andstorage.{3}Musicalapplications
oftenrequireanalysisof individualharmonics;in thiscase,filterspacing
mustmatchharmonicspacing.(4}Pitchtranslation(asopposed
to timescalemodification}
requiresspectralenvelopeestimationto soundconvincing.(5}Musicalsignals
maybepolyphonic.
(6}Lastly,musicalapplicationsfrequently
seektodistortsounds
in aninteresting
way;hence,they
ofteninvolveextremesof time and pitchscaling,selectivemodificationof
analysisdata,and novelcross-syntheses
and timbraiinterpolations.
Exampleswill bepresented
froma phasevocoderpackage
designed
explicitly for musicalapplications.
Societyof America
S19
TUESDAY AFTERNOON,
8 NOVEMBER
1983 SENATE/COMMITTEE
Session K. Underwater
ROOMS, 1:30 TO 4:40 P.M.
Acoustics II: Arctic Acoustics II
Henry Kutschale,Chairman
Lamont-Doherty
Geological
Observatory,
Palisades,
New York 10964
Charman's
Introduction•l:30
Invited Papers
1:35
KI. Characterization
of seaice.JamesP. Welsh(Head,PolarOceanography
Branch,Naval OceanResearch
& DevelopmentActivity, NationalSpaceTechnologyLaboratories,NSTL Station,MS 39529}
Somedefinitionsof icebergsand seaice are presented.Variousclassification
schemesfor seaice are discussed.
The morecommonseaicecharacteristics
arepresented
with examplesof measurement
techoiques
and
rangesof measured
values.Consideration
is givento potentialfor inferenceof acousticproperties
fromobservedandmeasured
seaicecharacteristics.
Generaloverviewisprovidedforapplications
ofArcticiceproperties measurement
experiments.
Theseexperimentsincludein-situ,airborne,and satellitemeasurements
to
obtainsurfacetruth of remotelysensedicecharacteristics
particularlyin the microwavefrequencies.
2:00
K2. Law-frequencyacousticpropagationin CanadianArctic waters.Gary H. Brooke(DefenceResearch
Establishment
Pacific,Victoria,BC, CanadaV0S lB0}
Underwateracousticpropagation
within,andsurrounding,
the CanadianArctic Archipelagoistypicalof
shallowArcticwater.That is,thepropagation
isstronglydependent
onbottomproperties
at lowerfrequencies
{< 40 Hz) butisincreasingly
influenced
by thesurface
at higherfrequencies
ducto thecharacteristic
upward
refractingvelocityprofilein thewatercolumn.Waterdepthsaregenerallylessthan600 m andaretypically
200-400 m. DREP hasmadepropagationmeasurements
in severallocationsand, hence,undera varietyof
propagation
conditions.In thispaperthe salientfeatu•s and trendsin the dataare discussed.
2:25
K3. High-frequency
acoustics
in theArctic.RobertE. Francois(AppliedPhysicsLaboratory,Universityof
Washington,
Seattle,WA 98195)
Comparedwith otheroceans,acousticpropagation
in theArctic is generallylimitedin rangeby upward
refraction,ice surfaceinteraction,and the increasedabsorptionlossat low water temperatures.
At shallow
depthsbeneaththeunder-ice
surface,thewatercolumnisverynearitsfreezingpointduringmostof theyear.
Considerable
salinityvariationoccursin thefreezingseason
because
of brinedisplacement
asiceisformedand
in themeltseason
because
of thelayeringof thenearlyfreshicemeltwaterovertheseawater.Thisresultsin a
positivedensitygradientwith a rather sharpincreaseat 20-50-m depth, wherethe older Arctic water is
encountered.
A densebiologicalpopulation,
analogous
to thedeepscattering
layerseenin theopenocean,is
observedat this pycnocline.
This thin layer, hashigh volumereverberation
strengthcomparedto values
observedin other oceans.A studyof theselayerssometimesrevealsthe presenceof internal waves.When
propagation
takesplacethroughthislayer,anomalously
highabsorptionattributedto scatteringis observed.
At 60-300 kHz, wehaveobserved
apparentincreases
in absorption
of from 10to 20 dB/km. The presence
of
theicecoverdecouples
the windfromthewatermass,resultingin greatlyreducedboundarylayermixing.This
allowsthemanydiscretelayersformedby thenaturalprocesses
notedaboveto persistoverlargeareasfor long
times.As a consequence
largeacousticfluctuationsoftenoccurfor smallverticaldisplacements
of sourceor
receiver.[Work supportby NAVSEA.]
K4. Site dependence
of low-frequencyAret'c ambientnoi•e and signalattenuation.Orest I. Diachok and
StephenC. Wales(Code5160,Naval Research
DC 20375)
Our understanding
of two significant,ice-related,low-frequency
(belowI kHz) underwateracousticphenomena,characteristic
of bothArcticandsub-Arcticenvironments,
isbrieflyreviewed.Measurements
suggest
that oceanwave-generated
noiseat the peripheryof the ice-covered
Arctic Oceanis generallyexceptionally
highwhenthe fetchis large,andcan haveverylongrangeeffects,whenpropagatedsignalsare not subjectto
significant
surfacescattering
andvolumeabsorption
losses.
Surfacescatteringdueto sea-iceridges,whichmay
be modeledasrandomlydistributedellipticalhalf-cylinders,
dominatesunder-icepropagationat frequencies
aboveabout20 Hz. Ray theoreticalcalculationsincorporatingthis modelare consistentwith observedsitedependent
transmission
lossdifferences
overa limitedfrequencyrange140-1000Hz). Resultsof newlower
frequency
wavetheoretical
calculations,
whichincorporate
thismodelanda suitablegeoacoustic
structure
of
020
Socielyof America
S20
theocean
bottom,willbepresented
andcompared
withdata.Initialconcepts
forextension
ofthisworktothree
dimensions
(including
randomly
oriented
ridges)
toenablemorerefinedpredictions
ofscattering/transmission
losses
and,in particular,spatialcoherence
losses
will beoutlined.
3:1S
KS. Measurementsof the verticalfield• of acousticsignalsandnormalmodepropagationin the Arctic Ocean.
T.C. ¾ang(Code5123,NavalResearch
DC 20375)
The verticalsoundfidds of cw signalsand shotspropagating
in the ice-covered
Arctic Oceanweremeasuredduringthe FRAM IV experiments
in April 1982.The measurements
weremadewith a verticalarray
consisting
of 28 hydrophones
extendingto a depth of 960 m. This experimentmarkedthe first successful
deployment
ofa largeapertureverticalarrayintheArcticenvironment.
Thispaperwill present
theresults
and
interpretations
oftheverticalarraydata.The1owest
ordernormalmodeamplitudes
andphases
weremeasured
fromtheshotsignals
received
simultaneously
onthe28hydrophones
oftheverticalarray.Themeasured
mode
amplitudes
arccompared
withthecomputed
normalmodeandusedasthebasisfor spatialfilteringof normal
modesfromthe cw signals.Intensitydistributions
of thecw signalsversusdepthare presented
for several
frequencies
below100 Hz. Spatialcoherence
of the cw signalsare studiedand comparedwith that of the
ambientnoise.The arrivalanglesof thelowestordernormalmodesaremeasured
fromthecwsignalsusingthe
modefilteringtechnique.The angulararrivalpatternof the cw signalsare plottedusingconventional
hectaforming.Temporalbehaviorof thecw signalswill beshown;phasetrackingbeamforming
is usedto enhance
the verticalarraygain.
ContdbutedPapem
3:40
K6. Seismic events in the Arctic Ocean. Ruth E. Keenan (Science
Applications,Inc., WoodsHole, MA 02543}and Ira Dyer {Department
of OceanEngineering,
MIT, Cambridge,MA 02139)
We presenttemporalandspectralcharacteristics
of abyssally
generated T phasesobservedin the Arctic Ocean.A large( • I kin} horizontal
hydrophonearraysuspended
throughthe icemadeit possibleto verifythe
eventasseismic.A simplepropagationmodelaccountsfor the basicfeaturesofeachevent.We identified
crustalandwaterwavearrivals•andthe
timedifference
between
thelongitudinal
crustalwaveandpeakfrequency
arrivaloftheTphaseestablished
therangeto thesource.The intersection
of thebearingof the Tphasewith themid-Arcticridgeprovideda corraboratingrangeestimate.T-phasesonogramsdisplaycharacteristicpear
shapesnotedby others.The spectrahavepeaklevelsat 5 and 15Hz and
behave
asymptotically
asfn,f -4 aboveandbelowtheirpeaklevel.The
durationoftheTphaseislongerthancanbeconsistently
accounted
forby
anyonemechanis
m. Possible
mechanisms
including
source
depth,multi-
edfor differenttypesof events.Interchannelcorrelationwasperformedto
obtaindistortioncharacteristics
of the propagation
path.Usingtheseresults,possible
pathsof propagation
fromsourceto receiverarediscussed.
[Worksupported
by ONR.]
4:10
KS. Someambientnoisemeasurements
in springice, Pt. Barrow, Alaska.
W. C. Cummings(OceanographicConsultants,5948 Eton Court, San
Diego,CA 92122}and D. V. Hnlliday {Tractor,Inc., 9150 Chesapeake
Drive, SanDiego, CA 92123}
Springice conditionsoff North Alaskaare confounded
by dynamic
changesresultingfrom leadopeningsand closings,rapidchangesin degreesandkindsof icecover,rapidlychangingwindconditions,
anddrifting floes.The measurements
weretakenin the springof 1982usinga 9nmi telemetering
link. [Worksupported
by theNorth SlopeBorough.]
ple bounces,dispersion,and swarmsare discussed.
[Supportedby SAI,
Inc. and ONR.]
3:55
4:25
K9.
TRISTEN/FRAM
IV
Arctic
ambient
noise
measurements.
R. Nielsen,F. R. DiNapoli,M. Feeher,D. Potter(NavalUnderwater
K?. icequ•kesin the Arctic Ocean.Peter$. Stein,NicholasC. Makris,
andIra Dyer (Departmentof OceanEngineering,
M]T, Cambridgc,MA
o2139)
Resemblingearthquakes,
stresscracksin a floatingice sheetdue to
effectsof winds,currents,andthermalgradientscanexcitevariousforms
of elastic/acoustic
wavepropagation.
The acousticemissionof several
suchicequakes
wererecordedduringexperimentson packice over the
easternArctic abyssalplains.Theseeventsoccurredin the nearfieldof a
l-km aperture,24-channelhydrophone
array.The signalswerebandpass
filtered from I to 80 Hz. A recursivetechniquewas usedto locate these
eventsandestimatethe groupspeeds.
Spectralcharacteristics
are present-
S21
d.A(•oust.
Soc.
Am.Suppl.
1,Vol.74,Fall1983
SystemsCenter, New London, CT 06320), and P. L. Stoeklin (Analysis
and Technology,North Stonington,CT 06359}
Approximately250 h of multichannelice campambientnoisedata
wererecordedby NUSC duringtheTRISTEN/FRAM IV experimentin
the BarentsAbyssalPlain,Arctic OceanduringApril 1982.Singlehydrophonedata wererecordedfrom variouselementsof boththe MassachusettsInstituteof Technology/WoodsHole Oceanographic
Institutehorizontal array and the Naval ResearchLaboratory vertical array. This
papercharacterizes
the averageambientnoiselevel,andits varianceasa
functionof frequency(to 2500 Hz), depth,and time. [Thiswork is funded
by ONR Code425-AR, ProgramManager,R. Obraeta.]
106th
Meeting:
Acoustical
Society
ofAmerica
$21
TUESDAY
AFTERNOON,
8 NOVEMBER
1983
DEL MAR/HELIX/SANTA
FE ROOMS, 2:00 TO 3:25 P.M.
Session
L. MusicalAcoustics
II: IntonationandScales
Donald E. Hall. Chairman
Departmentof Physics
and Music,CaliforniaState University,
6000J Street,Sacramento,
Cd 95819
Chairman's
Introduction---2:00
Invited Paper
2:05
LI. The tuningof Harry Partch's43 tones-to-the-octave
j •t intonationscale,andit's musicalendowments
and
consequences.
Danlee Mitchell (SanDiegoStateUniversity,Music Department,SanDiego,CA 92116)
Harry Partch(1901-1974)is the Americancomposernotedfor hisboldand uniquedepartureawayfrom
20th centurytuningand performance
practicesof our presentday Europeaninfluencedmusicmonolith.
Duringthe 1920'sPartchformulatedthetheoreticalparameters
of histuningsystem,basedonan interlocking
harmonicandsubharmonic
gridextendedto the 1lth partial.Thissystemfeaturesa "micro"tunedscaleof 43
tones-to-the-octave,
andjust harmonicrelationships
in ratiosof successive
integers4-5-6-7-9-I 1 thatsurpass
the resources
of 12-toneEqualTemperament.Not contentwith a meretheoreticalvictory,Partchthendevoted
hisentirelife to thebuildingof sculpturallybeautifulmusicalinstruments,
andtheemploymentof thesemany
instrumentsin his theatricallyorientedmusicalworks.Mr. Mitchell, Partch'scloseassociatefor the last 20
yearsof hislife, will presentan intimateviewof Partch'sworld.
ContributedPapers
2:35
L2. Peree!•ion of musicalintervaltaning.Donald E. Hall(Departments
of Physicsand Music,CaliforniaStateUniversity,6000J St., Sacramento,
CA 95819)
Pairsof toneshavebeengeneratedundercomputercontroland presentedto musicallytrainedsubjectsthroughheadphones.
Musical relevanceis increasedby usingfilteredpulsewavesrather than sines.The
stimulusintervalsareharmonic{bothtonesheardsimultaneously}
rather
than melodic.Theseintervalsare mistunedin varyingamountsin the
vicinityofeachtraditionalmusicalinterval(e.g.,aroundthe3:2frequency
ratio for the perfectfifth).Judgments
of the relativedegreeof perceived
mistuningare recordedand analyzed;althoughrelatedto judgmentsof
"dissonance,"
thesediffer in significantways.From the resultswe can
inferrelativeabilityto detectmistuningof differentintervalspecies.
We
findimportantdifferences
fromthetraditional"consonance
rank"ordering,and pointout someimplicationsfor theoriesof keyboardtuning.
2:50
importancethan the presence
of beats.Smallamountsof mistuninggo
unnoticedor mayevencausean increaseof the intonationquality.
3:05
L4. Phantom be•ts in mistaned chords. L L. Hall, M. V. Mathews, and
L.A. Roberts(Bell Laboratories,
Beatsareheardin slightlymistunedmusicalintervals.For example,a
mistunedfifth with frequencies•= 804 Hz andf2 = 1204Hz will produce4 beatsper second.
Thesebeatshavebeenattributedto interaction
betweenthe 3rd harmonicoff• at 2412Hz and the 2ndharmonicoff2 at
2408 Hz. However,4 beatsper secondcan be heardwhen the mistuned
fifth is playedwith puresinusoids
whichhaveno harmonics.
A second
hypothesis
attributesthesephantombeatsto interactionbetweencombinationtonesf•- f• at 400Hz and2f• - f2 at 404 Hz. Experimentalresults
supportingthesecondhypothesis
are presented.If onecombinationtone
is removedby a cancellationtoneofappropriateamplitudeand ph•tse,the
beatscannolongerbeheard.If tonesareaddedto a perfectlytunedfifth so
asto approximate
the combination
tonesproducedby a mistunedfifth,
the resultingstimulusis difficultto distinguishfrom the mistunedinter-
1.3. Perceptionof melodicand harmonicintonationof two-part musical
fragments.RudolfA. Rasch•Instituteof Musicology,Drift 21, 3512BR
Utrecht, The Netherlands}
val. Similar results were obtained for mistuned fourths, attributable to
Shortmusicalfragments
consisting
of a melodypart anda basspart
weremistunedin variouswaysandto variousdegrees.
Theywerepresentedto a groupofsubjects
f•r ajudgmentofthequalityof intonationandfor
an identificationof the mistunedpart. Mistuningwasappliedto the melodic frequency
intervalsof themelodypart and/or thebasspart Imelodic
mistuninglaswellasto thefrequcnlcy
intervalsof simultaneous
tonesin
melodyandbassIharmonicmistuning).Resultsindicatethat the melodic
3:20
mistuning
ofthemelodyparthasthelargestinfluence
ontheperception
of
the intonation,followedby the harmonicmistuning,while the melodic
mistuning
of thebassislessimportant.
Whenmistuning
ispresent
in both
melodyandbasspart, mostlythemelodyisconsidered
to bethemistuned
part.Whenthesound-pressure
levelsofthetwopartsareunequal,
thereis
a tendencyto considerthelouderpartasthemistunedpart. In thepercep-
tionofharmonic
mistuning,
thedeviating
intervalsizeisprobably
ofmore
S22
J. Acoust.Sac.Am.Suppl.1, Vol.74, Fall 1983
inletactionbetweencombinationtonesf• --f• and 3ft -- 2f2.
13. Modality and suffixeffectsin memoryfor music.Linda A. Roberts
{Bell Laboratories,Murray Hill, NJ 07974 and RutgersUniversity, New
Brunswick, NJ 08903}, David R. Millen, Caroline Palmer {Rutgers
University, New Brunswick, NJ 08903), and Vicky C. Tarttot (Bell
Laboratories,Murray Hill, NJ 07974 and RutgersUniversity,Camden,
NJ 08102)
Three experimentswereconductedto explorethe well-documented
modalityand suffixeffectsfound in language,usinganotherdual-code
symbolsystem:music.In all threeexperiments,
subjectsweretestedfor
immediateserialrecallof musicalnotes.In experiment!, moderatelyand
highly trainedmusiciansrecalledrandomorderingsof notescontained
withinthespanof an octave{D to D). The highlytrainedmusicians
dem-
Societyof Amedca
S22
onstrated
a recencyeffectfor bothvisualandauditorypresentation.
Moderatelytrainedsubjectsdemonstrated
the effecttypicallyobservedfor
language:
a recencyeffectwasfoundonlyfor theauditorycondition.In
experiment2, the target noteswere from a musicallyrestrictedrange
(D,F,A) andtherateof presentation
wasincreased
to discourage
linguistic
TUESDAY AFTERNOON,
8 NOVEMBER
recodingof stimuli.Resultsindicateda recencyeffectfor bothmodalities
and an overallauditorymodalityadvantage.Resultsof experiment3 Ivisualpresentation
onlyI showeda largerrecencydecrease
(suffixeffect}for
an appendedvisualnote than for a toneor a written letter. A dual-code
representation
of musicis proposed.
CHAMBER
1983
ROOM, 1:30 TO 4:20 P.M.
SessionM. EngineeringAcousticsIh Numerical Techniquesand Others
Roger L. Kerlin, Chairman
•4ppliedResearch
Laboratory,Pennsylvania
State University,
P.O. Box30, StateCollege,Pennsylvania
16801
Chairman's
Introduction•l:30
ContributedPapers
1:35
MI, The finite elementmethodin acoustics.Earl Geddes(Electricaland
ElectronicsDivision,Ford Motor Company,Dearborn,MI 48121)
From thevariationalfieldequations
for problemsin acoustics
onecan
derivethe finite elementapproachto their solution.From this approach
the applicationof a standardfiniteelementmethodIFEMI programto a
problemin roomacoustics
wasperformed.
The roleof theacoustic
variables,thematerialconstants,
boundaryconditions,
etc.,asrequiredfor the
FEM programwasexamined.The needfor complexarithmeticin the
analysis
of a nonconservative
systemandin themodelingof realsources
was shown.The FEM eigenvectorsand eigenvalueswere then usedto
assemble the Green's function in the form of a data base. This Green's
function was then to be used to examine the acoustic behavior of the room
at lowfrequencies,
i.e.,belowtheSchroeder
frequency.
1:50
Many longitudinalvibratorsemploya multi-elementstackof piezoelectric ceramicrings as the active component.In order to designsuch
transducersit is desirableto be able to measurelongitudinal33-parametersof piezoelectric
ceramicsusinga single-ring
geometry.Existingone-
dimensional
modelsarenotadequate
todescribe
the"longitudinal"
mode
for typicalringsdueto intermodalcoupling.A piezoelectric
finiteelement
modelwas usedto relateresonantfrequenciesto 33-ceramicparameters
for certain selectedring geometries.However, sincepiezoelectricfinite
elementsare notgenerallyavailable,a simplifiedmodelwasdevelopedin
whichthenecessary
computations
canbeperformed
ona handcalculator.
Guidedby the finiteelementresults,idealizedmodeshapeswereusedin
conjunction
with anenergymethodin orderto obtainthesimplifiedmodel. The resonantfrequencies
predictedby the simplifiedmodelwerein
excellentagreement
with thoseobtainedusingthefiniteelementmethod.
This new modelcanbe usedto analyzea broadrangeof ring geometries.
The authorshaveusedtheaforementioned
modelsto obtain33-piezoelectric parameters
from measurements
of resonantfrequencies
andlow-frequencycapacitance
on ceramicrings.
M2. The additionof piezoelectricpro.riles to structuralfinite element
progrmnsby matrix manipulationswith applicationsto underwater
acoustics.Graham MeDeatmon, Lyle Pauer, and Richard Scherch
(Goodyear
Aerospace
Corporation,
Department
456G2,12l0 Massilion
Road, Akron, OH 44315)
The capabilityto analyzematerialshavinglinearpiezoelectric
propertieswasdevelopedfor structuralfiniteelementprograms.Of the many
methods with which this could be achieved, the method chosenwas to add
thepiezoelectric
properties
by matri,xmanipulation
of elasticandheat
transferelementmatrices.This methodis independent
of the elemental
shapefunctions.
It thereforehastheadvantages
ofconverting
manyvarietiesof structuralfiniteelements
intopiezoelectric
finiteelementswith one
generalcodingand as the stateof the art improvesfor the structural
elementsso will the piezoelectriconeswithout additionalor new programming.Otherwise,eachvarietyof piezoelectric
elementandimprovementswouldhaveto beprogrammed
separately.
Thiscapabilitywasadded to MSC/NASTRAN by .GoodyearAerospaceCorporation.The
theorybehindthis methodand comparison
of finiteelementmodelsof
severalpiezoelectric
ceramicunderwater
acoustic
projectors
to experimentaldata are presented.
2:20
M4. An improvementof the finite radiating element formulation-Applicationto the modelingof a radiating free-floodedtransducer.
Rtgis Bossut(SintraAlcateI-Dtpartment
D. S. M., Z. I. desPaluds,
13400 Aubagne,France) and Jean-NoiflDecarpigny(ISEN, 3 rue
FrancoisBai•s,59046Lille Cedex,France)
At low frequencies,
the limit of a free-flooded
cylinderfarfieldisvery
far from the acousticcenter.Thus,modelingthissubmerged
structureby
thefiniteelementmethodrequiresa largenumberof fluidelements,when
the radiationboundaryconditionis represented
by an outgoingspherical
(monopolar)
wave.A radiatingelementhasbeencreated,that usesa radi-
atingimpedance
of bothmonopolarand dipolafwaves.With this new
element,the radiatingsurfacecanbe muchcloserto the transducer,and
thenthe numberof fluidelementsdecreases
significantly.
Unfortunately,
one cannotobtain directlythe farfielddirectivitypattern,becausethe
radiatingsurfaceisinsidethenearfieldzone.However,it ispossible
tofind
it by a simplealgorithm.Thisalgorithmcanalsobeusedin an acoustical
tank whenever its size is too small to measure the far acoustic field of a
largetransducer.
2:35
M3. Analysis of intermodal coupling in piezoelectric ceramic rings.
GeorgeW. Bcnthien(Code 7122, Naval Ocean SystemsCenter, San
Diego, CA 92152)and Gordon E. Martin (Martin AcousticsSoftware
Technology,
P.O. Box86050,SanDiego,CA 92138-6050)
S23
MS. Efficiency enhancementof thermo-acousticsourcesthrough highvelocity motion. N. P. Chotiros (Applied ResearchLaboratories,The
Universityof Texasat Austin, P.O. Box 8029, Austin, TX 78712)
S23
A theoreticalstudyof thenno-acoustic
sourcesin the contextof sonar
applications
wasundertaken.The mainobjectives
wereto improveencrgy
efficiencyand to providea meansfor beamsteering,usinga moving
thenno-acoustic
source.The resultsshowthat improvements
in energy
efficiencyof severalordersof magnitudeare possible
at very largeMuch
numbers.(This is quitedistinctfrom peakintensityefficiencywhichoccursat Much 1.)The resultsalsoshowthe possibilityof beamsteering
by
movingthethenno-acoustic
sourcein a numberof ways.The resultssuggestthatthethenno-acoustic
sourcemay,in certainsonarapplications,
be
a viable acousticprojector.[Work supportedby Officeof Naval Research.]
2:50
M6. An application of SEA to helicopter structure borne no'se. D.
L. Hawkings(Engineering
Division,WestlandHelicopters
Ltd. Yeovil,
Somerset,
England}
The paperdescribes
an exploratoryapplicationof SEA to helicopter
structure borne cabin noise. The work was focused on a fall-scale center
cabin testsectionof advancedstructuraldesign,rather than a complete
helicopterfuselage.Severaltheoreticalmodelsweredeveloped,differing
in the complexityof the structuralrepresentation
adopted.The maindifficultiesencounteredin the modelingprocessarosefrom the composite
sandwich
construction
of thewallpanels,andin particularexpressing
the
couplinglossfactorsfrom the beamlikeframeelementsto thesepanels.
Numericalpredictions
basedon thesetheoriesweremadeof theexpected
vibrationlevelsaroundthestructure,andtheacoustic
pressure
withinthe
cabin.Thesepredictions
werecomparedwith measured
resultsfromthe
trial structure.Goodoverallagreementwasfoundwith the morerefined
model,althoughthecrudermodelstillgaveacceptable
predictionof noise
levelsacrossthe frequencyrangeconsidered
{250-8000Hz}. It is concluded that SEA is potentiallya valuabletool for predictinghelicoptercabin
noise.[Worksupported
by U. K. MUD.]
unimportantcomparedto other geometricaland acousticfactorsfor a
rangeof thickness
of practicalinterest.A physicalbasisis presented
for
the observedvariation of the radiation resistancewith temperature.
[Worksupported
by NASA.l
3:35
M9. Transitionfromthe nonlinearKingintegralto sphericalpropagation
for a finite amplitude sound beam. Jerry H. Ginsberg (Schoolof
MechanicalEngineering,
GeorgiaInstituteof Technology,Atlanta,GA
30332}
The propagation
of finiteamplitudewavesradiatingfrom a baffled
pistonhasbeendescribed
in termsof directionalsphericalwaves[J. C.
Lockwood, T. G. Muir, and D. T. Blackstuck,J. Acoost. Soc. Am. 53,
1148-11530973}]. That analysispredictswaveforms
at largedistances,
providedthatcomparable
informationisknownat a reference
locationin
thefarfield.Lockwood
eta/. usedthisapproach
basedon assuming
that
lineartheoryis accurateat the referencelocation.Suchan assumption
is
inaccurate
whenthesourcepressure
levelissufficient
to generatesignificantnonlineareffects(growthof higherharmonicsanddepletionof the
fundamental}
withinthenearfield.The presentworkdescribes
theinterfacingofthespherical
propagation
theoryandthenonlinearKingintegral
[J. I4. Ginsberg,J. Acoust.Soc.Am. Suppl.1 71, S3011982}].The latter
theoryis usedin this approachIo evaluatethe nonlinearwaveformat the
referencelocation.Comparingthe resultsof interfacing,and of direct
propagation
accordingthe nonlinearintegralformulation,with experimentaldataprovides
a strong.validation
forboththeories.
Theadvantage
of usingdirectirespherical
wavetheoryliesin itssuperiorcomputational
efficiency
anditsabilityto describeshockformation.[Work supported
by
ONR, Code425-UA, and NSF, Grant MEA-8101106.]
3:50
MI0. Sound reflection from a fluid-loadedand maskedelastic plate. P.
3:05
M7.Surface
intensity
andradiation
loading
oncylindrical
surfaces
via
•
methods.P. Stepanishenand H. W. Chen (Departmentof Ocean
Engineering,
Universityof RhodeIsland,Kingston,RI 0288!}
A numericalapproachis presented
to evaluatethe surfaceintensity
and radiationloadingon a finite cylindricalsurfacewith a known harmonicradial velocitydistribution.The approachis basedon a combined
FFT and Green'sfunctionmethod[P. Stepanishen
and H. W. Chen,J.
Acoust.Soc.Am.Suppl.173,S22(19831].
Surface
pressure,
intensity,
and
radiationloadingarerapidlyobtainedvia the useof standardFFT methods.The spatialfluctuationsof the surfacepressureand intensityfor a
knownvelocitydistributioncan thusbe readilyinvestigated.
Numerical
resultsare presented
to illustratethe spatialvariationof surfacepressure
and intensityas a functionof axial mode shape,circumferentialmode
number,and frequency.Negativeintensityregionsand edgeeffectsare
clearly observedin the resultsat low frequencies.
3:20
MS. A temperaturecorrelation for the radiation resistanceof a thick-
walledcircularductexhaustinga hot I•s. J. R. Mahan (Departmentof
Mechanicaland AerospaceEngineering,West Virginia University,
Morgantown,WV 26506),J. G. Cline (GeneralDynamicsCorporation,
D. JackinsandG. C. Gaunaurd(NavalSurfaceWeaponsCenter,White
Oak, SilverSpring,MD 20910)
We haveextendedavailablecomputercodesthat predicttheclassical
reflections
andtransmissions
of soundfieldsthroughsetsof planeelastic
layers[i.e.,D. FoldsandC. Loggins,J. Acoust.SUe.Am. 62, 1102-1115
{1977}].Thepresentlayersseparate
possibly
dissimilarfluids,arepossibly
viscociastic,
and are isonifiedfrom one side.The resultswe displayineludereflection{R } and transmission
{T} coefficients
asfunctionsof frequencyfandincidence
anglesO.This computational
toolhasbeenusedto
predictthe reflections
from a singlefluid-loadedelasticplateideallycovered with a lossylayer of homogeneous
viscociasticmaterial, isonified
from the coatedside.Resonances
in the coefficients
are analyzedin the
light of the resonance
scatteringtheory{RST},whichhasnot yet been
appliedto coatedplates.The presentmodelservesto assess
theeffectivenessof the maskinglayer to reducethe reflectionsfrom the metal plate.
The predicteddisplaysof calculations
arepresented
for valuesof thematerial param•ers in the rangescommonlyfound in practice.The Iossy
natureof the absorbinglayercomplicates
the otherwisereal parameters
present
in theanalysis,
andwequanti,tatively
determine
theshiftsin resonancelocations,the wideningof the resonancepeaks,and the overall
reductionof the returnedreflectionscausedby the masker'sviscociasticity.
4.-05
Fort Worth. TX ?6101), and J. D. Jone• (Mechanical Engineering
Department, Virginia Polytechnic Institute and State University,
Blacksburg,VA 24061)
It isoftenusefulto know the radiationimpedanceof an unfiangedbut
thick-walledcircularduct exhaustinga hot gasinto a relativelycold surroundings.Resultsbasedon data availablein the literature[N. Fricker
andC. A. Roberts,Acustica38, 124-130119771;
A. Cummings,J. Sound
Vib. 52, 299-304 (1977)]and a newexperimentalstudyconfirmthat the
reactivecomponentis insensitive
to temperature,while the resistivecomponentincreases
with the temperaturedifferencebetweenthe gasflowing
fromtheductandthesurroundingair. A temperaturecorrelationisdevelopedpermittingpredictionof the radiationresistance
from a knowledge
of this temperaturedifference.The effectof wall thicknessis shownto be
S24
J. Acoust.Soc. Am. Suppl.1, VoL 74, Fall 1983
M 11. Distn'butionof resonancefrequenciesof coupleddynamicsystems.
G. MaidanikandL.J. Maga(DavidW. TaylorNaval ShipResearchand
DevelopmentCenter,Bethesda,MD 20084)
Finite, uncoupleddynamicsystemshaveresponsemaximaat specific
frequencies,the resonancefrequencies,the distribution of which can be
ascertained.When the dynamicsystmsare coupledand, therefore,inter-
act with eachother,the couplingaffectsthedistributionof the resonance
frequencies.
In thispaperthedynamicsystems
aremodeledasone-dimensionalwave-bearing
systems
andthecouplingiseffected
viathetransmis,
sioncoefficients
of thejunctionsbetweenthe systems.The natureof the
changein the distributionof the resonancefrequenciesis examinedin
somesimplecases.
106th Meeting:AcousticalSocietyof Arnodca
$24
TUESDAY AFTERNOON, 8 NOVEMBER 1983
CALIFORNIA ROOM, 1:00TO 3:35P.M.
SessionN. ArchitecturalAcoustics
III, NoiseII, andShockandVibrationII: ActiveSoundandVibration
Control
Oliver L. Angevine,Chairman
AngevineAcousticalConsultants,Inc., 7349 Davis Road, WestFalls, New York 14170
Chairman's Introduction•l:00
Invited Papers
1:05
NI. Waveformsynthesis•TheEssexsolutionto eauceiling
periodicnoiseandvibration.G. B. B. Chaplin
(WolfsonCentrefor theElectronicCancellation
of NoiseandVibration,Universityof Essex,WivenhoePark,
Colchester
C04 3SQ,England)
Thepaperwill givea basicdescription
of thespecial
methoddeveloped
bytheEssexGroupforcancelling
noiseand vibrationof a periodicnature.Oneof theadvantages
of the methodis that the anti-noiseor anti-
vibration
isproduced
bysynthesis
anddoesnotdepend
onmeasurement
oftheoriginalnoiseorvibration.
The
anti-noise
andanti-vibration
cantherefore
beinjected
at precisely
therighttimesincenosignalprocessing
delayisinvolved.
Examples
willbegivenofapplying
thesystem
tocancelling
thenoiseat theexhaust
ofa diesel
engineandthevibrationat itsmounting
points,andtocancelling
noisewithina cab.Thesystem
isalsohighly
selective
andit ispossible
to cancelonesource
of noisewhilstleavingothernoisesources
untouched.
Experienceon cancelling
theexhauststacknoiseon a cargoshipwill bediscussed.
1:35
N2. Activenoisecancellation
in duets.Jiri Tichy (The Pennsylvania
StateUniveristy,StateCollege,PA
16802),GlennE. Warnaka(LordCorporation,2000WestGrandviewBoulevard,P.O. Box 10038,Erie, PA
16514-0038),
andLynnA. Poole(ThePennsylvania
StateUniveristy,StateCollege,PA 16802)
Thispapersummarizes
thestateof activenoisecancellation
in ducts.Theapplication
ofactivefeedback
to
reducethe soundenergypropagation
throughthe duct is primarilyimportantat low frequencies
because
passive
silencers
areverylarge,andtheattenuations
achieved
arerelativelysmall.In itsclassical
configuration,
thenoisefielddetected
by a signalmicrophone
isphaseinvertedandtimedelayedby an adaptivefilter.This
signalisthenreradiatedintotheductfroma soundsourceat theductwallor locatedremotelyandconnected
bymeans
ofa waveguide.
Theadaptive
filteriscontrolled
bya microphone
locatedintheducttosense
thenoise
reductionandadjusttheentiresystemfor optimumoperation.
Thispaperanalyzes
the effects
of the signal
microphone
position,
type,andlocationof thecancellation
soundsources,
andsensing
microphone
location.
Optimumoperationrequiresconsideration
of higherordermodesandthenearfieldof thecancellation
source,
includingevanescent
waves.Resultsobtainedwith practicalconstructions
illustratethe greatpotentialof
activesystems
to attenuate
noisewithdiscrete
spectra,
randomnoise,aswellastransients
arepresented.
2:05
N3. Activecontrolof noisein enclosed
spaces.
GlennE. Warnaka,JohnM. Zulus(LordCorporation,
2000
West GrandviewBlvd., P.O. Box 10038, Erie, PA 16514-00381,Jiri Tichy, and Lynn A. Poole (The
Pennsylvania
StateUniversity,StateCollege,PA 16802)
Activemethods
forcontrolling
noisehavebeendemonstrated
tobefeasible.
Astheyarecompact
involume
andlowinweight,
activecontrols
seem
verypromsing
forcontrolling
low-frequency
noiseinenclosed
spaces,
particularlyin transportation
vehicles.
Nevertheless,
certaindifficulties
arisedueto themodalstructure
developedwithintheenclosed
spaces,
because
thecancellation
sources
mustproduce
anexactmatchoftheunwanted noisefieldin orderto cancelit. Similarly,the nonuniformnatureof the noisefieldposespxoblems
in
detection
of thenoise.Thispaperdiscusses
theprogress
whichhasalreadybeenmadein controlling
interior
noiseandshowsthatthereareseveralapproaches
thatmaybeadopted.The methodsdependon whetherthe
noise
originates
withinthespace
orfromsources
outside
thespace.
If thesound
enters
thespace
bypenetration
fromtheoutside,
thenthemethodofpenetration
canbeimportantindetermining
thelocationofthecancelling
sources
andthedetectingmicrophones.
The technicalpotentialandthe latitudeof applicationindicatethat
thereisconsiderable
promisefor activecontrolof noisein enclosed
spaces.
2:35
N4. Activesystemsfor globalattenuationof noise.M. J. M. Jessel(CNRS-LMA, B. P. 71, F-13277 Marseille
Cedex9, France)andO. L. Angerinc(AngevineAcousticalConsultants,
Inc., 7349DavisRoad, WestFalls,
NY 14170)
Theoreticalapproaches
to activenoiseabsorption
[G. A. Mangiante,J. Acoust.Soc.Am. 61, 1516-1523
(1977)]provide
criteriathatmayproveuseful
forthedesign
ofanysystem
foractivenoise
attenuation,
especialS25
S25
ly onewhichmustproduce
attenuation
in all directions
arounda complex
soundsource.
(I ) Topological
fitness:
a propernetof"anti-sources"
oughtto surroundcompletely
eithertheprimarynoisesource{s),
or thespaceto
besilenced.
(2}Directioity:
eachanti-source
oughtto radiateonlytowardsthespaceto besilenced.
(3}Concentration:practical
system
design
requires
substituting
thetheoretical
continuous
distributions
ofanti-sources
by
discrete
ones.Thisapproach
hasbeensuccessfully
appliedto reducing
theaudiblehumof an actualelectric
substation
transformer.
Theactiveabatement
method
iseasier
fordiscrete
frequencies,
suchasthespectrum
of
transformerhum,andis mosteffectiveat the relativelylow frequencies---120,
240, 360,and480 Hz--most
prominentin thetransformer
humspectrum.
A relationhasbeenfoundexperimentally
for the attenuation
achievable
versus
thenumberofsources
foreachof thesehumfrequencies.
Theactiveattenuatorinterferes
less
with the normalventilationandCOOling
of a transformer
thando passive
methods.
Activeabatement
also
allowsattenuation
differingin differentdirections.
3:05
NS. Coherentactivemethods
for applications
in roomacoustics.
Dieter Guicking(DrittesPhysikalisches
Institutder Universit/it,Buergerstr.
42-44,D-3400Goettingen,WestGermany}
An adjustment
of reverberation
timein roomsis oftendesiredevenfor low frequencies
wherepassive
absorbers
fail.Amongtheactive(electroacoustic}
systems,
incoherent
onessuchas"assisted
resonance"
permit
prolongation
of reverberation
timeonly,whereas
coherent
activemethods--as
proposed
byH. F. Olsonsince
1953--allowsoundabsorption
as well. A coherent-active
wall liningconsists
of loudspeakers
with microphones
in frontandadjustable
controlelectronics.
Themicrophones
pickup theincidentsoundanddrivethe
speakers
suchthat the reflectioncoefficient
takesprescribed
values.An experimental
devicefor the onedimensionaleasehasbeendevelopedandallowsreflectioncoefficients
betweenalmostzeroand about1.5to be
realizedbelow1000Hz, employing
movingcoilor specially
developed
extremely
flatelectretloudspeakers.
The extension
to threedimensions
is beinginvestigated;
problemsarisemostlyfrom diffractioneffects.The
actualstateof the experimental
work includinga comparison
with modelcomputations
will be outlined.
Furthermore,
someideasaboutactivediffusers
arepresented.
In contrasttopassive
"Schroeder
diffusers"
with
inherentfrequency
dependence,
activediffusers
arebasically
broadband
systems.
TUESDAY AFTERNOONi 8 NOVEMBER 1983
FORUM
ROOM, 1:30 to 4:50 P.M.
SessionO. PhysicalAcousticsII: GeneralTopicsI
Steven L. Garrett, Chairman
Physics
Department,Naval Postgraduate
School,Monterey,California93940
ContributedPapers
1:35
O1. Reciprocity calibration of "secondsound"transducersin superfluid
helium S. L. Garrett (Physics Department, Code 6lGx, Naval
PostgraduateSchool,Monterey,CA 93940)
The reciprocitytheoremhasbeenusedfor over 40 yearsto facilitate
absolutecalibrationsof electroacoustic
transducers
from purelyelectrical
measurements,without referenceto a primary acousticalstandard.A
generalizationof this calibrationprocedureto reversiblesecondsound
transducers
in He 11will bedescribed.
The symmetryof two-fluidhydrodynamicsis usedto derivean expression
for the secondsoundspecific
acoustictransferadmittance,thuspermittingabsolutemechanicalmea-
1:50
02. An experimentaltestof acousticalreciprocitycalibrationappliedto
thermaltransducers
in superfluidheliumJ. Valdivia,Jr., B. R. Ogg,R.
K. Yarber, and S. L. Garrett (PhysicsDepartment,Code61Gx, Naval
Postgraduate
School,Monterey,CA 93940}
An experimentwill bedescribedwhich hasverifiedan extensionof the
reciprocitycalibrationtechniqueto reversiblethermal transducers
in superfluidhelium. A plane-waveresonatorof circularcrosssectionwas
perature range from 1.15ø to 1.9øK, the Tisza approximationand the
thermodynamics
of an idealBose-Einsteingas[F. London,Superfluids,
Vol. II, Sec.7] leadto a transferadmittancewhichisquadraticin temperature. This generatesa calibrationconstantthat has the experimentally
convenientfeatureof beinga linear functionof absolutetemperature
cappedat bothendsby reversible
teflonelectretdiaphramswhichcontainedmany razor slits to generateor detectthermal waves(second
sound).The resonatoralsoincorporated
a thermophone
andadc biased
carbonresistance
thermometerto setindependent
upperandlowerlimits
ontheamplitudeof thetemperature
oscillations
withintheresonator.
The
acoustical
resonance
datawasacquiredandanalyzedbya computercontrolled systemdescribedpreviously[D. V. Conte and S. L. Garrett, J.
Acoust.Soc.Am. Suppl. 172, S82 (1982}].The temperatureexcursions
measuredby the reciprocitymethodfell betweenthe upperand lower
surement
of temperature
oscillations
in superfluid
helium.In the tem-
[f(T) = 21.31T-- 17.01+ 0.17g•/2 .K-• S--3/2].
Applications
to non-
limitswhich,for lowermodes,
wereseparated
byonlya fewpercent.
At
linearhydrodynamics,
photoacoustic
spectroscopy,
andthe characterization of porousdiaphramsecondsoundtransducerswill be suggested.
highermodesthe lower limit departedfrom the upperlimit due to the
thermalinertia of the resistance
thermometer.Temperatureexcursions
[Worksupported
by theNPS FoundationResearch
Program.]
smaller
than10-• 'K/[(Hz}•2] weredetectable
usingtheelectret
trans-
S26
J. Acoust.
Soc.Am.Suppl.1, Vol.74, Fall1983
106thMeeting:
Acoustical
Societyof America
S26
ducers
anda pre-amplifier
witha noisefloorof 10-s V/[(Hz)•/2].[Work
supported
by theNPS FoundationResearch
Program.]
2:05
03. Comparison
of procedures
for determination
of aroustienonlinearity
of some inhomogeneous
materials. L. Bj•rn• (industrial Acoustics
Research
Group,TechnicalUniversityof Denmark,Building352,DK2800Lyngby,Denmark)
The widespread
useof ultrasonicenergyin medicaldiagnosis
and
therapyandtherecentresearch
showingtheexistence
of nonlinearacoustic effectsin inhomogeneous
materials,likebiologicalmedia,haveledto a
stronglyincreased
interestin investigations
aimingat providingenough
information
for anevaluation
of thesecond
ordernonlinearity
ratioB/.4
as a tissuecharacterizing
parameteron a par with attenuation,impedance,etc. The severaltechniquesusedfor the determinationof B/d
roughlyfall into two maingroups,finite-amplitude
methodsandthermodynamic-acoustic
methods.
The B/.4 valuesdetermined
usingvarious
techniques
of thetwo maingroupsarestronglyscattered,
showinga de-
2:50
06. Ultrasonic study of oil/water emulsions stabilized with nonionic
block copolymers.M. A. BarrettGultcpe, M. E. Gultcpc, J.
L McCarthy, and E. B. Yeager (UltrasonicResearchLaboratory,
Departmentof Chemistry,CaseWesternReserveUniversity,Cleveland
OH 441061
An incrementin soundvelocityat 2 MHz hasbeenobservedas the
emulsion
globulesizedecreases
withtimein a water,toluene,andpolyoxethylene(POE•polyoxypropylcne(POP)blockcopolymer
system.The
observed
effectdepends
onthecopolymer
concentration
andislargestfor
theblockcopolymercomposed
of 50% POE-50% POP moleties.A generalacoustical
treatmenttakingintoaccountviscous
lossin theemulsions
globulesas well as surroundingliquid and heat conductionacrossthe
interfacefailsto explainthe observedvelocityincrement.Aqueoussolutionsof the abovecopolymershowsassociation
effectsasevidencedby a
breakin the soundvelocityversusconcentrationcurveat approximately
15g/l. [Work supportedby ONR.]
pendenceon the procedureused, which makes it difficult to draw any
validconclusions.
The paperdiscusses
advantages
and disadvantages
of
thetechniques
usedhitherto,aimingat an explanation
of thereasons
for
thedeviations
betweenthepresentB/.4 resultsfor biological
media.The
necessary
accuracy
in thedetermination
andthereliabilityin theexploitationofB/d asa tissuecharacterizing
parameterfor clinicaluseareemphasized.
2:20
04. Ultrasonic evidencefor structural relaxation in large unilamellar
liposomes. Philip R. Strom-Jensen,Richard L. Magin, and
Floyd Dunn (Bioacoustics
ResearchLaboratory,Universityof Illinois,
Urbana, IL 61801)
The ultrasonicabsorptionof largeunilamellarvesicles(averagediameter 0.2/•m) was determinedin the frequencyrange0.5-5 MHz. The
liposomes
werecomposed
of a 4:1 mixtureby weightof dipalmitoylphosphatidylcholineand dipalmitoyl phosphatidylglycerol.
A large increase
in absorptionoccursat the solidto liquid-crystallinephasetransitiontemperature(42 øC)of the pure lipid vesicles.This increasein absorptionis
interpretedasa structuralrelaxationof the "melting"fatty acidchains
occurringwith an averagerelaxationtime of 76 ns.The liposomes
were
alsofound to be extremelypermeablenear the transitiontemperature,
releasingencapsulatedcytosinearabinoside.Addition of cholesterolor
gramicidin to the liposomebilayer broadenedthe ultrasonicabsorption
andreducedtheeffiuxof cytosinearabinoside
at the transition.Gramicidin, in additionto broadeningthe transition,slowsthe isomerization
of
bondsin thehydrocarbon
chainsof thelipids.A concentration
of 5 mole
percentgramicidinincreased
theaveragerelaxationtimeto 210ns.[Work
supported
in partby grantsfrom theNationalCancerInstitute,National
Institutesof Health, and the AmericanCancerSociety.]
2:35
05. Nearfield of a pistonsourcein an absorbingmedium.Wesley
L. Nyborgand R. Bruce Steele(Departmentof Physics,Universityof
Vermont,Burlington,VT 05405)
Medical exposures
to ultrasoundfrom unfocusedsourcetransducers
usuallyoccurat distances
fromthesourcewhicharenotgreatenoughto
justifya farfieldapproximation.
In orderto analyzebiophysical
interac-
3:05
07. Sound absorptionin aqueousmixtures of MgSO4 and HCI. C.
C. Hsu(Departmentof ElectricalEngineering,
ChungChengInstituteof
Technology,Taoynan,Taiwan335,Republicof China)andF. H. Fisher
{MarinePhysicalLaboratoryof the ScrippsInstitutionof Oceanography,
Universityof Californiaat SanDiego, San Diego, CA 921521
Soundabsorption
measurements
weremadeat 25 øCoverthefrequency rangeof 30-300kHz for aqueous
mixtureof 0.02M MgSO4 andHCI,
usinga sphericalresonator
method.At I atm,theexcess
soundabsorption
measuredfor a mixtureof 0.1 M HC1 is negligiblewhile that of 0.05 M
HCI showed
a maximum
absorption,
(aA)m•X 106,of9.49+ 0.21at214
kHz and that of 0.01 M HCI, 68.90 + 0.71 at 161 kHz. AT 307 arm the
mixtureof 0.05 M HC1 showeda maximumabsorptionof 5.78 + 0.14 at
205kHz. Theseresultswill bediscussed
in termsof normalmodecoupling
Of HSO4 and MgSO4dissociation
reactions.The observeddecreasein
absorptionas HCI is addedcannotbe explainedby ion-pairingconcepts
alone.
3:20
08. Shapeoscillationsof microparticleson an optical microscopestage.
Zhu Zhe-ming
• andRobertE. Apfel(YaleUniversity,
P.O. Box2159,
New Haven, CT 06520)
Forcesarisingfrom modulatedacousticradiationpressure
havebeen
usedin the pastto produceshapeoscillationsof dropsin order to study
surfaceproperties
[e.g.,P. L. Marstonand R. E. Apfel,J. Acoust.Sec.
Am. 67, 27 (1980)andC. -J. Hsu and R. E. Apfel, J. Acoust.See.Am. 70,
S90(1981)]andto studytheoscillating
drop'sinternalflowpatterns[E.
Trinh, A. Zwern, and T. G. Wang,J. Fluid Mech. 115,453 (1982)].We
haveextendedthisworkto studysurfaceproperties
of muchsmallerparticles(8 to 200 gm, approximatediameter)by fabricatinga stagefor an
opticalmicroscope
thatincorporates
a 10-MHz,piezoelectric,
quartzdisk
electreded
in sucha wayasto allowthetransmission
of light througha
centralregion.The quartz disk formspart of a thin chamberinto which
themicroparticles
in a hostliquidcanbeinjected.Establishing
ana acous-
tic standingwavein thechamberhasenabledus to studyshapeoscillationsfor dropsrestingon a surfaceof thechamberandfor dropsacoustically levitatedaway from solid containersurfaces.At high acoustic
tions which occur in the exposedmedium, it is necessaryto considerde-
amplitudesdrop fissionhasbeenproduced.We shall presentdata and a
tailsof the nearfield,takingabsorptioninto account.A formulation,in
termsera lineintegral,givenbySchoch[A. Schoch,Akust.Z. 6, 318-326
photographic
recordfor hydrocarbon
dropsin water.We hopealsoto
present
results
forbiological
cells,sincetheinvestigation
oftheproperties
of their membraneswas the originalmotivationfor this work. [Work
supportedby the NationalInstitutesof Health, (3rant 1R01-GM30419,
(19411]
fora pistonsource
proves
to beusefulforthispurpose.
A paraxial
approximationwhichhe derivedleadsto an analyticalexpression
which
appliesevento a centralregionof theimportant,butcomplex,fieldwhich
existsjust in front of the source.In this papercomputedplotswill be
andthe U.S. Officeof NavalResearch.]•lAIso
at NanjingUniversity,
People'sRepublicof China.
shown. comparing results obtained by use of solutionsand approxima.
tiensgivenby Rayleigh,Sehoch,andothers.Thesecomparisons
giveinformationontheconditions
underwhichvariousapproximations
arevalid, and on the influenceof absorption
on the fielddistributions.
[Work
3:35
supportedby the National Institutes of Health, ResearchGrant GM-
09. Sampletransportofmevitated
objectsin a dual temperatureresonance
chamber.J. Robeyand E. Trinh (JetPropulsionLaboratory,California
08209.]
Instituteof Technology,Pasadena,
CA 91109)
S27
J. Acoust.Sec. Am. Suppl.1, Vol. 74, Fall 1983
$27
ExPerimental
studies
showthefeasibility
oftransporting
anacoustically levitatedobjectin an elongatedresonance
chamberfilledwith a
gaseousmedium,and havingits oppositeend zonesat widely different
temPeratures
(35øand 500øC).Theoreticalconsiderations
describemode
andplane,cylindricalandspherical
surfaces.
Thebehaviorof theacoustic
pressure,
potential,
andforcesforselected
modes
fromeachgeometry
is
presented.
The applicationof thesemodesto the fieldof acousticlevitation isalsodiscussed.
[Worksupported
by NASA.]
behaviorand the conditionsfor optimumpowertransferinto the heated
regionaswellasthedynamicpressure
distribution
for varioussimpleand
complexmodes.By properlyintroducingselectedcombinations
of these
modes,positioningand movementalong the longitudinalaxis and
throughthe temperaturegradientare possible.
The reducedgravityof
spacewouldprovidea usefulenvironmentfor applicationof sucha system
in theareasof materialprocessing,
althoughtheexperimental
workhere
hasbeencarriedout in thelaboratoryunder1 g withlow-density
materials.
4:20
O12. Propagation
of standing
wavesin axisymmetric
cavitiesenclosing
an inhomogeneous
medium.M. EI-Raheband P. Wagner(Applied
Mechanics, Jet Propulsion Laboratory, California Institute of
Technology,
Pasadena,
CA 91109}
Thispaperstudies
howgradients
in speed
of soundc anddensity
p
influence
standing
waves
inanaxisymmetriccavity.
Thecandp gradients
3:50
O10. Method for separationof acousticlevitation and rotation modes
leadingto arbitrary axesof rotationJ. L. Allen and M. Barmatz (Jet
PropulsionLaboratory,CaliforniaInstituteof Technology,Pasadena,
CA 91109}
A methodfor separating
acousticlevitationandrotationof smallobjectshasbeendeveloped
andtestedexperimentally.
Samplerotationin an
acousticalresonance
chamberrequiresa phasedifferencebetweentwo
equalfrequency{degenerate}
modes.Therefore,thismethodusesoneset
of nondegenerate
modesfor levitationandhigherordersetsof degenerate
modesfor rotation.This separationof modesmay be accomplished
by
appropriatechoicesof chamberdimension
ratiosproducingup to three
setsofdegenerate
orthogonal
higherordermodes.
Byappropriate
excitation of thesesetsof modes,arbitraryaxesof rotationmay be achieved.
This techniquefor onerotationaxiswasverifiedexperimentally
usinga
rectangularchamber.Sphericalsampleswerestablyleviratedwithoutrotationusingthe threeorthogonalfundamentalmodes,androtatedabout
thez axisby generating
a phasedifference
betweenthedegenerate
third
andfifthharmonics
of thex andy directions,
resPectively.
A videotapeof
theselevitationexperimentswill be presented.[Work supportedby
areassumed
independent
of radialandcircumferential
coordinates
of the
cavityandto varyonlyalongitsaxis.Theeffects
onpropagation
ofthec
andp gradients
arestudiedseparately.
First,the problemwith a step
functionasc gradientin a cylindricalcavityis treatedin detailsinceit is
amenable
to analyticalsolution.A smoothc gradientdescribed
by exponentialfunctions
isconsidered.
In thiscase,a transfer
matrixcoupled
toa
numerical
integration
procedure
isadapted
to thesolution
of thedifferentialequation
governing
theaxialdependence.
Thequasilinear
c2gradient
followsandit alsoyieldsto analysis.
Thepoorenergy
transmission
characteristics
oftransverse
standing
waves
incylindrical
cavities
withcgradientpromptedconsideration
of a geometry
thatincludes
twocylindrical
segments
with differentcrosssections
joinedby a conicalconnector.
The
transfer
matrixmethodcouples
theacoustics
ofvarious
segments
ofcavities.The radialdependence
in theconicalsegment
isdetermined
by the
methodof shootingwhilethe axialdependence
followsfrom numerical
integration.
Theanalysis
isthenextended
to cavitieswithconcentric
center bodies.An approximation
considers
piecewise
conicalfrustraand
leadsto discontinuous
pressure
gradients
at thejunctionof conjoined
segments.
The approximateanalysisis testedagainstnumericalresults
from an accuratesimulationthat invokesa Green's function and surface
elements
withaccountmadefor mediuminhomogeneity.
NASA.]
4:35
4:05
Oll. Acousticforcepotentialon a spherein rectangular,cylindrical,and
sphericalresonators.
M. Barmatz(JetPropulsionLaboratory,California
Institute of Technology, Pasadena,CA 91109} and P. Coilas
ß(Departmentof Physicsand Astronomy,California State University•
Northridge, Northridge,CA 91! 30)
Generalized
expressions
oftheacoustic
force
potential
onasphere
in
rectangular,
cylindrical,and sphericalgeometryhavebeendeveloped.
The methodof Gor'kov[L. P. Gor'kov,Soy.Phys.Dokl. 6, 773 (1962}],
validforarbitrarysoundfieldswasusedtoderivethese
expressions
in th•
limit of smallsampleradius(kR • 1}. The criticalpointsof the force
potential,whereall the forcecomponents
are zero,wereinvestigated.
Generalexpressions
for the coordinates
of the potentialminimafor various modes were determined from theoretical considerations and an anal-
ysisof computergeneratedpotential contour graphs.Besidesisolated
minimapoints,nonisolated
minimawerefoundconsisting
of lines,circles,
S28
O13. Teat of the nearfieldholographytechniqueusingan unbafiled,
uniformlyoscillatingdisk. Todd B. Beyer and Julian D. Maynard
(Department
of Physics,
Pennsylvania
StateUniversity,
UniversityPark,
PA 16802)
Experimentalresultsof nearfieldholographymeasurements
of the
radiationfrom an unbarlied,uniformlyoscillatingdiskhavebeencomparedwith the exacttheoretical
solution.The experimental
sourceis a
disk I m in diameterconstructed
of an aluminumhoneycomb
material
thatis lightweight
andstructurally
rigid.Eightdriverslocatedbeneath
thediskcanbeindividuallyadjusted
sothatthedisk'ssurfacevibratesinphasewithconstant
amplitude.The radiationeflleieney
determined
from
themeasurements
attwofrequencies
I 150Hz, 250Hz}agrees
closely
with
theradiationefficiency
calculated
fromtheexacttheory.Thetheoretical
solutionmakesuseof oblatespheroidal
functions
tocomputethepressure
onthesurfaceof an idealrigiddiskvibratingwithuniformnormalvelocity. [Worksupported
bytheNationalAeronautics
andSpace
Administration.]
Societyof America
$28
TUESDAY AFTERNOON, 8 NOVEMBER 1983
DEL MAR/HELIX/SANTA
Session P. Musical Acoustics IIl:
Wind Instruments
R. Dean Ayers, Chairman
Departmentof Physics-,4stronomy,
CaliforniaState University,LongBeach,California90840
Chairman's
Introduction---3'.35
ContributedPapers
3:40
Pl. The effects of the flaring bell on the normal frequenciesof a
trombone.J. Duane Dudley and William J. Strong (Department of
Physicsand Astronomy,BrighamYoungUniversity,Provo,UT 84602)
to-edgedistanceis4-12 ram,andthejet velocityliesbetween5 and30 m/
s. In resemblance
to a commonpracticein organpipeconstruction,
the
piecewhoseedgeis struckby thejet is unsymmctrical,
consisting
of a 45'
wedgemountedsothat onesideis parallelto the centerline of thejet.
As sinusoidal waves encounter the bell of a brass wind instrument,
theyareeffectively
reflectedby theflaringpart of thebore.A givenfrequencyiseffectively
reflected
fromthatpartof thebellwherea significant
change
in boreradiusoccurswithina wavelength.
Hencethelongerwavelengthsreflectfrom pointscloserto the inlet endof the bell than do the
shorterwavelengths.A computercalculationof the equivalentlengths
corresponding
tothenormalfrequencies
showsthiseffect,andshowshow
thefrequency
shiftsdependontheshapeof thebore.Throughthiseffect,
the bell makesan importantcontributiontowardsmakingthe normal
frequencies
harmonic.
3:SS
I)2. Effectof theplayer'svocaltractonthetonequalityof reedwoodwind
instruments.
John Backus(Physics
Department,Universityof Southern
California,LosAngeles,CA 90089-1341)
It hasbeenarguedby woodwindinstrument
playersthattheconfigu-
rationof thepJayer's
vocaltracthasaneffectonthetonequalityof the
4**25
P4. The conical bore in musical acoustics.R. Dean Ayers, Lowell
J. Eliason, and Daniel Mahgerefteh (Department of PhysicsAstronomy,CaliforniaStateUniversity,Long Beach,CA 90840}
A review of textbooks and research literature reveals that there is
roomfor improvement
in thetreatmentof thissimplebut importantbore
shape.We useplotsof acoustic
pressure
standingwavesto showstudents
in a descriptive
coursethata complete
coneandan openpipeof thesame
lengthhavethe samenaturalfrequencies.
Theseplotsalsopredictthe
qualitativebehaviorfor the frequencies
of a frustumclosedat the small
endand suggest
a rigorousapproachto their calculation.Incorporating
theopenendcorrectionfor a straightpipeplusa correction
for viscosity
and thermalconductivityin the calculationresultsin agreementwith
experimental
valuesto within0.5%. In orderto understand
the inharmonieityof the frustum'sfrequencies
froma differentapproach,we have
calculated
thepressure
impulseresponse
forreflection
fromitsclosedend.
We findthat thisconsists
of a deltafunctionplusan inverted,exponentially decaying
wake.Experimental
observations
confirmboththatshapefor
theimpulseresponse
anditscontribution
totheevolution
of thewaveform
throughseveralreflections.
instrument
whenplayed.Thismatterisbeinginvestigated.
Thefollowing
arrangement
hasbeensetup: A "clarinet"is simulatedby mountinga
clarinetmouthpiece
andreedona pieceofbrasstubingofsuchlengthasto
soundthe noteD3 whenblowri,usinga foamneoprene
"lip" v,dth the
reed.A microphone
isattachedto themouthpiece
to monitoritsinternal
pressure.
Theopenendof thebrasstubeissealedontotheendofa 4-in.diamtube 10ft longfilledwith soundabsorbing
material.By attachinga
PS. Recorder multiphonics.R. Dean Ayers, Lowell J. Eliason, and
vacuum cleaner to the other end of the 4-in. tube, the "clarinet" can be
David Forel {Departmentof Physics-Astronomy,
California State
"blown,"asit were,in reverse,with the reedendout in the open.Various
systemscan now be attachedto the mouthpieceand their effecton the
University,Long Beach,CA 90840)
internalwaveformof themouthpiece
determined.
Resultssofar indicate
thattheeffectof theplayer'svocaltracton theinstrument's
tonequality
shouldbenegligible.
[Worksupported
by theNSF.]
A systematic
studyhasbeenundertakento identifyand analyzeall
possible
multiphonics
on a popularbrandof plasticrecorder(Aulos,alto
voice).The absence
of a bellat the endof the recordercombines
with the
open-holecutoff effectto guaranteestrong,nonharmonicbore resonances,and many of the forked fingeringsproducestablemultiphonics
whenblownsomewhathard.The morestableandourallyinteresting
multiphonicshave two strongspectralcomponents,
one supportedby the
4:10
P3. Edgetonespectra. A. W. Nolle {Departmentof Physics,The
Universityof Texasat Austin, Austin, TX 78712}
It iswell knownthat asthe velocityof an airjet impingingon anedgeis
increased,
variousregimesof periodicoscillation
arefoundin whichthe
frequency
increases
withjet velocity.It will beshownthatalsothereare
narrowrangesin whichthesignalconsists
of two or morecomponents,
notharmonicallyrelated,andvariousintermodulation
products.Ultimately,asthejet velocityincreases,
the signalbecomes
a noiseband.Extensivedataonthesephenomena
will beshown.In thepresentworkthejet-
S29
J. Acoust.Soc. Am. Suppl. 1, Vol. 74, Fall 1983
fundamentalbore resonanceand the other by the fourth or fifth resonance.Hcterodynedescendants
of thesecomponents
arcalsofound,but
rarely with comparablestrength.The lessinterestingmultiphonicshave
just onestrongcomponent,
oftenat thethird resonance,
with noticeably
weakercomponents
beatingagainstit. Somefingerings
will producemore
than one multiphonic,dependingon the breath pressureand/or attack
used.One factorthat may be significantfor stabilityis the fact that the
edgetonei•elf goesmultiphonicat theblowingpressures
used,without
any feedbackfrom the bore.
S29
TUESDAY
AFTERNOON,
8 NOVEMBER
1983 TOWN AND COUNTRY
ROOM, 2:30 TO 4:11 P.M.
SessionQ. SoeechCommunicationII: SpeechRecognitionand ProcessingSystems
Hisashi Wakita, Chairman
SpeechTechnology
Laboratory,Divisionof MEL TEK Corporation,
3888StateStreet,SantaBarbara,California93105
Chairman's
Introduction--2:•0
ContributedPapers
2:35
Q1. A reference speech recognition algorithm: An approach to
characterizing speech data bases. James L. Hieronymus and David
S. Pallett(NationalBureauof Standards,Washington,DC 20234)
One way to characterizethe relativerecognitiondifficultyof speech
data basesis to usea referencespeechrecognitionalgorithm.This approachwasfirstsuggested
byR. K. Mooreat theRoyalSignals
andRadar
Establishment.
A preliminaryalgorithmfor thispurposehasbeenpublished[G. E. CholletandC. Gagnoulet,Proc.1982IEEE ICASSP,20262029(1982)].Currently,an isolatedutterancereferencealgorithmunder
developmentin our laboratoryincludesautomaticendpointdetectionand
a trainingtechniquewhichaverages
severaltokensof eachutterance.Mel
scaleccpstralcoefficients
are usedin conjunctionwith dynamic time
alignmentin both trainingand recognition.Recognitionaccuracyand
performancestatisticsare presentedalongwith distancemeasures
for best
andsecond-best
match.Histogramsof the ratioof second-best
to first-best
scoresare plotted as a measureof data baseconfusability.If the ratio
histogramhasconsiderable
populationnearunity,thereissignificant
dangerofconfusion.
Otherdescriptors
characterizing
properties
ofthespeech
data baseare presented.
Preliminaryresultsof researchon confusability
measuresare reported.
2:47
Q2. One-pass,speaker-independent,
isolateddigit recognitionsystem.
George Vysotsky(AcousticsResearchDepartment,Bell Laboratories,
The systemdescribedin this paperis an outgrowthof onepresented
earlier[J.Aeoust.Sec.Am. Suppl.172, S30(1982)].It isa combinationof
deterministic
andprobabilistic
approaches
to isolatedwordrecognition.
The mostdistinguishing
featuresof thenewsystemarea real-time,onepassalgorithmandtheuseof telephone-quality
speechratherthanbroadbandmicrophonespeech.This new versionis targetedto a singlechip
implementation
with therequirement
that thesystemusesno morethan
256bytesof RAM and 8000bytesof ROM. The systemmakesdecisions
basedona single20 msframeoftenfeatures(withnolongtermstorageof
previousframes).Preliminarysegmentation
and matchingare combined
tosignificantly
reduceboththenumberoftenf usablewordsat eachrecognition point as well as the memoryrequirementfor references
obtained
duringthemultispeaker
training.The systemwasevaluatedon a tendigit
vocabulary(1000tokens,21 talkers)and showedan accuracyof 94.4%
with a 3.1% error rate, and a 2.5% rejectionrate. The effectsof usinga
one-pass
algorithmon total performance
arealsodiscussed.
2:59
Q3. Speaker-independentisolated word recognition for small-size
hardwareusingmultiplevaluedWalshMel-cepstrum.M. Watari (C&C
SystemsResearchLaboratories,NEC Corporation,4-1-1 Miyazaki,
Miyamae-Ku, Kawasaki-City, Kanagawa 213, Japan)
In thispaper,themultiple-valued
WalshMel-cepstrumisproposed
as
a speechparameterfor a small-sizespeechrecognizer.The new speech
analysisisbaseduponthemultiple-valued
Walshtransforminsteadof the
Fouriertransformusedin the standardMel-cepstrum.This makesit possibleto obtaingoodspeechparameters
by usinga smallmicrocomputer.
$30
The analysisprocesshasfour stages:the multiplevaluedWalsh transform, the logmagnitudecomputation,the Mel-sealeconversion,
andthe
inversemultiplevaluedWalsh transform.The multiple-valued
Walsh
transformoperatorusesmultiple-valued
coefficients
{p/2"+ q/2"j)corre-
sponding
to ej• usedin the Fouriertransform.
Thisoperation
requires
only additions,subtractions,
and shifts.Speaker-independent
isolated
digitrecognition
experiments
werecardedoutto evaluatethenewspeech
analysismethod.The recognition
error ratesfor WalshMel-cepstrum,
multiple-valuedWalsh Mel-cepstrum(16 valued),and Mel-cepstrum
were 6.4%, 3.2%, and 3.1%, respectively.
3:11
Q4. A syllable-basedconnected-digitrecognizerfor telephonespeech.
D. Kahn (AcousticsResearchDepartment, Bell Laboratories,Murray
Hill, NJ 07974)
Thispaperdescribes
a system
for theautomaticrecognition
of digits
spokenin connectedstrings.The input is standardtelephone-quality
audio,bandlimitedto 200-3200 Hz, spokenin a room with a background
noiselevelof 60 dBA. The firststepperformedis a segmentation
of the
incomingstringinto syllables.Important featuresof the syllabification
algorithm[D. Kahn,J. Acoust.Sec.Am. Suppl.I 73, S88(1983)]are(a)
the analysisis basedsolelyon the energycontour,with no spectralinformation, and (b) syllablesjudgedto be unstressed
are appendedto the
precedingstressed
syllable;thisisrelevantonly in thecaseof "seven,"and
resultsin the syllabicanalysisbeingequivalentto a segmentation
into
digits.The remaininganalysiscentersaroundan Itakura-typedynamicprogrammingmatchbetweeneachextractedsegmentanda setof stored
digit templates.The templatesarethemselves
derivedfrom segments
extractedfrom telephone-quality
connected-digit
strings.
3:23
Q$. Evaluation of a signal-averaging method for the measurement of
signal-to-noiseratios in speech.JamesHillenbrand (Departmentof
Communicative Disorders, Northwestern University, 2299 Sheridan
Road, Evanston,IL 60201)
Many abnormalvoicequalitiesare characterizedby unusuallylarge
amountsof noise.Although the presenceof noiseis easyto identify,precisequantificationof signal-to-noise(S/N) ratios is a difficult problem.
Yumoto, Gould and Baer [J. Acoust.Soc. Am. 71, 1544-1550(1982)]
developed
a techniquebasedonsignalaveraging.Usinga sustained
vowel
segmentedinto pitch periods,the signalcomponentof the S/N calculation is definedas the averageof the individualpitch periods.The noise
componentis estimatedby successive
subtractionsof the averagesignal
from individualpitch periodsof the originalvowel.In the presentstudy,
theaccuracyof thisteehniquewasevaluatedin a seriesof computersimulations.A synthesized
vowelwasmixedwith varyingamountsof synthesizednoise.S/N ratiosvariedovera 36-dBrange.Known S/N ratioswere
comparedwith S/N ratioscalculatedby theYumotoet al. technique.
The
correlationbetweencalculatedand actual S/N ratioswasnearly perfect
(r = 0.99) and the meanabsoluteerror wasonly 0.1 riB. Resultsare also
reportedfor testsinvolvingnaturallyproducedvowelsmixedwith synthesizednoise.[Work supportedby NIH.]
$30
3:35
An 8-bitZ80 microprocessor
wasusedfor logiccontrolwithstorage
of
programs,
textfilesanddigitizedspeech
on harddisk.Speech
sampling
ratesof 10and 12.5kHz wereutilizedfor digitalg-bit(256amplitude
levels)
speech
storage
andreconstruction.
Speech
phrase
lengths
varied
Q6. TheSIGPRO signalprocessing
software
development
system.
]an
I. Wolitzky(Be11
Telephone
Laboratories,
Inc.,MurrayHill, NS07974)
TheSIGPROsystem
isdesigned
toassist
inthedevelopment
ofdigital
signalprocessing
software.
Byfreeing
theuserfromsuch"bookkeeping"
from 2 to 20 s.
tasksasfilemanagement,
memoryallocation,controlflowdecisions,
vari-
ablenameanddefaultparameter
assignment,
anderror-andtype-checkingandcorrection,
theSIGPROsystem
allowsa signalprocessing
softwaresystem
to bespecified
solelyin termsof standard
"buildingblock"
modules
andtheconnections
between
them.A libraryof approximately
100suchmodules,
forperforming
suchoperations
ascorrelation,
filtering
and filter design,Fourier transforms,LPC synthesis,etc., is included,
alongwitha mechanism
foreasilyaddingnewmodules
to thesystem.
The
3:59
QS. A Imrtablephonetles
laboratory.Hector JaykinandRobert vander
Veen IPhoneticsLaboratory,LinguisticsDepartment,UCLA, Los
Angeles,CA 90024)
PIPS IPortableInstrumental
Phonetics
Station)is a portableboxdesigned
forgathering
andanalyzing
aerodynamic
andotherphonetic
data
in thefield.It contains
twopressure
transducers
mounted10cmapartin a
system
iswrittenentirelyin thec programming
language,
andgenerates
asitsoutputa c program
thatcanbecompiled
toproduce
correctimplementationof thespecified
system,
eitherasan executable
programor asa
C-callablesubroutine
(that may,in turn, be integratedinto the module
library).The programruns under virtual-memoryversionsof the Un-
singletubewith accompanying
amplifiers,a high-speed
chartrecorder,a
Rothenberg
airflowmeasurement
system,
anda miniaturestorage
oscilloscope.Circuits constructedat UCLA provide(1) preamplificationto
ix(TM)operating
system.
(Unixisa trademark
of BellTelephone
Labora-
strengthen
weaksignals,
(2)amplification
todrivethechartrecorder
gal-
tories,Inc.)
vanometers
(3)rmsenergyenvelopes
ofac signals,
and(4)FM modulation
anddemodulation
thatcanrecordandplaybackonechannelof relatively
high-frequency
dataor twochannels
of low-frequency
dataon a single
track of a portabletape recorder.An experimenter
normallyusesthe
othertrackofa stereotaperecorder
foranaudiorecording,
although
the
twotypesof FM encoders
canbeusedsimultaneously
to provideup to
threechannels
of FM recording
on a stereotaperecorder.Rechargeable
3:47
QT.Storageandretrievalof qualitydigitizedlongspeech
phrases
usinga
microcomputer.
Henry S. Todd (Departmentof ComputerScience,
BrighamYoungUniversity,Provo,UT 84602)
batteriescandrivemostof thecircuits.At present,the PIPS hasbeenused
in theU.S.,China,andtheSouthernSudan.[Worksupported
byNIH and
NSF.]
Twomicrocomputer
digitalspeech
storageandretrievalsystems
were
designed
andevaluatedin a computer-assisted
instructionenvironment.
TUESDAY
AFTERNOON,
8 NOVEMBER
1983
SUNRISE ROOM, 1:00 TO 4:35 P.M.
SessionR. Psychological
andPhysiological
AcousticsI: Acousticsof Echolocating
Animalsin Air
Patricia Brown, Chairman
Departmentof Biology,University
of California,LosAngeles,California90024
Invited Papers
1:05
R1. Neuralrepresentation
of bisonarinformation
in theauditorycortexof themustached
bat.NobuoSuga
(Departmentof Biology,Washington
University,St. Louis,MO 63130)
Forecholocation,
themustached
bat(Pteronotusparnellii
rubiginosus}
emitsorientation
sounds
containing
uptofourharmonics,
eachofwhichconsists
ofa longconstant-frequency
{CF)component
followedbya short
frequency-modulated
(FM)component.
Theauditory
system
ofthisspecies
extracts
different
typesofbisonar
information
fromcomplex
orientation
sound
andechopairsandrepresents
these
systematically
intheseparate
areas of the cerebral cortex. Nine clustersof combination-sensitiveneuronshave thus far been found in the
auditory
cortex.
Twoofthese
clusters
makinguptheCF/CF areaconsist
ofCFt/CF2andCFs/CF3facilitation
neurons
whicharetunedto particularDopplershifts,i.e.,targetvelocities
from8 to -- 2 m/s. Theremaining
sevenclusters
consist
of differenttypesof FM-FM neurons
whicharetunedto particularechodelays,i.e.,
targetdistances.
Threeof theseclusters,
makinguptheFM-FM area,consist
of FM t-FM2,FM t-FM3,and
FMs-FM, facilitation
neurons.
TheFM-FM areaprojects
bilaterally
to thedorsalfringe{DF)andventrolateralIVL) areasof thenonprimary
auditorycortex.The DF areaconsists
of threeclusters
of FM-FM facilita-
tionneurons.
TheVL areacontains
a smallcluster
offacilitation
neurons
thataretunedonlyto theFM t-FM2
combination.
TheFM-FM arearepresents
targetdistances
from7 to 310era,whiletheDF arearepresents
thesefrom 14to 140cm. [Worksupported
by I-R01-NS 17333.]
1:50
112.Flutteringtargetdetectionin horseshoe
bats.Hans-UlrichSchnitzler(LehrstuhlZoophysiologie,
Eberhard-Karls-Universituat,
D-7400Tuubingen,
FederalRepublic
ofGermany)
$31
J. Acoust.Sec.Am.Suppl.1, Vol.74, Fall 1983
Societyof America
B31
The rhythmicalmodulations
in insectechoes
causedby themovingwingsarebehaviorally
relevantinformationforhorseshoe
bats.Byevaluating
thisinformationthebatsareabletodetectinsectechoes
evenin strong
background
clutterand probablyto classifydifferentspecies.
Transmitterand receiverof the horseshoe
bats'
echolocation
areespecially
adaptedfor theprocessing
ofthisbehaviorallyrelevantinformation.An adaptation
of the transmitteris the Dopplershiftcompensation
whichkeepsthe carrierfrequencies
of the insectechoes
withinan "expectation
window"anduncouples
theinsectechoes
fromthebats'flightmovement.
Adaptations
of thereceiverarethespecialized
structureof thecochleawith thehighlyexpandedfrequencyrepresentation
in
the rangeof the insectechofrequencieswhich leadsto a strongoverrepresentation
of sharplytunedneurons
with specialresponsecharacteristicsthroughoutthe whole auditorypathway.Thereby the batsestablishan
"analysiswindow" in the receiverwhichcorresponds
to the "expectationwindow" causedby the transmitter
characteristic.
ContributedPapers
2:35
R3. Echolocation and foraging behavior of Hipposideros ruber
(Chiroptera).
G. P. Bell and M. B. Fenton(Departmentof Biology,
CarletonUniversity,Ottawa, Ontario, CanadaKIS 5B6)
Althougha greatdealof recentliteraturedealswith the neurological
and anatomicalaspectsof Doppler-shiftcompensation
(DSC)by some
bats,thereare a fewdata on the foragingbehaviorof thesespecies.
Wc
studiedthe foragingof Hipposideros
tuberin Zimbabwe,andconclude
from its behaviorand echolocationcallsthat it is capableof DSC. These
batsselectedmothswhich wereflutteringtheir wingswhethertbe prey
were flying or sitting on the substrate.If, during an attack, the moth
stopped
flutteringits wings,thebatterminated
itsapproach.
Pursuits
of
flyingandsittingtargetswereequallysuccessful,
with thebatscapturing
thetargets40% of thetime.Controlexperiments
indicated
thatthebats
did not usevisionor the soundof flutteringto locatetheir prey. DSC
appears
to bea meansof rejecting
clutter.[Worksupported
by NSERC,
Canada.]
2:50
R4. Echolocationbehaviorin a "flycatcher"bat. Hioposiderosdi•tdems.
Patricia E. Brown and Robert D. Berry (Department of Biology,
UCLA, LosAngeles,CA 90024andNaval WeaponsCenter,ChinaLake,
CA 93555)
Echolocation
behaviorandsonarpulsedesignin free-ranging
Diadem
horseshoe
bats {Hipposideros
diadema)were studiedduring the NSF-
sponsored
expedition
to Chillagoe,Australia.To followindividualbats
under field conditions,crystal-controlledradio transmitterswere at-
tachedto thebats.This producedvaluabledataon homerange,activity
patterns,and foragingbehavioras well as permittingthe recordingof
echolocation
signalsof knownbatsunderfieldconditions.
In itsforaging
area,a bat wouldhangfrom a limb, acoustically
scanning
for a passing
beetle.Upondetection,thebatbrieflytrackedits preybeforedartingout
to captureit andreturningto thesameroost.Hipposideros
diademaemploysa CF/FM signalwith a restingfrequencyof 55 kHz. Theyarecapable of Doppler-shiftcompensation,
alteringthe CF componentin response to movements of nearby objects. While Rhinolophus
ferrurnequinum
will lowerits restingfrequencyto compensate
for itsown
flightspeed,
it doesnotreacttonegative
Dopplershiftscaused
byreceding
objects.
Hipposideros
isstationary
forpreydetection,
andcompensates
for
both negativeand positiveDoppler-shiftedechoesgeneratedby approachingandrecedinginsects
byloweringandraisingtheCF component
of its sonar pulses.
3:05
RS. Mechanisms of sonar pulse production by oilbirds. Roderick
A. Suthersand Dwight Hector (Medical SciencesProgram, Indiana
University,Bloomington,IN 47405)
The echolocating
clicksofoilbirds(Steatornis
caripensis)
aregenerated
in two bronchialsemisyringes.
Eachclick hasa durationof 20 to 60 ms
andmayconsistof a continuous
broadbandsoundor bedividedbya short
silent interval into two shorter sounds.Electromyograms,together with
measurements
of subsyringeal
pressure,trachealpressure,and the rate of
trachealairflow,showthat clicksare preceded
by contractionof thester-
S32
J. Acoust.Soc. Am.Suppl.1, Vol. 74, Fall 1983
notrachealis
muscles
whichmovethesyrinxcaudad,causing
adduction
of
thesyringeal
membranes
duringexpiratoryairflowandinitiatingphonation.Subsequent
contractionof a previouslyunclescribed
syringealmuscle
terminatesthe click by rotating a syringealcartilageand abductingthe
externaltympaniformmembranes.This syringealmuscledoesnot con-
tract duringlongerdurationvocalizations.
It is thusspecialized
for the
productionof clicklikesounds.Simultaneousmeasurement
of the rate of
airflow througheachsemisyrinxindicatesthat during someclicksone
semisyrinxcloseswhile the other remainsopen.This is the first evidence
that airflow through each side of the syrinx can be independentlycontrolledduringpronation.[Work supportedby NSF.]
3:20
R6. Acuity of echolocationin the oilbird, Steatorniscaripensis.
David
B. Thompsonand Roderick A. Suthers(Medical SciencesProgram,
Indiana University,Bloomington,IN 47405}
The neotropicaloilbird echolocates
in totally dark caveswith a click
which has most of its energy between 0.5 and 3.0 kHz. The acuity of
echolocationwasmeasuredwith an array of stationarycylindrical obsta-
cles(diameter8.9, 3.2, or 0.5 cm} which wereshiftedbetweentrials to
preventthebirdsfrom learningtheirposition.Birdsweretestedin a dark
roomand observedwith an infraredviewer.Flightsthroughthe row of
obstacles
werescoredashits,light touches,or misses.The birds'ability to
negotiatethe 3.2-cmarray wassignificantlybetterthan with 0.5-cmobstacles,indicatingthat oilbirdscan acousticallydetect3.2-cm-diamobstacles.This is considerably
smallerthan the 20-cmthresholdof previous
studies[M. Konishiand E. 1. Knudsen,Science204, 425-427 (1979}].
Like echolocating
swiftlets[D. R. GriffinandD. Thompson,Behar.Ecol.
Sociobiol.10, 119-123 11982}]and bats, oilbirdscan detectobstacles
whosediameteris a fraction of the wavelengthof their echolocating
pulses.[Work supportedby NSF.]
3:35
R7. Increased low-frequency sensitivity in the ears of Kauai moths:
Responseto the acoustic signals of the Hawaiian Hoary Bat. James
H. Fu!lard [Department of Zoology, Erindale College, University of
Toronto, Mississauga,Ontario, Canada L5L 1C6] and Jacqueline
$. Bellwood {Department of Entomology, University of Florida,
Gainesville,FL 42611}
The auditorysensitivityof tympanatemothsfrom theislandof Kauai
wasstudiedto examinethe sensoryeffectsplacedon theseinsectsby the
site'ssole bat species,Lasiurus cinereussemotus(Hawaiian Hoary Bat}.
Audiogramswere neurnlogicallydeterminedand then subdividedinto
four bandwidthsto renderan estimationof sensitivity(audiogramarea}at
5-25, 30-50, 55-75, and 80-110 kHz. Comparedto mothsanalyzedfrom
sitesin Canada,Africa,andPapuaNew Guinea,Hawaiianmothsreveala
reducedhigh-frequency
{ > 50 kHz} sensitivitycoupledwith a significantly highersensitivityto frequenciesbelow 30 kHz. Tuning is very broad
with bestfrequenciesextendingfrom 9 to 33 kHz for variousspecies.Freeflying individualbats were recordedas they hauntedat the samesite
wheremothswerecaptured.L. cinereusemitstwo distinctsignalsas it
flies:a typicalFM, harmonicallycomplemented,
echolocation
call centeredat 27.9 kHz and anotherFM signalof 9.8 kHz, commonlyemitted
during agonisticencounterswith other bats while foraging.We suggest
$32
A newmethod
hasbeen
developed
forcontinuously
monitoring
the
thatthisbatgleans
echolocation
information
fromitslow-frequency
socialcallandtherebyprovides
anothersetofacoustic
frequencies
towhich
sympatricmothshavebecomesensitive.
[Worksupported
by National
Geographic
SocietyandNSERC.]
directionin which an echolocating
bat is pointingits head.Two light
emittingdiodesare mountedon thebat'sheadandtheir positions
read
sequentially,
undermicroprocessor
control,usinganx-y positionsensing
photodiode.
The microprocessor
calculates
the angleof the line between
the two light emittingdiodeswith respectto an initialdirection,and the
locationof the midpointof thisline.Readingscanbe madeovera 360ø
3:$0
range
withanaccuracy
of -I-1ø,ata rateof 100/s.Thisdevice
hasbeen
RS. Re•ponse•of cerebellsrunits in FM and CF-FM bats to acoustic
stimuli. Philip H.-S. Jen, Tsutomu Kamada, and Xindc Sun (Division
of BiologicalSciences,
The Universityof Missouri,Columbia,MO 65211)
usedto determinethebat'sheadaim in measurements
of horizontalangular resolution.Simultaneous
monitoringof thebat'ssonaremissions
providesdata on how informationis integratedovertime by the bat. Results
of thesestudieswill be discussed.
[Work supportedby NIr-t and NSF.]
With puretonepulses(35- and 0.5-msrise-decaytimes),a total of 499
unitsfromFM bats(Myotislucifugus
andEptesciusfuscus)
and401 units
fromtheCF-FM bats(Pteronotus
parnelliiparnelliiandPteronotus
par-
nelliirubiginosus)
wereisolated
froma largeareaofthe,cerebellar
vermis
and hemispheres.
Response
latenciesrangedbetween1.2 and 68 ms but
mostwerebelow10ms.Phasicunits,phasicburstera,andtonicunitswere
4:20
observed.Threshold curves of these units were either narrow, broad, or
irregular. In the CF-FM bats, units with BFs between60 and 63 kHz
RI0.
Ech01ocation
behavior
andneuronal
representations
ofsound
suggest
that animal sonarcanbe modeledin termsof a spectrogramcorrelation
process.Recentexperimentalresults,however,indicatethat batsmay be
sensitive
to thefinestructureof thesignal-echo
cross-correlation
function
(J. A. Simmons,Science204, 1336I. This sensitivitycannotbe explained
by crosscorrelationof spectrograms.
Spectrogram
deconvolution
or an
analysis-by-synthesis
procedurecanbe usedto reconstructa signalfrom
its spectrogram,
asidefrom an arbitraryphaseshift.Crosscorrelationof
two suchreconstructed
signals,with the samearbitraryphaseshift as-
sensitiveto a downwardsweepingFM stimulusthan to a puretonepulse.
An upwardsweepingFM stimuluswasaseffectiveasa 35-mspuretone
pulse.A studyof directionalsensitivityof 47 unitsshowedthat 33 units
were most sensitive to a sound delivered from the front. The other 14 units
weremostsensitive
to a sounddelivered
from20'-30• lateral.[Worksupportedby NSF 8007348andUSPH 1-K04-NS-00433
to P. Jen.]
signedto both, yieldsthe requiredsensitivityto cross-correlation
fine
structure.The waveformreconstruction
procedureis accurateonly if
spectrogram
filtersare not smoothwindowfunctionsas in man-made
processors,
but havelargetime-bandwidthproduct,e.g.,sharpriseand
slowdecayin thefrequency
domain,asin criticalbandmodelsof hearing.
Thisfilterpropertyinsuresthatthefilterambiguityfunctionhasthesame
or largersupportin therange-Doppler
planeasthesignalambiguityfunction, a necessary
conditionfor spectrogram
deconvolution.
4:05
R9. A newmethodfor measuring
hem]aim in echolocating
bats.W.
Mitch Masters and James A. Simmons (Institute of Ncuroscicncc,
University
ofOregon,
Eugene,
OR 97403)
TUESDAY
AFTERNOON,
8 NOVEMBER
Spectrogram processing in echolocation. Richard A. Altes
(ORINCON Corporation,3366 N. Torrey PinesCourt, La Jolla, CA
92037)
corresponding
to thepredominant
CF frequency
weresharplytunedand
showedoff responses
uponcessation
of the stimulus.In bothbats,variationof BFsof isolatedunitsfrom penetrations
withinthesamelobewas
smallerthanthosefromdifferentlobes.A studyof frequencytuningand
representation
suggests
that a bat'scerebellum
caneffectivelyprocess
the
predominant
components
of biologically
significant
signals.Responses
to
a 4 msupwardanddownwardsweeping
FM stimuliandpuretonepulses
werestudiedin 70 unitsof the Eptesicus
fuscus.Most unitsweremore
GOLDEN
1983
WEST ROOM, 1:00 TO 4:25 P.M.
SessionS. PsychologicalAcousticsII: Masking and Noise Discrimination
Dominic W. Massaro, Chairman
Departmentof Psychology,
Universityof California,Santa Cruz, California95064
Chairman's
Introduction--l:00
ContributedPapers
1:05
S1. Stimulusparametersgoverningconfusioneffectsin forward masking.
DonnaL. Neff• andDanielL. Weber(BoysTownNationalInstitute
for Communication Disorders in Children, 555 N. 30th Street, Omaha,
NE 68131}
Confusioneffectsin forward masking occur when the listener has
difficultydiscriminating
a suprathreshold
signalfrom the preceding
masker.Confusioneffectswereexaminedfor "pulsing"forwardmaskera
quencyor 20-30 Hz resolvedconfusion.For maskerscomposed
of 10-,
20-, or 40-mspulses,the signaldelay necessaryto resolveconfusionincreasedwith masker-pulse
durationbutwastypicallylessthan 10ms.For
thesethreepulsingmaskers,signaldurationslessthanonehalfor greater
thantwicethemasker-pulse
durationwerenecessary
to resolveconfusion.
[Work supported
by NSF, NIH, andtheUniversityof Nebraska.]• Presentaddress:Laboratoryof Psychophysics,
Harvard University,33 Kirkland Street,Cambridge,MA 02138.
1:25
composed
of repeated
burstsofa sinusoid
followedby a sinusoidal
signal.
Differencesbetweenthe level,frequency,and duration of the signaland
an individualmaskerpulse,as well as offset--onset
delay were varied to
determinethe changenecessary
to resolveconfusion.For maskerscomposedof 20-mspulses,changesin signallevelof 1-5 dB or in signalfre-
$33
S2. The occlusion-impedance
of the ear canal and its influenceon the
occlusioneffect and external physiologicalmasking.Christoph P•ssclt
(Lchrstuhlf'tira]lgcmeineElektrotechnikund Akustik, Ruhr-Universit•it
Bochum,Postfach102148,West Germany)
$3:3
Boneconduction
(BC}asthelimitingfactorfor thesoundprotection
rateofearplugsandearmuffscanbecalculatedby models.A modelof this
kindispartofa dummyheadsystem,recentlydeveloped
in our laboratory
forobjective
soundattenuation
measurement
ofsoundprotection
devices.
Basedontheseparation
of BCintoexternal-,
middle-,andinner-ear
components,the modelallowsdetermination
of BC accordingto the actual
typeof occlusion.
BC is mainlyaffectedby theacousticimpedance,
seen
ß outwards from the entrance to the ear canal. We have measured this "oc-
clusion-impedance"
for differentoccludingdevices.
Sampleresultswill be
presented.
The occlusioneffectis, then,determinedby theocclusionimpedanceand, also,by the relativevibrationsbetweenskulland earmuff,
thelatterdepending
on the mechanical
impedance
of earmuffand underlyingskinas well as on the vibrationmodesof the skull. Further,the
physiological
noisespectrum,
asgenerated
in theexternalear,is affected
by theocclusion
impedance
too,thusleadingto a characteristic
external
physiological
masking,
formerknownasthe"missing
6-dBeffect."[Work
partly supportedby Ministerffir Wissensehaft
und For•zhung,NRW.]
The combined effect of a backward and forward mask has often been
notedto be difficultto predicton the basisof the maskingobtainedfrom
eithermaskeralone.Thisreportdescribes
thenonlineareffectsof a backward maskon the shapeof forward maskingtuning curves.Five-point
psychophysical
tuningcurveswereobtainedin twoobservers,
using200ms forward maskersof 500, 750, 1000, 1250, and ! 500 Hz, and a 10-ms,
IO00-Hzsignalpresented
at 40 dB SPL. The forwardmaskhad a 2-ms
risc/fall timeand the signalwasfast-gated3 msafterthe forwardmask.
The backwardmaskwasa 100•msburstof white noise,presented3 ms
afterthesignaloffset,with a fastrise/fall.Tuningcurveswereobtainedin
quiet, and with backward maskersof 20, 50,and 80 dB SPL. Tuning
curvesbecamesharperas the levelof the backwardmaskwasincreased.
The tipof thetuningcurvedroppedbyat least20dB in thepresence
of the
80-dBbackwardmask,and by lessthan 10 dB at otherfrequencies.
The
resultsare discussed
in termsof the strategies
employedby listenersto
detecta signalin thepresence
of a forwardmask.[Worksupported
by
NSERC.I
2:45
1:45
S3. Frequencydiscriminationof tonespresentedeither insideor outside
of "notches" in band-reject noise. David S. Emroerich, Deborah
A. Fantini, and William S. Brown {Departmentof Psychology,State
Universityof New York at StonyBrook,StonyBrook,NY 11794)
At the 104thmeetingof thisSocietywe reporteddataconsistent
with
the notionthat, in frequencydiscrimination,informationis integrated
overa widefrequency
range.Thesedatawereobtainedfromsubjects
who
wereaskedto discriminatetoneswhichwerepresentedin the centersof
"notches"of variouswidthsin backgrounds
of band-rejectnoise.The
presentresearch
extendstheearlierfindingsby presenting
the tonesclose
totheedgesof bandsof rejectedfrequencies
in an attemptto determinethe
relativeimportance
of activityfromfrequency
regionshigherand lower
than the nominalfrequencies
of the tonesbeingdiscriminated.In addition, controlexperimentswereconductedin which the toneswerepresentedin thepassbands
of band-reject
noiseratherthaninsidethenotches.
Againtheresultssuggest
thatactivityremotefromthepeakof thedistributionof activitycreatedby the presentation
of a tone is importantin
frequency
discrimination.
A reasonable
interpretation
of thedataisthat
remoteeffectsextendmorewidelyon the high-frequency
sidethan on the
low-frequency
sideof the tonesto bediscriminated.
Thisinterpretationis
somewhatcloudedby the unexpectedfindingthat in someconditions
addingto the spectralcontentof the noisebackground
improvedrather
than impairedperformance.
2:05
S4. On the form of the maskingfunction for intensity discriminationof
S6. Detection cues in forward masking and their relationship to offfrequency listening. William S. Yacullo (Section of Communicative
Disorders,Rush-Presbyterian-St.
Luke'sMedical Center,Chicago,IL
60612} and Paul J. Abbas {Departmentof SpeechPathology and
Audiology,Universityof Iowa, Iowa City, IA 52242}
Previousstudies[D. Johnson-Davies
and R. D. Patterson,J. Acoust.
Soc.Am. 65, 765-770 {1979)and B. J. O'Loughlinand B.C. J. Moore,J.
Acoust.Soc.Am. 69, I 119-1125{1981)]suggest
thatoff-frequency
listeningis a majorfactorcontributing
to sharpness
of psychophysical
tuning
curves.The presentstudyis designedto evaluatethe contributionof offfrequency
listeningto thesharpness
of psychophysical
tuningcurvesasa
functionof temporalcharacteristics
of boththe variablemaskerand stationarymaskerusedto restrictlisteningto a narrowregionsurrounding.
the probeusingthe restricted-listening
tuningcurveparadigmfirst employedby Johnson-Davies
and Patterson(1979}.Conventionalforwardmaskedpsychophysicai
tuningcurvesinitiallyweregenerated
usingstimuli of varyingtemporalcharacteristics
{sinusolds,
AM and QFM tones,
andAM noise}
asthevariablemasker.Restricted-listening
tuningcurves
subsequently
wereobtainedutilizingfixed-levelstationarymaskers100
Hz wideof differingtemporalcharacteristics
IQFM tone,AM noise,and
syntheticnoisecomprised
of sinusoids
of equalamplitude,randomphase
relation,andspaced1Hz apart)whichweregatedwith thevariablemasker. Resultssuggest
that the off-frequency
listeningeffectobservedutilizing a tuningcurveparadigmis largelydependenton the temporalcharacteristicsof both variableand stationarymaskers.Assumingdiffering
detection
mechanisms
for maskers
of varyingtemporalcharacteristics,
it
appearsthat thedifferentdetectioncuesarenotequallydependent
on offfrequencylistening.
pure-tones.Neal F. Viemeisterand Sid P. Bacon (Departmentof
Psychology,
Universityof Minnesota,Minneapolis,MN 55455)
The publisheddataon intensitydiscrimination
of tonesdoesnot permit detailedcharacterizationof how the differencethreshold(AI) varies
with intensity(I } overa wideintensityrange.In thepresentstudy,maskingfunctions
•A] vsI }wereobtainedfor200-ms,I-kHz toneburstsovera
115-dBrangewith I variedin 2.5-or 5-ribsteps.For intensities
between5dB SL and 95-rib SPL, the maskingfunctionswere in reasonableagreement with recentreports:the Weber fraction,AI/I, wasapproximately
constantup to 40 dB SPL andthendecreased
monotonically
up to 95 dB
SPL. For I nearabsolutethreshold,somesubjectsshoweda slight"sensitization," in which AI was below absolute threshold. Above 100 dB SPL,
the Weber fraction increasedmonotonicallywith increasingintensity,
suggesting
mild "saturation."Thesedata shouldpermit more refined
modelingof intensitydiscriminationof tonesand of certain complex
waveforms.
[Supported
by NINCDS NS12125.]
3.-O5
S?. Masking ability of forward maskers of varying temporal
characteristics. William S. Yacu!io (Section of Communicative
Disorders,Rush-Presbyterian-St.Luke's Medical Center, Chicago,IL
60612} and Paul J. Abbas {Departmentof SpeechPathology and
Audiology,Universityof Iowa, Iowa City, IA 52242}
It hasbeensuggested
that the detectioncuesfor simultaneously
presentedsinusoidaland noisemaskersare different[D. Green, J. Acoust.
Soe.Am. 41, 1517-1525 [ 1967)and D. Weber and R. Patterson,J. Acoust.
Soe.Am. Suppl.I 68, S37 {1980}].The presentstudywasdesignedto
evaluatemaskingabilityof forwardmaskersof varyingtemporalcharacteristics.Conventional
forward-masked
tuningcurvesweregenerated
utilizinga sinusoidal
probeandfourtypesof stimulifor themasker:a sinusoid, quasi-frequency-modulated
IQFM) tones, AM tones, and AM
narrow-band noise 100 Hz wide. These maskers were selected as their
2:25
S5. Forward masking tuning curves obtained in the presence of a
backward
noise
masker.
Brian
R. Shelton
and
John
C. Booth
(Departmentsof Psychologyand CommunicativeDisorders,University
of WesternOntario,London,Ontario,CanadaN6A 5C2)
S34
envelopes
possess
a widerangeof amplitudefluctuation.The AM and
QFM tones(50 Hz wide)had identicalspectralstructures,yet distinctly
diffe•nt temporalcharacteristics.
Differencesin maskereffectiveness
wereevaluatedby comparingthe tuningcurvesgeneratedusingthe varioustypesofmaskers.Resultsindicatethatstimuliwith amplitudefluctu-
ationsthat are largeand randomin nature{AM noise}exhibitgreater
SocietyofAmerica
$34
forwardmaskingabilitythat stimuliwith eitherminimalor no envelope
variation{QFM toneand sinusoid)
or large,yet periodic,amplitudeperturbations{AM tone).This differencein maskingability is exhibitedon
thehigh-frequency
branchandwithinthetip regionof thetuningcurve.it
is suggested
that differences
in maskingability may reflectthe useof
differentsignaldetectioncues.
3:25
$8. Improved 1-bark bandwidthauditory filters. Andrew $ckcy and
Brian A. Hanson(SpeechTechnologyLaboratory,3888 State Street,
SantaBarbara,CA 93105)
A criticalbandfilteringfunctionattributedto Schroeder
[A. J. Fourcin,Rapportcur,
"Speech
processing
by manandmachine,"
in Theodore
H. Bullock(1977},Recognition
of Complex.•cousticSignals,Dahlem
Konferenzen,Berlin]is modifiedsoasto {i}ensurel-bark bandwidth,(ii}
haveasymptotic
slopeswhichreflectmaskingcharacteristics
of the humanear,and{iii}attainsitsmaximumat 0 bark.A bankof thenewfilters
spaced
at l-barkintervals
ispresented,
anditssmoothing
effectona vowel
spectrumis illustrated.
with thenoiseburstssampledrandomlyfor eachtrial. Performance
improvedas a functionof bandwidth,as wouldbe expectedbasedon the
increasein informationin thestimulus.However,performance
changed
nonmonotonically
asa functionof duration,eventhoughthereisa similar
increase in information
as duration increases. For each of the four band-
widths,performance
improvedup to a durationof 25.6 ms,but declined
with furtherincreases
in duration.Subsequent
experiments
wereconductedtoexplainthedecrease
in performance
for longerdurations.The results
will be discussed
in termsof the peripheraland centraldeterminants
of
performance
for thistask.[Worksupported
by NIH.]
4:05
S10. Changes in differential sensitivity for frequency modulation in
noise-exposed
chinchillas.William W. Clark, BarbaraA. Bohnc,and
GlenisR. Long{CentralInstitutefor theDeaf,St. Louis,MO 63110)
Frequencymodulationdiscriminationthresholdswereobtainedfor
two chinchillasbefore,during,and after exposureto an octavebandof
noisecenteredat 0.5 kHz, 95 dB SPL,for 54days.Duringexposure,
when
the animals had threshold shifts of 35-45 dB, differencelimens for fre-
quencymodulation(DLs)wereimpairedby ten-foldfor centerfrequen3:45
$9. Discrimination
of noise as a function of bandwidth and duration.
ThomasE. Hanna(Laboratoryof Psychophysics,
HarvardUniversity,
33 Kirkland Street,Cambridge,MA 02138}
A same-differenttaskwasusedto studythe discriminabilityof noise
burstsasa functionof duration(0.1,0.4, 1.6,6.4, 25.6, 102.4,or 409.6ms)
andbandwidth(50,200,800,or 3200Hz} of theburst.Eachtrial containedeitheridentical(same)or independent
(different)
samples
of noise,
S35
J. Acoust.
ciesbelow2.3 kHz; at 2.3 kHz andabovetheywerecompletelyunaffected.
Thirty daysafterexposure,whenthresholdshiftshad recoveredto about
25 dB, DLs recoveredabout halfway (fivefoldreduction)for the low-
frequencystimuli;high-frequency
DLs remainednormal.Histological
evaluation of the cochlea from these two animals showed losses of outer
haircellsin theapicalturnaveraging
30%,anda basal-turn
lesionin one
animalat a point60% of thedistancefrom theapex.The resultsof this
studyextendour previousobservation
that the baseand the apexof the
cochleaareaffected
differentlyby exposure
to noise.[Worksupported
by
NINCDS.]
106thMeeting:
Acoustical
Society
ofAmerica
S35
WEDNESDAY
MORNING,
9 NOVEMBER
1983
TOWN AND COUNTRY
ROOM, 9:00 A.M. TO 12:05 P.M.
SessionT. SpecialPlenary Session:Applicationsof Signal Processingto Acoustics
Wayne T. Reader, Chairman
David W. TaylorNa•l ShipR&D Center,Bethesda,Maryland 20084
Chairman's Introduction---9:00
Invited Papers
9:05
T1. Acousticsignalprocessing:
An in•erd•iplinary field.JamesF. BartramIRaytheonCompany,Submarine
SignalDivision,Portsmouth,
RI 0287!)
This paperpresentsan overviewof the field,from the perspective
of the recentAssociateEditor for
AcousticSignalProcessing,
Journalof theAcousticaiSociety
ofAmerica(JASA).The subjcctmatterisdefined,
botha• to whatit isnot•s wellasto whatit is,andthehistoryof theJournalcategoryisbrieflypresented.
The
authorstresses
thefactthatsignalprocessing
cutsacross
all nineoftheSociety's
technicalareasandmanyother
nonacoustical
scientific
disciplines.
To emphasize
theinterdisciplinary
characterof signalprocessing,
an examinationof thesubjectmattercontained
in thevarioussignalprocessing
paperspublished
in JASAandother
journalsin the pastthreeyearsis presented.
9'.35
T2. Digital signalprocessing
and auditoryphysiology.J. B. Allen (AcousticsResearchDepartment,Bell
Laboratories,
Digital signalprocessing
techniques
are veryimportantto the areaof auditoryneurophysiology
sincethe
auditorysignalsmustbe carefullycontrolledand becausethe data collectionparadigmsare frequentlyquite
complicated.
in thistalk I shalldescribea computersystemthat isjointly usedby Bell Labsand Columbia
Presbyterian
Hospital.Keyissues
includemethods
forreal-timedataacquisition
at 10-/.tscc
rateswhilerunning
a full operatingsystemon the host computer,D/A and A/D hardwarewhich producelessthan 0.01%
distortionfor singletone signals,real-timelinear systemidentificationmethods,and acousticimpedance
measurement methods.
10:05
T3. Applicatiousof dlgitalsignalprocessing
in computertousle.Garth Loy and Mark Dolson(Computer
Audio ResearchLaboratory,Centerfor Music Experimentand RelatedResearch,Q-037, Universityof
California,SanDiego,CA 92093)
Recentdevelopments
in signalprocessing
haveopenedmanynewlinesof inquiryin computermusic.Areas
wheresignalprocessing
techniques
areappropriate
includemeasurement
andobservation,
signalrepresentation,transformation,
analysis,andsynthesis
of musicalsound.Topicsaddressed
iu thispaperincluderepresentationalrequirements
for music,segmentation
and analysistechniques
suchas linearpredictivecoding,the
phasevocoder,datareduction,filtering,andsynthesis.
Exampleswill begivenwithinthecontextof a digital
signalprocessing
paradigmdeveloped
at C.A.R.L. thattightlycouples
thefacilitiesof UNIX operatingsystem
with researchtoolsfor computermusic.
10:35
T4. Coherenceanalysis applied to structural acousticproblems.J. S. Bendat (J. S. Bendat Company, 833
MoragaDrive, LosAngeles,CA 90049)
This presentation
discusses
signalprocessing
techniques
and engineering
requirements
for solvingstructural acousticmultipleinput/outputproblemsusingordinary,partial,and multiplecoherence
functions.
Practicalmattersare includedon formulationof models,selectionof input records,time delaybiaserrors,
measurement
interference
effects,
andstatistical
sampling
errors.Thesetopicsarecoveredin thebookbyJ. S.
BendatandA. Ci. Piersol[Engineering
Applications
of Correlation
andSpectralAnalysis(Wiley-Interscience,
New York, 1980)].Recenttwo-input/one-outputmodelsemployingthesemethodsare: (1) spaceshuttletile
problems
whereit isrequired
todetermine
theresponse
oftilesduetopressures
fromacoustic
noiseinputsover
the tiles,versusthat from correlatedpanelvibrationinputsunderthe tiles(performedby A. G. Piersol);(2)a
noisesourceidentificationproblemwhereit is requiredto determinethe relativecontributions
of a structurebornenoiseinputgenerated
in an engine,versusa correlatedcoolingfannoiseinputfroma fan mountedonthe
engine,to a farfieldsoundoutput(performed
by W. Ci.Halvorsen).
S36
J. Acoust.Soc.Am. Suppl.1, VoL74, Fall 1983
S31•
11:05
TS. Nearfieldacousticalholographic
techniques
usedto visualizeradiatedsoundfields.J. D. Maynard
(Departmentof Physics,The Pennsylvania
StateUniversity,UniversityPark, PA 16802)
The termsignalprocessing
iscustomarilyusedin referenceto theanalysisof dataobtainedasa functionof
time;similarlythetermimageprocessing
refersto theenhancement
of two-dimensional
spatialdata.For wave
fields,suchasopticalor acoustical
fields,thewaveequationcouples
thespaceandtimevariables
andpermitsan
extremelypowerfulsignalprocessing
technique
referredto hereasgeneralized
holography.
In thistechnique
temporaldataaremeasured
overa two-dimensional
spatialsurface,andthedataareprocessed
to reconstruct
and visualizethe entirethree-dimensional
wavefield.The powerof this techniquearisesfrom the enormous
expansionof informationwhich occurswhen goingfrom the two-dimensional
measurement
to the threedimensional
reconstruction.
Althoughthetheoryof generalized
holography
isexact,conventional
opticaland
acoustical
holographysuffersfromseriousintrinsiclimitations,suchasthe spatialresolutionbeinglimitedto
theradiatedwavelength.
At The Pennsylvania
StateUniversitywearedeveloping
a newacoustic
generalized
holographic
technique,calledNearfieldHolography,whichovercomes
the limitationsof conventional
holography.In thistechnique
a briefmeasurement
with a microphone
arraycanbe usedto visualizethe surface
motionof a complexvibratingstructure,to reconstructthe entirethree-dimensional
soundpressurefield,
particlevelocityfield,andvectorintensityfield,andto maptheflowof acoustic
energyfromthesources
to the
farfield.With thissystemonemaypinpoint(withincentimeters)
acousticenergyproducingsources
on vibratorswith smallstructuralfeatures(suchasmusicalinstruments)evenwhenthe radiatedwavelengthis several
meters.In this talk our most recentNearfieldHolographyequipmentand processing
algorithmswill be
described,
and computergraphicreconstructions
of vibratingsurfaces(movingin real-time)and radiated
soundfieldswill be shown.[Nearfieldholographyresearchis supportedby the Officeof Naval Research
(Physics
Program)andtheNationalAeronautics
andSpaceAdministration.]
11:35
T6. Signalprocessing
techniquesusedin underwateracoustics.V.C. Anderson(Marine PhysicalLaboratory
oftheScripps
Institution
ofOceanography,
University
ofCalifornia,
SanDiego,CA92152)
Thetwounderlying
goalsof mostsignalprocessing
applications
in underwater
acoustics
aredetection
and
estimation
ofa signalin thepresence
ofuncertainties.
Theuseofstandard
techniques
suchasmatched
filtering,
prewhitening,
andadaptiveparameter
estimation
bringsintoplaynewdimensions
of technology
in thefaceof
thewidevariabilityanduncertaintyin parameters
of thesignalandthebackground.
This paperwill presentan
overviewof signalprocessing
applications
in the field.
WEDNESDAY AFTERNOON, 9 NOVEMBER 1983
CABINET
ROOM, 1:30 P.M.
Meeting of StandardsCommitteeS2: Mechanical Shock and Vibration
to be heldjointly with the
Technical
Advisory
Group(TAG)MeetingforISO/TC 108Mechanical
Vibration
andShock
P. H. Maedel, Jr. Chairman S2
Westinghouse
ElectricCorporation,
LesterBranch,P.O. Box 9175,Lester,Pennsylvania
19113
G. Booth, Chairman TechnicalAdvisoryGroup for ISO/TC 108
220 Clark Avenue,Branford, Connecticut06405
StandardsCommitteeS2 on MechanicalShockandVibration.Workinggroupchairswill presentreportsof
theirrecentprogress
onwritingandprocessing
variousshockandvibrationstandards.
Therewill bea reporton
the interfacesof S2 activitieswith thoseof ISO/TC 108 (theTechnicalAdvisoryGroup for ISO/TC 108
consists
of members
ofS2,S3,andotherpersons
notnecessarily
members
of thosecommittees).
Reportonthe
ISO/TC 108meeting,held from 19-30 September1983.
S37
d. Acoust. Soc. Am. Suppl. 1, Vol. 74, Fall 1983
108th Meeting: AcousticalSociety of America
S37
SUNRISE ROOM, 1:00 TO 3:00 P.M.
SessionU. Psychologicaland PhysiologicalAcousticsII (Poster Session)
Patrick W. B. Moore, Chairman
Code512, Naval OceanSystemsCenter,Kailua, Hawaii 96734
Chairman's
Introduction---l.'00
All posters
will bedisplayed
from1:00-3:00P.M. To allowall contributors
anopportunityto seeotherposters,
contributors
of odd-numbered
paperawill be at their postersfrom 1:00-2:00P.M. andcontributors
of evennumberedpaperswill be at their postersfrom 2:00-3:00P.M.
UI. The effect of contralateralstimulationon spontaneous
acoustic
emissions.
JohnH. Grose(AuditoryResearchLaboratory(Audiology),
NorthwesternUniversity,2299 SheridanRoad,Evanston,IL 60201}
45% for Silentswearers,and 26% for E-A-R wearers.Previousresearch
indicates
that the%BW statisticfor a protectedor non-noise
population
with pastaudiometrictestexperiencewill be lessthan 30%.
Subjects
exhibiting
spontaneous
acoustic
emissions
(SAEs)werepresented with wideband noise in the ear contralateral to that in which their
SAE wasbeingrecorded.The SAE magnitudes
weremonitoredwhilethe
noisewasincremented
in 5-dBsteps.SomeSAE components
weremarkedlyreducedwith increasing
contralateral
stimulationwhileothers
pearedto be enhanced,despitefrequencyseparations
betweencomponentsof lessthan200Hz. Theeffects
werein theorderof 3-10 dB,though
occasionally
greater,andthethresholdfortheSAE changewasgenerally
belowthe acousticreflexthresholdfor that subject.The rms levelof the
car canal noisein the ipsilateralear was also monitoredto ensurethat
U4. A new approachto auditory depth perception.R. W. Gatehouse
(Department9f Psychology,Universityof Guelph, Guelph, Ontario,
CanadaNIG 2Wi}
Acousticdepthjudgmentstudieshavegenerallyusedstaticposition
sources,
andaskedsubjects
to estimatethedistanceof onesourceonly,or
onesourcerelativeto a second.Here, blindfoldedsubjectswereaskedto
"align" a moveableroedialsagittalplanecomparisonsourcewith a static
l.O-kHzstandard,3 m awayfromthem.The comparison
source's
starting
none of the observationswere a result of transcranial transmission of the
stimulus. Pure tones were substituted for the noise in order to determine
positioncouldbe at 0 (position
of standard),+ 100or +__
200cm away
whethertheeffectwastuned;howeverno sharptuningwasobserved.
alternatedin 3-sburststill theSindicated"alignment"wasachieved.Half
thesubjects
receivedthe 1.0and0.7 kHz pairingfirstthenthe 1.0and 1.3
kHz pairingandviceversa.Threetrialsweregivenfor eachpairingfrom
each starting position.The mean error scores(i.e., mean differences
between"true" andestimatedsourceposition}wereanalyzed.The results
U2. Theperception
of individual"harmonics"
of a ripple-noise
spectrum.
E.M. Burns,M. Cotban{Purdue
University,
WestLafayette,IN 47907),
L.L. Feth,andV. Kirby(University
of Kansas,Lawrence,
KS 66045}
A series
ofexpetiments
wereperformed
inordertocomparetheability
of listeners
toobtainpitchinformation
froma single"harmonic"
(ripple)
of a ripple-noise
spectrumwith theirabilityto obtainsimilarinformation
froman equivalently
filteredwhitenoisespectrum.
Theexperiments
in-
and was either a 0.7- or 1.3-kHz
narrow-banded
tone. The two sources
indicate that observers overestimate the distance of the standard when
initial positionof the comparisonis closeto them,and underestimate
it
whenthe comparisonstartsfrom beyondthe "0." Comparisonfrequenciesperformances
did not differ.The resultspartiallyconfirmMershon
and Bowers[Percept.8, 311-322 (1975)]usinga morestandarddepth
perceptionparadigm.
eluded:(I } a studyto determinetheabilityof listenersto "hearout" indi-
vidualripplesfroma ripplenoiseusingPlomp'sparadigm[Piomp,J.
Acoust.Soc.Am. 36, 1628-1636(1964}],{2}the determinationof "fre-
quency"JNDs for individualripplesandfor narrow-band
noises,
{3)the
determination
of "fundamental
frequency"
JNDs (byrandomizing
rippieswithintrials),and{4)musical-interval-identification
studies.The resultsarediscussed
in relationtotemporally
based
visavisspectrally
based
models
of ripplenoisepitchperception.
[Supported
by NINCDS.]
US. Listeners' identification of human-imitated animal sounds. Norman
1. Lass,SandraK. Eastham,TammieL. Wright,AudreyR. Hinzman,
KarenJ. Mills,andAmy L. Hefterin(Department
of Speech
Pathology
andAudiology,805Allen Hall, WestVirginiaUniversity,P. O. Box6122,
Morgantown,WV 26506-6122)
dB. Larry H. Royster (Departmentof Mechanicaland Aerospace
Engineering,North CarolinaStateUniversity,Raleigh,NC 27650}and
The purposeof this investigationwas to determineif listenerscan
accurately
identifyhuman-imitated
animalsounds.
A totalof20 speakers,
tenfemalesandtenmales,recorded
theirimitations
of cows,cats,dogs,
pigs,andsheep.
A mastertapscontaining
therandomly
arranged
recordingswaspreparedandpresented
to 30judgeswhowereaskedto identify
theimitatedanimalsandto ratetheconfidence
of theirjudgments
on a
seven-point
ratingscale.Resultsindicatethat:{1}listeners'accuracywas
Julia Doswell Royster IEnvironmentalNoise Consultants,Inc., Cary,
relatively
highforall fivehuman-imitated
animals;
{2}imitations
ofdogs
NC27511}
weremostaccuratelyidentified,followedby sheep,cows,cats,and pigs;
U3. The evaluation of the effectivenessof three hearing protection
devicesat an industrial facility with a daily TWA of approximately 107
Three hearing protectiondevices(Norton Sigma Comfit earplug, SafecoSilentaearmuff,and E-A-R foam earplug}were comparedfor their
effectiveness
in preventingboth daily temporarythresholdshifts(TTS}
andshiftsbetweensequentialannualaudiograms(%BW statistic)[L. H.
Roysterand J. D. Royster,in PersonalHearing Protectionin Industry
IRaven,New York, 1982)].The hearingprotectiondevicesvariedsignificantlyin preventingTTS. ComfitwearersexhibitedthelargestTTS shifts,
which differed from zero at 500-4000 Hz. SignificantTTS was found for
Silents wearers at 500 Hz, and for E-A-R wearers at 1000-2000 Hz. E-A-
R wearersshowednonsignificantimprovementsat 3000-6000 Hz, and
Silentswearersshowedsignificantimprovementat 6000 Hz. Employees'
previousthreeannualaudiogramswereevaluatedto compare%BW valuesfor the wearer groups.Thesevalueswere 53% for Comfit wearers,
$38
J. Acoust.Soc.Am. Suppl.1, Vol. 74, Fall 1983
{3} for all five animals investigated,listeners'accuracywas greaterfor
female-imitated
thanmale-imitated
sounds;
{4)listeners'
confidence
ratingswerehighest
forsheepfollowedbycows,dogs,cats,andpigs;and{5}
listeners'confidence
ratingswerehigherfor female-imitated
than maleimitatedanimalsounds
(withtbeexception
of dogsounds}.
Implications
of thesefindingsand suggestions
for futureresearchare discussed.
U6. Effects of signal starting phaseon diotic and diehotic detection in
reproducible
noisemasker•.R. H. Gilkey and B. Kollmeier'• {Central
Institutefor the Deaf, 818 S. Euclid, St. Louis,MO 63110)
Dolan,Hirsh,andYost[J.Acoust.Soc.Am. 70, 886-887{1981)]and
Gilkey, Hanna, and Robinson[J. Acoust.Soc. Am. Suppl. I 68, S59
106thMeeting:AcousticalSocietyof Amedca
S38
noisemaskerunder diotic (NoSo)presentation.However, detectability
variesonlyslightly,if at all, asa functionof phaseunderdieboric(NoS•r)
conditions.
In thepresentexperimentan adaptivetwo-alternative
forcedchoiceprocedure
is usedto obtaindetectionthresholds
for a 500-Hztonal
decayofactivityiscomparedto a similardioticconfiguration
in whichthe
levelof thenoiseisdecreased
by 15dB.The resultsindicatethatthedecay
of activityin the binauralsystemis more"sluggish"than the decayof
activity in the monauralsystem.[Work supportedby NINCDS Grant
NS. 03856, and the Fulbright Commission,FederalRepublicof Germany.]•1AlsoDrittesPhysikalisches
Institut,Universityof Goettingen,
signalin the presence
of eachof six individualsamples
of reproducible
FederalRepublicof Germany.
(1980)]haveshownthatthedetectability
of a tonalsignalvariesgreatlyas
a functionof thephaserelationship
betweenthesignalanda reproducible
noise.Six binaural conditions(NoSo, NuSo, NrrSm, NoSm, NnSo, and
NoSrr)wereinvestigated
in combinationwith sixsignalstartingphases(0ø,
60ø, 120ø, 180ø, 240ø, and 300'). The results indicate that although the
magnitudeof the phaseeffectdecreases
with larger maskingleveldiffer-
ences,it issimilarin formfor all conditions
with thesamemasker.[Work
supported
by NINCDS Grant NS 03856,andtheFulbrightCommission,
FederalRepublic
ofGermany.]'• Alsoat DrittesPhysikalisches
Institut,
Universityof Goettingen,FederalRepublicof Germany.
U10. Predicting masking by combinations of simultaneous maskers.
Robert A. Lutfi (Auditory Research Laboratory, Northwestern
University,Evanston,IL 60201)
In a previous
paper[Lutfi,J. Acoust.Soc.Am. 73, 262-267(1983)],I
proposed
the followingrule for predictingmaskingby combinations
of
simultaneous
maskcrs;
X,. = [X• + X• + ...X•,] l/p, wbercX, X2.....
U7. Perceived rate of randomly modulated sounds.Hisashi Kado
(CentralInstitutefor theDeaf,St. Louis,MO 63110andElectrotechnical
Laboratory,Sakura,lbaraki 305, Japan)
The common measuresusedin evaluatingthe magnitudeof a noise
(L•, Lcq,andetc.)correspond
to first-andsecond-order
statistics
of the
distributionof soundlevels.There are, however,perceiveddifferences
between sounds that have the same values of these statistics. It is therefore
necessary
to considerthe spectralpropertiesof the waveformenvelope
which correspondto higher-orderstatistics.In the presentexperiments
thesubjectcompares
a teststimulusanda referencestimulusand selects
theonewhichappearsto befluctuatingmorerapidly.The reference
stimulusis a noisewhosewaveformenvelopeis a noisewith a low-passcutoff
whichvariesfrom0.125to 8 Hz. The pointof subjective
equalityisdeterminedby adjustingthemodulationfrequency
of the teststimulus,a sinusoldallymodulatednoise,in an adaptiveprocedure.The resultsindicate
that whenthemedianfrequencyof thespectrumof theenvelopeisabove1
Hz, it is a reasonablygoodpredictorof the subjectiverate, when the
medianis below 1 Hz the'modeis a betterpredictor.[Work supportedby
NINCDS.]
US. Effect of presentationlevel on the SSW test with hearing-impaired
adults. Patricia A. Flynn, Jeffrey L. Danbauer, Dennis J. Arnst,
Monica C. Goller, and Sanford E. Gerber (Speech Department,
Universityof California,SantaBarbara,CA 93106)
The effectsof varyingpresentation
levelon the StaggeredSportdale
Word (SSW)testscoresof sensorineural
hearing-impairedsubjectswere
investigated.Subjectswere 15 adults having cochlearhearing losses
between30 and 50 dB (re: PTA). Performance-intensity
(PI) functions
weregenerated
usingsubjects
SSWtestscores.
Eachsubjectreceivedall
40-SSWtest items,but the PI functionswere generatedby presenting
itemsnumbered1-10 at 20 dB SL (re:threefrequencyPTA); 11-20 at 30
dB SL; 21-30 at 40 dB SL; and 31-40 at 50 dB SL. Theseresultsfor the
hearing-impaired
werecompared
tofunctions
reportedearlierfor normal
subjects[P. C. Doyle, thesis,Universityof California,SantaBarbara
(19811].The PI functionswereanalyzedfor "competing"versus"noncompeting"conditions,
anddifferences
betweensubjects'
raw SSWscores
andworddiscriminationscoresasa functionof presentation
level.Practical andtheoreticalimplications
for theclinicalpresentation
of theSSW
test at the variousintensitylevelsto hearing-impaired
adultsarc discussed.
U9. A comparison
of thetemporalresponse
of the auditorysystemunder
dichoticanddioticconditions.
B. Kollmeier• andR.H. Gilkey(Central
Institutefor the Deaf, 818 S. Euclid, St. Louis,MO 63110)
Mostof theclassical
experiments
on binauralmaskinghaveheldthe
interauralphaseof the noise,as well as that of the signal,constant
throughout
theobservation
interval.In thisexperiment
thedetectability
ofa 500-Hztonalsignalisinvestigated
in thepresence
ofa 2000-Hzlowpassnoise,whichisswitched
fromNrr toNo at themidpointof theobservation interval. For a 20-ms Srf signalthere is approximatelya 15 dB
increase
in detectability
whenit ispresented
latein theinterval,relativeto
earlyin theinterval.The timecourseof thechangein detectability
canbe
usedas an indicationthe decayof activityin the binauralsystem.This
S39
d.Acoust.Soc.Am.Suppl.1, Vol.74, Fall1983
X, arc the individualmaskingeffectsof the maskers,
X,. is the combined
effect,and 0.20<œ< 0.33. In thispaper,the rule is usedto predictthe
resultsof severalexperiments
in whichtheindividualeffects
of maskers
in
the combinationare known [Bilger,J. Acoust.Soc.Am. 31, 1107-1109
(1959);Green, J. Acoust.Soc. Am. 41, 1517-1525 (1967);Canahl, J.
Acoust. Soc.Am. S0, 471-474 (1971);Pattersonand Nimmo-Smith, J.
Acoust.Soc.Am. 67, 229-245 (1980)].With the possibleexceptionof the
study by Bilgcr, a singlevalue ofp (= 0.3) yields predictionsin good
agreement
withthedata.Therulealsopredicts
somegeneralcharacteristics of the results of studies in which the individual effects of the maskers
are not knownbut can be estimated[Johnson-Davies
and Patterson,J.
Acoust.Soc.Am. 65, 765-770 (1979);O'Loughlinand Moore, J. Acoust.
Soc.Am. 69, 1119-1125(1981)].[Worksupported
by NSF andNIH.]
Ull. The effect of signalSPL on interaural time discrimination.Marion
F. Cohen, Anne E. McClave, and Patricia Gregorio Pollanck
(Departmentof Communication
Sciences,
The Universityof Connecticut,
Storrs,CT 06268)
Interauraltimejndsfor a partiallymaskedsinusoidalsignalweremeasuredas a functionof signalSPL, with the signalpresentedat a constant
signal-to-noise
ratio of approximately10 dB aboveits maskeddetection
threshold.
The 250-, 500-, or 1000-Hzsignalrangedin levelfrom 13to 58
dB SPL. The maskerwasa continuouswhitenoise.A blockup-downtwointervalforced-choiceprocedurewasused.Resultsshowthat interaural
time discriminationimproveswith increasingsignalSPL despitethe constantS/N ratio, indicatingthat signalSPL is a primarydeterminantof
precisionof interauraltime discrimination.When thesedata are comparedwith jnds measuredat the samesignalSPLsbut with no masker,
they are nearly identical at 500 Hz. At 250 and 1000 Hz they are nearly
identical at the higher signallevelsfor two of the three subjects.At the
lower signallevels,the jnds measuredin the presenceof the maskerare
somewhatlarger,but demonstratea similardecreasewith increasingsignal level.The differences
notedacrossfrequencymaybedueto theeffect
of the internal noise. [Work supportedby NIH Grant No. 5 R01
NS16802.]
U12. Response
durationsand falsealarm reactiontimes.JohnL. Orr
(Department
of Physiology,
University
of TexasHealthScience
Center,
Dallas, TX 75235)
ThreeLong-Evans
ratswereinitiallytrainedtodepress
andholddown
aresponse
leverinthepresence
wideband
whitenoise
pulsing
at6.7Hz for
a variable
periodbetween
4 and6 s to obtaina 45-mgfoodpellet.This
reinforcement
schedule
is thesameasoperatinga one-lever
press-release
psychophysical
procedure
witha variableforeperiod
of 2-4 s anda 2-s
trialdurationwithonlyno-signal
trials.Theinitialtrainingof thenonsignal trialcorrectresponse
of holdingtheleverdownthroughout
thetrial
permitsthe measurement
of the temporal
characteristics
of thebackground
levelofrelease
responses
intheabsence
ofa history
ofcontingent
reinforcement
for releasing
thelever.After trainingto asymtotic
perfor-.
manccon the nonsignaltrials alone,50% signaltrials (wherethe noise.
pulsation
ratechanged
to 12.5Hz)wereincluded.
Discrimination
training,,
wasfollowedby changes
in response
durationhistograms
andfalsealarm
reactiontimehistograms.
In twoof thethreerats,therewasanincrease
m
theprobability
of incorrectleverreleases
3-6 s aftertheleverwasde-.
SocietyofAmerica
S39
pressed.
[Worksupported
byNIEHS grantROLES02750
to R. M. Lebovitz.]
UI3. Auditory evokedpotentialasymmetriesin right- and left-handed
listeners.L. J. Hood, D. A. Martin, and C. L Berlin (Departmentof
Otorhinolaryngology
and Biocommonication,
KresgeHearingResearch
Laboratory,LouisianaState UniversityMedical Center, 1100 Florida
Avenue,New Orleans,LA 70119)
Waveformsand powerspectraof acousticsignalsusedto elicit the
auditorybrainstemresponse
wereanalyzedwith respectto electricaland
acousticaldifferences.
Signalswereof alternatingpolarityandincludeda
dcpulse,toneburstsof0.5and4.0 kHz, a 4.0-kHztonepip,anda 2.0-kHz
logon.The earphone
faithfullytransduced
thetemporaldimension
of the
5.0-msburstsand pipswhile the logon{450ps} and the click (100
durationswereon the orderof ten timesgreaterthan the electricalinput.
Earphonedistortionincludedthe lossof well-defined
energypeaksanda
spreadofenergytohigherfrequencies.
Signalpolaritywasnotmaintained
WhileDecker[ASHA 23, 803(1981}]reportednorelationship
of handednessto auditorytract preferencein the auditorybrainstemresponse,
we know of no data for the middleand late potentials.This studyexamines
the relationshipof binanralinteractionand lateralasymmetryin the middle and late potentialsto handedness.
Binaural,right monanral,and left
monanral100-pspulseswerepresentedto six right-handedand six left-
throughthe earphone.
handednormal-hearing
subjects
in fourconditions
of earphone
andelectronicsrotations.Middle andlatepotentialdatawereanalyzedstatistically usinga time seriesANOVA. Lateral asymmetriesand binaural
interactionwere derivedby subtractingleft from right responses
and
summedmonauralfrom binauralresponses,
respectively.
Data indicate
of Medicine,Indianapolis,IN 46223)
individual differencesin the amount and direction of asymmetry. The
characteristicsof binaural interaction and lateral asymmetry, the rela-
tionshiptohandedness,
andtheinfluence
ofstimulus
andrecording
asymmetrieswill bedescribed
for themiddlelatencyandlatepotentials.
[Supportedby NINCDS •NS11647, the LouisianaLionsEye Foundation
and the Eye and Ear Foundation.]
UI4. Crib-o-gram(COG) and ABR effect of variableson test results.
Laura B. Wright and Leonard P. Rybak (Departmentof Surgery,
SouthernIllinoisUniversitySchoolof Medicine,Springfield,IL 62702}
Thisstudycompared
sevencategories
of apparently
relevantinformation concerningthe Crib-o-gram(COG) as screeningtestand evaluated
the followingvariables:birth weight,gestationalage at birth, Apgar
scoresat I and 5 min, apnea,ototoxicdrugs,numberof dayson assisted
ventilation,and gentamicinbloodlevels.Low birth weight,early gestational age, and apneawere significantlycorrelatedwith COG results.
Thirteen
of the 55 newborns tested failed the COG at least twice before
havingtheABR testgiven.TwelveinfantshadnormalABR andonehad
samedegreeofhearingloss.Consequently
therateoffaiscpositivefinding
is veryhigh.In spiteof thehighriskfactorsof the newborns,gentamicin,
Apgarscores,
or numberof dayson a ventilatorwerenotimplicatedasa
causeof hearingloss.[Work supported
by Deafness
ResearchFoundation.]
UIS. Effects of cochlearhigh-frequencyhearing loss on BSER. Neil
T. Shepard{OtologicalResearchLaboratories,Henry Ford Hospital,
2799 W. Grand Boulevard,Detroit, MI 48202) and John C. Webster
(22250ProvidenceDrive, Suite701, Southfield,Ml 48075)
Theextensive
useof Brainstem
EvokedResponse
Testing(.BSER}for
the detectionof masslesionsinvolving the VIIIth nerve necessitates
knowledge
of theeffects
of hearinglossof cochlearoriginonBSER.Thirty-one ears displayingvarying degreesof sensorineural,high-frequency
{beginning
above500 Hz) lossof sensitivityof eochlearoriginweretested
with BSER. A 100-/isrectangularpulsewasusedto exciteTDH-39 earphonesat a rateof 11.3pulses/s.Utilizingmonauralstimulationat two to
fiveintensities
perear,responses
wereobtainedfroma vertexto ipsilateral
mastoldelectrodemontage.Linearregression
analysislinesfor wavesI,
Ill, and V lateneiesversusaveragedegreeof lossfor variouscombinations
ofaudiometrietestfrequencies
are shown.The dependence
of BSER wave
latencieson individualandaudiometrictestfrequencies
and variouscombinations at and above 1 kHz are shown via the use of correlation coeffi-
cients.The resultscomparewellwith earlierresults[A. C. CoatsandJ. L.
Martin, Arch. Otolaryngol.103, 605-622 {1977}]and imply the dependenceof resultson click stimulusparametersand earphonespectralcharacteristics.
Alsosuggestions
for normatirelimitsof waveV latencyshift
for varyingdegrees
of high-frequency
cochlearhearinglossare given.
UI6. Auditory brainstem responsesignal transduction through a
Telephonics
TD•-39 earphone.
C. CharlesOlsen(Department
ofSpeech
andHearingSciences,
TexasTech.University,Lubbock,TX 79410}
•40
UI7. The electrically inducedauditory brainstemresponsein the guinea
pig. D. D. Brownand R.T. Miyamoto (Departmentof OtolaryngologyHead and Neck Surgery,Riley HospitalA56, Indiana UniversitySchool
The cochlearimplantisa clinicallyusefulprosthesis
for selected
deaf
patientswhocannotbenefitfroma hearingaid.However,thepoorspeech
discriminationand limited dynamicrangegenerallyachievedwith the
implantindicatethat therearea numberof basicandappliedquestions
to
beanswered.Usingacoustically
andelectricallyelicitedAuditory BrainstemResponse
(ABR) techniques,
we haveestablished
an animalmodel
(guineapig}to helpusanswersomeof thesequestions.
We arepresently
studyingtheeffectof electrodelocationon theelectricalABR. The single
activecochlearelectrode
is locatedin eitherthebasalor apicalturn.The
returnelectrodelocationsarethetemporalismuscle,theeustachian
tube,
or the bulls. By choosingthe properpolarityof the biphasicstimulating
pulse,theelectricalartifactcanbeminimizedandvirtuallyall of theABR
canbeobserved.Normatiredata for theelectricalABR and preliminary
resultsof theelectrode
placement
studywill be presented.
UIS. Complete reconstructionof the auditory system: Adult gerbil.
David M. Harris and Michael Timmins (Department of
Otolaryngology-Headand Neck Surgery, University of Illinois at
Chicago,Collegeof Medicine, 1855 West Taylor Street,Chicago,IL
60612)
The object of our work is the reconstructionof the entire auditory
systemof the adult gerbil.The methodsto bedescribedincludeperfusion
with a vital stain,fixationand decaleification,
photography
of the cut
surfaceof thetissueblock(entirehead)duringcollectionof serialsections,
tracingand digitizingstructures
of interestfrom the photographic
data
andcomputergraphicreconstructions.
The imagederivedfromdigitizing
is confirmedby histologicalstainingand examiningeachsection.Such
reconstructionsallow visualizationin three dimensions,or in horizontal,
coronal,or sagittalsections.
Thesedataallowfor exactmeasurement
of
structures
andtheir topological
interrelationships.
The auditorysystem
depictedwill includenervouspathwaysas well as inner and middle ear
structures.
A quantitativelyexactreconstruction
permitsa precisedeterminationof multiple physiologicalrecordingsites,for us a most impor-
tant application.[Worksupported
by NIH.]
UI9. Recovery from saturation in lateralization of high-frequency
stimuli. Ervin R. Halter and Thomas N. Buell (Department of
Psychology,
Universityof California,Berkeley,CA 94720)
Lateralizationof trainsof high-frequencyclicksimproveswith both
the numberof dicks in a train ln}andinterclickinterval{ICI}. Functions
relatinglog thresholdto log n are linear;however,the absolutevaluesof
the slopesdecreasefrom the optimal--O.5 toward 0.0 with shorterICIs
Igeneraily10 ms or less).We have arguedthat shallowerslopesare the
resuliofa formofrate-dependent
saturation
whichreduces
theamountof
binaural information
derived from successive clicks in the train. The de-
cay of the proposedsaturationwasmeasuredhereby presentingtrains
with an ICI of 2.5 ms but with eachtrain brokenby eitheroneor three
pauses.Of interestwasthe durationof the breakneededto fully recover
from saturation.A pauseof 7.5 msprovedto be sufficient,implyingthat
thesaturationresponsible
for shallowslopesin log-threshold,
Iog-nplots
is the resultof an activeprocessratherthan of fatigue.[Supported
by
Nm.]
Societyof America
S40
GOLDEN WEST ROOM, 1:00TO 3:00 P.M.
SessionV. Psychological
AcousticsIII: Psychophysical
TuningCurvesandLoudness
Edward C. Carterette, Chairman
Department
of Psychology.
Unioersity
of California,LosAngeles,
California90024
Chairman's Introduction--l:00
ContributedPapers
1.'05
VI. A neural-counting
modelbasedonphysiological
characteristics
of the
peripheral auditory system: Application to loudnessestimation and
intensitydiseriminafion.
G. Lachs,R. AI-Shaikh,Q. Bi(Dcpartmentof
ElectricalEngineering,The PennsylvaniaStateUniversity,University
Park, PA. 16802), and M. C. Teich (Department of Electrical
Engineering,
ColumbiaUniversity,New York, NY 10027)
We havepreviously
usedan energy-based
neural-counting
model,incorporating
spreadof excitation,receptorsaturation,spontaneous
neural
activity,andrefractoriness
in theprimaryauditoryfibers,to predictthe
outcomeof a numberof neurophysiological
andpsychoacoustical
experiments[M. C. Teich,etaL,J. Acoust.Soe.Am. Suppl.I 71,S18(I 982);G.
Lachsetal.,IEEE Trans.Syst.,Man.Cybern.SMC-13,No. 5 (1983)].We
wishalsoto incorporate
the frequency
characteristics
of the middle-ear
transmission
function,andthecochlearmappingfunction.This placesa
numberof constraints
on the allowedparameters
of the theory.We diseusatheparametervaluesrequiredfor our theoreticalsystemto effectively p•dict theoutcomeof loudness-estimation
and intensity-discrimination experiments,both for pure-toneand variable-bandwidthnoise
stimuli.[Worksupported
by NSF.]
1:15
V2. Choice of stimulus parameters for measurement of auditory
functions.FredericL. Wightman,Israel Raz, ThereseM. Velde,and
John H. Grose (Auditory Research Laboratory (Audiology),
NorthwesternUniversity,2299 SheridanRoad, Evanston,IL 60201)
As a preliminaryto a large-scale
studyof the interrelationsamong
severalauditoryabilities,we conducteda separateexperimentin orderto
determinewhichstimulusconditions
wouldbestdiscriminate
amongsubjects.Usinga forced-choice
forwardmaskingparadigmin all conditions,
weobtained,from 12normailisteners,
eight6-pointpsychophysical
tuning curveswith probefrequencies
from 500 Hz to 4 kHz, two 10-point
unmaskingpatterns(oneeachat 1 and 3 kHz), and two 4-pointfunctions
relatingcombination-tone
(2f l-f2) levelandf2/f I ratio(oneeachat 1and
3 kHz). Data from individualsubjects
werefit with low-orderpolynomiais,andthecoefficients
of thesepolynomials
wereenteredintoananalysis
of variance.The majorconclusions
whicharosefromthisanalysisare:(I)
Frequency
resolution,
to theextentit ischaracterized
byforward-masked
PTCs,isadequatelyrepresented
by two six-pointPTCs,oneat I andone
at 3 kHz. (2)Two-toneunmaskingis independent
of frequency,and thus
one unmaskingpattern, at either I or 3 kHz can be usedto represent
unmasking.(3) Combination-tonegenerationis also independentof frequency,sothe slopeof only oneCDT vsf2/fl function,at either 1 or 3
kHz, canadequately
characterize
CDT generation.
[Worksupported
by
NINCDS.]
adults.Measuresof psychophysicai
tuningcurves,suppression
(asindicatedby theextentof unmasking
caused
by severalsuppressorsl,
andthe
audibilityregionof 2f l-f2 wereobtainedwithanadaptiveforward-maskingdetectionparadigm.Speechperception
in noisewasevaluatedwith the
nonsense
syllabletestviaa computer-controlled
("bestof three"I adaptive
procedure.The relationsamongfunctionsweretracedwith multivariate
analytictechniques.
Basedon theseanalyses,
weconcludethat:(1)Sharphessof tuning is intimately related to Combination Tone Generation
{CTG} but not to suppression.
{21CTG is not relatedto suppression.
(31
Aspectsof speech
perception
in noisecanbeaccounted
for by information
on frequencyselectivityand nonlinearities.[Work supportedby
NINCDS.]
1:45
V4. Adaptive,forced-choice,loudness-balance
testsin normallisteners.
Craig C. Wier (Departmentof SpeechCommunication,Universityof
Texas, Austin, TX 78712}, Elizabeth Huckins (Departmentof Speech
and Hearing Sciences,University of Washington,Seattle,WA 98195),
and Robert S. Schlauch {Department of Speech Communication,
Universityof Texas,Austin,TX 78712J
An adaptive,two-interval,forced-•hoiceprocedure(Jesteadt,1980}
wasusedto obtainABLB and modified-MLBloudness-growth
functions
for a partially masked,2000-Hz toneburst.Subjectsweresix normally
hearingadults.Steinbergand Gardner {1937)and Stevensand Ouirao
{1967)showed
thatthecomparison
of theloudness
ofa tonein quietwith
the loudnessof the sametone partially maskedproduced"recruiting"
loudness-growth
functionsfrom normally hearinglisteners.For the
ABLB conditionin thepresentstudy,a pulsed,widebandmaskingnoise
waspresented
toonlyoneear.The levelof thetonein noisewasvariedand
comparedwith the levelof the tonein quietpresented
alternatelyto the
oppositeear. in the modified-MLBprocedure,the tonewaspresented
monaurally,alternatelyin quietandin thepresence
of a pulsed,wideband
maskingnoiseto thesameear.Two noiselevels(3and33dB N 0)andeight
standard-tone
levelswereused.The loudness-growth
functionsobtained
binaurailyand monaurallywerevirtuallyidentical.The resultsof these
experiments
validateJesteadt's
adaptiveprocedurefor the measurement
of loudnessgrowth.A comparisonof the ABLB and MLB data suggests
thata similar,partial-masking
procedure
couldbeusedto developa mortaural,single-frequency,
loudness-balance
testforclinicaluse.[Worksupportedby DRF andNINCDS.]
2:00
V$. The relation betweenloudnessgrowth and intensity discrimination.
Robert S. Schlauch, Craig C. Wier (Department of Speech
Communication, University of Texas, Austin, TX
78712I, and
ElizabethHuckins(Departmentof Speechand HearingSciences,
Universityof Washington,Seattle,WA 98195}
V3. Relationsamongauditoryfunctionsin normallisteners.Israel Raz,
Fr•:lea'ic L. Wightman, John H. Gross, and Therese M. Velde
•Auditory ResearchLaboratory(Audiology),NorthwesternUniversity,
2299 SheridanRoad, Evanston,1L 60201)
The interrelationsamongfrequencyselectivity,nonlinearities,
and
speechperception
in noisewereexaminedin 24 normal-hearing
young
$41
J. Acoust. Sos. Am. Suppl. 1, Vol. 74, Fall 1983
Tbe notionthat the intensity-difference
limencan be usedasan indirect test of loudnessrecruitmeat is an old idea. However, to date, a firm
quantitativerelationbetweenthe two measures
hasnot beenestablished.
We considertheproblemasonein whichloudness
isrelatedto theoverall
stimulusmagnitudeand intensitydiscriminationis a reflectionof the accuracywith whicha loudness
judgmentcanbemade.Sincefor puretones
loudness
and intensitydiscriminationcovaryasfunctionsof intensity,for
106th Meeting: AcousticalSociety of Amedca
S41
ResearchLaboratories,
7036 Educationand ResearchBuilding,Henry
Ford Hospital,Detroit, MI 48202),Donald N. Elliott, Peter Boisvert
(Department
of Psychology,
WayneStateUniversity,Detroit,M148201},
and Ivan Hunter-Duvar(Hospitalfor SickChildren,Toronto,Ontario,
a specific
intensityonequantitycanbeinferredfromtheother.To testthis
relation,adaptiveABLB loudness-growth
functionswereobtainedfor a
2000-Hz, 500-mspuretonefrom a normallyhearinglistener(partially
maskedmonaurally)and a listenerwith a moderate,unilateralsensorineuralhearingloss.Intensity-discrimination
performance
wasmeasured
Canada M5G IXg}
for the same2003-Hz tone, at severallevels,in both earsof eachsubject.
We havebeeninvestigating
thesquirrelmonkey(Saimirisciureus}
asa
suitableanimalmodelfor testingthe effectsof noiseon hearing.Our
previousresearchhas showna similaritybetweenhumanand squirrel
monkeytemporarythresholdshift(TTS}growthwith time in the noise.
The goalof thisstudywasto measurethefrequencyspreadof Trs to five
differentindustrialnoisesfor bothhumansandsquirrelmonkeysandto
comparethe results.Fifteenhumansubjectsand six squirrelmonkeys
wereexposedto eachof thefivenoisesfor 8 h, and TTS wasmeasuredat
ten differentfrequencies
rangingfrom 250 Hz to 8 kHz. In the experimentswith humans,fivefrequencies
weretestedtwice(counterbalanced)
aftereach8-hsession.
In thesquirrelmonkeyexperiments,
a complete8-h
exposure
wasrequiredforeachfrequencytested,sinceonlyonefrequency
Intensity-recruitment
functionsderivedfrom thesedata are very similar
to the obtainedloudness-recruitment
functions.[Work supportedby
DRF and NINCDS.]
V6. A enmparison of the relative merits of four psyehophysieal
procedures.Brian R. Shelton and Irene Scarrow (Department of
Psychology,
Universityof WesternOntario, London,Ontario, Canada
N6A 5C2I
The efficiencyof four psychophysical
proceduresto estimatethe detectionthresholdof a brief 100•Hz sinusoldpresentedin noisewasas-
could be measuredeachtime the monkeyswere removedfrom the noise.
sessed in naive observers. Six threshold estimates were obtained for ten
subjects
in 50-trialadaptiverunsusingeachof fourprocedures:
two-alternativeadaptivestaircase,
two-alternative
maximum-likelihood,
three-alternativeadaptivestaircaseand the three-alternativemaximum-likelihood method.The four procedures
producedequivalentthresholds,
althoughthe staircaseprocedures
providedbiasedmeasurements
in the
initial runs.A trial-by-trialanalysisof the variabilityof thresholdestimatesrevealeda markedadvantageto the useof threealternativeswith
the adaptivestaircase,
but not with the maximum-likelihood
procedures.
The dataprovideinformationregarding
therelativeefficiency
of thefour
procedures,
and recommend
that particularprocedures
shouldbeusedin
specificinstances.
In general,the commonlyusedtwo-alternative
adaptive staircaseis the least efficientprocedureof the four, and the threealternativeadaptivestaircaseprovidesthe mostrapidand reliablethresholdestimates.
[Worksupported
by NSERC.]
2'.3O
V7. Frequencyspreadof TTS in humansandsquirrelmonkeysexposedto
industrial noises. Donald W. Nielsen, Diane Brandt (Otological
WEDNESDAY
AFTERNOON,
9 NOVEMBER
The resultsindicatethat in predictinghumanTTS fromthesquirrelmonkeyTTS for theseexposures,
TTS wouldbeoverestimated
at 750Hz and 1
kHz andunderestimated
at 5.6kHz, whereas
theTTS at otherfrequencies
wouldcorrespond
closely.[Work supported
by NIOSH.]
2:45
VS. Vibrotactile sen.•tion as a function of hand preferenee. Ronald
T. Verrillo (Institute for Sensory Research, Syracuse University,
Syracuse,
N¾ 13210J
A psychophysical
matchingprocedure
wasusedto assess
thesubjective magnitudeof vibrotactilestimuli in right-, left-, and ambi-handed
subjects.No thresholddifferences
werenoted.At suprathreshold
levelsof
stimulation,enhancementof sensationby a precedingstimuluswas the
samein all groupswhenbothstimuliwerepresented
to eitherhandipsilaterally. However,when stimuluspairs were presentedcontralaterally,
onlyright-andleft-handers
showed
enhancement
andsuppression
effects.
No contralateraleffectswereobservedin ambi-handers.The resultssuggestthat bilateralneuralconnections
in right- and left-handers
may be
different from those of ambi-handers.
1983
SENATE/COMMITTEE
ROOMS,
1:00 P.M.
SessionW. UnderwaterAcousticsIII: BottomInteraction(Pr6cis-PosterSession)
DeWayne White, Chairman
NORDA, NSTL Station,Mississippi
39529
Chairman's
Introduction--l:00
ContributedPapers
1:05
WI. The application of stepwisecoupled madesto a refracting ocean
usingGalerkin's method.Richard B. Evans•Naval OceanResearchand
thesearchfor thecomplexeigenvalues
with a moretractablematrixeigenvalueproblem.Numericalresultsbasedonthisapplication
arepresented.
[Work supported
by NORDA.]
DevelopmentActivity, NSTL Station,MS 39529)
The methodof coupledmodesdeveloped
JR.B. Evans,J. Acoust.Soc.
Am. 74, 188-195•1983}]for a homogeneous
watercolumnwith stepwise
depthvariationsoft penetrable
attenuating
bottomisappliedto a realistic
oceanenvironmentwith generalsound-speed
profiles.The main complication associatedwith this application is causedby having to find the
complexeigenvalues
for the rangeindependentsectionsand not by the
rangedependence.
To handlethis problem,the Galerkinmethodis employedwith anappropriately
chosenorthonormalbasissetwhichreplaces
S42
1:09
W2. A description of surface-wavescattering using a stepwisecoupledmode approach. C. Feuillade (ODSI Defence Systems Inc., 6110
Executive Boulevard, Rockville, MD 20852 and NORDA, NSTL
Station,MS 39529}
We haveextendedthe methodof stepwisecoupledmodesto describe
propagationthrougha mediumof variabledepth due to surfacewaves.
Societyof America
S42
Thisfacilitates
themodeling
ofacoustic
scattering
froma roughsurface.
The methodmaybeappliedto describe
scattering
withina waveguide
witha roughsurface,
or to modelenergylosses
dueto scattering
outof a
surface
duct.Numericalprocedures
havebeencodified
tosolvetheequationsresultingfromtheanalysis
andsomeexamples
areprovided.
1:13
W3. Soundfieldfluctuationin shallowwaterwavegulde.
C. S. Clay, Y.
Y. Wang,and E. C. Shane(Departmentof Geologyand Geophysics,
Universityof Wisconsin-Madison,
Madison,WI 53706)
The soundintensityfluctuationinducedby the fluctuationof the surfacein a shallowwaterwaveguidewasanalyzedby usingthe adiabatic
approximation
of the normalmodetheory.The soundfieldfluctuation
canbecategorized
into two parts:(I) The phasefluctuationof the normal
modecorresponds
to the fluctuationof the horizontalcomponentof the
wavenumber
(i. TolstoyandC. S.Clay, OceanAcoustics,
pp.222-236).(2)
The fluctuation
of theeigenfunction
corresponds
to thefluctuationof the
verticalcomponentof the wavenumberand the fluctuationof the local
waterdepthandthe localsourceandreceiverpositions.
The randomness
ofthefieldintensity
defined
asr/= SQR[(•2_ • 2)/••] wascalculated.
It
wasfoundthatthefluctuation
of thesecond
category
canbethedominant
comparing
with thefirstcategory.
The calculatedresultalsoagreeswell
withtheexperimental
resultconducted
in a watertank[Y. Y. WangetaL,
Chin.Phys.2, 515(1982)].
1:17
W4. Sedimentcontributionsto groupvelocityin shallowwater. David
W. Oakleyand RobertA. Koch (AppliedResearchLaboratories,The
Universityof Texasat Austin,Austin,TX 78712-8029)
Dispersion
curvesareusedto examinetheeffectofsediments
ongroup
velocity,andtheproblemfurtherdissected
by a directlookat therelative
contributions
of the sedimentlayersto the groupvelocityintegral.The
environments
of interesthavewaterdepthslessthat ! 50 m andsediment
thickness
of the orderof 50 m. The rangeof frequencies
considered
is
between25 and 600 Hz. A systematicvariationof s•iment typesand
velocityprofileswill beexaminedto findfeaturesof thedispersion
curves
whichmightbe usedto extractinformationaboutthe bottomfrom shot
data. In the presence
of stablewatervelocityprofiles,gradientsin the
soundvelocityin the sedimentcanbedetected,ascanlayering,provided
suchlayersare nearthe water-sediment
interface.Highly variablewater
soundvelocityprofileslimit informationavailableconcerning
the sedimentto grossfeatures
suchassediment
type.[Worksupported
by Naval
OceanResearchand DevelopmentActivity.]
1:21
WS. ShallowwaterwaveguidecharacterizationusingHankel fransforms.
James F. Lynch and George V. Frisk (Department of Ocean
Engineering,
WoodsHole Oceanographic
Institution,WoodsHole, MA
02543)
A coherentprocessing
techniqueis proposedfor the characterization
of shallowwaterchannels.For a horizontallystratifiedoceanandbottom,
themethodconsists
of measuring
themagnitudeandphaseversusrange
ofthepressure
duetoa cwpointsource
andHankeltransforming
thisdata
to obtainthe depth-dependent
Green'sfunctionversushorizontalwavenumber. The Grcen's function contains all the information
1340(19801].
Anefficient
computational
scheme
forcalculating
reflection
coefficients
hasbeendeveloped
for a sediment
layerusingtheBlotequationswith depth-dependent
coefficients.
The qualitativeeffectsof theinhomogeneous
sediment
properties
(in comparison
with uniformproperties}are studiednumerically.
[Work supported
by the Officeof Naval
Research.]
W7. Acoustic reflection from ocean abyssal plains. Herbert Frcese
(Arete' Associates,Arlington, VA 22202), Ioannis Besieris, and
Werner Kohler (VirginiaTech, Blacksburg,VA 24061}
Existingbottomlossandpulseresponse
data,measured
at a varietyof
grazingangles,frequencies,
and locations{Sohmand Hatterasabyssal
plains,BlakePlateau,Floridashelf,andGulf of Mexico},will bereviewed.
A comparison
of data with existingtheoreticalmodelswill be made.
1:33
we. An investigationof acousticinteractionwith the oceanbottomfrom
experimentaltime seriesgeneratedby explosivesources.David Knobles
(Applied ResearchLaboratories,The Universityof Texas at Austin,
Austin, TX 78712-8029)
Receivedtime seriesfrom explosivesourcesin a thin sedimentenvironmentare comparedto simulatedtime seriescalculatedby a ray theory
model.The comparisons
are madein variousfrequency
bandstoaidin the
identification
of sedimentpenetrating
arrivalsby takingadvantage
of the
frequency
dependence
of theabsorption
of thesediment.For largeranges,
mostof the receivedenergyrefractswithin the sediment.As the range
decreases,
the fractionof receivedenergydue to reflectionsat the watersedimentinterfaceincreases.
Discrepancies
betweentheexperimental
and
simulatedtime serieswill bepresented
and interpretedin termsof reflec-
tionsfromthinlayerswithinthesediment
andnonspecular
basement
reflections.
[Work supported
by NavalOceanResearch
andDevelopment
Activity.]
1:37
W9. Estimated spatial coherence from a layered ocean bottom. T.
W. Tunnell (NORDA Code 340, NSTL Station,MS 39529)
In thismodelingstudysubsurface
layeringeffectson the spatialcoherenceof bottom-interactingsoundwere investigated.The oceanbottom
was modeledas alternatinglayersof clay and clayey silt. A silty clay
bottomwasusedasa control.Complexreflectioncoefficients
werecalcu-
latedusinga plane-wave
multilayermodel[G. J. Fryer,J. Acoust.So:.
Am. 63, 35-42 (1978)].Usinga frequency
averaging
technique,
estimates
of the spatialcoherence
wereobtainedasa functionof grazinganglefor
fixedsensor
separation.
Theresultsindicated
thatsubsurface
layeringcan
seriously
degradethespatialcoherence
at frequencies
above100-200Hz.
The spatialcoherenceis considerablylessaffectedby subsurface
layering
at veryshallowgrazingangles(100or less)or verysteepgrazingangles(75'
or greater).[Worksupported
by NORDA.]
about the
channelnecessary
to solvetheforwardproblem,includingthenatureof
the discreteand continuousspectraand the plane-wavereflectioncoefficient of the bottom. Characteristics of the Green's function can also be
usedto inferacoustic
properties
of thebottom.Resultsfor simpleexampiesarepresented
usingsynthetic
dataandimplications
forthenonstratified case are discussed.
1.-41
W10. A WKB-numeriealintegrationmethodfor computingbottomloss.
Terry ForemanandRichard Pitre(AppliedResearchLaboratories,
The
Universityof Texasat Austin, Austin, TX 78712-80291
Computation
ofbottomlossat manyfrequencies
andgrazinganglesis
a computationally
intensive
process.
At highfrequencies
andlargegraz1:2S
W6. Wave reflection from a sediment layer with depth-dependent
properties.M. Stern, A. Bedford, and H. R. Millwater (Applied
ResearchLaboratories,The Universityof Texasat Austin, Austin, TX
78712-8029)
S43
The predictionof reflectioncoefficients
for thewater-sedimentinterfaceisstronglyinfluenced
bythephysical
natureof thesediment
(aviscoelasticporousmaterialsaturated
bya liquid)andthedepthdependence
of
themechanical
properties
[E. L. Hamilton,J. Acoust.Soc.Am. 68, 1313-
d. Acoust.Soc. Am. Suppl.1, Vol. 74, Fall 1983
ing angles,the numericalintegrationof the wave equationcan be very
slow.Whenshearwavegeneration
isan importantprocess,
theproblemis
exacerbatedbecauselow shearwavespeedsimply shortwavelengths
and
thereforesmallintegrationstepsizes.The WKB approximation
methodis
veryrapidand accurateat shortwavelengths,
but is inaccuratenearturningpoints.The hybridintegrationmethoddescribed
herecombines
both
S43
methodsby dividingthe integrationdomaininto WKB and numerical
integration
{turningpoint}regions.
Duetothefrequency
dependent
sizeof
the turningpointregion,the accuracyand computational
effortof this
hybridmethodareonlyweaklydependent
on frequency.[Work supported by Naval OceanResearchandDevelopmentActivity.]
1:4•
Wll. Optimum frequencyof acousticpropagationin shallowwater. D.
A. Gcrshfeldand A. I. E!ler (Naval ResearchLaboratory,Washington,
DC 20375)
The effectof variousbasicphysicalandenvironmental
parameters
on
the optimum frequencyof propagationin the ocean is investigated
throughtheuseof a modelthatis computationally
simpleto evaluate.A
closedform expression
for predictingtransmission
loss{forthe Pekeris
case}is obtainedby applyingthe Poissonsumformulato transforma
slowlyconverging
transmission
lossexpression
{consisting
of a sumover
thenormalmodes}
intoa rapidlyconverging
serieswhereonlya fewterms
are neededto predictreasonable
losslevels.A comparisonof spectrum
levelsbetweenthe derivedlossexpression
and a sophisticated
normal
modetransmission
lossmodelshowscloseagreementfor the frequencies
of interest.The resultsshowthat the optimumfrequencyis stronglydependentuponthe respective
depthsandseparation
distanceof thesourcereceiverpair.The modelisusedto explorethedependence
of theoptimal
frequency
onseveralparameters.
[Worksupported
byONR Code425UA
and NAVSEA Code63R.]
1:49
W12. Seaflooraenusticbackscattermeasurements
usingSEA BEAM. C.
P. deMoustier(MarinePhysicalLaboratoryof theScrippsInstitutionof
Oceanography,
Universityof California,SanDiego,CA 92152)
WEDNESDAY
AFTERNOON,
9 NOVEMBER
Acousticbackscatter
from theseaflooris measuredusingthe 12-kHz
SEA BEAM multibeamechosoundingsystemaboardthe R/V THOMAS
WASHINGTON.
During a cruisein the easterntropical Pacific,a very
densesurveyof a 15- X 20-mile manganese
nodulearea wascarriedout,
and the acousticreturnsfrom the 16 beamswere recordeddigitallyon
magnetictape.Usingtheintensityof thespecularreturnfor eachping,a
reflectivitymap of the area wasproduced.The patchiness
of the nodule
coverage
isevidenced
by definitehighsandlowsin thereflectivitypattern.
Thismaplaterservedasthebasisfor a nearbottomsurveyusingtheDeep
Tow instrumentation
packageof the Marine PhysicalLaboratoryand
there is remarkableagreementbetweenthe two setsof measurements.
Bottomphotographs
takenthroughoutthe areaalsoconfirmthe nodule
distribution.This papercomparesanddiscusses
theseresults.
1:$3
W13. Acousticexplorationof oceanfloor propertiesbasedon the ringing
of sediment
layer resonances.
AntonNagl, Herbert0berall,and
Kwang-BockYoo {Department of Physics, Catholic University,
Washington,DC
It hasrecently
beendemonstrated
[A. Nagl,H. 0befall,andW. R.
Hoover,IEEE Trans.OeoscLElectron.GE-20, 332{1982}]that thephysical properties
of a layeredoceanfloormay in principlebe determined
from an analysisof the resonances
in frequency,or in angleof incidence,
which appear in bottom-reflectedacousticsignals.Here, we study the
possibility
ofprobingthecharacteristics
ofisolatedresonances
byemployingsinusoidalpulsetrainsof sufficientduration;thiscontrastswith conventionaltechniques
basedonthetraveltimesof shortpulses,wheremany
resonances
contributesimultaneously
to the reflectedamplitude.It is
foundthat theresonances
manifestthemselves
by a ringingof thesignal,
andby a characteristic
interference
betweenthe specularcomponent
and
thefieldsresultingfrommultiplereflections
withina layer.[Supported
by
the Officeof Naval Researchand by the Collegeof Marine Studies,Universityof Delaware,wherepartof thisworkwascardedout].
1983
SAN DIEGO ROOM, 1:00 TO 3:00 P.M.
SessionX. ArchitecturalAcousticsIV: Acousticsof WorshipSpaces{PosterSession}
Ronald L. McKay, Co-Chairman
Bolt Beranekand NewmanInc., 21120 VanowenStreet,CanogaPark, California91303
David Lubman, Co-Chairman
David Lubman and Associates,
2217 VistaDel Sol, Fullerton,California92631
Chairman's Introductlon--l:00
The acousticenvironmentof a worshipspaceoftenmustbe hospitableto bothspeechand music,and this
frequentlymustbe accomplished
while dealingwith an architecturalform that is not conduciveto good
hearingconditions.Considerable
creativityis,therefore,requiredof theacousticaldesigner,usuallyemploying
both room-acousticand electro-acoustic
techniques.The creativitychallengeseemsto be increasingwith an
apparenttrendtowardworshipspacesthat canseatthousands
and serveasperformingartsfacilitiestoo.
Acousticalconsultants
and otherswho havebeeninvolvedwith the worshipspacedesignchallengehave
beeninvitedto presentpostersdisplaying
theirsolutions.
Thesewill form a basisfor display,discussion,
and
archival record.
Posterswill be presented
by the followingpersons
and organizations:
Ann Boyer, Jaffe Acoustics,Inc., Norwalk, Connecticut
O. L. Angevine,AngevineAcousticalConsultants,Inc., West Falls, New
York
Facilities:Chapelat UniversityPark, Akron, Ohio; SerbianOrthodox
Church,Aliquippa,Penusylvania;
United Presbyterian
Church,CuyahogaFalls,Ohio;RiversideBaptistChurch,Denver,Colorado.
S44
Facilities:Universityof RochesterInterfaithChapel,Rochester,New
York; Lake AvenueBaptistChurch, Rochester,New York; Randall Memorial BaptistChurch, Amherst,New York.
S44
EdwardA. Daly, Daly Engineering
Company,Beaverton,
Oregon
F•cEffies:
SaintTherese
CatholicChurch,Porthad,Oregon;
FirstUnited
MethodistChurch,Corvallis,Oregon;First Churchof the Nazarene,
Portland,Oregon;United Churchof Christ Congregational,
Forest
Minorn Nagata,M[noru Nagata,AcousticEngineer& AesodatnsCo.,
Ltd., Tokyo, Japan
Facilities..
St.Anselm's
Priory,Tokyo,Japan;
St.Ignatius
Church,
Tokyo,
Japan;ShigaSacred
Garden,Shigaraki,
Shiga,Japan.
Grove, Oregon.
RogerC. Noppe,Purcell + Noppe + Associates,
Inc., Chatsworth,
David Joiner,Joiner,-Pelton-Ro•e,Inc., Dallas,Texas
California
Facilities:First BaptistChurch of Orlando, Orlando, Florida; Lovers
LaneUnitedMethodistChurch,Dallas,Texas;Sanctuario
deGuadalupe,
Monterrey,Mexico;GrandAvenueBaptistChurch,Fort Smith,Arkan-
Facilities:
Whitesburg
BaptistChurch,Huntsville,Alabama.
Denn'sA. Paoletti, Paoletti/Lewitz/AssociatesInc., San Franciaco,Ca-
sa•
lifornia
Bertrant Y. Ktn•ey, Jr., Consultantin Architectural Acoustics,Gainesville, Florida
Facilities:Hope LutheranChurch,Daly City, California;Community
Presbyterian
Church,Danville,California;Beth EdenBaptistChurch,
Oakland,California;Glad TidingsPentecostal
Church,Victoria,B.C.,
Facilities:
First LutheranChurch,Gainesville,
Florida;Crossroads
Church of Christ, Gainesville, Florida.
Canada.
Jack B.C. Parcell,Parcell + Noppe -F Asso•iate• Inc., Chatsworth,
Larry Kirkegeard,R. LawrenceKirkegurd & Associates,Inc, Lom-
California
bard, Illinoh
Facilities:St. Matthew'sEpiscopalChurch,PacificPalisadea,
California
Facilities:CalvaryLutheranChurch,GoldenValley,Minnesota;House
of HopePresbyterian
Church,SaintPaul,Minnesota;Trinity Episcopal
Church,Portland,Oregon;Seventh
Day AdventistChurch,Collegedale,
L. W. Sepmeyer,Ludwig W. Sepmeyer,ConsultingEngineer,Los Angeles,California
Tennessee.
Marshall Long, Marshall Long/Acoustics,Santa Monica, California
Fact7ities:
Grace BretherenChurch, Long Beach,California;/3race
BretherenChapel,LongBeach,California.
StephenM. Sessler,Newcomb& Boyd,Atlanta,Georgia
Facilities:St.MargaretMary Church,WinterPark,Florida;MissionValley Free MethodistChurch,SanGabriel,California.
Facilities:
TempleIsrael,Memphis,Tennessee.
Daniel W. Martin, l•miel W. Martin AcousticalConsultant,Cincinnati,
fornia
Ewart A. Wetherill, Bolt BeranekandNewmanInc., CanogaPark, Cali-
Ohio
Facilities..
MemorialChurch,StanfordUniversity,Paio Alto, California;
Chapel,OccidentalCollege,Los Angeles,California;St. Basil Catholic
Church,LosAngeles,California.
Facilities: St. JamesChurch of White Oak, Cincinnati, Ohio.
Ronald L. McKay, Bolt Beranek and Newman Inc., CanogaPark, California
Arthur K. Yeap, AD! Group,San Francisco,California
Facilities:First Church of the Nazarene, Pasadena,California
Facilities. Bethel Church, Lodi, California.
WEDNESDAY
AFTERNOON,
9 NOVEMBER
COUNCIL
1983
ROOM, 1:00 TO 2:50 P.M.
SessionY. Noise III: CommunityNoise
Gerald J. Franz, Chairman
SilencingTechnology
Associates,
P.O. Box 695, Bayview,Idaho 83803
Chairman's Introduction---l:00
ContributedPapers
1.-05
YI.
Highway identificstina of exlmnst system noise problems. F.
M. Kessler(Dames& Moore,6 CommerceDrive, Cranford,NJ 07016),
E. DiPolverc (NJDEP, Trenton, NJ 08618), and M. Van Ouwerkerk
(Dames& Moore, Cranford, NJ 07016}
thepass-by
soundlevelof all vehicles.
The second
teamconsisted
of an
inspectionofficerand a personmaking stationarysoundlevel measurements.A majorityof thevehiclescalledloudby the"spotting"officerhad
pass-bysoundlevels5-10 dB belowthepass-bystandardfor that classof
vehicle.This indicatesthat thequalityof thesoundemittedbysuchvehicles is distinctive and that the officers are able to detect defective exhausts
To reducethe numberof excessively
noisyvehicleson the road, a
simplifiednoisecontrolenforcement
procedurewasdeveloped
andtested.
This procedureutilizesthe "trained" ear of enforcementofficialsin detectingfaulty,modified,or absentmufflersand exhaustsystems.The purposeof this studywasto evaluatewhetheror not the trainedcar canbe
utilizedas a screening
devicefor "probablecause"to stopa vehiclefor
priorto thedefects
causing
theexcessive
noiseto exceedthepass-by
stan-
inspection
oftheexhaust
system
resulting
in thecitationof thedriverfora
Y2. Somesimilaritiesin communityresponseto aircraft and road traffic
noise.S. Fidell (Bolt Beranekand Newman Inc., 21120 VanowenSt•et,
CanogaPark, CA 91305)
mechanicallydefectiveexhaustsystem.Two teamsconductedthesetests.
The firstteamincludedthe "spottingofficer"anda personwhorecorded
S45
J. Acoust. Soc. Am. Suppl. 1, VoL 74, Fall 1983
dard. Numerousadditionalfindingsare discussed.
1:20
106th Meeting: Acoustical Society of Amodca
S45
A socialsurveywasundertaken
in thevicinityof a majorair carrier
airport.Oneofthetwoneighborhoods
wasexposed
tonoise
duetoaircraft
operations
at aboutLa, = 70dB.Theotherneighborhood
wasexposed
to
roadtrafficnoiseat aboutLa, = 62 dB. A briefstructured
interviewcon-
ducted
bytelephone
revealed
a'number
ofsimilarities
incommunity
response
tothetwonoise
exposure
environments.
Theseincluded
reports
of
sleepinterference
andhabituation
to noiseexposure.
Differences
in observed
prevalence
ofannoyance
in thetwoneighborhoods
wereattributableto thedifferences
in exposure
levels.
Facedwithmakinga choicebetween
acquiring
residences
andclearingtheproperty
versus
acoustically
insulating
them,theSt.LouisAirport
Authorityundertook
a demonstration
projecttodevelop
firmdataonthe
cost and value of retrofit acoustical insulations for residencesin the air-
portenvirons.
Sixwoodframehomes,
typicalofmostofthehousing
stock
in the area,weremodifiedusingstandardavailableconstruction
techniquesandmaterialsin an effortto improvetheirinsulationagainstaircraft noise.Noiseexposuremeasurements
weremadebeforeand after
modifications.
Thispaperreportsthedetailsof theretrofitmodifications
employed
andtheireffectiveness
in reducing
exposure
to aireraRnoise.
¾3. The eifects of communitynoise on modular and manufactured/
mobilehomes.MonesE. Hawleyand GeoffreyM. Back(JackFaucett
Associates,
5454WisconsinAvenue,ChevyChase,MD 2815}
Dwellings
whicharebuiltin factories
andtransported
to theirsites
accountfor an increasingly
importantfractionof newhousingconstructionin theUnitedStates.Abouthalf of thesehouses
areplacedin clusters
withotherfactory-built
homes.
Theinteriorsources
ofnoiseandtheinsulationagainstnoisefromexteriorsources
wereinvestigated
andcompared
with those for new site-built houses.Manufactured houses(formerly
calledmobilehomes),
whichhavean integralchassis
for transportation,
must be built in conformance with federal standards. Modular homes,
whichare removable
from theirtransporters,
arebuilt to stateand local
building
codes.
Theresultisthatfactory-built
houses
haveinternalnoise
levelsandexternal-to-internal
noiselevelreductions
equivalent
tothoseof
comparable
site-builthouses.
However,exteriorcommunity
noiselevels
frequently
arehigherfor factory-built
homesthanfor site-builthomes
because
of the way thesitesarechosen.[Work supported
in partby the
U.S. EnvironmentalProtectionAgencyundercontractnumber68-01-
2:20
Y6. An overgroundexee• soundattenuation(ESA] study. Robert
G. Powell(AFAMRL/BBE, Wright-PattersonAir Force Base,OH
45433}
In ordertobetterpredictcommunitynoisefromAir Forceoperations
an extensivestudyon overgroundexcesssoundattenuation(all attenuationin excess
of inversesquareandair absorption
losses}
wasconducted
at Wright-PattersonAir ForceBase.The uniqueaspects
of thisstudy
were the methodsusedto acquirethe referencenoiselevels,procedures
usedto obtainup and downwindpropagated
noise,and the all-weather,
radio-controlled
microphonerecordingsystems.
To be presented
are the
experimental
designandsamples
of ESA valuescalculated
fromthenoise
of 400 plusgroundrunupsof a KC-135A aircraftpropagating
alonga
2400-mmicrophonearray. Also to be discussed
are the availabilityand
formatof thebasicacousticand meteorological
datafrom thisstudy.
6159.1
2:3•
l:S0
¾4. The effect of eurvedvehielepath on averagesoundpressurelevel
GregoryS. DavisandC. E. WallaceIDepartmentof Mechanicaland
Aerospace
Engineering,
ArizonaStateUniversity,Tempe,AZ 8528?)
A mathematicaltheoryispresented
whichpredictsaveragenoiselevels for curvedaircraftflight paths.The error in computingequivalent
noiselevelsbyassuming
a straightflightpathandthenbending
it tofollow
thecurvedflightpathisevaluated
asa function
oftheshape
ofthecurved
flightpathandthelocation
of theobserver.
Thetheoryisexperimentally
verifiedusinganautomobile
ona curvedtesttrack.It isshownthatfora
givenobserver
location,
theamountof errorincreases
astheamountof
pathcurvature
increases.
Alsoit isshown
thatfora givencurved
path,the
amountof error increases
asthe observerlocationismovedawayfrom the
curvedpath.In somecases
theerrorincurredissignificant
andisin excess
Y7. Analysisof overgroundexcessattenuation.Dwight E. Bishop(Bolt
13eranek
and Newman Inc., 21120 VanowenStreet,CanogaPark, CA
91303}
The noiseandmeteorological
dataacquiredby the Air ForceAMRL
at Wright-PattersonAir ForceBasehasbeenanalyzedto determinethe
factorsmostinfluencing
theexcess
soundattenuationat differentfrequenciesand distances.Multiple regressionanalysesof the excesssoundattenuation(thedifferencein noiselevelsmeasured
at differentpositions
referredto thereference
positionlevelsafteradjustmentfor inversesquare
andair absorption
losses}
indicatethatthestrongest
variables
influencing
the excesssoundattenuationare the wind componentin thc directionof
soundpropagation,
thetemperature
gradient,andthegroundcover{grass
versus
snow}.Regression
coefficients
rangedupto theorderof r• = 0.8.
Plotsof thevariance
accounted
for(r:}values
asa function
of frequency
of 3 dB.
showtwodistinctpeakswhichshiftdownwards
in frequency
asdistance
increases.
At low frequencies
(belowabout200 Hz), the mostsignificant
variableisgroundcover.For thehigherfrequencies
themostsignificant
YS. Airport related residential•consficalinsulationdemonstration
project.J. T. Wcissenburger
{Engineering
Dynamics
International,
St.
attenuation
valuesasa functionof windcomponent
andtemperature
gradientwill becomparedto resultsfromotherstudiesandtheoreticalmod-
Louis, MO 63124)
els.
variable is the wind component.Curves showingthe measuredexcess
S46
106thMeeting:
Acoustical
SocietyofAmerica
S46
WEDNESDAY
AFTERNOON,
9 NOVEMBER
1983
FORUM ROOM, 1:00 TO 3:05 P.M.
SessionZ. Physical AcousticsIII: General Topics II
Robert T. Beyer,Chairman
Department
of Physics,
BrownUniversity,
Providence,
RhodeIsland02912
Chairman's
Introduction--l:00
Contributed
i:05
Zl. Removalof the assumptionof planeprimary wavesin the theory of
the nonscatteringof soundby sound.Peter J. Westervelt(Applied
ResearchLaboratories
of theUniversityof Texas,P.O. Box8029,Austin
TX 78712)
The virtual sourceof combinationfrequenciesis well known to be
Q= • (c•/St)(
p,P2),
where,6'
= Po2Co4[2 + (d2p/dp2)m
] andthepressureof eachof thetwoprimarywavesmaybeexpressed
aspl = a, cos
andp2= a2cos•P2,
wherethea'sandtheeikonals,
the½'s,depend
onthe
four-radius
vectorxi (referto "eikonal"in theindexof anylateeditionof
Landauand Lifshitz, The ClassicalTheoryof Fields).The restrictionto
planeprimarywaves
implicitin myderivation
ofQ [J.Acoust.Soc.Am.
35,535-537{1963)]waslaterremoved
byme[Proc.Univ.of TexasNonlinearAcoustics
Symposium,
editedbyT. G. Muir,pp.167-181(1970)].
The
presentpaperreportsa functionR whosed'Alembertian
equalsQ when
theregionof interaction
commonto bothprimarywavesresides
many
primarywavelengths
fromeachof the two sources.
It turnsout that
R = [8(a/at) la,a2[(a½,/&,)(a½2/axi)
l 'sinr•lsin•21 in which
(d½,/0x.)(•½2/•x
i)means
Vfl.V½2
- c6-2½,½•
Thus
V2R-- C•2• = Q
plustermsthatarenegligible
if theprimaries
arenotcollinear
sincethese
termsareoforderE - ' andE - 2smallerthanQ whereE = •b+ i•otisthe
space-only
dependent
eikonal.E, andE2havemagnitudes
of theorderr•
2 • ' andrv••- I, respectively,
wherer I andr2arethedistances
fromthe
interaction
regiontotheprimarysources
ofwaveshavingdominant
wavelengths
2, and•:, respectively.
Theconclusion
isthatnoscattering
occurs
outsidetheinteraction
regionof twowaves,neitheroneof whichneedsto
bestrictlyplane,nor for that mattersteadystate.
1:17
Z2. Acousticsignalshavingbothpositiveandnegativenonlinearity.M.
S. Cramer(Engineering
Scienceand Mechanics,
VirginiaPolytechnic
Instituteand StateUniversity,Blacksburg,VA 24061}and A. Kluwick
tInstitutfuerStroemungslehre
und Waermeuebertragung,
Technische
UniversitaetWien, A-1040, Vienna, Austria}
ThequantityF •t 1/ p)lOpa/8p) frequently
occurs
in thenonlinear
acoustics
of bothgasesandliquids.Herep is the density,a the sound
speed,andthederivativeis takenat constant
entropy.It is well known
thatwhenF> 0 Ipositive
nonlinearity},
pulsesandperiodicwavetrains
steepen
forwardto formcompression
shocks.
WhenF < 0 (negative
nonlinearity},
thesteepening
isbackward
andexpansion
shocks
form.When
thesignalamplitude
issufficiently
largecompared
toF, thelocalvalueof
Fmay varyfrompointtopointinthewaveandthesubsequent
behavior
is
quitedifferent
thanthecases
having
eitherpositive
ornegative
nonlinearity everywhere.This phenomenacan occurfor singlephaseNavierStokes
fluidsandthepresent
paperwillprovidea description
ofthepropagationinthislattercase.Results
ofinterest
include
shock
splitting,
shock
waveshavingsonicconditionseither upstreamor downstream
of the
shock,andcollisions
betweencompression
andexpansion
shocks.Under
certainconditionsit wasfoundthat the ultimatedecayof a mono-signed
pulseisproportional
to thenegative
one-thirdpowerof thepropagation
time rather than the classicalnegativeone-halfpower.
Papers
A theoreticaland experimentalstudy of moving thermoacoustic
sources
is presented
in thispaper.The inhomogeneous
linearwaveequationfor a fluidcontainingheatsources
[P. J. WesterveltandR. S. Larson,
J. Acoust.Soc.Am. 54, 121-122 (1973)]is usedto derivethe acoustic
response
h (t) of a mediumexcitedby an impulseof light.The pressure
radiatedbya lasersource
movingatconstant
speed
overa watersurface
is
thendescribed
intermsofa convolution
between
theimpulseresponse
h (t }
and the optoacoustic
sourcestrengthwhichis proportional
to dl/dt,
whereI (t) represents
thelaserintensity.
In somelimitingcases
offarfield
radiation,thecomputedpressure
waveforms
canbecomparedwith previouswork[L. M. Lyamshev
andL. V. Sedov,Soy.Phys.Acoust.27(I),418(1981).]An experimental
studyisalsoin progress.
The motionof the
laserbeamoverthewatersurfaceat velocities
up to Mach2 isachievedby
meansofa rotatingmirror.Thelaserisexcitedin theconventional
non-Q-
switched
mode,witha pulsedurationof I ms.[Worksupported
byONR.]
1:41
ZA. Dark-fieldmagneto-elastic
nondestructive
testingtechnique.
Jacques
R. ChamueW (The Charles Stark Draper Laboratory, Inc., 555
TechnologySquare,Cambridge,MA 02139)
In thefieldof nondestructive
testing,greatadvantages
canbcobtained
if a dark-fieldtechnique
canbe achieved.
A magneto-elastic
technique
generating
soundwavesonlyin the presence
of a defectandfromtbe
defectisdescribed
(nodefect--nosoundwavesin thematerialundertest}.
The magneto-elastic
technique
generates
three-dimensional
information
aboutthe defectlocation,dimensions,and characteristics,unlike conven-
tionalultrasonic
NDEtcchniq9cs
where
thedefect
isused
asascatterer
of
incidentultrasonicwaves.Eddy currentsarc generatedin the material
undertestwith a currentcarryingconductor.A magnetis placedsuch
thatitsmagnetic
fieldisparalleltothecurrentcarryingconductor.
Elastic
wavesare generated
in the conductive
materialundertestonlyat the
crackedgesfromtheinteraction
of themagnetwithtransverse
eddycurrentsflowingaroundthedefect.Thegenerated
elasticwavesaredetected
with an ultrasonicreceivertransducercoupledto the material.An array
of receivers
maybeusedto triangulateon thedefectandalsoto character-
izc theproperties
of thedefectfromthe 3-D information.
Conventional
EMAT(electromagnetic
acoustic
transducers)
areused
togenerate
elastic
wavesin the material even when no defectsare present;the magneto-
elastictechnique
depends
on thepresence
of a defectto createtheelastic
waves.Preliminaryexperimental
resultsarepresented
together
withother
potential
applications
ofthenewconcept.
•1Theauthoriscurrently
with
Sohoquest,
P.O. Box 584, Sudbury,MA 01776.
1:53
Z5. Self-seunnlng-lineelectro-elastic NDE technique. Jacques
R. Chamuel
al (The Charles Stark Draper Laboratory,Inc., 555
Technology
Square,Cambridge,MA 021391
A contactless
self-scanning-line
electro-elastic
nondestructive
testing
technique
isdescribed
capableof determining
in realtimethepresence,
location,number,and sizeof defectspresentalonga linearpath on the
surface of a conductive material under test. In one embodiment, the NDE
probeconsists
of a magnetostrictive
delaylineplaced
in closeproximity
Z3. Soundgeneration
by a movinglasersource.YvesH. Berthelotand
Nicholas
P. Chotiros(AppliedResearch
Laboratories,
TheUniversity
of
Texas at Austin, P.O. Box 8029, Austin, TX 78712)
$47
with thesurfaceto beinspected.
A currentcarryingwireplacedadjacent
andparalleltothedelaylineisusedtoinduceeddycurrents
in thematerial. The presence
of a crackcreatestransverse
eddycurrentsinteracting
Societyof America
S4'?
locallywiththemagnetostrictive
delaylinelaunching
elasticwavesin the
delayline.The elasticwavesaregenerated
onlyat thecrackedgelocations
alongthedelayline.Spatialinformation
regarding
crackedgelocations
is
preserved
in thetimeinformation.
An ultrasonic
receiver
coupledto the
delaylineisusedto detecttheelasticwavestravelingin thedelayline.The
self-scanning-line
electrn-elastic
NDE probeisnotsusceptible
tothepresenceof elasticwavespropagating
in the materialundertest.The new
conceptisapplicable
tofiatandcurvedsurfaces
includingpipeinspection.
Conventional
eddycurrenttechniques
arenotselfscanning
alonga linear
pathgivingonlyan integrated
response,
indicatingonlythepresence
and
not the locationand numberof defects.Applicationof the conceptto
automation
willbediscussed.
a)Theauthoriscurrently
withSohoquest,
P.O. Box 584, Sudbury,MA 01776.
2.'O5
7_,6. Nonlinear transient response of electrostatic loudspeakers.
JuergenSchroeter(Bell Laboratories,Murray Hill,. NJ 07974 and
Lehrstuhlf. Allg. E-Teclinikund Akustik,Ruhr-Universitaet,Postfach
102148, D-4630 Bochum, Federal Republic of Germany) and Man
Moban Soodhi(HellLaboratories,Murray Hill, NJ 07974)
When an electrostatic
loudspeaker
(ESL)is usedasan acousticpulse
generator
[seeM. M. SondhiandJ. R. Resnick,J. Acoust.Soc.Am. 73,
985-1002(1983)for onesuchrecentapplication],
it maywellbedesirable
to operateit at levelsat whichits motionis highlynonlinear.Available
analysesof ESLs are inadequatefor suchapplicationsbecausethey are
concernedwith computingsine-waveresponse
and estimatinglow-level
harmonicdistortion.To fill this gapwe havedevelopedan algorithmto
computethegeneral,nonlineartransientresponse
of a circularESL to a
circularlysymmetricexcitation.Our formulationis generalenoughto
allow multiplesupportof the membraneat an arbitrarynumberof concentticcircularridgeson the backplate.Our analysisincludesthe effects
of a backcavity,a perforatedbackplate,and the couplingof the membranemotionto theeigenmodes
of a cylindricalimpendartec
tubein front
of themembrane.
(Theprogramcanbeeasilymodifiedfor otherconfigurations,e.g.,whenthemembrane
is in an infinitebaffle.)We will present
somecomputedresultsandtheir comparisons
to measureddata.
2:29
7,8. Experimentalstudyof internal noiseon a shellsubmittedto boundary
layer excitation. JacquelineLarcber, Jean-Marc Parot, and Jean-
Paul Berhault(Soci6t6Metrarib, BP 182,69132EcullyCedex2, France)
A studyhasbeendoneof theacousticperformance
of elasticmaterial
shells,surroundedby a heavyfluid. submittedto a turbulentboundary
layer excitation.Measurementsof internal noiselevelsunder localized
excitation,in frequency
bands,showgoodagreement
with theresultgiven
by a statisticalenergymodel.Theseresultsshowsignificanteffectsof the
structuralpropertiesand materialfor a givenshellshape.The results
agreewell with noiseand vibrationmeasurements
in a reciprocitysituation{actionof an internalnoisesourceon thestructure}.Flexuralwavesin
the shellmaterial,althoughsubsonic,
playa majorrole.
2:41
Z9. Experimental investigat'onof nonlinear crossedbeam scatteringin
the presence
of turbulence.Murray S. Korman(Dopartmentof Physics,
U.S. Naval Academy,Annapolis,MD 21402}
An experimentalapparatushasbeenconstructedto measurethe nonlinearscatteringof two mutuallyperpendicular
crossedsoundbeamsin
thepresence
of turbulence
Ifroma submerged
waterjet).Resultsareused
to measureand characterizethe turbulentflow.The pulsedbeams{I.90
and 2.10 MHz} are generatedfrom I-in.<liam transducers,suspended
fromperpendicular
radiusarmsthat arefreeto rotate360' in a horizontal
plane.The transmittersand 4-MHz receiverare located1 and 2 m from
theinteractionregion,respectively.
Oneexperimental
difficultyis theinabilityto distinguish
betweenscattering
from the interactionregionand
othernonlinear
processes.
Aspartofthecalibration
procedure
thenonlinearscattering
of a cylinderisinvestigated.
Measurements
showthatscatteringat anglesnearthe main primarylobesare extremelydifcult to
measuredue to the inabilityto separateout the scatteredfieldof (a}one
primarybeaminteractingwith (b}the scatteredlinearfield of the other
primarybeamfrom the cylinder.Preliminaryresultsfrom the scattering
by turbulence
and by a cylinderwill be presented.
[Work supported
by
NRL (PhysicalAcousticsBranch)and USNA.]
2:53
ZlO. Sound radiation from a concave or a convex dome in a semi-infinite
2:17
Z7. Analysis of acoustically excited structures using holographic
interferometrywith thermoplasticfilms. JosephA. Clark (Acousto-
Optics Laboratory,MechanicalEngineeringDepartment, Catholic
Universityof America,Washington,DC 20064)
Experimental
studies
of thetransientandmodalresponse
of vibrating
bodiesexcitedby soundfieldswill be described.Reusablethermoplastic
film is utilizedwith an automatedhologramrecorderin order to more
convenientlyobtain real-time and time-averageholograms.This ap-
proachfacilitatesinteractiveanalysisanddesignof vibratingstructures.
Typical structuresbeingcurrentlystudiedare membranesexcitedboth
resonantlyand nonresonantlyby airbornesound.Membrane structures
appropriate
for spatiallyresolved
measurements
of radiatingsoundfields
andturbulentboundarypressure
fiddswill bediscussed.
[Research
sponsoredby O.N.R. andD.T.N.S.R.D.C.]
S48
tube. Hidco Suzuki (CBS TechnologyCenter, 227 High Ridge Road,
Stamford,CT 06905)
A previous
study[H. SuzukiandJ.Tichy,J. Acoust.Soc.Am. 69,4149 {1981}]showedthata concave
or a convexdomein aninfinitebafflehas
radiationcharacteristics
that are differentfrom thoseof the flat piston.
These results indicated that a concave or a convex dome in a lossless tube
mayalsohavedifferentradiationcharacteristics
thana similarlymounted
fiat piston.This problemwasinvestigated
usingthesamemethodas the
previousstudies.The resultsshowthat the farfieldsoundpressureresponserisesby about0.5 to 0.7 dB in the frequencyrangeka = 2.2 to 2.8
forbothconcave
andconvexdomeshavingtheheight-to-radius
{a}ratioof
0.5 to 1.0.As expected,
theradiationresistance
increases
byabout13% to
! 7% over the radiationresistancein the low-frequencyregion.The radiation teacranceis verysmall at low frequencies
but becomescomparable
to the resistance
at frequencies
aboveka = 2.5. The reactanteis always
negativebelowthe cutofffrequency.
Societyof America
S48
WEDNESDAY
AFTERNOON,
9 NOVEMBER
1983
CHAMBER ROOM, 1:30 TO 3:05 P.M.
SessionAA. EngineeringAcousticsIII: TransducerMaterials
Robert M. Gorman, Chairman
Bolt Beranek and Newman, Inc., Union Station, New London, Connecticut06426
Chairman's
Introduction--l:30
ContributedPapers
1:35
AAI. Shockresist•nt PVDF hydrophones.
T. A. Henriquezand Mary
Lou Miller {NavalResearchLaboratory,UnderwaterSoundReference
Detachment,P, O. Box 8337,Orlando, FL 32856}
Previous
research
successfully
det•onstrated
theuse
oftubular
PVDF
in a shockresistant
hydrophone
fT. A. Henriquez,"ApplicationofTubular PVDF to ShockResistantHydrophones,"
in Proceedings
of theInternationalSymposium
of AppliedFerroelectrics
0983}]. The l:nesent
work
continuedthe developmentand refinementof a shockhardenedunderwater transducer. Nonvoided as well as voided tubular material with an
outerdiameter
ofinor «in.wasusedastheactiveelement
ineachdesign.
To evaluate
theeffects
ofstress
rodmaterialandcircumferential
prestress,
thefree-fieldvoltagesensitivity{FFVS}wasrecordedfor eachtransducer.
The response
of the elementwasdependentuponthe acousticcoupling
betweenthe compression
bolt and rubbermandrilwithin the tube and
betweenthe rubbermandriland the tube itself.The hydrophones
were
alsoexposed
to scaleddownexplosiveteststodeterminetheirruggedness.
The resultssupportpreviousfindingsthat tubularPVDF canbe utilized
asa broadbandstandardhydrophone.
[Work supportedby NAVSEA.]
1:50
AA2. UnderwaterIranaducerwetting agents.L. E. Ivey and C. M.
Thompson{NavalResearch
Laboratory,UnderwaterSoundReference
engineering.A fundamentallimit belowwhich one cannotreducethe
appearance
of coronalieswith thetransduction
material,thatis,thepiezoelectric ceramic itself. The corona characteristics of over 2500 lead
zirconate-leadtitanateceramicringshavebeendeterminedand the resultsusedto modela muchlargerringpopulationfromwhichpredictions
canbemadeaboutthecoronaperformanceoftransducers
assembled
from
theserings.A summaryof the informationto be presentedis that:
Populations
of "as-fired"ceramicringshavesignificantly
highercorona
inceptionvoltagesthanringswith surfaces
finishedby machinegrinding.
{2}Two distinctively
differenttypesof coronahavebeenidentified,oneof
whichcanbepartially"cured"by sulfurhexafluoride.
{3}The coronadata
for the ringshavebeenfit to a Wetbulldistributionmodelandappliedto a
"weak-link"modelto predictthebestperformance
thatcanbeexpected
from the assembled
transducer.
[Work sponsored
by the SonarTransducerReliabilityImprovement
Program,NAVSEA.]
2:20
AA4. Analysis of segmented cylinder ceramic transducers using
multiportinterconnection
techniques.
MichaelP. Johnsonand Stephen
C. Thompson {SystemsEngineering Department, Ocean Systems
Division,Gould DefenseSystems,Inc., Euclid Avenue,Cleveland,OH
44117)
or dirty underwateracoustictransducershasbeenaroundsincethe first
For manyyearstransducer
analysisusingmultiportinterconnection
techniques
hasbeensuccessfully
appliedto tonpilzdesignsand other
transducer
typesin whichthevibratorymotionisentirelyone-dimensional. The analysisof radiallyvibratingcylindricalceramicelements
has
generallyusedeitherempiricallyderivedequivalentcircuitmethodsor
calibration facilities were established in 1941. An air bubble driven at its
hasstarted
directlyfromthedifferential
equations
of motion.
Forseg-
resonancefrequencyhas a measurableinterferenceeffecton the transducer'scalibrationresponse.
The bubbleproblemcan be eliminatedby
mentedcylindersit is possibleto performan approximateanalysisusing
linearnetworkanalysismethods.This allowsthe useof standardmulti-
thoroughly
treatingthetransducer
witha wettingagentafterthegrease
portanalysis
computer
codessuchas$EADUCER
to performmuchof the
andoil havebeencleanedoffwith a strongdetergent.
The wettingagentin
somecasescan alsoact as the alegreaser.
There is a controversyamong
present-day
calibrationfacilitiesasto whichwettingagentisbest.A surveywasmadeof theNavy-sponsored
underwater
transducer
calibration
facilitiesto determinewhich wettingagenteachwas using.Each was
calculation.Furthermorethesemethodseliminatethe needfor empiricism.Calculatedradiationimpedance
andfinitemountingsurfaceimpedance effectscan be directly included.A descriptionof the methodand
comparison
of theresultswith previous
methodswill beprovided.
Detachment,P.O. Box 8337, Orlando, FL 32856}
Theproblem
ofair bubbles
formingandclingingtothesurface
ofoily
usinga differenttype.Samples
of eachtypewereobtained
andevaluated
at NRL-USRD. Thetestsperformed
weresurfacetensionmeasurements,
computability
measurements
with severalpopulartypesof rubbermaterials,andacoustictestsof eachtypeonstandardtransducers
in the USRD's
LakeCalibrationFacility.The resultsof thesetestsshownin theformof
curves,equations,
and tabulateddata validatewhichwettingagentsare
bestto useas surfaceacting agents.
2:35
AAS. On the construction of linear-response hydrophones. Mark
B. Moffett{Naval UnderwaterSystemsCenter,New London,CT06320),
Theodore A. Henriquez, and Mary Lou Miller {Naval Research
Laboratory, Underwater Sound Reference Detachment, Orlando, FL
32856)
E. Montgomery (TexasResearchInstitute. Inc.)
Most hydrophone
elementsin usenowadays
canbeclassified
eitheras
volume-modeelementsor as piezoceramicelements.Although volumemodeelementsare usuallyquite linear,nearlyall havelow capacitance,
andso,in practice,are usedin conjunction
with preamplifiers.
Preamplifiers, however,can be nonlinearand are not usuallysuitablefor closerangeparametricsourcemeasurements.
Piezoceramic
elements
havehigh
Transducers
are frequentlyplaguedby the presence
of coronawhich
can adverselyaffectthe performanceand lifetimeof the unit. Sitesat
whichcoronacanoccurincludethe wiring,spacing,configuration,sharp
electrodeedges,etc.,but thesecanbe minimizedwith properdesignand
theydo not work well in the volumemode,and sothey are usuallyconfiguredsoas to exposeonly oneelementsurfaceto the acousticpressure.
Suchconfigurationsinvariablyrequirebondsof somesort, e.g., two ceramic hemispheres
are gluedtogetherto form a sphericalhydrophone.
2:05
AA3. Corona characteristics of transducer ceramics. R. W. Timme, L.
P. Browder{NavalResearchLaboratory,UnderwaterSoundReference
Detachment, P.O.
Box 8337, Orlando, FL 32856), and R.
849
J. Acoust.Soc. Am. Suppl. 1, VoL 74, Fall 1983
capacitancesand therefore can be used without preamplifiers.However,
S49
The cthylene-propylene-terpolymer
(EPDM) classof elastomers
has
been widely suggestedbut rarely usedin underwateracousticdevices.
Recommendations
for its useusuallyresultfrom a recognitionof its low
acousticlosses
andgoodmatchof soundspeedanddensitywith seawater.
The hesitations
aboutusingœPDM's resultfrom unknownsin its engi-
Nonlinearity
of anepoxybondappears
toaccountfor thenonlinearity
of
F42D sphericalhydrophones.
Linear-respous½
hydrophones
suitablefor
usewithparametric
sources
at closerangecanbeconstructed
with volume-modeelements.
If cablelengthscanbekeptshort{• 10m},nopream-
plificrshouldbeused.Otherwise
a passive
low-pass
filtershouldprecede
thepreamplifier.
[Worksupported
byNavalMaterialCommandandNaval SeaSystems
command.]
2:50
AA6. EPDM
rubber as an underwater acoustic window. Coriey
M. Thompson,
RodgerCapIn,andMichaelJ. Lizzi(NavalResearch
Laboratory,UnderwaterSoundReferenceDetachment,P.O. Box 8337,
Orlando, FL 32856)
WEDNESDAY
AFTERNOON,
9 NOVEMBER
1983
neeringproperties
ofbondabilityandtearstrength.
The reportedmarginal bondabilityandtearstrengthwereinvestigated
asa functionof œPDM
formulation.Specifically,the effectsof filler typeand amount,sulfuror
peroxidecuretypeand loading,and polymerparameters
on bothengineetingandacoustic
properties
will beshown.With carein designing
the
EPDM formulation,thismaterialcanhaveacousticproperties(bothrhoc andattenuation}asgoodasnaturalrubberand environmentalresistance
superior
to neoprenes.
œPDM'scompatability
withcastoroil isthebestof
all commonclasses
of elastomers.
The resultsof manytestsconfirmthat
whileEPDM's bondabilityand tearstrengthare not equalto neoprenes,
theyare nevertheless
adequatefor mostapplications.
DEANZA/MESA
ROOM, 1:00 TO 3:05 P.M.
SessionBB. SpeechCommunicationIII: Voice Characteristics
ITT
Kung Pu Li, Chairman
DCD, 100dOCarroll Canyon,San Diego, California92131
Chairman's
Introduction---l:00
ContributedPapers
BBl. Recognitionof famousvoicesforwardsandbackwards.Diana Van
Lanckcr
(Phonetics
Laboratory,
Department
of Linguistics,
UCLA,Los
Angeles, CA 90024), Jody Kreiman (Department of Linguistics,
Universityof Chicago,Chicago,IL 60637 and PhoneticsLaboratory,
Departmentof Linguistics,UCLA, Los Angeles,CA 90024), and
Karen Emmorey (PhoneticsLaboratory,Department of Linguistics,
UCLA, LosAngeles,CA 90024)
To investigate
familiar voicerecognition,samplesof famousmale
voicesweretape-recorded
andeditedon a PDP-I 1/34 computer.Three
listening
taskswereprepared.
Subjects
indicatedwhethertheyrecognized
voicesfrom (I) 2-s samples;(2) differentand reordered2-s samplespresentedalongwith six choices;and (3) 4-s samplespresentedbackwards
(rerandomized
and refoiled).Ninety-sixsubjectsweredividedinto four
groups,threeby ageand onegiventhe backwardspresentation
first.For
task I, the meanrecognitionrate was 17%. In task2, subjectscorrectly
The ability of 40 subjectsto recognize25 famousmale voiceswas
investigated.
Sampleswere tape-recordedand editedon a PDP-I 1/34
computer.Three differentlisteningtaskswereprepared.Subjectsindicatedwhethertheyrecognized
voicesgivensixchoices:
(I) from2-ssamples;
(2}from excerptedwords(meanduration481 ms;and(3)from excerpted
and concatenatedstringsof vowels(meanduration 494 ms). The same
voiceswere usedin all tasks.Subjectsweredividedinto two groups.For
onegroup,the taskswerepresented
in the order2-stexts,words,vowels.
For group two, the reverseorder was presented.A two-way ANOVA
revealednoeffectof presentation
order.Subjects
correctlyidentified61%
of the voicesthey knew {ascertained
by a questionnaire)
given2-s texts,
40% of the voicesgivenexcerptedwords,and 34% givenvowel strings.
Subjectsperformedsignificantlybetteron the 2-staskthanon the word or
vowelstasks.There was no significantdifferencebetweentheir performance on the word and vowels conditions. These results show that voices
can be.recognizedgivenlimited amountsof voiceinformation.[Work
supportedby NIH Grant No. 4-443944-31117.]
identified69.5% of the voicesthey knew (ascertainedby questionnaires}.
Recognitionfor knownvoicespresentedbackwardswas 12.8% lessthan
for voicespresentedforwards.In the groupgiventhe voicesbackwards
first, a similar difference(12.5%) was observed.A two-way ANOVA
BB3. A speaker recognizability test for communications systems.
comparing
thefourgroupsontasks2 and3 revealedmaineffects
of group
and task, but no group-by-taskinteraction;thus differences
in perfor-
Panos Papamichalisand George DoddingtonITexasInstrumentsInc.,
P.O. Box 226015, MS 238, Dallas, TX 75266}
mancebetweenforwardsand backwardspresentations
were unchanged
acrossthe four subjectgroups.These resultsindicatethat voicerecognition canbeachievedgivenonly limitedinformationwhichincludesrate,
pitch,and pitch range.[Work supportedby NIH Grant No. •. •.•.394431117.]
1:17
1:29
A SpeakerRecognizability
Test (SRT) hasbeendesigned
whichtries
to establishhow well a givencommunications
systempreserves
a spcaker's identity.Contrary to previousefforts,no attemptis madeto identify
the cuesusedby listener•for speakerrecognition.Instead,listenersare
askeddirectlyto identifya speakerwho saysan utterance.The test is
constructed as follows: Several sentences are collected from five male and
fivefemalespeakers.
Onesentence
fromeachspeakerisusedasreference.
BB2. Recognitionof famousvoicesgivenexcerpted vowels,words,and 2-
The listeningteam consistsof ten listeners.Each listeneris presented20
s texts. Karen Emmorey, Diana Van Lancker (PhoneticsLaboratory,
Department of Linguistics, UCLA, Los Angeles, CA 90024I,
different•entences
andisaskedto identifythespeakerof eachoneof them
by comparingit with the ten referencesentences.
Amongthe issuesconsiderealin the designof the testis the choiceof speakers,the useof refer-
andJodyKreiman
(Department
of Lin•uisties,
University
of Chicago,
Chicago,IL 60637andPhonetics
Laboratory,Departmentof Linguisties,
S50
encesentencesfrom the sameor different sessionsof data collection, and
the useof processed
or unprocessed
speechfor reference.
Societyof America
S50
1:41
BB4. Intonation,pitchheight,andvoicequalityas indicatorsof speaker
attitude. Klaus R. Schercr, Kim Silverman, and D. Robert Ladd
(Departmentof Psychology,
Universityof Giesscn,6300Giessen,West
Germany}
Utterances
fromrecorded
interviews
wereratedforattitudeconveyed.
Stimuli were presentedin both the original audio versionand various
degradedversions.ludgmentsof backwardsand random-splicedversions
correlatedhighly with originals,while judgmentsof low-passfiltered
pitchcontours
didnot.Thissuggests
attitudeisconveyed
directlybyvoice
qualitylargelyindependent
of pitch contour.However,judgmentsof
originals
show(1}correlations
between
absolute
pitchheightandratings
of speakerarousal,and(2)interactions
betweenlinguisticcategories
of
inlonation
andsyntaxin j.udgments
of more"cognitive"
attitudes
like
"friendly"and "critical"(e.g.,finalriseswereratedfriendlyon yes/no
questions
butcriticalin WH questions).
Thisshowsthatit isimportantto
considerthelinguisticstructureof intonationandtheaccompanying
text
in studyingintonationalcuesto attitude.Maskingor merelyaveraging
acoustic
characteristics
ofF0 will obscure
theseinteractions.
[Worksupportedby German ScienceFoundation.]
1:53
BB5. Suppressionof noise in speech using PARCOR analysis.
Atsushi Mano and Shinji Ozawa (OzawaLaboratory,Departmentof
Electric Engineering,Faculty of Scienceand Technology,Keio
University,3-14-1,Hiyoshi,Kouhoku-ku,Yokohama,223$apanl
In thispaper,a new noisesuppression
algorithmis presented
for reducingany kind of background
noisein speech.This noisesuppressor
usesthree kinds of filters. The first filter, which is the inverse lattice filter
implementedby PARCOR analysisof noisepart, makesany colored
backgroundnoisesinto whitenoises.The secondfilter,whichis the white
noisesuppressor
usingspectralsubtraction,reducesthe white noisecomponentsin speech.
The thirdfilter,whichisthenoninverse
typeof thefirst
one,restoresthespeechdistortedby the firstfilter.The algorithmwhich
detects
nonspeech
periodsiscombined
withthisnoisesuppressor,
andthe
characteristics
of thesefiltersadaptivelyfollowthe nonstationarynoise
environment.The traffic noiseand jet enginenoise,etc., were usedto
estimate
thissystem.
As a resultof thetests,wecouldimprovethespeech
to noiseratiomorethan20 dB. Andat thesametime,wecouldimprove
the articulationof thespeech.
2:05
BB6. A model for the synthesisof natural soundingvowels. Donald
R. AllenandWilliamJ. Strong{Department
ofPhysics
andAstronomy,
BrighamYoungUniversity,ProvoUT 84602}
A modelhasbeendeveloped
whichisdesigned
to preserve
someof the
naturalhess
thatisusuallylostin speech
synthesis.
A parameterized
function is usedto producean approximationto the cross-sectional
area
throughtheglottis.A circuitmodelofthesubglottal
andglottalsystemis
usedtogenerate
thevolumevelocityof theair throughtheglottisfromthe
lung pressureand the time-varyingsupraglottalpressure.The tract is
represented
by it inputimpedanceimpulseresponse
whichcanbe calculatedfrom the areafunctionof the tract. A convolutionof the input impedanceimpulseresponsewith the volumevelocitydeterminesthe su-
praglottalpressure.
Theequations
relatingtheabovetwoonditions
forthe
volumevelocityare solvedsimultaneously.
The outputof the modelis
generatedby conyGivingthe resultingglottal volume velocitywith the
transferfunctionimpulseresponse
of the tract. A comparisonis made
betweenvowelssynthesized
with and withoutthevocaltract glottalflow
interaction.Listeningtestsshowedthat thoseyowleswith theinteraction
werepreferredasmorenaturalsoundingoverthosewithoutthe interaction.
In encoding
synthetic
speechfor vocabulary
storageandreproduction, currenttechniques
requirestoringat leastfiveor six bitsof coded
pitch valueper frame.Due to the slowvariationof pitchcontours,it is
possible
to describe
thesecontours
asa sequence
of simplepitchpatterns.
If eachpatternin thesequence
isappliedtoa subunitof thecodedphrase
or word,eachsubcontour
can furthermorebe approximatedin termsof
simplelinearfunctions.
The pitchpatternis selected
by pickingthebest
matchbetweenthe targetor natural subcontourand onecontourfrom a
libraryof predefined
simplepitchcontours.
Bystoringonepitchpattern
contourperspecificsubunitin speech,a considerable
savingsin vocabu-
larystorage
maybeachieved.
Informallistening
testsshowthatthedegradationin speechqualityis minor.
2:29
BBg. Periodic repetition of multi-pulseexcitation. Bishnu S. Atal and
BarbaraE. Caspers(AcousticsResearchDepartment,Bell Laboratories,
Murray Hill, NS 07974}
B. S. Atal and J. R. Remde {Proc.ICASSP 82}describeda methodfor
determiningthe multipulseexcitationfor LPC speechsynthesis.We find
that, evenfor reasonably
periodicspeechwaveforms,thesecondarypulses
in the multipulseexcitationdo not showsimilarperiodicbehavior.What
istheinfluenceof thislackof periodicityin theexcitationon thequalityof
synthetic
speech?
We haveinvestigated
thisquestion
by introducing
controlled periodicityinto the multipulseexcitation.The excitationwasfirst
segmented
into individualpitchperiods.For everysequence
of n pitch
periods,themultipulsepatternfromthepitchperiodin themiddleof each
sequence
wasthenusedto repeattheexcitationpatternin theothern - I
surrounding
pitchperiods.In thisprocess,
theoverallamplitudeenvelope
of the utterancewasleft unchanged.
We find that as manyas 15periods
may be repeatedwithout introducingsignificantaudibledistortionin the
syntheticspeech
signal.However,repetitionof a singlemultipulsepattern
acrossall voicedsegments
of an utteranceproducednoticeable
coloration
in syntheticspeech.
We will discuss
furtherimplications
of theseresultsin
this paper.
2:41
BB9. Optimizing pulse amplitudes in multipulse excitation.
Sharad Singhal{AcousticsResearchDepartment, Bell Laboratories,
Murray Hill, NJ 07974}
MultipulseexcitationlB. S. Atal and $. R. Remde,Proc. ICASSP 82]
isanattractivewayof modelingtheinput to theLPC synthesis
filterat low
bit rates.In the methoddescribedby Atal and Remde,the amplitudesand
locationsof thepulsesaredeterminedin successive
stages--onepulseat a
time.At eachstage,onepulseisdeterminedto achievemaximumreductionin theweightedmean-squared
errorbetweentheoriginalandsynthetic speechwaveforms.For closelyspacedpulses,successive
optimization
of individualpulsesis inaccurate,and oftenrequiresadditionalpulsesto
compensate
for inaccuracies
introducedearlier.Thisproblemcanbeonly
partly correctedby reoptimizingall pulseamplitudesat the end. This
paperdescribes
a methodwhich locatess pulseat any stageby jointly
optimizingitsamplitudetogetherwith the amplitudesof all pulseslocated
upto thatstage.As a resulttheamplitudes
of all pulsesarekeptoptimalat
everystage,andverylittle inaccuracyis introducedevenif the pulsesare
closelyspaced.The newmethodprovidessignificant
improvements
in the
SNR--by as muchas 10dB in somesectionsof speech.
2:53
BBI0. Doesa Bernoulliforcecausevelardoublebursts?John Kingston
{Pbonology Laboratory, Linguistics Department, University of
California, Berkeley,CA 94720}
Multiple intensitypeaks,"doublebursts,"arecommonin the release
2:17
BB7. Pitch encoding using simple unit pitch patterns. Kathleen
M. Ooudie, Kun-Shan Lin, and Gene A. Frantz (ConsumerProducts
Group, TexasInstruments,P.O. Box 10508,M.S. 5707, Lubbock,TX
79408}
S51
J. Acoust.Sec.Am. Suppl.1, VoL74, Fall 1983
of velar stops. Kealing. Westbur•. and Stevens [I_ Acoust. Soc. Am.
Suppl.167, S93{1980)]suggest
thatshortlyafterthevelarrelease,a rateof
air flowarisesbetweenthe tonguedorsumand the softpalatehighenough
to pull thembacktogetherby a Bernoulliforcelike that whichdrawsthe
vocalfoldstogether.The releaseof this secondcontactproducesa second
burst. If a high rate of air flow causesthis second,brief closure,then
$51
unaspiratedcontrastsdo. Alveolarreleases
vary muchlessacrossvowels,
doubleburstsshouldoccurmoreoftenafter/k/than/g/, sinceintraoral
air pressure
duringclosureishigherfor thevoiceless
stopthanthevoiced
one. Intensity measurements
of the initial portionsof the burstsof
butpeakintensity
isreached
approximately
10mslaterafterIt h] than[d]
sityfor velars---Icast
intensebefore[u], mostbefore[i], with [^] inducing
or the It] whichfollowsIs]. Evidently,the pointof contactwith thesoft
palateor themovementto thefollowingvowelmechanically
determines
burst intensityfor velars,while for alveolarsaerodynamicfactorsare
weak to moderatebursts--morethan the voiced/voiceless
or aspirated/
more potent.
[kh,sk,g,th,st,d
] before[i,A,U]showvowelqualitydetermines
burstinten-
WEDNESDAY
AFTERNOON,
9 NOVEMBER 1983
DEL MAR/HELIX/SANTA
SessionCC. Musical AcousticsIV: The Violin Octet and Other Stringed Instruments
Carleen M. Hutchins, Co-Chairman
CatgutAcousticalSociety,Inc., 112 EssexAvenue,Montclair,New Jersey07042
Bertram Turetsky, Co-Chairman
MusicDepartment,Universityof California,San Digeo,La Jolla, California92093
Chairman's !ntroduction•l:30
Invited Paper
1:35
CCI. Theviolinoctet.CarleenM. Hutchins(CatgutAcoustical
Society,Inc., 112EssexAvenue,Montelair,
NJ 07042)
Eightnewviolinfamilyinstruments
ingraduated
sizesprojectthetonequalityoftheviolinintoseven
other
toneranges,
representing
thefirsttimea consistent
theoryof acoustics
hasbeenappliedtoa familyof musical
instruments.
Undertakenin 1956at theinstigation
of HenryBrant,theyresemble
instruments
constructed
in
Europeduringthe 16thand17thcenturies.
Usingearlyviolintests,F. A. Saunders,
JohnC. Sehelleng,
andC.
M. Hutchinsferretedout a controllingcharacteristic
of theviolin:namelythetwo mainresonances
withina
semitone
of thetwoopenmiddlestrings.
Thesetworesonances
aredifferently
placedin viola,cello,andbass.
Schelleng
andHutchins
developed
a mathematical
scaling
theoryandHutchins
spentnearly10yearsadapting
andconstructing
instruments
according
to theseparameters.
The firstconcertwasat Harvardin 1963,a
memorialto F. A. Saunders;a secondin 1967at the New York YMHA. There are over 50 compositions
and
arrangements
for the OCTET, whichhastraveledthousands
of milesfor concerts
andlecturedemonstrations•ne setpermanently
in England,anotherin Stockholm,
witha composer
contestandconcertfor the
"SwedishMusical AcousticsConference1983." Violin makersin the USA, Europe,and Australia are con-
structingtheinstruments
whicharedescribed
in "THE VIOLIN OCTET" availablefromtheCatgutAcoustical Society.Personalwork time privatelydonated;machineryand acoustical
equipmentfundedby: John
SimonGuggenheim
MemorialFoundation,
MarthaBairdRockefeller
FundforMusic,AmericanPhilosophicalSociety,ArnoldHoffmanFoundation,
GeorgeMacDonaldFoundation,Estatesof VirginiaApgar,Helen
Rice,EuniceWheeler,and the Harriett M. BartlettFund of the CatgutAcousticalSociety,Inc.
ContributedPapers
2:05
CC2. Violin sound s•nthe•i• from flint p•ineiplc•. Gnbriel Weinreioh
(IRCAM, 31, rue Saint-Men'i, 75004 Paris, France and Randall
Laboratory,Universityof Michigan, Ann Arbor, MI 48109•
A simplecomputermodelof a violinhasbeenconstructed.
It consists
of two arrayscarryingthe forwardand backwardwaveson the string,
appropriate
reflection
rulesat thebridgeandfinger,a bowof finitewidth,
anda combination
of paralleltwo-polefilterstosimulatetheradiativityof
the violinbody.The stringis assumedto be nondispersive,
althoughan
equivalentamountof dispersion
can be includedin oneor bothof the
boundaryconditions.The instantaneous
forceexertedby the bow on the
stringisformulated
asa single-valued
functionof theirrelativevelocity.
The outputsignalcanbeconverted
intosound.The modelhasbeenused
to studya numberof phenomena,
includingthedynamicchanges
in the
$52
Helmholtzmotionwhenthebowvelocitychanges,
andin particularthe
startingtransients.
2:20
CC3. Characterizingguitar •ound using time-evolvingspectra. E.
Paul PalmerandLinda Zuvich(DcpartmentofPhysiesandAstronomy,
BrighamYoungUniversity,Provo,UT 84602)
The soundof a guitaror similarinstrumentcanbe characterized
by
the time evolutionof its partialsand its noiselikesoundcomponents.
This
includesthe establishment
or generationof noise,familiesof partials,and
formantsandresanances
by thenatureof thepluckingandthecharacter-
isticsof theinstrument.
It particularlyincludes
thedecayandinterchange
of energyamongall the soundcomponents.
The investigation
of these
Societyof America
S52
components
isfacilitated
by usinglinearandlogarithmic-frequency
spectral analysis
andby usingvariable-length
timewindowsin acquiringdata
en soundbox
is replacedaltogetherby a graphite-epoxy
soundboard
grill
backedbyan inflatablebladderin theshapeof a normalguitarbody.Both
instruments
aredemonstrated,
andtechniques
for creatingaligned-fiber
graphiteinstrumentcomponents
with room-temperature
"time-set"rather than "thermo-set"epoxyresinsarediscussed.
to beanalyzed.Displaysof time-evolving
spectrademonstrate
the different characteristics
of classes
of guitarssuchas classicaland steelstring
and the differences
betweenmembersof each class.The relationships
amongmeasurable
soundparameters
andguitarqualityandguitardesign
and construction will be discussed.
2:s0
2:35
CC5. The lidsof pianosandharpsichords
anacoustictransformers.Edith
L. R. Corlissand CharlesH. Corliss(ForestHills Laboratory,2955
AlbemarleStreet,NW, Washington,De 20008}
CC4. An inflatable guitar. Timothy P. White (Journalof Guitar
Acoustics,219 North Main Street,Ann Arbor, MI 48104)
It isreadilydemonstrated
thatblocking
thesoundhole
ofa steel-string
acousticguitardoesnot significantly
affectthe instrument's
tone.Wavelengthconsiderations
indicatethatthehighfrequencies
to whichourears
aremostsensitive
radiatedirectlyfromtheguitar'ssoundboard.
It iscom-
monknowledge
amongluthiersthat,indetermining
thetoneofaninstrument,thestiffness
anddampingproperties
of theguitar'ssoundboard
are
ofparamount
concern.
In thisstudy,thetraditional
wooden
architecture
oftheguitar'ssoundboard,
typicallya spruce
veneerreinforced
withvariablewoodenbracing,isreplaced
ona commercial
production
instrument
witha graphite-epoxy
',grill"supporting
a thinsynthetic
polymermembraneundertension.In anotherinstrument,theguitar'straditionalwood-
WEDNESDAY
AFTERNOON,
9 NOVEMBER
The lid of a grand pianomay be closedaltogetheron the case,removed,or raisedto a fixedpositionby a stick.Many largerinstruments
areequippedwith a shortstickasan alternativeto thelongstick.Raising
the lid to thesealternativepositionschangesthe tonecolorto an extent
perceptible
to theplayerandtheaudience.
Thiseffectis measured
more
readilywitha harpsichord
because
thepluckingactionisessentially
independentof the player'stouch.Usinga harpsichord
built by C. Randall
Taylorin 1966,theauthorshaveinvestigated
theeffectof adjustingthelid
to a numberof positions.
The changeproduces
measurable
alterationsin
theoutput.Theeffectissimilarto hornloadingona loudspeaker,
andwill
be discussed
from this standpoint.
1983
CALIFORNIA
ROOM, 12:30 TO 2:35 P.M.
SessionDD. Psychological
andPhysiological
AcousticsIII, NoiseIV, andCCEA: Effectsof Man-Made
Noise on Animals
William C. Cummings,Chairman
Oceanographic
Consultants,
5948Eton Court,SanDiego,California92122
Chairman's
Introduction--12:30
Invited Papers
12:35
DD1. Audiograms
for largecetaceaas:
A proposed
methodfor fieldstudies.SamH. RidgwayandDonald
A. Carder(Code5142,NavalOceanSystems
Center,SanDiego,CA 92152)
In thegreatmajority
ofcetaceans,
thesense
ofhearing
hasnotbeenstudied.
Therearenoaudiograms
on
anyofthegreatwhales.
To us,theABR (Averaged
Brainstem
Response}
technique
seems
theonlywaytoget
suchdataon thelargerspecies.
We haveusedtheABR in smallercetaceans
suchasDelphinus,
Tursiops,
and
Delphinapterus
torecord
audiometric
data.Finewiresaboutthesizeofa humanhairareinserted
intothehead
througha hypodermic
needle.Baretipsof theinsulated
wireoverthevertexandmastoldregionpickup
electrical
potentials
(electroencephalogram
orEEG}.TheEEGisamplified,
filtered,
andtaperecorded
during
periods
whensound
pulses
arepresented
through
a hydrophone.
Weobserve
theABRbysynchronous
averagingoftheEEGfor10to25msaftereachpulse.
Thesound
intensity
andfrequency
arevariedtodetermine
the
threshold
at eachfrequency,
thereby
producing
anaudiogram
for theanimal.Audiometric
datawouldbe
helpfulin assessing
theimpactof humangenerated
acoustic
events
onwhales.
Wehavedeveloped
a portable
systemthatwe hopewill enableusto makemeasurements
on whalestrappedin fishermen's
nets,cetaceans
stranded in tidal basins,or animals that beach themselves.
12:50
DD2. Compatibilityof shipsand whalesin GlacierBay, Alaska.JamesH. Johnson(NationalMarine
MammalLaboratory,NationalMarineFisheries
Service,7600SandPointWay N.E., Seattle,WA 98115}
GlacierBay,southeast
Alaska,normallya summer
feeding
groundfor humpback
whales,
wasabruptly
abandoned
in midsummer1978,promptingchargesby environmentalists
that increased
vesseltraffichad
driventhemout.Subsequent
research
focused
on whale-preyrelationships,
vessel
effects
on whales,andthe
overallacousticenvironment
of GlacierBay comparedto nearbyareaswherewhalescontinueto feedin
undiminished
numbers.Preystudiesshoweda highcorrelationbetweenwhaledistributionand preyabun-
$53
d.Acoust.
Soc.Am.Suppl.1, VoL74, Fall1983
106thMeeting:
Acoustical
SocietyofAmerica
$53
dance;in 1982a groupof whaleschoseto spendmostof thesummerfeedingin thebusiest,
noisiest
partof the
Bay. Behaviorstudiesshowedwhalesare affectedby vessels
up to 3-kin away,but reactionswereof short
duration,and meaningin termsof possiblephysiological
stressand cumulativeeffectis unknown.Acoustic
studiesrevealedminordifferences
betweenthe Bay andcomparison
areas{e.g.,"white sound"from effervescenceof meltingglacierice,andsporadic
seismic
noisel,whichpresumably
arelongstanding
phenomena
that
do not explainthe recentreductionof whales.Humpbacksare graduallyreoccupying
the Bay,possiblythe
resultof current traffic regulationsand restrictionson numbersof vesselsallowedentrance.However,a
"crash"of whalepreystocksin 1978still cannotbediscounted.[Work supportedby NationalPark Service,
NationalMarine FisheriesService,and Alaskacruiseshipindustry.]
ContributedPapers
l:OS
DD3. Behavioralandphysiologicalresponses
of captivebelugawhalesto
playbacks
of drillingnoise.Jeanette
A. ThomasandRonaldKastelein
(HubbsSeaWorld ResearchInstitute, 1700 SouthShoresRoad, San
energylosses
rangebetween20 and40 dB perrangedoublingfor thesame
frequencies.Lossesincreasedwith increasingfrequency.[Work sponsoredby NOAAs NationalOceanSurvey,Officeof Oceanography
and
Marine Services.]
Diego, CA 92109}
1:35
Therehasbeenrecentconcernthat noisefromdrillingplatformsmay
havedetrimentaleffectson marine animals.Unfortunately, little data are
availableon the hearingcapabilities
of marinemammalsand their responses
to man-made
noise.Theobjectives
of ourstudywereto playback
underwaterrecordings
of drillingnoiseto captivebelugawhalesandassess:(11behavioralresponses
suchas respirationrate, dive interval,
changes
in socialcombinations,
andchangein usageof areasin thepool,
and (21physiological
responses
monitoredby changesin bloodchemistries,especially
cetecholamine
levels.Baseline
behavioral
andbloodvalues were collected for two males and two females housedat Sea World,
SanDiegofor a 30-dayperiod.Playbacks
wereconducted
for 9 daysprecededby pretestobservations.
Theplaybacks
wererecordings
of SEDCO
708platformandsynthesized
drillingnoiseprojected
at about150dB re: I
/•Pa. The mannerin whichbehavioralparameters
andbloodchemistry
valueschangedduringthe playbacksof drilling noisewill bediscussed.
1:15
DD6. Aeonstietestingproceduresfor determiningthe potentialimpactof
underwaterindustrial noiseon migratinggray whales.CharlesI. Maline
and Paul R. Miles (Bolt Beranekand Newman Inc., 10 Moulton Street,
Cambridge,MA 02238}
A procedure
wasdeveloped
for observing
the trackpatternsandbehaytotof migratinggraywhalesoff Soberaries
Pointsouthof Monterey,
California. A seriesof acousticplaybackswere made at realisticlevels
froman anchoredvesselto simulatethepresence
of oil andgasdevelopmentandproductionactivities.In anotherseriesof tests,a seismicsurvey
vessel
witha 4000-in?air-gunarraywasnavigated
at progressively
decreasedrangesfrom the migratingwhales.This was followedby a test
sequence
using
avessel
witha single100-in.
-•airgun.Source
characteristic
andacoustictransmission
lossmeasurements
weremadeto permitprediction of the noiseexposure
for the nearbysubjectanimals.Exposurelevels
for whichobserved
behavioralchanges
occurredweredetermined.[Work
supported
by Dept.of Interior,MineralsManagement
Service.]
DD4. Behavioralresponses
of wildbelugawhalesIDelphinapterus
leucas•
to noisefrom oil drilling. Frank T. Awbrey and Brent S. Stewart(Hubba
SeaWorld ResearchInstitute,1700SouthShoresRoad,SanDiego,CA
92109}
Two seasonsof field observations
and playbackexperimentswith
southwest
Alaskanbelugawhaleshasestablished
thatwild whalesin their
naturalhabitatrespondmorenegativelyto suddenchanges
in soundlevel
than to sustained
sounds.Recordings
of noisefrom SEDCO 708 drilling
platformwereprojected,underwaterat 163 dB re: I pPa sourcelevel.
Whaleslessthan i.5 km from the sourceusuallyreactedto onsetof the
noiseby swimming
away.In twoinstances,
groupsof whalesthatwereat
least 3.5 km from the noisesourcewhen playbackstartedcontinuedto
approach.
Onegroupapproached
within300m beforeall or part turned
back.The othergroupsubmerged
andpassed
within 15m of theprojector.
Resultswereconsistentwith observations
of captivebelugas.
1:25
DD$. Sound and vibration levels in a ringed seal lair from seismic
profilingon the ice in the Beaufort Sea. D. V. Holliday (Tracor, Inc.,
9170 Chesapeake Drive, San Diego. CA 92123). W. C. Cummings
(Oceanographic
Consultants,
5948EtonCt., SanDiego,CA 92122),and
D.E. Bonnett(Tracor,Inc., 3505AndersonHill Road,Silverdale,WA
99393)
The ringedseal(Phocahispida)habitaton Alaska'sNorth Slopeis
subjected
to intensivelocalseismicenploration.During the winterand
springmonths,this sealconstructs
and maintainslairs for restingand
birthingon theicesurfaceundera snowcover.Measurements
of airborne
sound and vibration levels in a lair and underwater sound levels beneath
1:45
DD7. Effectsof underwaternoiseon migratinggray whalesoff the enast
of California.ChristopherClark IRockefellerUniversity,Tyrrel Road,
Millbrook, NY 12545}, Peter Tyack {Woods Hole Oceanographic
Institution,WoodsHole, MA 02543},James Bird ( 16Mead St., Apt. :•2,
Allstoa, MA 02134}, and Victoria Rowntree IWeston Road, Lincoln,
MA 017731
The potentialeffects
of man-made
underwater
noiseson thebehavior
of gray whalesIEschrictius
robustus}
off the Coastof centralCalifornia
werestudiedduringtheir southernand northernmigrationin 1983.In
January, two shore-basedthcodolite tracking sites recorded whales'
swimmingpatternsas well as behavioralactivitieswhile underwater
sounds{productionplatform,drilling platform,semisubmersible,
drillship, helicopter,or killer whale, Orcinusorcal were transmittedfrom a
vesselanchoredin the middleof the nearshoremigratorypattern.In April
and May, whenthe majorityof whalesweremother-calfpairs,threetheodolitetrackingsitesrecordedswimmingpatterns,behavior,andrespiration timesfor individuals.Experimentalnoisesourcesconsisted
of eithera
seismicvesseloperatinga 40-gun array, a vesseloperatinga singleair gun
or a stationaryvesselbroadcasting
eitherdrillshipor killer whalesounds.
The behavioralmeasuresusedto assaydisturbanceincludeddeflectionof
normalmigratorypattern,speedof travel, individualrespiration,synchronizingof mother and calf respiration,and ratesof behaviorssuchas
breachingor underwaterexpiration.[Work wassupportedby Minerals
Management
Service.]
1:55
the lair are reportedas a function 0f range to a seismicsoundsource
(Vibroseis")
operating
on theicenearReindeerIsland,northof Prudhoc
Bay, AK. Propagationlossesfor underwatersoundin the bandbetween
10 and 70 Hz werefrom 10 to 20 dB per doublingof range.Vibration
S54
DDS. Responses
of gray whales(Eschrichtius
robustus}
to nonbiological
noise. Marilyn E. Dahlheim (Department of Zoology, University of
British Columbia, Vancouver, BC, Canada V6T 2A9 and National
Societyof America
$54
Marine Mammal Laboratory,National Marine FisheriesService,7600
Sand Point Way N.E., Seattle, WA 98115) and H. Dean Fisher
(Department
ofZoology,UniversityofBritishColumbia,Vancouver,
Be,
CanadaV6T 2A9}
In orderto focuson theproblemof increasing
nonbiological
noisein
theenvironment
of thegraywhale(Eschrichtius
robustus)
andto answer
the questionas to howthisspecies
usesits acousticsignalingmostefficiently,a studywasundertaken
at LagunaSanIgnacio,BajaCalifornia
Sur,Mexico,in February1983to determinethe responses
of graywhales
to projectedsoundsources.
A seriesof underwater"playback"experimentswereconducted.
The playbackincludedtheprojectionof nonbiologicalas well as biologicalsoundsources.
The acousticaland behavioral
responses
of thewhaleswererecordedduringpretrial,trial, andpost-trial
playbackperiods.Soundswere projectedback only during the "trial"
periods.With theonsetof increased
levelsof man-madenoise,thegray
whale's acousticalactivities increased,as did the sourcelevelsof their
calls.Observations
onthebehavioral
activities
ofthesewhalesin response
to increased
noiseresultedin {1)prolongeddivetimesand{2}directmovementsonthepartof thewhalesawayfromthetransducers.
The acoustical
andvisualresponses
of thewhalesappearto differdepending
uponthe
soundstimulibeingpresented.
5948 Eton Court, San Diego, CA 92122)and D. V. Holliday (Tracor,
Inc., 9150Chesapeake
])rive, SanDiego,CA 92123)
Oneeffectofman-made
underwater
noiseispossible
maskingor other
interference
with soundsof whalesrequiringknowledge
of the source
level.In conjunctionwith a technicalfeasibilitystudyof acousticallocationin northernAlaska[W. C. Cummings,
TracorDoc.No. T-83-06-002U (1983)]numerouswhalesoundsourcelevelsweredeterminedbasedon
accuratedistances
usinga three-hydrophone
arraybaselineof 2.4 km. In
termsofdB re: 1/zPaat 1m (peakspectrumleveloverthedurationof each
signal),24 localizedsongelementsrangedfrom 158to 189,median 176.5
dB. The 33 localizedmoansrangedfrom 129to 170,medianof 158riB.At
a distanceof 10km, thisimpliesa theoreticalreceived
signal-to-noise
ratio
for songsof 36 dB, baseduponthe observedmedianambientlevelat 500
Hz, or 16 dB at maximumnoiselevel.However,baseduponour experiencewith theprevailingshallowwaterpropagation
losses
andnoisecharacteristics,
theS/N ratioof songs
canbeexpected
to approach
0 at about
15km, withmoans,5-10 kin. [Worksponsored
by theNorth SlopeBorough.]
2:05
2:25
DD9. Preliminary measurementsof sound attenuation by snow over a
DDI1. Interaction between offshore geophysicalexploration activities
and bowheadwhales in the Alaskan Beaufort Sea, Fall 1982. Donald
K. Ljungblad(Naval OceanSystemsCenter,Code5131,SanDiego,CA
92152}
model seal lair. William C. Cummings (OceanographicConsultants,
5948 Eton Court, San Diego, CA 92122) and D. V. Holliday (Tracor,
Inc., 9150 ChesapeakeDrive, SanDiego, CA 92123}
Becauseof their winter habit of denningin snow aboveArctic ice,
ringedseals,Phocahispida,may beexposedto airborneman-madenoise.
Incidentalto acousticalstudiesof winterseismicexploration[D. V. Ho]]i-
dayetal., J. A½oust.
Soc.Am. Suppl.l, thismeeting]a seriesof measurements was undertaken of airborne tones received in a model seal lair. Five
successive
layersof snow blockswere addedaround the sensor.Seven
tonesfrom 105to 10 $10 Hz wcrcplayedfrom a loudspeakerat two distances,0.8 and 11.5 m, throughthe accumulativefive layers(maximum
thickness,0.9 m}. This studywas undertakenoff PrudhoeBay, Alaska,
April 1983).The resultsindicatedan increasing
transmission
lossthrough
the "lair" wall of about6 riB/doubledthickness,an increasingdependencewith frequency{Hz}, and evidenceof significantpropagation
throughthegroundpath.It istentativelyconcluded
that,in thissituation,
snowmaybcan effectivebarrierfor higherfrequencyairbornenoise,but
attenuationis limited by flankingpropagationthroughthe underlying
medium.[Worksponsored
by NOAAs NationalOceanSurvey,Officeof
Oceanography
and Marine Services.]
2:15
DD10. Source levelsof bowheadwhale soundsdetermined by acoustical
array localization.William C. Cummings(Oceanographic
Consultants,
$55
Out of concernaboutthepotentialeffectsof marineacousticgeophysical surveywork on westward-migrating
bowheadwhales(Ba[aenamysticetus),the U.S. Minerals ManagementSer0ice(MMS), in consultation
with the U.S. National Marine FisheriesService(NMFS}, implementeda
programfor monitoringand regulatingsuchwork in the AlaskanBeaufort Seaduring1981and 1982.In 1982a twin-turbine,high-wingaircraft
was usedto surveysystematically
blockscoveringapproximately1400
km-*nearactively"shooting"
seismic
survey
vessels.
Directvisualobservation wassupplemented
by the useof sonobuoys
to listento and record
underwatersoundsmadeby vessels,
air guns,and whales.In additionto
the systematicsurveys,sustainedbehavioralobservationsof bowheads
weremadeon an opportunisticbasis,with the objectiveof identifying
possible
differences
in behaviorbetweenwhalesexposedto seismicsounds
and whalesnot exposedto seismicsounds.No major changesm whale
behavior(e.g.,flight reactions}wereobserved.Testsof statisticalsignificancewereappliedto data on numberof blowsper surfacing,meanblow
intervalper surfacing,surfacetimes,and dive times.Only meansurface
time of "adults" (i.e., all whalesother than cowsand calves)in the presenceand absenceof seismicsounds(1.67 + s.d.0.85 rain and 1.36 _+s.d.
0.59 min, respectively)was statisticallysignificant(t = 1.988, df= 89,
p < 0.05}. No statisticallysignificantdifferenceswere detectedfor other
behavioralparametersin the presenceand absenceof seismicsounds.
Societyof America
$55
WEDNESDAY
AFTERNOON,
9 NOVEMBER
1983
TOWN AND COUNTRY
ROOM, 3:15 TO 5:15 P.M.
Plenary Session
Frederick H. Fisher, Chairman
President,AcousticalSocietyof /lmerica
Presentation of Awards
HonoraryFellowshipto MauriceA. Biot
Trent CredeMedal to Eric E. Ungar
SilverMedalin Theoretical
andAppliedAcoustic•
to EugenJ. Skudrzyk
SilverMedal in SpeechCommunicationto Kenneth N. Stevens
Concert
BertramTuretzky, Conductor
Professor,
MusicDepartment,Unioersity
of Californiaat SanDiego
Musicianswill playa varietyof musicalpieceson thefamilyof eightstringinstruments
developed
by Carleen
M. Hutchinsand the CatgutAcousticalSociety.
WEDNESDAY
EVENING,
9 NOVEMBER
1983
6:00 P.M.
Busses
beginshuttleserviceto SanDiegoAerospaceMuseumand BuffetDinner
S56
S58
THURSDAY MORNING,
10 NOVEMBER 1983
SENATE/COMMITTEE
ROOMS, 8:00 TO 11:55A.M.
Session
EE. PhysicalAcoustics
IV andUnderwater
Acoustics
IV: Acoustical
Properties
of PorousMedia
Thomas J. Plona, Chairman
Schlumberger-Doll
Research,
P.O. Box307,Ridgefield,
Connecticut
06877
Invited Papers
8:05
EEl. Acoustic
properties
of porous
media.DavidLinton Johnson
andThomasJ. Plona(Schlumberger-Doll
Research,
P.O. Box307,Ridgefield,
CT 06877)
Thelong-wavelength
acoustic
properties
of two-component
composites
isreviewed
andit isshownthatin
orderfor sucha system
to havetwodistinctlongitudinal
modes,
onecomponent
mustbea fluid,theothera
solid,andeachmustformitsownpercolating
cluster.
TheBlottheory,whichtreatsthetwodisplacements
ona
separate
andequalfooting,is shownto givean excellentdescription
of a widevarietyof suchsystems
which
include:
thediffusive
modein polymergels,4th soundin superfiuid/superleak
systems,
thediffusion
of a fluid
pressure
pulsethrougha poroussolid,andtheadditional"SlowWave"recentlyobserved
in a varietyof watersaturated
porous
materials.
It isshownhowonecanindependently
measure
all thenecessary
inputparameters
andsuccessfully
calculatethe effectof fluid saturationon the measured
speeds.
The essential
connection
between
theacoustic
properties
andtheelectricalproperties
of poroussolidsismade.Finally,it isshownthat,
ingeneral,
standard
multiplescattering
theories
withinthesinglesiteapproximation
areintrinsically
incapable
ofgiving
even
aqualitative
description
oftheacoustic
properties
ofsuch
bipercolating
systems;
theexception
is
whenonecomponent
doesnot percolate
asoccurs,for example,in a suspension.
8:30
EE2. Marine sedimentacoustics.Robert D. Stoll (109 Oceanography,Lamont-DohertyGeological
Observatory,Palisades,
NY 10964)
Theprediction
ofvelocityandattentuation
in acoustic
waveswhichpropagate
throughmarinesediments
is
of keyimportance
in manysurveillance
andexplorationtechniques.
A mathematical
modelof thesediment
mustreflecttheinfluence
of suchparameters
asporosity,overburden
stress,
particlesize,andlithification.
The
general
theoryof Biothasbeenusedtoconstruct
a modelwhichhasbeensuccessful
in estimating
propagation
characteristics
in a widevarietyof sediments.
Two kindsof viscous
dampingareincludedin themodel.One
dealswith theoverallmotionof the interconnected
fluid fieldwith respectto the skeletalframe.The other
accounts
for localfluidmotionnearthegraincontacts
whichproduces
a viscoelastic
response
similarto the
"squeeze
film" phenomenon
in lubricationtheory.Recentexperimental
data for sandstone,
sand,silt, and
othersediments
showthatthevariousformsofviscous
dampingproducea frequency
dependent
Q in virtually
all water-saturated
sediments.
New dataarepresented
for sandandsilt in thefrequency
rangeof 2-1500 Hz
whichdemonstrates
theeffectsof bothkindsof viscous
damping.[Work supported
by ONR.]
8:55
EE3.Internalfrictionandmodulus
dispersion
influidsaturated
porous
rock.B.R. Tittman,J.R. Bulau,and
M. Abdcl-Gawad(RockwellInternationalScience
Center,ThousandOaks,CA 91360)
In the exploration
for gasandoil, the interpretation
of seismic/acoustic
well loggingdatarequiresan
understandingof the interactionbetweenacousticwavesand rock under in-situ conditions,i.e., combined
effects
of pressure,
temperature,
andporefluid.Our recentlabstudies
haverevealed
a significant
internal
frictionpeakandan associated
modulusdispersion
in eoconino
sandstone
whenthe frequency(88-550Hz)
and/orfluidviscosity
(0.0025-!3.5poise)isvariedatelevated
effective
pressures
to 3.4X 107Pa.Theresultsarc
consistent
with a linearrelaxation
mechanism
involvingthe flowof a ruscous
intergranular
fluidwith a
characteristic
timeproportioned
tofluidviscosity.
Theliquid"squirt"-type
modelofO'ConnellandBudiansky
(1977)predicts
a relaxation
peakat thevalueof frequency-viscosity
observed
in thisstudy.
The presentation
will discuss
the experimental
approach,
the data,their interpretation,
andtheirapplication
to exploration
seisinology.
[Worksupported
by Consortium
of Petroleum
Companies.]
9:20
EEA.Onthedragandvirtualmass
cOefficients
inBiot'sequations.
A. Bedford,
M. Stern,
andR. D. CostIcy
(AppliedResearch
Laboratories,
The Universityof Texasat Austin,Austin,TX 78712-8029)
Considera hypothetical
experiment
in whichthesolidconstituent
of a fluid-saturated
porousmediumis
subjected
to a uniformoseillatorymotion.Biot'sequations
canbesolvedfor thedragandvirtualmasscoeffi-
$57
J. Acoust.Soc.Am;Suppl.1, Vol. 74, Fall 1983
$57
cientsin termsof theresulting
oscillatory
motionof thefluid.Assuming
theporestobecylindrical,themotion
of thefluidhasbeendeterminedby subjecting
thewall of a cylinderof viscouscompressible
fluidto a uniform
oscillatorymotionandaveraging
the resultingfluiddisplacement
overthe volumeof thecylinder.Motions
parallelto andnormalto the axisof the cylinderhavebeenconsidered.
In the caseof motionparallelto the
cylinderaxis,theobtainedcoeffcients
areequivalent
to thosederivedbyBiot[J.Acoust.Soc.Am. 28, 179-191
(1956)]andHovemandIngram[J.Acoust.Soc.Am.66, 1807-1812{1979)].Bysuperimposing
theparalleland
normalcases,
thecoeffcients
for cylindricalporesat an arbitraryangleto thepropagation
directionhavebeen
obtained.Then, by averagingwith respectto the angle,the coefficients
havebeendeterminedfor a material
containing
poresof randomorientation.[Worksupported
by theONR.]
ContributedPapers
9:45
EES. Theoreticaland experimentalstudyof porousabsorbingmaterial.
J. -L. Berry, J. Nicholas,and B. Malrical (D6partement
de g6nie
m6canique,Universit6de Sherbrooke,
Sherbrooke,
Canada,JIK 2R 1}
Porousceramichasraisedconsiderable
interestgiventhe greatnum-
berofapplications
of itsabsorbing
andinsulating
properties,
bothindoors
and outdoors.Numerousexperimentswith a Kundt tube enableus to
evaluatethesoundabsorbing
characteristics
of ceramicsamples
with variable flow resistivities
{5-100 cgs},thickness(20-90 mm} and porosities
(60%-80%}. The mostimportantfactorswereshownto beflowresistivity
and thickness.Subsequently,
a theoreticalanalysiswas carriedout in
termsof normalincidenceabsorptioncoeffcientusingthe followingimpedancemodels:Delany andBazley,Beranek,eremet, and morerecently
Attenborough.Material thicknessand the presenceof rear air space(or
other material}are alsotaken into accountin order to simulatemore
accuratelypracticalsituations.It was found that Cremer'sapproach
adaptedempiricallyto ceramicsgivesthe bestprediction.Thanksto this
study, the optimal flow resistivityand thicknessmay be determinedto
obtainthebestcost/performance
ratio.•1AlsoatC.R.I.Q.,Ste.-Foy,
Quebec,Canada
GIV 4C7.
significantly
reduces
the scattering
losses
(byan orderof magnitudeat a
givenfrequency
in dry glassbeads}.
Decreasing
porefluidcompressibility
producesa corresponding
decrease
in the scatteringlosses.
This work
showsthat theoreticalmodelsbasedon suspensions
are not adequate
whenthegrainsareinteracting
to forma solidframe.The presentdata,
alongwithprevious
dataforfusedglassbeads,suggest
thatthescattering
strengthis relatedto thecontrastbetween
theacoustic
properties
of the
composite
and of the grains.
10:15
EES. Estimationof the components
of anisotropicpermeabilityfrom
observations
of acousticanisotropy.Wm. MansfieldAdams (Hawaii
Instituteof Geophysics,
Universityof Hawaii,HonoluluHI 96522),
StephenW. Wheatcraft,and JohnW. Hess(DesertResearchInstitute,
Universityof Nevada,Reno,N V 89506)
Decisions
onpositioning
of monitoring
wellsin thevicinityof hazardouswastesitescanbesignificantly
affected
by knowledge
of thenatural
anisotropichydraulicconductivity.That the verticalpermeabilityis
usuallylessthan the horizontalpermeabilityis well known:however,the
9:55
EE6. Grain contactsand viscousrelaxation.William F. Murphy, III,
Kenneth W. Winklet, and Robert L Kleinberg (Schlumberger-Doll
Research,P.O. Box 307, Ridgefield,CT 06877}
A micromechanical
modelis developedfor acousticattenuationand
dispersionin sedimentarymaterialssuchas sandstones.
The theory de-
cribestheresponse
of two grainsin contactto smallsinusoidal
loadings.
Surfaceenergyandfluidsaturationareincludedexplicitly.Grain surfaces
are microscopicallyrough and irregular. We postulatethat contact
betweengrainsformsnumeroussmallsolid-solidcontactsand that narrow interconnected
gapsremainbetweenthe surfaces.As the grainsoscillate, liquidmustbe squeezed
out of and suckedbackinto the gaps.The
contactrelaxationundernormalforceishydrodynamic.The theoryoffers
a unified explanationof severalheretoforeapparently unrelated experimental observations.The resultingequationspredict the stiffnessand loss
asa functionof frequency,effectivepressure,fluid adsorption,saturation,
viscosity,and temperature.Insofaras the micromechanical
predictions
relateto continuumacousticproperties,the agreementwith observationis
excellent.
anisotrophy
in thehorizontalplanemayinfluence
thechoiceof positions
forthosemonitoring
wellsthataredowngradient
fromthewaste-managementarea.Very little informationon the horizontalanisotropy
is available. Furthermore, field measurementsto estimatethe horizontal anisot-
ropyare expensive
because
at leastthreeinteractingwellsare necessary,
withmorethanthreebeingpreferred.The Kozenyequationsuggests
that
directionalanisotropyof the electricalconductivityof a porousmedia
shouldcorrelatecloselywith the anisotropy
of the permeability
[S. J.
Pitson,Geological
WellLog.4nalysis
(GulkPubLCo., 1981},p. 135].A
closerelationship
shouldalsoexistbetween
theacoustic
anisotropy
and
the anisotropy
of the permeability.
Recentadvances
in techniques
for
measuringacousticvelocitiesin a boreholemakeit feasibleto obtainesti-
matesof theanisotropy
of thepermeability
fromobservations
of theanistropyof theseismicvelocities.
[Worksupported
by EPA.]
10:15
EE9. The absorptionof sound by anisotropicporous layers.
Shawn Burke{Dept.of MechanicalEngineering,
Massachusetts
Institute
of Technology,Cambridge,MA 02139}
An analyticalmodelwhichdescribes
the effectof a directionalanisot-
ropyof acoustical
properties
in poroussoundabsorbers
ispresented.
The
10:05
EE7. Effects of pressureand fluid saturant on ultrasonic scatteringin
obliqueincidenceimpedanceof an anisotropicporouslayer is derivedin
termsof the material'sflow resistance,
effectivemass,and phasevelocity
measured
in two directions.The impedance
boundaryconditionis shown
glass beads. Kenneth W. Winklet and William F. Murphy, III
(Schlumberger-DollResearch,P.O. Box 307, Ridgefield,CT 06877)
tobestronglydependent
upontheabsorber's
transverse
complexvelocity,
aswellason theangleof incidence.
Valuesof theimpedance
andoblique
incidenceabsorptioncoeffcientfor a layer of Fiberglasare calculated
Compressionalwave phasevelocity and attenuationhave been measured in packingsof unconsolidatedglassheadsas functions of external
confining pressure.Samples were studied when vacuum dry and when
usingexperimentalanisotropicparameterdata. The random incidence
soundabsorptioncoeffcientis thencalculatedfor threeboundarycondition modelsof the Fiberglas,overfrequencies
rangingfrom 300-1200 Hz.
The anisotropicmodelpredictsabsorptioncoefficients
that agreebetter
saturatedwith diffcrcnt pore fluids. Prcssurc/porefluid combinations
werechosento minimizenonscattering
Jossmechanisms.
Phasevelocity
exhibitsnegativevelocitydispersion
andattenuationisproportionalto the
fourth powerof frequency.Increasingconfiningpressure(to 15 MPa)
S58
with reverberation
chamberdatathaneitheran isotropicbulkreacting
modelor a locallyreactingmodel.The absorptioncoeffcientis shownto
be insensitiveto weakanisotropies.
Societyof America
10:35
EEIO. Sound propagationin Hell with partially locked normal
component. Steve Baker, Daniel Rudnick, a• and lsadore Rudnick
(Department
of Physics,
UCLA, LosAngeles,
CA 90024)
Weconsider
theconsequences
ofintroducing
a flowresistance,
R, into
thesuperfluid
equations
ofHel•.Wefind:(I) Thedimensionless
quantity
thatcharacterizes
flowresistance
in He• isR/p•to•r. (2)In a superleak
Theworkreportedhereisanextension
of thatby Kuntz[NASA CR
167979,September
1982;seealsoJ. Acoust.Sec.Am. Suppl.1 69, S80
(1981
}],whoinvestigated
thenonlinear
behavior
ofintense
sound
propagatingthroughair-filledbulkporous
materials.
Theprimarypurpose
of
thecurrentworkistoexplainsomeof Kuntz'sexperimental
observations.
Ourmodelisbased
ontheassumption
thatthenonlinear
flowresistivity
of
thematerialisfar moreimportantthantheordinaryhydrodynamic
nonlinearities
thataffectanopenfluid.It isfurtherassumed
thatthenonlin-
there is a continuous transition from first to fourth sound and from second
earresistance
termis proportional
to eitheru2sgn(u)or u3,whereu is
soundtoa diffusive
thermomechanical
(TM) waveasr increases
from0 to
oo.(3)In a pressure
released
system(suchasa shallowpuddleof He• ona
particle velocity. Both forms lead to harmonic distortion of the "cubic"
flat substrate)thereisa continuoustransitionfrom secondsoundto a TM
surfacewaveand from gravitywaveto a diffusiveTM surfacewaveasr
areexclusively
oddharmonics.
Thisandotherpredictions
aresupported
by Kuntz'sdata.The modelis thusverified.[Worksupported
by NASA
increases
from0 to co.(4)Foreachsystem
theattenuation
perwavelength
forthepropagating
modeisa maximumnearr = 1,decreasing
monotonicallyasr•O, •o. [Worksupported
by ONR.] •1Present
address:
Scripps
and ONR.]
Instituteof Oceanography,USCD, LaJolla,CA 92093.
type.In thiscasethedistortioncomponents
of aninitiallysinusoidal
wave
11:15
EEl4. A comparison between Biot model predictions and shear wave
attenuation measurementsin unconsolidatedlaboratory sediments.
10:45
EEll. Acousticscatteringcorrectionin a superleakpartially filled with
superfluldhelium. S. Baker, J. Marcus, G. Williams, and I Rudnick
(Departmentof Physics,University of California, Los Angeles,CA
90024)
The index of refraction n has been measured for the sound mode which
propagates
in a superleak
partiallyfilledwithHe•l sothattheliquidforms
a film on the powdergrains.The modeis a thickness
wavein thisfilm.
Motivatedby a modelwhichtreatsthescattering
fromthepowdergrains
independently
from the scatteringfrom the vaporspaces,we determine
thevalues
ofbetain theequation,
n2= f o,p o,, wherefisthefraction
of the porevolumefilledwith liquidHef• and P is the fractionof the
volumeoccupied
by bothliquidandvapor4He.The valuesof betaare
interpreted
in termsof thetortuosityof the microscopic
geometry.
The
scattering
correctionhasbeenmeasured
for0.3 < f< 1.0.In thisrangethe
agreement between the data and the model is excellent with values of
/•j•0.71 and/g2_•1.3.Whenf=
1,theporesarefilledwith liquidandthe
system
isa fourthsoundresonator.
Thevalueof n2isin excellent
agreementwith directlymeasured
fourthsoundvalues.[Work supported
by
ONR•]
Burlie A. Brunson(PlanningSystemsIncorporated,7900 Westpark
Drive, Suite600, McLean, VA 22102)
Shearwaveattenuationmeasurements
weremadeusingthreedifferent water-saturated
sediments.
The sedimentassemblages
usedin theattenuationmeasurements
includedwell-sortedsphericalglassbeads,a
well-sorted
angularquartzsand,anda moderately
sortedangularquartz
sand.The mediangrainsizeof the sedimentswasheld constantwhile the
grainshapeandsizedistributions
werevaried.Sediment
physicalproperties were measuredunder the sameconditionsprevailingduring the
acousticmeasurements.
The propertieswereusedasinputsto a theoreticalattenuationmodelbasedon theBlottheoryof propagation
of wavesin
porousmedia.The modelallowedattenuationversusfrequencypredictions to be madefor eachof the three sedimentassemblages
over the
measurement
frequencyrangeof 1-20 kHz. The resultantcomparisons
betweenthe measuredand predictedattenuations
demonstrated
the importanceof usingmeasured
modelinputsobtainedundercontrolledlaboratoryconditionswhentheoreticalmodelcapabilitiesarebeingevaluated.
The modelcomparisons
shedsignificantlight on the abilityof thisparticular model to predict shear wave attenuationin nonidealsediments.
[Work supportedby NORDA.]
11:25
10:55
EEl2. Couplingof airbornesoundinto the porouselasticsurfaceof the
Earth. Henry E. Bass,Lee N. Bolen,and JamesM Sabatier(Physical
AcousticsLaboratory,The Universityof Mississippi,University,MS
38677)
The surfaceof theEarthcanbemodeledasan elasticmediumpermeated with pores.This porousnaturehasenabledprior investigators
to
explainmeasurements
ofsoundpropagation
in thevicinityoftheEarthby
describing
thesurfaceasa locallyreactingboundary.Physically,onecan
envisionthepressure
variationsassociated
with soundwavepassage
forcingair flowin thepores.Someof thisenergyislostto theporewallsdueto
viscous
dragandthermalconduction.
Viscousdragcauses
thesolidskeletonto movegivingriseto a seismicwavein theframe.Thiswavehasbeen
measuredwith geephones.This physicaldescriptionconformswell to
Biot'sdescriptionof soundwavesin a porousmediumand that theoryhas
beenusedto modelthecouplingprocess.
Specifically,
thecomplexpropagationconstants
havebeencalculatedusinga codedeveloped
by Attenboroughwhich includesporetortuosityand thesepropagationconstants
havebeenusedto computegeophone
andburiedmicrophone
response
in
a porousmediumbelowan air half spaceand abovean elasticlowerhalf
space.Computerresponse
will becompared
withmeasurements
reported
earlier.[Worksupported
by ARO.]
11:05
EEl3. Propagationof intensesoundin fibrousbulk porousmaterials.
D. A. Nelson,D. T. Blackstock(AppliedResearchLaboratories,The
Universityof Texasat Austin,P.O. Box8029,Austin,TX 78712-8029),
and N. D. Perreira (Departmentof Mechanical Engineering,The
Universityof Texasat Austin,TX 78712)
S59
J. Acoust.$oc.Am.Suppl.1, VoL74, Fall1983
EELS. Grain shape and sorting effects on shear wave attenuation in
unconsolidatedlaboratory sediments.Burlie A. Brunson (Planning
SystemsIncorporated,7900 WestparkDrive, Suite 600, McLean, VA
22102)
Shearwaveattenuationmeasurements
were made usingceramicbimorphtransducers
to excitetransversevibrationsin a cylindricalcolumn
of unconsolidated
sediment. Three different water-saturated
sediments
wereusedin anattempttodetermine
theeffects
ofgrainshapeandsorting
on the frequencydependence
of attenuation.The meangrainsizeof the
sedimentswasheld constantwhile the grainshapeand sizedistributions
werevaried.The sedimentassemblages
usedin the attenuationmeasurementsincludeda moderatelysortedangularquartz sand,a well-sorted
angularquartzsand,andwell-sortedsphericalglassbeads.The moderately sortedsandshowedthe greatestattenuationover the measurement
frequencyrangeof 1-20 kHz. The well-sortedsandand the glassbeads
showedgenerallylower attenuationwith the beadsbeingthe leastlossy
propagationmedium. All three sedimentsshowedevidenceof viscous
attenuationdueto fluid-to-grainrelativemotion.Thismechanismleadsto
a nonlineal'
relationship
betweenattenuation
andfrequency.
[Worksupportedby NORDA.]
11:35
EEl6. Effectsof the hydraulicanisotropyand the elasticanisotropyof a
porous bottom on the acoustic propagation in shallow water.
Tokuo Yumamoteand Mohsen Badicy(Divisionof OceanEngineering,
RosenstielSchoolof Marine and AtomsphericScience,Universityof
Miami, Miami, FL 33149-1098)
The layeredanisotropicporousbottom was modeledby the stressdisplacementmatrix derivedfrom the Blot equationsfor the anisotropic
Societyof America
559
porousmedia.The effectson the acousticmodeattenuationof the anisotropyin thepermeabilityandtheelasticmoduliof sediments
werecalculatedfor therealisticrangeof thephysicalproperties
of naturallyconsolidatedsanddeposits
andthefrequencyrangeof 10-3000H z. It wasfoundthat
the anisotropyin permeabilityhasa significantinfluenceon the acoustic
modeattenuationwhile the anisotropyin the elasticrapdullhasa small
influence.[Worksupported
by ONR.]
We haveinvestigated
theultrasonic
properties
of water-saturated
porousgraphiteas a planarsampleis rotatedin the field of an ultrasonic
beamoverthe frequencyrangeof 0.1-10 MHz. Amplitudespectraare
calculated
for a rangeof rotationalanglesandshoweffectsdueto reflection and refractionof the beam,mode conversions,and extensiveattenu-
ation and dispersionin the bulk materials.Correctionsdue to the finite
widthanddiffraction
ofthebeamaretobetakenintoaccount
toshowany
shiftsin timedelaythatmightaffectthe accuracy
of thedata.Energy
conversion
toa shearmodeat "normal"incidence
isclearlydemonstrated
in the time domainsignalsand shownto accountfor shiftsin apparent
11:45
amplitudeof the longitudinalmode.Our resultsdemonstratethe effecEEl7. Angle-resolvedspectroscopyof fluid-filled porous graphite.
tiveness
ofdigitalsignalprocessing
andselective
windowing
in FFT anal-
J. F. Muratore and Herbert R. Carleton(Collegeof Engineering
andAppliedScience,
SUNY at StonyBrook,StonyBrook,NY 11794)
ysisin studyingthedifferentmechanisms
involvedin thebehaviorofsuch
highlydispersive
materials
subject
to elasticwavepropagation.
THURSDAY
MORNING,
10 NOVEMBER
1983
COUNCIL/CHAMBER
ROOMS, 9:00 A.M. TO' 12:20P.M.
SessionFF. EngineeringAcousticsIV and Musical AcousticsV: Harry F. OlsonMemorial Session
Harry B. Miller, Chairman
Code3234, Naval UnderwaterSystemsCenter,New London,Connecticut06320
Chairman's Introductionre9:00
Invited Papers
9:08
FF1. Somepersonalrecollections
of earlyexperiences
onthenewfrontierof electroacoustics
duringthelate
1920s
andearly1930s.
FrankMassa
(Massa
Products
Corporation,
Hingham,
MA 02043)
Duringthisbriefpresentation,
timewill beturnedbacka half-century
to permitsomepersonal
recollections
ofearlyexperiences
asweexploredthenewfrontiersin electroacoustics.
Theavailabilityofthevacuumtubefor
theamplification
of weaksignals
madepossible
the practicalapplication
of a varietyof wide-range
lowsensitivity
transduction
techniques
for thegeneration
andreproduction
of sound.Our trainingin electrical
engineering
provided
anunderstanding
ofelectrical
measurements
anddesign
techniques
thatwecouldadapt
for newspecialized
usesduringour earlystagesof acousticmeasurements
andelectroacoustic
research.
The
demands
of the newtalkingpictureindustryfor improvedelectricalrecordingandreproduction
of sound
helped
finance
thecosts
ofelectroacoustic
research
whichresulted
inrapidprogress
inthesoundreproduction
andrecording
industry
duringtheearly1930s.In lessthana decade
thereproduction
ofsoundwastransformed
fromtheprimitive
limitedfrequency
rangeofthemechanical
phonograph
tothehighqualityelectrical
recordingandreproduction
madepossible
by therapidadvances
in electroacoustic
engineering.
9:35
FF2. RTSKED, a real-timescheduled
language
for controlling
u musicsynthesizer.
M. V. Mathews(Bell
Laboratories,Murray Hill, NS 07974)
H. F. OlsonhelpedcreatetheRCA synthesizer.
Thismachine
wasthefirstto usesophisticated
digital
control.Controldatawerepunched
intoa widerollof papertapeusinga binarycode.Newtechnology
has
superseded
papertape•butcontrolremains
theprincipalproblemfor modernsynthesizers.
Precise
controlof
thetimingof eventsin musicis difficultfor storedprogramcomputers.
A controllanguage
isdescribed
in
whichthecomputer
executes
a schedule.
A schedule
differsfroma normalprogramin thatcommands
andthe
timesat whichthesecommandsareexecutedareseparatelyspecified.
thusmakinga cleanseparationbetween
whatthecomputerdoesandwhenit isdone.Timescanbespecified
in absoluteterms(waitsomanymillisec-
onds)orbespecified
in relativeterms(waituntila performer
presses
a particularkey).Thelanguage
isintended
tocontrol
real-time
performance.
It allows
theflexible
combination
ofinformation
froma score
inthecomputer memorywith information
generated
by the performerplayingon a keyboardor on othersensors.
Early
experiments
indicatethatRTSKED iseasyto learn,pleasant
to use,andpowerful.
10:05
FF3.Theory,ingenuity,
andwishfulwizardryin loudspeaker
design•Ahalf-century
of progress?
George
L. Augspurger
(Perception
Inc.,Box39536,LosAngeles,
CA 90039)
Duringthepast50 yearsthecourse
of professional
loudspeaker
designhasbeenwell-documented.
The
historyof high-fidelity
consumer
products
islessfamiliarandmoreerratic.Loudspeaker
designers
seemto
S60
J.Acoust.
Soc.
Am.Suppl.
1,Vol.74,Fall1983
106t
hMeeting:
Acoustical
Society
ofAmerica S60
haveembodied
threearchetypes
invarying
proportions:
theelegant
theoretician,
theinspired
tinkerer,
andthe
wishful
wizard.
A briefexamination
ofsome
oftheirenduring
successes,
ephemeral
favorites
andresounding
failuresispresented.
10:35
FF4.Some
reinafire
onelectro-mechano-acoustieal
circuits.
LeoL. Beranek
(7Ledgewood
Road,Winchester,
MA 01890)
Theadvanced
development
ofelectro-mechano-acoustical
circuits
dates
intheUSAfromFirestone
(1933},
Mason(1941),
Olson(1943},
LeCorbeillier
andYueng(1952),Bauer(1953),
andBeranek
11954).
Although
the
connection
between
theequations
ofradioandacoustic
wavemotionwasclearlyrecognized
byHelmholtz
and
pointed
upbyRayleigh,
theuseoflumped-element
circuits
wasbrought
onbytheadventofradio.Significant
useof electrical
(radio)analogies
wasmadebyDarrieus
(France,1929)andHaehnle
(Germany,
1932).This
papertreatstheperiodin whichOlson's
workwascentered
andcitessome
examples
ofproduct
development
thatwereinfluenced
by theconcepts
of electro-mechano-acoustical
circuits.
11:05
FF5. Magneticrecording,ImStandI}resent.Marvin Camras(IIT ResearchInstitute,10 West35th Street,
Chicago,IL 60616}
Whyistheoldcomplaint
true:"Theancients
havestolen
ourinventions?"
Therearegoodreasons:
It iseasy
to propose
something,
difficultto makeit work.Excellentideasareoftendiscarded
whena triflingmistake
givesnegative
results;
latera luckierdiscoverer
getsthecredit.Casehistories
in magnetic
recording
illustrate
thesepoints.Metalparticletapewasproposed
95 yearsago.Highfrequency
biashaditsrootsin theMarconiMuirheadwireless
detector
of 1902.Digitalrecording
goesbackat leastto Morse'stelegraph
of 1840.The
rotating-head
principle
usedfor videorecorders
datesbackaboutthreedecades
beforeit became
practical.
Sendust
usedin the latestrecording
headswasinventedin 1936.Magneticdisks,theimportantmemoryof
personal
computers,
weredemonstrated
in about1905.Soundstriping
formotionpicturefilmgoesbacktothe
early 1920s.Personalexperiences
of failuresand successes
are related.
11:35
FF6. Fifty years of stereoIlhonographs:
A eal}sulehistory. C. Roger Anderson(ShureBrothersInc.,
Evanston,IL}
Fromthe45' diskrecording
system
shownin the 1933benchmark
stereoworkof Blumleinto thepresent
daygenerations
of pickupswithultrasonic
capabilities
isa longevolution
of analyticandengineering
effort.
Thispaperisa recognition
of advances
alongtheway,suchasthetheoryof tracingdistortion,styluscontours,
transducer
principles,
lightandstiffmovingsystems,
trackingrequirements,
andthedesigninsightthatledto
contemporary
pickupswhichperformsuperblyat l-g stylusforce.
11:50
FF7.
Engineering
highlights
oftheLPrecord.
Daniel
W.Gravereaux
(Recording
Research,
CBS
Technology
Center,227 High RidgeRoad,Stamford,CT 06905}
For 35years,thelong'playing
microgrove
33•rpmdiskrecordhasbroughtthehighest
fidelityprogrammingof anymassmediato theconsumer.
Thisisdueto thevaluedeffortsof manyengineers,
scientists,
and
technicians
inthedevelopment
andimplementation
ofmicrogroove
mastering
techniques,
cuttingandplaying
transducers,
electroplating,
stamping
techniques,
lacquerblanks,cuttingstyli,mastering
lathes,presses,
and
vinylformulation.
Thispaperpresents
a fewofthehighlights
intheengineering
ofthemoststandardized
sound
medium in the world--the
LP.
12:05
FFS. Reminlselng--Thestereol•honic
record.H. E. Roys(RCA Records,327 S. PascoChico,GreenValley,
AZ 85614)[Authorwill not presentpaper.]
The authorbecameactivein thesoundrecordingfieldin theearly 1930sand remainedactivein that field
untilretirementin 1967.When,in 1957,twoslightlydifferentsystems
of recordingstereophonic
recordswere
introduced
forstandardization
hewasa member
oftheengineering
committee
oftheRecordIndustryAssociationof AmericaandChairmanof thePhonograph
Committeeof theElectronicIndustriesAssociation.
The
situation
wasuniquein thatstereophonic
recorders
andpickups
werenotreadilyavailable
andthechoicefor
standardization
had to be basedlargelyupontheoreticalconsiderations.
The differencebetweenthe two was
slight.The V-L systemrecordedonechannelverticallyandthe otherlaterally.The 45-45 systemrecorded
bothchannels
vertically,
butat a 45øanglewithrespect
to thesurface
ofthedisk.Recordengineers
in Europe
gatheredanddecidedin favorof the45-45 system.Engineers
in thiscountrydid likewise.Thusfor thefirsttime
in thehistoryof records
a common
agreement
withrespect
to standardization
wasreached
priorto mass
production.
S61
J. Acoust.Soc.Am.Suppl.1. Vol.74. Fall1983
Societyof America
•611
THURSDAY
MORNING,
10 NOVEMBER
1983
CALIFORNIA
ROOM, 9:00 TO 11:50 A.M.
SessionGG. ArchitecturalAcousticsV and Noise V: Measurements,Methods, and Materials
Alfred C. C. Warnock, Chairman
NationalResearchCouncilof Canada,Divisionof BuildingResearch,
MontrealRoad,Bldg.M-27, Ottawa,Ontario,
Canada K1A OR6
Chairman's Introductinn•9:00
ContributedPapers
9:05
GGl. Spatinltrnnsformationofsoundfields.
J•rgen HaitiandOle Roth
(Briiel& Kj•er, N•erumHovedgade18,DK-2850 N•erum,Denmark)
In thispaperit will bedemonstrated
howcrossspectrameasured
by a
modified1/3 octaverealtimeintensityanalyzerduringa planarscancan
beusedto predictpressure,
particlevelocity,and intensityin a half-space
not containingthe sourceof the (noise)field. We just have to assumea
ratherlimitednumberof significant
uncorrelated
components
in the total
source.In the nearfieldregionon bothsidesof the scanplanethe field
quantities
areevaluated
usinga nearfieldholography
technique
similarto
thetechniquedescribed
by Williams,Maynard,andSkudrzyk[J. Acoust.
Soc.Am. 68, 340-344 (1980)]for analysisof coherentsoundfields.Outsidethe nearfieldregionHelmholtz'integralequationis usedfor the prediction. The combined method allows various simulations to be carried
through.For examplewe can estimatea planar sourcedistributionby
meansof theholography
method,simulateanattenuation
of somepartof
thesource,andinvestigate
theeffectof thisattenuationon thefieldin the
entiresourcefree half-space.
9:20
GG2. A transducerand processingsystemto measuretotal acoustic
energydensity.Marc Schumacher
andElmerL. Hixson(Departmentof
ElectricalEngineering,
The Universityof Texasat Austin,TX 78712)
A four-microphone
orthogonalarrayis usedto determinetheacoustic
pressure
andthe threecomponents
of acousticvelocityoverthe rangeof
300-3000Hz. Signalsaresquaredandsummedto producepotential,kinetic, andtotalenergydensity.The threecomponents
of theintensityvector
canalsobedetermined.
Thedevicehasbeendesigned
for thestudyof and
improvedmeasurements
in reverberantand partiallyreverberantsound
fields.Somepreliminarymeasurements
in a reverberationroom will be
presented.[Work supportedby IBM Corp., Communications
Products
Div., Austin,TX.]
9:50
GG4. Acousticintensitymeasurements
in the reflectiveenvironment.
A. Mielnicka-Pate(Departmentof Engineering
Science& Mechanics,
Iowa StateUniversity,Ames,IA 50011}
The two-microphone
intensitymethodwas usedto investigate
the
intensitydistribution
andradiatedpowerof severalsources.
The sources
usedweretwo openpipesof 30-ramand 95-ram diameterand an alumi-
numcircularplateof 100-mmdiameter.The pipesandplateweremount-
ed with baffles.
The investigations
wereconfined
to the low-frequency
rangeof plane-wave
propagation
insidea pipe.The experiment
wasperformed in the nearfield and farfield of the sourcesin the reflective environ-
ment.The theoreticalandexperimental
resultswill bediscussed
for both
intensityandradiatedpower.The influence
of thesourceimpedance
will
beanalyzed
fortheintensity
measurements,
particularly
at pointslocated
closeto thesource.Theintensityerrorthatcanoccurdueto thepartial
absorptionof the reflectedwavesby the sourcewill bediscussed.
10:05
GGS. Effect of the sound field structure on the measurement of acoustic
intensity.G.W. ElkoandJiri Tichy(GraduateProgramin Acoustics,
P.
O. Box 30, StateCollege,PA 16801)
The effectof instrumentation
phaseandmagnitudeerroron the measurementof theactiveand reactiveacousticintensityfor differentsound
fieldswill be discussed.
We will showexperimentalresultsof measurementsmadefor theactiveandreactiveintensityin somesemireverberant
fields.An easymethodtocalculatetheeffects
ofphasebiaswillbepresented and demonstratedfor the experimentallymeasureddata. The measuredresultswill be comparedto theoreticallypredictedvaluesand the
measuringsystemwill be described.
9:35
GG3. Soundintensityerrorsin a reactivefield. JeanNicolasand
Gilles Letoire(Universit6de Sherbrooke,
G6niem6canique,
Sherbrooke,
CanadaJIK 2RI)
During the pastyearsmanyin situintensitymeasurements
havebeen
conductedby the authorslookingaheadfor a betterunderstanding
of the
phenomenainvolved when quantifyingsound power of a particular
sourcein the presence
of externalperturbstingnoise.It becameevident
that the limitationsdependon the followingquestion:is the field progressiveor reactive?A generalformulationisdevelopedfor bothtypesof field.
In a reactivefield,the fact that the instantaneous
phasevariationof the
pressu.re
isdifferentfrom that obtainedfor a progressive
fieldis takeninto
account.This leadsto enormousuncertainties
that havenocommonmagnitudewith errorsassociated
with progressive
field.In order to determine
theseuncertaintieswhen measuringsoundpower, a modelwith two or
morepoint sourcescreatingvariousdegreesof reactionon the measurement envelopeis used.It showsthe action and interactionof the main
parameters(powerratiosof the sources,distance,number,and spreadof
measurementpoints).Interestinglyenoughit is shownthat an increasein
the number of points does not reduce the uncertainty in the case of a
highlyreactivefield.
S62
J. Acoust.Soc. Am. $uppl. 1, Vol. 74, Fall 1983
10:20
GG6. A portable, low-cost, digital system for room acoustics
measurements.Robert D. Essen IArtec Consultants,Inc., 245 Seventh
Avenue, New York, NY 10001)
A portabledigitalacquisitionandanalysissystemhasbeendeveloped
arounda low-costmicrocomputer.
The systemconsists
of a programmable transientsignalgeneratorand an acquisitionand analysissection.
Designedprincipally for impulseresponsemeasurementsin both full scale
and modelrooms,the acquisitionsystemhasbeenconfiguredfor portability and easeof usein the field.Data is "captured"directlyinto the computermainmemoryand is storedin digitalform on floppydisks.A resident graphicsmodule can be used to display the impulseresponsein
variousformsand to displaythe soundenergydecaycurvecomputed
fromtheimpulseresponse
bybackwardintegration.
Generalpurpose
signal processing
softwarehas beenwritten for computationof Fourier
transforms,
powerspectra,cepstra,anddigitalfiltering.The useof Wiener filteringfor the deconvolutionof room impulseresponseand source
signalis beingimplemented,and is the subjectof a companionpaper.
Someresultsof measurementsmade in existingperformancespaceswill
be presented.
S62
10:35
GG7. Acquisitionand analysisof architecturalacousticdata usinga
microcomputer.E. Paul Palmer and Rodney Price (Departmentof
Physics
andAstronomy,BrighamYoungUniversity,Provo,UT 84602)
A microcomputer
iseasilyadaptedtothetaskofacquiring
upto 32-k
samples
of 8-bitdigitizedacoustic
dataat ratesup to 20 k bytes/s.This
makesit suitablefor acquiringandanalyzingarchitectural
datasuchas
impulseresponse,
reverberation
time,speechintelligibility,etc.We will
comparecomputer-simulated
and experimentally
obtainedimpulse-response
datafor a simplerectangular
room.Comparisons
will bemadefor
dataacquiredusinganintegrated-signal
sparksoundsource,a pseudorandom-sequence,
white-noisesource,and a swept-sine
source.Difficulties
metin usinga pseudorandom
sequence
of lengthdifferentfroma powerof-twowill bediscussed.
Somelimitationsmetin usinglow-resolution,
8bit data will be indicated.Systemvariationsand improvements
will be
firstorderregression
isfittedto theensemble
averageof a suitablenumber
ofdecaymeasurements.
Suggestions
by Bodlund;HalliwellandWarhock;
and Bartelfor detectingcurveddecaysare evaluated.Two additional
methods
are proposed.
It is demonstrated
with thehelpof statistically
simulated,
curveddecays
thata second-order,
linearregression
provides
a
betterestimateof the initialdecayratethana firstorderregression;
the
penaltyin calculation
timeisnotsevere.
Guidelines
for futureinvestigationsare proposed.
11:20
GG10. Comparisonof impedancemeasurement
techniques.
J.T. Mason,
G. B. Mills, S. L. Garrett (PhysicsDepartment, Code 61Gx, Naval
PostgraduateSchool,Monterey, CA 93940), and JamesL. Wayman
(MathematicsDepartment, Naval PostgraduateSchool,Monterey, CA
93940)
noted.
10:50
GGS. Influenceof reverberationroomvolumeon measuredabsorption
coefficients.A. C. C. Warnock (National ResearchCouncil Canada,
Divisionof BuildingResearch,
NoiseandVibrationSection,BuildingM27, Ottawa,Ontario,CanadaKIA OR6)
Theacousticimpedances
ofa Helmholtzresonator
andporousmaterialsweremeasuredusingtwo differenttechniques.
The firstmethodused
the conventionalStandingWave Ratio technique.The secondwas the
two-microphonetechniqueof Chungand Blaser[J. Acoust.Soc.Am. 68,
907-921(19801].
Thecalculability
of thefrequency
dependent
Helmholtz
resonator
impedance
allowedthemethodsto becompared
for bothabsolute accuracyand realtireprecision.[Work supportedby theNPS FoundationResearchProgram.]
Recentabsorptionmeasurements
in four roomsrangingin volume
from16to 250m3suggest
thatthemeasured
coefficients
depend
on the
logarithmof the room volume;i.e., smallerroomsgive smallercoefficients.Similareffectsaresuggested
by roundrobinmeasurements
in other
countries.Absorptioncoefficients
are alsofoundto dependon the decay
ratein the reverberation
roomwithoutthespecimen.
Theseresultswill be
presentedand their implicationswith respectto standardtestswill be
discussed.
11:45
GGI1. Effect of sealants on the sound absorption coefficients of
acousticalfriable insulatingmaterials.Mary K. Lory (Departmentof
Speechand Hearing, Universityof California at Santa Barbara, Santa
Barbara, CA 93106) and James L. Wayman (Department of
Mathematics,U.S. Naval PostgraduateSchool,Monterey, CA 939401
11:05
GG9. Best estimates of initial decay rates in reverberation rooms.
Richard M. Guernsey(Cedar Knolls AcousticalLaboratories,9 Saddle
Road, Cedar Knolls, NJ 07927)
The desideratum
in laboratorydecaymeasurements
is to geta good
estimateof the decayrate of the reverberantfield immediatelyafter the
sourceis turned off. When a decayis the superpositionof two or more
modeswith differentdecayratesthelevelis nota linearfunctionof time.
Thus we want to detect a curved decay and make a best estimateof its
initialdecayrate.Currently,a realtimeanalyzercontrolledby a digital
computerprovidesthe bestpracticalmeasurementof decays.A linear,
THURSDAY
MORNING,
10 NOVEMBER
Acousticalfriable insulatingmaterials(AFIM I, which often in the
pasthavecontainedasbestos,
havebeenusedfor soundcontrolsincethe
mid-1930s.Becauseof their widespreaduseand the easeof fiberdissemination,friableasbestos
materialsare consideredto bethe majorsourceof
asbestos
fibercontaminationin the indoorenvironment.Encapsulation
of
asbestosmaterialswith a commercialsealantproduct is one of several
methodsusedto controlpotentialasbestos
exposurein rooms.A sealant
productthat preserves
mostof the acousticalpropertiesof the materialis
preferredin thisusage.In thisstudy,AFIM samplematerialsweretreated
with sixtypesof sealantsandtheeffectson normallyincidentabsorption
coefficients
from 100-2500 Hz weremeasuredusinga fixed,dual-microphonetechnique."Penetrating"type sealantswerefoundto havea less
detrimentaleffecton soundabsorptionthanthoseof a "bridging"type.
1983
SUNRISE
ROOM
9:00 TO
11:35 P.M.
SessionHH. PhysiologicalAcousticsII: Measurementof the Ear; EvokedPotentials
David L. McPherson, Chairman
Departmentof Pediatrics,Universityof California,Irvine, 101 City Drive, Orange,California92668
Chairman's Introduction--9:00
Cont•buted Papers
9:05
HH1.
Probe measurement of eardrum SPL
Previously,we reportedresultsfrom simulatorstudiesof techniques
for remotemeasurement
of eardrumSPL in hearingaid occludedears.
in occluded real ears.
SamuelGilman,DonaldD. Dirks,andDavidG. Hanson(Department
of HeadandNeckSurgery,Room62-129, CHS UCLA, LosAngeles,CA
90024)
S63
Thesedata providedmeansfor calibratingremote-measuring
probes
whichincludedtheeffectsof earcanallengthandimpedance
at theeardrum. The presentpaper presentsdata with respectto the accuracyof
probe/earmold measurementsof eardrum SPL in real ears. Measure-
Societyof America
$63
merits were made on fresh cadaver ears in which the eardrum SPL was
independently
measured
witha micro-miniature
microphone
placedadjacent to the eardrum.
Simulator-derived
corrections obtained from the
previousstudywereappliedto the probe/earmold
measuring
systemto
compensate
for ear canallengthand assumed
eardrumimpedance.
Results from several ears showed the wide variation associated with individ-
ual car measurements
and correctedprobe/earmolderrorsof lessthan
+ 4 dB for frequencies
up to 6.0 kHz.
elicitedbya 60-dBHL click.Theshallower
thefilterslope,thelongerthe
latencyandsmallertheamplitudeof theresponse;
themagnitude
of this
effectinteractswith cutofffrequency.There is little evidenceof differencesbetween48 dB/oct and96 dB/oct slopes,andthemaximumchange
wasbetween24 and 12dB/octfor mostcutofffrequencies.
Sinceacoustic
distortionproblems
increase
with increasing
roll-offsteepness,
it is suggestedthat48 dB/octisanoptimumvalueforbrainstem
auditoryevoked
response
masking
studies.
Theagedependence
of theseprinciples
will be
shownfor newborns.In general,all of the observedlatencyshiftsare
consistentwith knowntravelingwavemechanics.
9:20
HH2. Simplerrealizationof ear simulatorsusingtuningstubsinsteadof
10:05
Heimholtzresonators.
JuergenSchroeter(Lehrstuhlf. Alig. E-Teehnik
und Akustik, Ruhr-Universitaet, Postfach 102148, D-4630 Bochum,
FederalRepublicof Germany)
HH5. The BER, masking, and cochlear place. Robert Burkard and
Kurt Hecox (Waisman Center, University of Wisconsin-Madison,
Madison,WI 53706}
The Zwisloeki-andtheIEC711-earsimulators
arethewidelyacceptedstandarddeviceswhenevera mechanically
stablerepresentation
of the
humanear impedance
is needed,e.g.,for earphonecalibration.Though
thedesignof thesesimulatorsis rathercomplex[seeBurkhard,J. Audio
evokedresponse
(BER}are reported.The firstexperimentevaluatedthe
Eng.Soc.25,1008-1015
(1977)
forsome
related
problems],
theywerenot
in peaklatencies
anda decrease
in peakamplitudes
withincreasing
noise
intendedto reveal"correct"resultsabove10kHz. Recentlymeasurement
levelandrate.Highernoiselevelsandratesincreased
theI-V interval,and
produceda greaterihcreasein the III-V than the I-III interval.The
techniques
for obtainingearimpedances
dataup to 20 kHz havebecome
available[Joswig,Acoust.Soc.Am. Suppl.I 69, SI4 (1981)andHudde,
Acoust.Soc.Am. 73, 24-31,242-247(1983)].To construct
anearsimulator for highfrequencies
westudiedtheeffectof closed-end
stubsof small
diameterto replacethe lumped-parameter
resonators
usedsofar. These
stubsdonotrequireanyspecialdampingmaterial.Thegeometrical
tolerancesarehigh.An a priorierrorestimation
is possible
duringcomputer
simulation.
Predictedandmeasured
resultsagreewellenoughto makea
posteriorifine tuningredundant.
TWO
experiments
concerning
theeffects
ofmasking
onthebrainstem
effectsof noiseleveland rate on wavesI, III, and V. There wasan increase
second
experiment
usedthehigh-pass
subtractive-masking
technique
and
coratiedderived-response
bandwidthand within-bandnoiselevel.For
half-octave
derivedbands,thewithin-band
waveV latencyathighernoise
levelswasgreaterthantheunmasked
latencyof theimmediately
apical
band.The magnitude
of within-bandnoise-induced
waveV latencyshift
wasindependent
ofresponse
bandwidth.
Therelatively
largewithin-band
noise-induced
waveV latencyshiftcombinedwith the increasing
I-V
intervalwithincreasing
noiselevelsuggest
thata shiftin cochlear
region
of response
emanation
is notresponsbile
for mostof thewaveV latency
shiftwith increasing
noiselevel.[Worksupported
by NIH.]
9:35
HH3. Analogfilteringof the middlelatencyauditoryevokedresponse.
David L. McPherson and Lance Montgomery (Departmentsof
Pediatriesand Neurology, University of California, Irvine Medical
Center,101City Drive, Orange,CA 92668}
Therehasbeenconfusionon the originof waveP0 of the middlelatencyauditoryevokedresponse
(MLR). It hasbeensuggested
waveP 0 isa
residualof the effectsof restrictivefilteringof waveV of the auditory
brainstemresponse
(ABR). Twelvesubjectswereusedto studythe effects
of analogfilteringon waveV of the ABR, and wavesNO throughNc.
Monaural clickswere presentedat 70 dBnHL. Two seriesof 1024averageswerecollectedfor a 100-mssamplefor ninefilterconditions.
High-
passfilteringcaused
greaterdistortion
of thewaveforms
thandidchanges
in low-pass
filtering.Whenhigh-pass
filteringwasat or above150Hz, P 0
couldnot beconsistently
identified.It wasobserved
that filteringof both
the MLR and ABR haddifferentialeffectson ipsilateralversuscontralateral recordings.The later MLR waveformsshowedgreatervariability
10:20
HHr. The effectsof signal/maskerphaseconditionson the late cortical
response. Amy
B. Schaefer, Charles D. Martinez,
and
Douglas Noffsinger(AudiologyandSpeechPathologyW 126,University
of California,LosAngelesandVAMC WestLosAngeles,Wilshireand
SawtelleBoulevards,
LosAngeles,CA 90073}
Previousinvestigations
haveproducedindirectevidenceof a coherent
relationship
between
thepresence
andmagnitude
ofthebinauralmasking
leveldifference
IMLD) and thepatternof monauralearlyauditorybrainstempotentials
exhibitedby thesamesubjects.
Thisinvestigation
sought
electrophysiologic
changes
corresponding
to the presence
or absence
of
behavioralMLD by monitoringvia surfaceelectrodesthe late cortical
potentials(P I, N 1, P2, N2} arousedby signal/masker
configurations
known to producean MLD. Tonal stimuli of 500 and 2000 Hz were
presentedbinaurally along with binaural narrow-bandnoisecenteredat
the test frequencyunder SoNo and S•rNo signal/maskerphasecondi-
thaneithertheearlierMLR waves,or theABR waveV for changes
in
high-pass
filtering,especially
above150Hz. This studyis in agreement
withtheconceptofsimultaneous
recording
of theABR andMLR reportedbyScherg[M. Scherg,Electroenceph.
Clin.Neuro.54, 339-341(1982)]
althoughthatstudydid notdirectlyaddress
thequestion
of filteringef-
tions.
Twenty-five
young
(•' age:24.6yrs)normal-hearing
subjects
with
fects.
compared
to theSoNocondition.Suchchanges
didnotoccurin response
normalABR for 2000-and4000-Hztonepipsandnormal500-HzbehavioralMLD weretested.
A consistent
andstatistically
significant
increase
in the amplitudeand/or reductionin the latencyof onsetof the cortical
potentialswasevidencedfor 500-Hz stimulifor the S•rNoconditionwhen
to 2000-Hz stimuli. [Work supportedby NIH.]
9:50
10:35
HH4. High-pass masker slopes and the BAER. Kurt E. Hecox,
Tom Kilsdonk, and Mary Malischke (Waisman Center and the
Departmentof Neurology,Universityof Wisconsin-Madison,
Madison,
HH7. Hemisphericdifferencein evokedpotentialsto spatialsoundfield
stimuli. Y. Ando and I. Hosaka (Faculty of Engineering,Kobe
WI 53706)
University, Kobe, Japan657)
The use of analog filters is a nearly universalpracticein masking
studiesof auditoryevokedpotentials.Yet thereis little systematicinformation on the impactof certainaspectsof the filter'sproperties.This
studyreportstheresultsof varyingmaskingnoisecutofffrequency(8,4, 2,
1,and0.5 kHz) andslope(96,72, 48, 24, 12,and6 dB/oct),ontheresponse
fieldstimuliwerealternately
presented
witha lowanda highmagnitude
of interauralcrosscorrelation
(IACC). (Subjective
diffuseness
is the percept for soundfieldswith the low IACC.) Auditoryevokedpotentials
(AEP) from bothtemporalareas(T3 and T4)Offivenormalsubjects
for
$64
d. Acoust.Sec.Am.Suppl.1, Vol.74, Fall1983
In orderto producedifferentsubjective
spatialimpressions,
twosound
Societyof America
S64
11:05
eachstimuluswererecorded.Whena bandlimitedwhitenoisewaspresentedas a sourcesignal,amplitudesof AEPs over the right cerebral
hemisphere
weremuchgreaterthanthoseovertheleft,assimilarto previousresultsby severalinvestigators.
However,this tendencywasonly
weak,evenifs vowel(a)waspresented.
Furthermore,
it isgenerally
found
with the two soundsignalsthat (i) for the soundfieldswith highIACCS,
amplitudes
of AEPsovertherighthemisphere
werealwaysgreaterthan
thoseoverthe left, andthat (ii) time differences
betweenthe firstand the
secondmaximaof AEPs over the right hemispherewereclearlylonger
thanthoseovertheleft to thehighIACC fields.Fromthesefindings,the
rightcerebralhemisphere
isconsidered
to bedominantlyoperativefor the
auditoryspatialsensation.
HH9. Phase consistencyof evoked responsesto auditory stimuli
deliveredat highrates.Scott MakeigandRobeft GalambosIChildren's
HospitalResearch
Center,8001FrostStreet,SanDiego,CA 92123)
We will reviewourrecentresearchin evokedresponse
detectionusing
auditorystimuliat ratesaround40 Hz with emphasis
on response
phase
consistency.
Response
phaseoftenaggregates
at stimulus
intensities
producinglittleor norisein response
amplitudebeyondthelevelof thebackgroundEEG, andthuspromises
to be usefulin electricresponse
audiomerry.We notethat othershavepreviouslyproposedheavilyweighting
phasestatisticsin detectingresponses
to weak stimuli deliveredat low
rates(aroundI Hz). This sensitivityof evokedresponse
phaseto external
stimulationsuggests
that phaseof ongoingbrainactivitymaybereorganizedby weakstimulibeforethereisa detectable
increase
in netresponse
amplitude.
10:50
HHg. Human auditory steady state potentials analyzed with Fourier
analysis:The zoom technique.R. Dean Linden, Gilles Hamel, David
R. Stapells,and Terence W. Picton IHuman Neurosciences
Research
Unit, Universityof Ottawa Health Sciences,451 Smyth Road, Ottawa,
HHI0.
CanadaKIH 8H5}
M. Heinz, E. W. Bookstein,and R. V. Pagano(John F. Kennedy
11:20
Characteristics of the FFP to tonal stimuli. S. B. Resnick, J.
Institute, 707 N. Broadway,Baltimore, MD 21205}
The Fourier analysisof evokedpotentialshasseveraladvantagesover
The FFP to tone bursts of 12.8-ms duration was measured over a 51-
averaging.
Reganintroduceda "zoom"techniquethat manipulates
stimulusparametersduringthe analysis[Invest.Opthal. 12 669-679 (19731].
Sixsubjectsweretestedusingthistechniqueto assess
theeffectof stimulus
rateontheauditoryevokedpotentials.A 95-dBpeSPLtonewith 4-msrise
andfall timesanda 2-msplateauwaspresented
to therightea• at a rate
that increasedfrom 10 to 60 tones/sover 50 s. This analysiswascarried
out for four differentfrequencies
of the tone:500, 1000,2000, and 4000
Hz. The amplitudeand phaseoutputsfrom the Fourieranalyzerwere
repetitivelyrecordedduringthesweepin stimulusrateandaveragedover
msperiodusingmultichannel
recording
forseven
normal-hearing
adults.
Averagedresponse
waveformsbasedon 8192trialswereobtainedat each
of sevenfrequencies(between312 and 1250 Hz) at each of four signal
levels(10, 30, 50, and 70 dB nHL). The averagedwaveformsthenwere
subjected
to variousanalyses
including
bandpass
filtering(usingdigital
filterscenteredat the test frequencyand its secondharmonic),spectral
analysesfor selectedpost-stimulus
intervalsand crosscorrelation{with
the input stimulus).Preliminaryreviewof the data providesevidenceof
32sweeps.
Themaximum
amplitudes
ofthesteady-state
responses
forthe
thepresence
of theFFP at signalfrequencies
yieldingthelargestresponse
500, 1000, 2000, and 4000 Hz tonesoccurredat rates of 40/s, 43/s, 44/s,
andof markedalterationsin response
complexityasa functionof stimulus
and 46/s with amplitudes,of 1.42, 1.34,1.30,and 1.11#V, respectively.
This techniquemay be usedin "zooming"other parametersof interest
suchas intensity.
frequency
andlevel.Resultsof moredetailedanalyses
andcomparison
of
theFFP withresponses
to clicksandclicktrainswill bepresented.
[Work
supportedby NINCDS.]
THURSDAY
MORNING,
10 NOVEMBER
1983
GARDEN
ROOM, 8:30 TO 11:52 A.M.
SessionII. Speech Communication IV: Speech Perception
Ian Maddieson, Chairman
PhoneticsLaboratory,LinguisticsDepartment,Universityof California,405 Hilgard Avenue,LosAngeles,California
90024
Chairman's
IntroductionS:30
ContributedPapers
8:35
II1. Identification of transition frequency and duration changes in
syntheticspeechas a function of hearingstatusand age. Peter J. Ivory
andJohnF. Brandt(Bureauof Child ResearchLaboratories,
University
of Kansas,Lawrence,KS 66045)
Theidentification
ofsynthetic
speech
syllables
which
incorporated
identical formant transition frequencychangesin three different transition duration contexts(40, 120, 240 ms)or which incorporatedidentical
transitionduration changesin three differenttransitionfrequencycontexts(whereF2 locuswas800, 1520,or 2120 Hz} wasassessed
for young
S65
J. Acoust.Soc. Am. Supol. 1, Vol. 74, Fall 1983
and old normal-hearingand sensorineurally
hearing-impairedlisteners.
The older listeners,independentof hearing-impairment,
demonstrateda
significantdecrementin identificationperformancefor all experimental
continua.The hearing-impairedlisteners,independentof age, demonstrateda significant
decrement
in identification
performance
for most,but
not all, experimentalcontinua.Specifically,
identification
of syllablesin-
corporating
frequency
changes
wasnot significantly
affectedin the240msdurationcontextbut significantlypoorerin the contextsutilizingthe
two shortertransitiondurations.Furthermore, identificationof syllables
incorporatingdurationchangeswasnot significantlyaffectedin the 800Hz transitionlocuscontextbut significantlypoorerin the higherfrequency contexts.
$65
8:4?
9:23
I12. Speech
understanding
of olderadult•:A preliminary
study.Lois
L Elliott,Laura Lyons,andLu Ann Busse
(Northwestern
University,
2299 SheridanRoad, Evanston,IL 60201)
Forty-twonormalolderadults,aged60-75years,weretestedon a
batterythatincluded
theSpeech
Perception
inNoise(SPIN)test,conventional,andexperimental
puretonesensitivity,
theW-22testin quietand
I15. Perceptionof sine-waveanalogsto individualformantsof CV
syllables. Rosemary Szczesiul, Richard
E. Pastore, and
LawrenceRosenblum(Departmentof Psychology,StateUniversityof
New York at Binghamton,
Binghamton,
NY 13901)
The immediategoalof our research
wasto delineatethenatureof the
perceptual
consequences
ofthetypesofacoustic
changes
typicalofphon-
noise,
openandclosed-set
identification
ofsynthesized
syllables
thatdifferedintheplace
ofarticulation
feature,
syllable
discrimination,
theBlock
Design
subtest
of theWAISandtheConcept
Formation
subtest
of the
emecontrasts.In this studywe usedsine-waveanalogsof individualformant componentsof CV syllables.All of our sine-wavestimuli were dynamicin thattheywerecharacterized
byvariouschanges
in frequencyasa
Woodcock-Johnson
Psychoeducational
Battery.Resultsshowed
considerablevariabilityonall measures.
Onlyperformance
ontheW-22Testin
noise
andsensitivity
at 4 kHz weresignificantly
relatedtoabsolute
levels
function of time which mimicked characteristic formant transitions. Na-
ofperformance
onlow-(LP)andhigh-predictability
(HP)SPINtestsentences.
No testvariables
weresignificantly
relatedtorelative
performance
on HP and LP sentences.
The differingpatternsof resultsfor different
subjects
ofthishomogeneOuS
samplehavingexcellent
language
skillssuggested
that:(1)a largerstudyin whichlinguistic
abilities
weresystemati-
callymanipulated
mightproduce
adifferent
outcome
and(2)datafor400$•0 similarolderadultsmightshowsignificant
butdifferingpatternsof
processing
auditory
stimuli,particularly
in theextenttowhichcognitive
processes
contribute
tolistening.
[Worksupported,
in part,byNSF.]
ivelisteners
performed
bothlabelinganddiscrimination
tasksin response
to individualformantequivalents.
Preliminaryresultssuggest
somesimilarity betweentheperception
of speechandsine-wave
analogsto formant
components
bothin the demonstration
of categoricalperceptionandthe
locationof categoryboundaries.In general,the relativelydistinctcategoryboundariesseldomcorrespondeel
to thosewhichwouldbepredicted
by simpleinspection
of visualrepresentations
of the physicalstimulus
characteristics.
[Work supportedby NSF grantBNS 8003704to the secoad author.]
9:3•
I16. Perceptionof "modulation" in speechlikesignalsII: Discrimination
of frequencyextent as a function of spectral content and direction of
change.
Creighton
J. MillerandRobertJ. Porter,Jr? IKresge
Hearing
8:59
113. Exploring the "McGurk effect."Sharon Y. Manuel, Bruno
H. Repp, Michael Studdert-Kennedy, and Alvin M. Liberman
(HaskinsLaboratories,270 Crown Street, New Haven, CT 06511-6695)
McGurk discovered
that whena videotapeof a talkeris dubbedwith
similarbut mismatched
utterances,
theopticinformationexertsa strong
influenceon the speechthat is perceived,often without the observer's
awareness.
In severalstudies,weexploredfurthertheeffectsofconflicting
acousticandopticinformationon consonant
perception.
The following
questionswereasked:(1) Do subjectsreporta consonantevenwhenno
consonantal
cuesarecontainedin theacousticsignal{anisolatedvowel)?
{2}How is acoustic-optic
placeof articulationconflictresolvedwhen
acousticallyspecifiedmanner{e.g.,nasal,stop)restrictspossibleplacesof
articulation?
(31How far doesobservers'
awareness
of acoustic-optic
dis-
crepancy
reducecross-modal
integration?
[Worksupported
byNICHD.]
ResearchLaboratoryof the South,LSU MedicalCenter, 1100Florida
Avenue,Bldg. 124, New Orleans,LA 70119)
This is the secondin a seriesof studiesdesignedto evaluatelisteners'
perception
of modulationin speechlike
signals[R. PorterandC. Miller, J.
Acoust.Soc.Am. Suppl.173, S3(1983)].Thestudyexamines
discriminationof second
formantstimuliwhosecenterfrequency
traversed
a single
120 ms hayersinemodulationat their midpoint. Extent of frequency
changefor the stimulussetwasvariedin 20-Hz stepsacrossthe range,
100-400 Hz, both aboveand below the steady-statevalue of 1232 Hz.
Separatecontinuaweregeneratedwith and withoutthe presence
of a 769Hz firstformant.Pairedcomparison
discrimination
testswereconducted
with listenerstrainedtojudgewhichof thestimulichangedmost.Results
will bediscussed
in termsof their relationto themodulationpercept,and
to prior resultsof otherinvestigations
whichhavestudiedthe perception
of secondformanttransitionsin andoutof speechcontexts.[Supported
in
part,by NINCDS NS # 11647,The LouisianaEye andEar Foundation,
TheLouisiana
Lions,andTheKresgeFoundation.]
"•AlsoDepartment
of
Psychology,Universityof New Orleans.
9:•,?
9:11
If4. Judging sine wave stimuli as speechand as nonspeech.David
R. Williams, Robert R. Verbrugge,and Michael Studdeft-Kennedy
(HaskinsLaboratories,270 Crown Street,New Haven, CT 06510)
Interestin the perceptualequivalence
of "static"and"dynamic"stimuli spansbothspeechand nonspeech
domains.Previousinvestigations
of
speechstimuli have shownthat, given matchedsetsof three-formant
steady-statevowelsand vowelsflankedby consonantaltransitions,phoneticequivalence
is not definedby equalpositionalongthe two continua
[B. Lindbiotaand M. Studdert-Kennedy,
J. Acoust.Soc.Am. 42, 830843( 1967)].Forjudgmentsof relativepitch,ontheotherhand,ramptones
arejudgedto be nearlyequivalentin pitch to steady-state
tonesat their
endpointfrequencies[P. T. Brady et al., J. Acoust.Soc.Am. 33, 1357-
! 362(1961)]_
The presentsetof experiments
demonstrates
thisdifference
in categorization
of staticanddynamicstimuliusinga singletypeof stimulus. Two setsof sine wave stimuli {FLAT/CONTOUR)
were construct-
edby modelingthe frequencyandrelativeamplitudecharacteristics
of the
aforementionedspeechstimuli. When judged in termsof phoneticcatecortes(/u/ vs/i/), significantly
greaterproportionof/u/judgments were
117. Identification and discriminationof visually presentedsynthetic
consonant-vowelstimuli. Brian E. Walden and Allen A. Montgomery
(Army Audiology and SpeechCenter, Walter Reed Army Medical
Center,Washington,DC 20307)
Two-dimensionalvector-based
dynamicimagesrepresenting
the consonant-vowelsyllablesfoa/,/va/, and/wa/were producedon an intelligent graphicsystem.The startingconfigurationand steady-statevowel
were identicalfor thesethree stimuli. Visual presentationto subjectsreyealedthesestimulito be highlyidentifiablerepresentations
of the three
consonants.
Sixintermediate
stimuliwerealsogenerated
betweeneachof
thethreepossible
pairsof consonants
andrepresented
equaltransitional
stepsbetween
theexemplars.
Thethreeresulting
eight-itemcontinuawere
presentedfor identificationand discrimination(ABX paradigm).The
datarevealedthat the slopeof the identification
functionin the regionof
the phonemeboundaryand the locationofthe 50% pointdifferedfor the
three continua. Identification and discrimination functions, as well as
reproductions
of stimulusframes,will bepresentedto illustratethe phoneme boundariesand most distinctivephonerotecues.
observed
for theFLAT thanfortheCONq•OURcontinuum.
However,
whenthe sametwo setsof stimuliwerejudgedin termsof relativepitch
(HIGH versusLOW), no significantdifferencein response
patternfor the
two continuawasnoted.Thus the experimentsdemonstratethat two distinct responsepatternsmay be elicitedfor sinewave stimuli contingent
only on the expcrimenter's
instructions.
[Work supportedby NICHD.]
S66
9:S9
II8. Comparison of three performance measures obtained with
pereeptuallybalancedvowel continua. B. Espinoza-Varas(Psychology
Department,Universityof Calgary,Calgary,AlbertaT2N ! N4, Canada)
Societyof America
S66
The auditoryrepresentation
of formantfrequencyappearsto be consistentwith a scaleofcritical-bandunits:thebarkscale[Schroeder
etal., J.
Acoust.Soc.Am. 66, 1647-1652(1979}].This papercomparesmeasures
of identification,
discrimination,
andperceptual
distanceobtainedin vowel continuadividedinto"perceptually
equal"steps;i.e.,equalstepsalong
thebarkscale.The continuarangedfromeither/u/to/i/or from/3/to /
œ/.The400-ms,steady-state
vowelsweregenerated
usinga three-formant
parallelsynthesizer.
Within eachcontinua,thefrequencies
of F• and/%
werefixed,while the frequencydifferenceF2 - F• (or F3 - F2} varied
from •0.5 to = 7.0 barkin stepsof •0.5 bark.The fundamentalfrequency was 120Hz. Listenerswereaskedto identifyeachof thestimuliin the
continuaand to make a "vowel-goodness"
rating. The resultsare discussed
in thecontextof thequestionof whetherthebarkscaleisconsistent
with all three performancemeasures[Supportedby AHFMR and
NSERC.]
Medical ResearchLaboratory,Wright-PattersonAFB, OH 45433},
Jay Freedman, and Andy Rumbaugh {Air Force Institute of
Technology,Wright-PattersonAFB, OH 45433}
The effectof LPC voicetypeandof message
formaton thespeedand
accuracyof response
to voicewarningsignalswereinvestigated
at various
levelsof a simulatedmilitary inflightnoiseenvironment.LPC voicetypes
were male, female,and machine,and the messageformatswere voice
warning,repeatvoicewarning,and tone-voicewarning.The primarytask
wasa manualtrackingtaskthat requiredcontinuousattentionwhereas
the secondarytask requiredindividualmanual responses
to randomly
presentedwarning messages.A backgroundsignal of inflight aircraft
voicecommunications
waspresentedvia thesubject'searphonesthroughout the experiment.The voicewarningmessages
werealsopresentedvia
theearphones
at levelsof0, 5,and I 0 dB abovethisbackground
communicationlevel.Ten subjects
completedthe experimentaltaskswhilewearing
standardAir Forceflighthelmetsandoxygenmasksin thepresence
of the
10:11
emulatedaircraft noiseat levelsof 105 and 115 dB (SPL}. The effectsof
LPC voicetypeandmessage
formaton voicewarningeffectiveness
will be
presentedand discussed.
II9. Effect of voice type and messageformat on speedand accuracyof
response
to voicewarnings.Timothy R. Anderson(Air ForceAerospace
10:23-10:40
Break
ContributedPapers
10:40
II10, Sensitivity to rate-of-changeof frequency transition. Donald
G. Jamiesonand E. Slawinska{Departmentof Psychology,University
of Calgary,Calgary,Alberta T2N 1N4, Canada}
Weexamineda possible
psychoacoustic
basisfor therelativelyinvariant durationoverwhichthe rapidformantfrequencytransitionscueing
placeof articulationoccurin initial-position
stopconsonants
suchas
/ba/. Our stimuliconsistedof a 200-msduration compoundof a puretonefrequency
glidefollowedbya steady-state
pure-tone
stimulus.
Glides
covered
a fixedrangeof frequencies
(400-700Hz; 1500-2200Hz; or both
together}
overa variableintervalof time(10-90ms,in 10-mssteps}.
Three
experiments
examineddiscrimination
performance
in an AX paradigm;
on any trial X = .8 or X = {•,lñ one stepin a stimulusseries}.In each
experiment,
discriminability
( - In •u}tendedto achievea maximum,and
bias{ln,/•} tendedto achievea minimum,whenthe transitionoccurred
over50 ms.Theseresultssupportandextendearlierreports[A. Nabelek
and I. Hirsch,J. Acoust.Soc.Am. 45, 1510-15190969}] and appearto
reflecta specialperceptual
sensitivity
to frequency
changes
whichoccur
withinthe40-60-msintervalof timetypicalfortheanalogous
transitions
in naturalspeech.
[Worksupported
by NSERCandAHFMR.]
11:04
II12. PrecategoricalAcousticStore (PAS}: Is therean auditorysensory
memory? Diane Williams IPsychologyService {ll6-B}, VA Medical
Center, 150SouthHuntingtonAvenue,Boston,MA 02130}
The existenceof an auditorysensorymemorycalledPrecategorical
AcousticStoretPASIwasproposed
by CrowderandMorton[Percept.
Psychophys.
5, 365-37311969}]to accountfor boththe modalityand
suf•xeffectsobtainedin list-learningexperiments.
While PAS providesa
goodexplanationof theseeffects,the memoryhaslittle independent
empiricalsupport.PAS wasdirectlyinvestigated
in twoexperiments.
In the
firstexperiment,the subjecthearda subliminallypresented
word. The
subject's
taskwasto determinewhetherthe two wordswerethesame.In
the secondexperiment,the subjects
heardfour wordspresented
simultaneously
at normalintensity,andlater.read
a word.Thesubjects'
taskwas
to determine whether the word he or she read was one of the words that
wereheard.If the auditorystimuluswasrepresented
in PAS, thenperfor-
manceshouldbebetterif thevisuallypresented
probeappears
beforePAS
hasappreciably
decayed,
andperformance
shoulddecrease
with increasing probelags.In bothexperiments,
discriminability
performance
was
roughlyconstantwith increasing
probelags.This failureto supportthe
proposedPAS is discussed.
10:52
IIll. Fundamentalfrequencyand the comprehensionof simple and
complexsentences.Leah S. Larkey and Martha Danly (MIT 36-511,
SpeechCommunication
Group, ResearchLaboratoryof Electronics,
Massachusetts
Instituteof Technology,Cambridge,MA 02139}
The intelligibilityof sentences
with monotonefundamentalfrequency
11:16
II13. The pursuitof invariancein speechsignals.Leigh Lisker(Haskins
Laboratories,270 Crown Street,New Haven, CT 06510, and University
of Pennsylvania,
Philadelphia,PA 19104}
zero-phase
vocoder
wasusedto allowmanipulation
of fundamental
frequencycontours
andresynthesis
resulting
in speech
thatsounded
asmuch
likenaturalspeech
aspossible.
Sentences
werevocoded
andresynthesized
usingeithera monotone
contouror theoriginalcontour.Listeners'
reactiontimesto monotone
short,simplesentences
wereslowerby48 msthan
Wemayimaginea modifiedMuller-Lyerillusionin whichtwolinesof
unequallengthareperceived
asequalin differentcontexts.
Is thisanalogousto thecommonsituationin speech,
wheretwodistinctsignals,
e.g.,
deepandduke,arejudged"equal"with respectto their/d/'s? In the
visualcasetheterm"illusion"issusceptible
of precise
definition,allowing
usto speakof a mismatch
between
stimulusandpercept.In the speech
situationwe are confrontedwith problemsthat makeit very dif•cult to
their reaction times to the same sentenceswi•;hnormal fundamental fre-
pose,
letaloneanswer
thequestion
astowhether
the/d/commontodeep
quencycontours.Reactiontimesto longersentences
with complexsyn-
anddukereflects
a perceptual
invariance
thatisillusory.Identityof spell-
tactic structureswill alsobe presented.The resultssuggestthat an adequatemodelof speechperceptionand comprehension
mustincorporate
intonation.The contributionsof segmentaleffects,terminalfall, stressed
syllables,anddeclinationare considered.
[Work supportedby NIH and
theSloanFoundation.]
ing is only weakevidencefor perceptualconstancy,sincespellingis more
wasassessed
usinga sentence
verification
paradigm,
whichmeasured
listeners'reactiontime in judgingwhethera sentencewastrue or false.A
S67
J. Acoust.Sec.Am.Suppl.1, Vol.74, Fall1983
akinto phonological
thanphoneticrepresentation,
andat leastsomephonemrscomprise
phonetically
distinct"sounds."An exampleis provided
by thevoiceless
stopsof English.It canbeshownthat acoustically
identical segments
contributeto bdgin somecontextsand to ptk in others.
Societyof America
$67
11:40
Anotherexampleinvolves/wy/, whichmay be producedby the same
vocaltractconfiguration
in different
contexts.
Evenif somephoncmes
are
markedby acousticinvariants,not all of themare.[Work supported
by
II15. Neural responsepatternsto speechsounds•A model. Pierre
L. Divenyi {Speechand Hearing ResearchFacility, V. A. Medical
NICHD.]
Center, Martinez,
CA
94553 and 1.N.R.S.-Telecommunications,
Universit• de Qu6bec,Verdun, QuebecH3E IH6, Canada),Robert
V. Shannon(Departmentof Otolaryngology,
Universityof California,
San Francisco,CA 94143), and StephenR. Saunders(Bell-Northern
Research,Verdun, Quebec,H3E IH6, Canada)
11:28
We proposea four-stagemodelto represent
auditoryresponse
magnitudeover time and acrossfrequencychannels.The first stageperforms
spectralestimationby computingpowerat eachof the outputfrequency
channels.
Frequency
isscaledin basilarmembrane
distance
andtheinput
is passed
througha windowhavinga durationinverselyproportional
to
thefrequency.
The nextstagehasbeendescribed
earlierJR.V. Shannon,
J.
Acoust.Soc.Am. Suppl.! 65, S56{1979)];it portraysfrequency
analysis
in the cochlea.This stageincludesmechanisms
of cochlearfiltering{by
meansof two filter banks,one havingsharpand the other havingbroad
filters),nonlinearcompression
of the input power,and lateral suppression.The third stagemodelstemporaladaptationin the auditorynerve.
The final stageis a temporalintegrator.Speechsoundsanalyzedby the
modelacquireseveralinteresting
characteristics:
{i}The dynamicrangeof
the inputisgreatlyreduced{ < 15dB},(ii}bandpass
information{e.g.,the
onein formants,fricatives,etc.}is represented
asa spectraledgeat the low
sideof thebandpass
region,{iii}bursts{especially
high-frequency
plosives}
acquiretemporalsharpness,
{ivI individualglottalpulses
areclearlyvisible
onlyat highfrequencies.
[Worksupported
by !nstitutNationalde la RechercheScientifiquc,
theVeteransAdministration,
andgrantsby N.1.H.]
1114.Exploitinglawful variability in the signal:The TRACE modelof
speech perception. Jeffrey L. Elman and James L. McClelland
(Department
of Linguistics
andPsychology,
University
ofCaliforoia,San
Diego,La Jolla,CA 92093}
We describe
a modelof speechperception
in whichlawfulvariability
in thespeech
signalistreatedasa source
ofadditional
information,
rather
than as noise.Excitatoryand inhibitoryinteractionsamongnodesfor
phoneticfeatures,
phoneroes,
andwordsareusedto accountforaspects
of
eoarticulation,
aswell astheinteractionof bottom-upandtop-downprocessesin perceptionof speech.Two resultsfrom a workingcomputer
simulationof thismodelarepresented.
First,weshowhowthesimulation
is ableto processreal {digitized}speechand retunethe detectionof featuresand phoneroes
in accordwith the context.Second,we demonstrate
how perceptualbehaviorwhichappearsto beguidedby rulescanbe inducedwithoutanyexplicitrulesin thesystem.[Work supported
by the
Officeof Naval Research.]
THURSDAY
MORNING,
10 NOVEMBER
Session JJ. Shock and Vibration
III:
CABINET
1983
ROOM, 9:00 A.M. TO 12:20 P.M.
Statistical Methods for the Solution of Practical Vibration
Acoustical
Transmission
and
Problems
James A. Moore, Chairman
CambridgeCollaboratioe,
225 Third •4oenue,Cambridge,Massachusetts
02142
Chairman's
Introduction---9.'00
Invited Papers
9:05
JJ1. Phase estimationfor transfer function of multi degree-of-freedom-systems.
Richard H. Lyon
(Departmentof MechanicalEngineering,
Massachusetts
Cambridge,MA 021
The useof statisticalestimatesfor vibratoryresponse
isnowa well-established
procedureusingthe methods
of SEA. It hasgenerallybeenassumed
that whileonecouldestimatetheaverageresponse
in frequencybands,
statisticalmethodscansaylittle aboutthe phaseof response.
But the phaseis veryimportantin someapplicationsof transferfunctionanalysis,suchas waveformreconstruction,and it would be very desirableto have
procedures
forestimating
transferfunctionphaseonthebasisofgeneralstructuralfeatures
in thewaythatSEA
usessuchfeaturesfor estimatingaverageresponse.
Somerecentdevelopments
in the estimationof the phaseof
structuraltransferfunctionsshowpromisethat phasecanbe estimatedfrom generalsystemparameters.The
useof phaseinformationin waveformreconstruction
and the role of thesenew developments
in designing
inverse filters for such reconstructions are reviewed.
9:35
JJ2. An approachto the statisticalenergyanalysisof complexsystems.RichardG. DeJong{Cambridge
Collaborative,Inc., P.O. Box 74, Cambridge,MA 02142}
Theprinciples
of SEAhavebeenusedtoformulatea procedure
to analyzethedynamicresponse
ofcomplex
systems.This procedureallowsfor individualcomponents
of a systemto be modeledseparatelyand then
combinedwith othercomponents
to constructa completesystemmodel.An analysisis presented
that shows
ß68
J. Acoust.So•. Am. $uppl. 1, VoL74, Fall 1983
106th Meeting:AcousticalSocietyof Amedca
.•
thattherequirement
forahighmodaldensity
ineachcomponent
canberelaxed
undercertain
conditions
which
allowstheprocedure
to beusedat lowerfrequencies.
Theprocedure
hasbeenimplemented
in a computer
program,
andsomeexamples
of itsapplication
andcomparisons
to measurements
aregiven.
10:05
JJ3. Statist'calenergyanalysisfor beamnetworksin buildingstructures.M. ]. Sablik,R. E. Beissner,
H.
S. Silvus,
Jr.,andM. L. Miller*• (Southwest
Research
Institute,
P.O.Drawer28510,
SanAntonio,
TX 78284)
The statistical
energyanalysis
methodisappliedto a beamnetworkin a buildingstructure.A methodof
takingstructuralresonances
intoaccountisintroduced
intotheanalysis.
Couplinglossfactorsarecomputed
usingtransmission
coefficients
presented
inearlierwork[M. J.Sablik,J. Aeonst.SOC.
Am.72, 1285{i982);L.
Cramer,M. Heckl,andE. E. Ungar,Structural
BorneSound(Springer-Verlag,
NewYork, 1973)].
Transfer
functions
computed
fromthemodel
beamnetwork
arecompared
overa widefrequency
range
toexperimentally measured
transfer
functions
fromanequivalent
beamnetwork
inanexisting
building
structure
in whichone
of the beamsis vibrationallyexcited.Our resultsemphasizethat unlessresonance
effectsare takeninto ac-
count,thepredictions
of statistical
energyanalysis
will notdisplaythefinedetailsfoundin thefrequency
dependence
of transferfunctions
for realbuildingstructures.
a•FormerlywithSwRI.
10:35
JJ4. Helicopterairframevibrationtransmission
modelingusingstatisticalenergyanalysis{SEA•.Charles
A. Yoerkie(SikorskyAircraftDivision,UnitedTechnologies
Corporation,
Stratford,CT 06602)
Predicting
helicopter
cabinnoise
isa complex
issue.
It involves
sources
which•re bothacoustic/aerodynamicandvibratoryinnatureaswellasa compact,
highlyinterconnected
airframestructure.
Energytransmits
to thecabinvia bothairframestructureborne
andairbornepaths.Sincea largenumberof resonantstructural
andacousticmodesare excited,a statisticalapproach,whichtreatsthe response
of the modescollectivelyin
groups,isdesirable.
The methoddescribed
for modelingthehelicopterairframeandcabininteriorisStatistical
EnergyAnalysisISEA).An SEAmodel,fundedbya NASA LangleyResearch
Centercontract,ispresented
for
theSikorskyS-76ia4-13 passenger
commercial
helicopter}.
Thisoverallsource-to-receiver
modeling
approach
allowsfor evaluation
of variousnoisecontrolmeasures
in theconceptual
designstage.Expressions
havebeen
developedfor SEA parametersand the couplinglossfactorhasbeenrelatedto the more familiarvibration
transmission
coefficient.A full scalemeasurement
programwasconductedon the SikorskyS-76. Data are
presented
showingtheSEA parameters
andcomparisons
withtheanalyticmodel.Thesedataincludevibration
transmission
alongthebeam/panelstructureandtransmission
throughintermediate
acoustic
spaces
connected by both resonantand nonresonant
conditions.
In addition,data are presented
concerning
the effectsof
coherent
andnoncoherent
sourceexcitations
at distantresponse
points.[Worksupported
byNASA Langley.]
11:05
JJ5. A comparisonof measuredand predictedsoundlevelsin the spaceshuttle payloadbay. John F. Wilby,
Allan G. Piersol,and EmmaG. Wilby {BoltBeranekand NewmanInc., P.O. Box633,CanogaPark,CA
913051
An analyticalmodelto predictspace-average
soundlevelsin thepayloadbayof theSpaceShuttleat lift-off
hasbeendeveloped
usingpowerbalancemethods.
Thedevelopment
of themodelhasbeenreportedearlier[L.
D. PopeandJ. F. Wilby,J. Acoust.Soc.Am. 62, 906-911(1977}];it isnowpossible
to comparethepredictions
of themodelwith datafromthefirstthreelaunches.
Space-average
soundlevelsin thebaywereestimatedfrom
measureddata and the resultingspectracomparedwith predictions;discrepancies
were observedin the frequencyrangeabove125 Hz. Modificationsmadeto the analyticalrepresentation
for the payloadbay door
resultedin muchbetteragreement
betweenmeasured
and predictedsoundlevels.Payloadspresentin thebay
weremodeledanalytically,butthepredictedeffectsonspace-average
soundpressure
levelsweresmallbecause
of the smallsizeof thepayloads.[Work performedunderNASA ContractNAS5-26570.]
ContributedPapers
11:35
The methoddescribedmaybe usedto computecouplingcoefficients
for
SEA models.
J J6. Power transmission across a complex plate branch. Robert
C. Haberman, Donald T. Pan, and Thomas S. Graham (Bolt Beranek
and Newman Inc., Union Station, New London, CT 06320)
Finiteelementandclassical
techniques
werecombined
to computethe
transmission
and reflectionof vibratoryenergyacrossa platebranchwith
structuralconnectionstoo complexto be modeledwith classicaltechniquesalone.The procedurefor combiningthe modelsis outlinedand
numericalresultsare presented.Resultsare givenfor a simpleplateconneetion(whichagreeswith classicaltheory}and severalcomplexwelded
and riveted plate connections.For complexconnections,resultsare
shownto be very sensitiveto structuraldetailssuchasmassand contact
areaat thebrauch.Sincecontactareais in generalunknown,thissuggests
that powertransfercoefficients
shouldbeaveragedoverfrequencybands.
S69
11:50
JJ7. Point-force randomexcitation of a thin plate bent into an L-shape.
Emil(os K. Dimitriadis and Allan D. Pierce (Schoolof Mechanical
Engineering,GeorgiaInstituteof Technology,Atlanta, GA 30332}
The authors'modelfor randompoint-forceexcitation[J. Acoust.Soc.
Am. Suppl.I 73, S71{1983}]is refinedandsimplified.
The modalcrosscorrelationtermsintroducedby point forcesare accomodated
by using
the methodof imageswith only the nearestedgetaken into accountto
106th Meeting:AcousticalSocietyof Amedca
S69
approximate
thepowerinputto a finiteplateß
Arguments
analogous
to
thoseusedin roomacoustics[seefor example,.4coustics
(McGraw-Hill,
1981},p. 295]allowthe averagecross-correlation
term to beexpressed
in
termsof the powerinput ratio, finiteplateto infiniteplate.Statistical
energyanalysis
(SEA}parameters
arecornpuled
for the L-configuration
plateforthecases
whenall edges
aresimplysupported
andwhenall edges
are free,with Warburton'sRayleigh-Ritzmodesusedin the latter case.
Theanalysis
confirms
thattheSEAparameters
areverynearlyindependentof forceposition.Calculationscomparefavorablywith experiments
conductedon a freely suspendedL-configurationplate with different
sourcelocations
andtwo differentdampingconfigurations.
[Worksupportedby WhirlpoolCorporation.]
THURSDAY
MORNING,
10 NOVEMBER
1983
IZ-QS
JJS. Application of SEA in developinga high-frequencyvibration test
method.JeromeE. Manning (CambridgeCollaborativc,Inc., P.O. Box
74, Cambridge,MA 02142)
Thevibrationenvironment
in manyaerospace
environments
extends
to veryhighfrequencies
(• 100kHz}. However,because
of the limitation
in testequipment,
it isdifficultandoftenimpossible
to imposea vibration
specification
on an equipmentsupplierthat extendsbeyond4000Hz. This
presentation
illustrates
theuseof SEAto developtherequirements
for a
newtesttechnique.
GOLDEN
WEST ROOM, 8:30 TO 11:55 A.M.
SessionKK. Psychological
AcousticsIV: Discriminationof Frequencyand Periodicity
Peter M. Narins, Chairman
Departmentof Biology,University
of California,Los/lngeles,California90024
ContributedPapers
8:35
KKI. Effect of duration on pitch discriminationof complex sioonals
VirginiaM. RichardsandErvin R. Hafter(Department
of Psychology,
Universityof California,Berkeley,CA 94720}
Discriminationof modulationfrequencywasmeasuredusingtrainsof
n clicks{n = 4 to 52} presentedat a rate of 250/s. Each click was the
productof a 3500-Hzsinusoidanda Gaussianenvelope.
Threespectral
envelopes
wcrctested,havingstandarddeviations
of 350, 560, and 933
Hz. The rateof improvement
in performance
overdurationisreflected
in
a plotof log-threshold
vsIog-n.Thesefunctionsarewell definedby two
straightlines:for smallvaluesof n, the slopesare near -- 1.0,and for
largern's,theslopes
approach- 0.5.Thissuggests
a modelin whichtwo
factorsinfluencethe discriminationprocess.For small n's, the spectral
widthof individualcomponents
in theamplitudespectrumarereducedin
proportion
to thelengthof theclicktrain;thustheslopeof -- 1.0.With
furtherincreases
in n, statisticalaveragingreducesthe effectof neural
noiseby a factorof the square-root
of n; hencethe slopeof -- 0.5. The
modelfit well to all of the data,exceptthoseobtainedwith the widest
spectralenvelope.
This maybeduetogreatersensitivityto temporalinformationavailablein the low-frequency
regionsof thesewidebandclicks.
[Supported
by NIH.]
tunedauditorynervefibers.In onespecies,
theJapanese
macaque,thereis
ß someevidence
thatsuperiordiscrimination
of frequency
increments
may
relateto thedesignfeatures
of theanimal'svocalcommunication
system.
[Supported
by NSF, SloanFoundation,
andDeafness
Research
Foundation.]
9:15
KK3. Temporal microstructural rules for periodicity of random-
amplitudesequences.
Irwin Pollack(MentalHealthResearchInstitute,
Universityof Michigan,Ann Arbor, MI 48109}
We examinemicrostructuralrules for the emergenceof periodicity
formedby temporalsubpatterns
withinrepeatedrandom-amplitude
sequences.
Thespecific
subpatterns
wereweighted
eitherbysuccessive
replication,e.g.,AAABAAAB ... or by differentialamplitudeweighting,
e.g.,AAbAAb .... whereb is a reducedversionorB. For short-duration
subpatterns,
the dominantperiodicityis that of the entire repeatedsequence.For long-duration
subpatterns,
thedominantperiodicityisthatof
the individual subpatterns,depending upon the relative amplitude
weightingand the numberof replications.[Work supportedby NSF.]
9.35
8:55
KK2. Asymmetrical frequency d'scr'm'nation in primates. Joan
M. SinnoRand Michael R. Petersen(PsychologyDepartment,Indiana
University,Bloomington,IN 474(}5}
Auditoryfrequency
difference
limensat0.5, 1.0,2.0,and4.0 kHz were
measuredmonaurallyin humansandin fourOld World monkeyspecies:
Japanese
and rhesusmacaques
(Macacafuscata,Macacamulatta}and
vetvetanddeBrazzamonkeys(Cercopithecus
aethiops,
Cercopithecus
neglectus}.A go, no-go,repetitive-standard
discrimination
procedurewas
employedwi.thpositivereinforcement.
At certainfrequencies
and sensation levels,humansandmacaques
exhibitsuperiordiscrimination
for frequencyincrements,
whileunderthesesameconditions
theCercopithecus
species
exhibitsuperiordiscriminationfor frequencydecrements.
Possible codingmechanisms
to accountfor theseresultswill be discussed,
ineludingmonitoringrateincreases
versus
ratedecreases
in asymmetrically
S70
KK4. Detection of temporal changesin the pitch of complexstimuli.
William A. Yoat and Morris Moore (ParrelyHearingInstitute,6525 N.
SheridanRd., Loyola University,Chicago,IL 60626)
Therepetitionpitchof ripplenoisewastemporallyvariedtodetermine
therelationship
between
therateof pitchvariationandtheperception
of
pitch change.Listenerswere askedto discriminatebetweenfiat spectral
noiseand ripple noisewhoseripple densitywastemporallyvariedin a
sinusoidal
manner.The spectrumof thetcmporallyvaryingripplenoise
stimulus
wasI + m cos( 2f[ g(T)] •; wherefisfrequency,
rnisthemodulationdepthof the spectralripple,andg(T} = T+ Tsin 2fi, whereTis the
delayusedto generateripplenoise,Tis the rangeof pitchchange,
f is the
rate(Hz}of pitchchange,andt istime.The repetitionpitchof ripplenoise
ßisdirectlyrelatedto thedelay,T. At eachrateof pitchvariationthedepth
of modulation{m}wasvaried in the adaptive,forced-choicetask until the
listenerwasat 71% correctin hisor herabilitytodiscriminate
ripplenoise
106thMeeling:AcousticalSocietyof America
S70
from flat noise.For a varietyof conditionsthe resultsindicatethat listenersare unableto detectthechangein the pitchof ripplenoiseat ratesof
pitchchangethat exceed2-5 Hz. This in turnsimpliesthat the auditory
the relativeimportanceof thesecharacteristics.
Resultsindicatedthat
directexperience
with a targettonecontributes
little to discrimination
performance
aslongasthefrequency
contourof thepatternremainssta-
systemis slow(200-500msestimatedintegrationtimel in its abilityto
process
thecomplex
stimulus
ofripplenoise.[Workwassupported
bythe
NationalScience
Foundation.]
ble within certain limits.
10:55
9:55
KKS. Rate discriminationof high-passfiltered pulse trains. Glcnis
R. LongandJohnK. Cullen,Jr. (Department
of Otorhinolaryngology,
LouisianaStateUniversityMedicalCenter,New Orleans,LA 70119)
KKS.Deteetionoftonesinsynthetieplosivebursts.
C. L. Farrar,Y. Ito,
P.M. Zurek, N. I. Durlach, and C. M. Reed (ResearchLaboratoryof
Electronics,36.767, MIT, Cambridge,MA 02139}
The generalgoalof our researchis to understand
discrimination
betweensoundsthat differonly in spectralshape.The objectiveof this
Differencelimens(DLs)for trainsof 30-/xsimpulsesweredetermined
for repetitionratesof 50-, 100-,200-, 400., and 800 pulsesper second
underconditionsof no filteringand high-pass
filtering(I 15dB/oct) with
cornerfrequencies
of 2.5-, 5.0-, 7.5-,and 10 kHz. Noise,at 15-dBspectrumlevel,waslowpassed
(115dB/oct)at thecornerfrequency
of each
high-pass
filtercondition
andmixedwiththetrainsofpulsesto preclude
discrimination
onthebasisof potentiallow-frequency
signalcompounds.
specific
studywasto testthe notionthat the discriminability
of two
Measureswereobtainedfrom four trainedlistenersat a signallevelof 30
dB SL relativeto individuallydetermined
thresholds
for eachfiltercondi-
attemptto relatediscrimination
anddetection
resultsthroughtransformations
of"masking
difference
patterns,"
whichshowthedifference,
asa
functionof frequency,betweensignalthresholds
for the two maskers.
Further,we will describe
our progress
in developing
a generalpsychoacousticmodelfor discriminating
betweensounds
thatdifferonlyin their
tionandrepetitionrate.A twoalternativeforcedchoiceadaptiveprocedurewasused.The datasupportthehypothesis
thatresolution
of pulsetrainrepetition
rateinvol•esbothtemporal
andpitch-based
processes;
the
latterbecoming
ineffective
whenfrequency
resolution
of theearisinsufficientto resolveseparateharmonicsof the signal.[Work supported
by
soundsis monotonicallyrelatedto the differencebetweentheir simultaneousmaskingpattern(or, its corollary,that two soundsthat produce
equalmaskingare indiscriminable.}
Measurements
weremadeof the
thresholds
for tonesin two maskingnoises,onewith a/p/-shaped spectrum andthe otherwith a/t/-shaped spectrum.Data on discriminating
betweenthesetwo maskingnoiseshavebeenpreviouslyobtained.We
spectralshapes.
NIH.]
11:15
loft5
KK6. Temporaltuning curvesand their relation to frequencytuning
curves.AnnaC. Schroder
andEdward Cudahy•1(Syracuse
University,
805 SouthCrouseAvenue,Syracuse,NY 13210}
KK9. Development of auditory thresholds in young chickens.
LincolnGray (Departmentof Otolaryngology--Headand Neck
Surgery,Universityof TexasMedicalSchool,Houston,TX 77030)and
Edwin W. Rubel (Departmentof Otolaryngology--Headand Neck
Surgery,Universityof Virginia Medical School,Charlottesville,VA
22908)
Temporaltuningcurvesfor a 1000-Hz,10-ms,10-dBSL sinusoidal
signalwitha 500-,1000-,or 1500-Hz,10-mssinusoidal
maskerweremeasuredusinga 2IFC adaptive
procedure.
Frequency
tuningcurvesfor the
I 0 dBSL, 1000-Hzsignalwerealsomeasured
for 10-and500-mssimultaneousmaskers.Five normalhearinglistenerswereemployed.The frequency
tuningcurves
forthebriefmasker
werebroader
thanthoseforthe
longmasker,especially
on thehigh-frequency
sideof thesignal.Marked
differences
werenot foundbetweenthe temporaltuningcurvesfor the
threemaskerconditions.
The implications
of theseresultsfor relations
betweenauditoryfrequencyand temporalanalysiswill be discussed.
alPresentaddress:House Ear Institute, 256 South Lake Street, Los Angeles,CA 90057.
10:35
Absoluteauditorythresholds
wereestimatedin chickenswithin 12h
of birthandat 4 daysafterhatching.A two-interval,
forced-choice
staircaseprocedure
wasmodifiedto usemomentary
suppressions
in chick's
peepingasindications
of correctandincorrectresponses.
The estimated
thresholds
of bothageswerethesameat lowfrequencies
(250-500Hz). At
higherfrequencies
(1-2 kHz), however,
4-day-oldchickshadthresholds
about20 dB lowerthanthe0-day-oldchicks.Thusabsolutethresholds
are
a functionof bothfrequencyandage.Thesethresholds
arelikelyto reflect
perceptual
development
fortworeasons:
(a)Similarthresholds
fromboth
agesat lowfrequencies
showthatdevelopmental
differences
arenotdueto
differences
in the sensitivityof the testingprocedure;and (b) thresholds
obtainedfrom the 4-day-oldbirds are similar to other estimatesfrom
maturebirds.In conclusion,
responsiveness
to low frequencies
develops
beforeresponsiveness
to higherfrequencies.
[Worksupported
by NIH.]
KK7. Generalizationof learningin auditorypatterndiscrimination.M.
R. Leek (Departmentof Speechand HearingScience,Arizona State
University,Tempe,AZ 85287)
Frequency
discrimination
fortonesembedded
in a varyingsequenc•
of tenbrieftonescanbeextremelypoor.Yet afterrepeatedexposureto a
constant
tonalsequence,
listeners
demonstrate
discrimination
of changes
in a targetcomponent
almostasfineasforthetargettonepresented
alone
[e.g.,C. S.Watsonetal.,J. Acoust.
Soc.Am.60, 1176-1186
(1976)].It is
clear,however,whichaspects
of theconstantpatternarelearned,thereby
allowingthe listenerto overcomethe effectsof the surrounding
tonal
contextondiscrimination
of thetarget.Thisexperimentinvestigated
generalizationto newpatternsof the learnedtargetand learnedcontextto
assess
theircontributions
to patterndiscrimination.
Four listeners
were
trainedin a same-different
taskto discriminatesmallfrequencychanges
in a 920-Hz targettone,whichwasthe secondelementin a ten-tonepat-
tern.Frequency
difference
limensweresubsequently
determined
for the
learnedtargettoneembedded
in a differenttonalcontext,andfordifferent
targetswhenthe contextwasheldconstant.Listenerswereunableto
maintainsmalldifference
limensfor thetargettonewhenthesurrounding
elements
of thepatternwerechanged.Varyingthe targetin the learned
context,
however,
provedmuchlessdisruptive.
Variations
in thefrequenciesandthefrequency
contourof thelearnedcontextservedto illustrate
$71
11:35
KKI0. Phaseeffectsandprofileanalysis.David M. Greenand Christine
R. Mason {Laboratoryof Psychophysics,
Harvard University,33
Kirkland Street,Cambridge,MA 02138}
Randomizing
thephaseofthecomponents
ofa tonalcomplex
oneach
presentation
haslittleeffectondetection
ofanintensity
increment
of the
centralcomponent.The complexconsisted
of elevenequalamplitude
tonesrangingfrom200to5000Hz. Thespacing
between
adjacent
componentswasequalona logarithmic
frequency
scale.Thesignalwasa sinusoldaddedin-phase
tothecentral,1000-Hzcomponent.
Theoverallsound
pressure
levelofthesound
wasvariedoneachpresentation
according
toa
rectangular
distribution
witha rangeof 40 dB anda mediansoundpressurelevelper component
of 45 dB. Over 50 complexes
with different
waveforms
weregenerated
byrandomly
selecting
different
starting
phases
for eachcomponent.
Eightof thesewaveforms
wereselected,
andeach
waspresented
asthecomplexfor morethan500trialsin a 2AFC experiment.Thresholds
for a signaladdedto eachof thesedifferentcomplexes
hada total rangeof only2.4 dB. In a finaltest,we selected
a different
waveformon eachpresentation.
Signalthresholdwaselevatedby only3
dB. [Worksupported
by NIH.]
Societyof America
$71
THURSDAY
MORNING,
10 NOVEMBER
1983
TOWNE ROOM, 9:30 A.M.
Meeting of StandardsCommittee S12 on Noise
to be held jointly with the
Technical Advisory Group for ISO/TC 43/SC1 Noise
K. M. Eldred, Chairman S12
P. 0. Box 1037, Concord, Massachusetts 01742
H. E. yon Gicrke, Chairman,TechnicalAdvisoryGroup for ISO/TC 43/SC1
Chief,Bionics& Biodynamics
Division,AMRL/BB U.S. •4irForce,Wright,Patterson
.4FB,Dayton,Ohio45433
Workinggroupchairswill reporton their progressunderthe planfor the productionof noisestandards.
The
interactionwith ISO/TC 43/SCl and the recentTC 43/SCl meeting,held from 2-4 August1983,will be
discussed.
THURSDAY
AFTERNOON,
10 NOVEMBER
FORUM
1983
ROOM,
12:00 TO 12:40 P.M.
Education in Acoustics:Basic Acoustical Experiments
Mauro Pierucci, Chairman
Departmentof Aerospace
Engineering,
and Engineering
Mechanics,
SanDiegoState University,
SanDiego,California
92182
Chairman's Introduction--12.-00
Basicexperiments
illustrating
acoustical
principles
andaimedat acousticians
andnonacousticians
alikewill be
presented.
Emphasiswill beon ideasthat will furtherstimulatetheknowledgeof acoustics
at the undergraduate level.
Participants
Victor C. Anderson
Marine PhysicalLaboratory,Scripps
Institutionof Oceanography,
University
of
California,
.SanDiego,La Jolla,California92093
R. J. Piserehio
Departmentof Physics,
San DiegoState University,San Diego,California92182
S72
J. Acoust.Soc.Am.Suppl.1. VoL74, Fall 1983
Societyof America
$72
THURSDAY
AFTERNOONi
10NOVEMBER
1983
SUNRISE
ROOM,1:00
TO4:35P.M.
Session
LL. Psychological
andPhysiological
Acoustics
IV: Acoustics
of Echolocating
AnimalsUnderWater
Whitlow W. L. Au, Co-Chairman
Code512, Naoal OceanSystemsCenter,Kailua, Hawaii 96734
Ronald Schusterman, Co-Chairman
BiologyDepartment,
CaliforniaStateUniversity,
Hayward,California94542
Chairman's [ntroduction---l.-00
Invited Papers
l:OS
LLI, DolphinsoundproductJun:
Physiologic,
diurnal,andbehavioralcorrelations.
SamH. Ridgway(Code
5142,NavalOceanSystems
Center,SanDiego,CA 92152}
Themechanics
ofdolphinsoundproduction
wdlbereviewed
butmanyquestions
remain.Forexample,
do
thediagonalmembranes
functionsomewhat
asvocalcords?Doesthenasalplugserveasa primaryvibrating
source?Do the oasofrontalsacsserveas tuned, or tunable, resonators?Do the nasal sacsserveas acoustic
reflectors
andhelpto focussound?In general,therearethreetypesof soundsproducedby T. truncatus
and
othercloselyrelateddolphins--whistles,
burstpulsesounds,
andclicktrains.Click trains,generallyof high
peakfrequency,
areusedbydolphins
thataretrainedto performecholocation
tasks.All threetypesof sound
havealsobeensuggested
ashavingpotentialvaluefor communication.
I havefoundthat:(I} A singledolphin
mayproduceasmanyas50 000separatesonicepisodes
in a single24-hday {Theaveragedailysoundproductionismorelikea tenththisfigure};
{2}Peaksin soundproduction
occurin thehourbeforeandduringfeeding,
especiallythe first feedingof the day, and during the hour after sunset.It appearsthat dolphinsdisplay
aggression
and agitationby increasing
the pulsatilecontentof soundsand by emphasizing
the harmonic
structureof whistles.It is possible
that echolocation
evolvedfrom soundsfirstusedin aggression.
1:35
LL2. Insightsinto dolphinsonardiscriminationcapabilitiesfrom broadbandsonardiscriminationexperiments
with humansubjects.Whitlow W. L. Au and DouglasW. Martin (Naval OceanSystemsCenter,P.O. Box
997, Kailua, HI 96734]
A widevarietyof dolphinsonardiscrimination
experiments
havebeenconducted,
yetlittle isknownasto
thecuesutilizedby dolphinsin makingfinetargetdiscriminations.
HammerandAu [J. Acoust.Soc.Am.
1285-1293{19801]found a correlationbetweendolphindiscriminationcapabilitiesand the matchedfilter
response
of thetargetechoes.
Sonardiscrimination
experiments
havealsobeenconducted
with humansubjects
usingthesametargetsemployed
in theHammerandAu andotherdolphinexperiments.
Whendigitalrecord-
ingsmadeofthetargetechoes
ensonfied
witha dolphinlike
signalwereplayedbackat a s!owerratetosubjects,
humanscouldmakefinetargetdiscriminations
undercontrolledlaboratoryconditionsaboutas well asdolphinsunderlesscontrolledconditions.Mostof thecuesreportedby humansubjects
canbedescribed
by timedomainecho-features.
The resultsof severaldolphinsonarandhumanlisteningexperimenls
will bediscussed
along with the targetechocharacteristics.
ContributedPapers
2:05
LL3. Crit'cal ratio and bandwidth of the Atlantic bottlenosedolphin
(Tursiopstruncatus).Patrick W. B. Moore and Whirlow W. L. Au
(NavalOceanSystems
Center,P.O. Box997, Kailua,HI 96734)
Maskedunderwaterpure-tonethresholds
wereobtainedfor an Atlantic bottlenose
dolphinusingan "up-downstaircase"methodof stimulus
presentation
anda "go/no-go"response
procedure.
Broadband
noiseat
two levelswasusedto measurethe animal'scriticalratio at testfrequenciesof 30, 60, 90, 100, 110, 120,and 140kHz. For frequencies
of 100kHz
and below,the critical ratiosweresimilarto thosemeasuredby Johnson
[J3Acoust.Soc.Am. 44, 965-967 {1968}].The resultsindicatea sharp
increasein the critical ratio to 51 dB at l10 kHz followedby a slight
decline to 46 dB at 120 kHz. Different bandwidths of noise with very
sharpcutoffswereusedto measure
thedolphin'scriticalbandwidthat test
frequencies
of 30,60,and120kHz. Thecriticalbandwidth
wasapproxiS73
mately 10times(10 dB} wider than the critical ratio at 30 kHz and 8 times
wider{9dB}at 60 kHz. At 120kHz, the criticalbandwidthwasapproximatelythe sameas the critical ratio.
2:20
LL4. Peak sound pressurelevel and spectral frequency distributions in
echolocationpulsesof Atlantic hattienose dolphins, Tursiops trtmeatus.
Marion G. Ceruti, Patrick W. B. Moore, and SueA. Patterson{Naval
OceanSystemsCenter,Hawaii Laboratory,P. O. BOx997, Kailua, HI
96734)
We investigated
the relationshipbetweenpeaksoundpressurelevel
IPPL) andthe shapeof the spectralfrequencydistributionofecholocation
pulsesemittedby Atlantic bottlenosedolphins(Tursiopstruncatus}in a
targetdetectiontask.Two dolphinsweretrainedto stationon a bite plate
S73
andtail rest,echolocate,
and reporttargetcondition{presentor absent}.A
microprocessor
dataacquisition
system
[M. G. CerutiandW. W. L. Au,
J. Acoust.Soc.Am. 73, 1390-1392{1983}],wasusedto collectamplitude
and frequencydata for eachpulseand monitorsubjects'responses.
Ten
sessions
of 50 trialseach{25targetpresentand25 targetabsent,presented
randomly}werechosenfor eachsubjectfrom sessions
conductedduring
Nov. 1982.Pulseswereclassified
as"bimodal"or "unimodal,"depending
on the numberof maximain the frequencyspectrumbetween30 and 135
kHz. For bimodalpulses,thedegreeof bimodalityBI, alsowasmeasured
bysummingthemaximumintensities
usingtheinterveningminimumasa
baseline.
The resultscollapsed
acrosssubjects
yielded15 670bimodaland
12 383 unimodelpulses.The meanPPL for bimodalpulseswas207 dB
re:! HPa andfor unimodalpulses,197dB. The Pearsonproductmoment
correlation coefficient between BI and PPL was 0.69. Peaks in the aver-
agedbimodalspectrumoccurredat 60 and 135kHz or beyond,whilethe
averaged
unimodalspectrum
waspeakedat 120kHz. Thesefindings
suggestthat bimodalfrequencydistributions
duringhigh-pressure
echolocation represents
a physiological
process
in the pulseemissionsystem.
2:35
When the echolocationdetectionabilitiesof a belugawhale and a
bottlenosedolphinwere testedon identicalcylindricaltargetsand distanees,theyhad interpulseinterval(IP1)distributions
whichweredifferent, whiledetectionaceuracyshowednosignificantdifference.Bottlenose
dolphin pulse trains show a predictableand systematicrelationship
betweenthe distanceto a detectedtargetand time betweenecholocation
pulses,thuspermittingan inferenceof attendingdistanceJR.H. Penner
andJ. Kadane,J. Acoust.Soc.Am. Suppl.1 68, S97(1980)].The beluga
whalepulsetrainscontained,at all targetdistances,
a firstIPI component
startingaround30 msand increasingto 60 msand a secondIPI componentbetween200 to 220 mswhichbecamemorenumerousastargetdistanceincreased.
The transitionzonebetweenthefirstandsecondcomponentscontainedvery few intervalcounts.The interpulseintervalswithin
the transitionzoneincreasedastargetdistanceincreased.If thebottlenose
dolphinIPI patternsare acceptedas models,and similarassumptions
regardingattendingdistanceare appliedto the belugawhalepulsetrain,
the pictureis oneof alwaysscanningout to 30 m; followedby shortscan
out to 160 m. Subsequent
targetdetectionwork usingspheresinsteadof
cylindersas targets,showedthe sameIPI distributionpatternsfor the
belugawhale.
LLS. Apparent echolocationby a sixty-day-old bottlenoseddolphin,
Tursiopstruncatus.Donald A. Carder and Sam H. Ridgway(Code
3:20
5142, Naval OceanSystemsCenter,SanDiego, CA 92152)
LLS. Comparativeobservationson odontocetesonarsignalsfrom captive
Little is known about the ontogenyof echolocationin dolphins.A
bottlenosed
dolphincalf born at our facility in San Diego Bay wasobservedcontinuouslyfor two hourseachday and randomlyat other times.
Squeals
wereheardabouttenseconds
afterbirthandwhistlelikecallssoon
thereafterbut we did not noticehead scanningmovementsconcurrent
with high-frequency
pulsesuntil thedolphin'ssixtiethday of life. On this
day we noticedthat the calf wouldexamineitemssuchasa humanfoot
insertedin the waterby approaching,
headscanning,and pulsing.A hy-
drophoneplacedin the water elicitedthe samebehavior.Sevenpulse
trainswererecordedat distances
of 1-3 m. Peakfrequencies
rangedfrom
33 to 120 kHz with 3-dB bandwidths of 28-81 kHz.
animals.CcesKamminga(InformationTheoryGroup,Delft University
of Technology,Mekelweg4, Delft, The Netherlands)
In thispapera comparativeanalysisof typicalsonarsignalsof several
species
of littoral andriverincdolphinsin captivityis presented.
The sonar
waveshapescomparedincludethoserecentlyobtainedfrom two species,
whoseacousticbehaviorhasnot beendescribedpreviouslyin literature,
i.e., the off-shoreLagenorh.•nchus
albirostris
and the freshwaterpopula-
tionof lrrawadi;Orcaellabrevirostris.
Thelatterfit verywellin thepicture
established
thusfar from a largecollectionof echolocation
data.A study
of thesesonarsignalsrevealsthe noteworthyfact that--apart from the
Commerson'ssignal--they all sharea rather simple,basicwave shape.
This can best be understood and classified in terms of the well-known
2:•0
LL6. Target detection:Belugawhaleandbottlenosedolphinecholocation
abilitiescompared.
CharlesW. Turl andRalphH. Penner(NavalOcean
SystemsCenter,Hawaii Laboratory,P.O. Box 997, Kailua, HI 96734}
An experimentcomparedthe echolocationabilitiesof a belugawhale
anda bottlenose
dolphinto detectfivetargetsof the samesizeandtarget
strength( + / -- 2 dB)at distances
from40 to 120m. The performance
for
both animalsat 40, 60, 80, and 100 m exceeded90% correct detection;
however,performanceat 120 m rangedbetween60% to 62% correct
detection.The belugawhaleand the bottlenose
dolphinweretestedwith
thesametargetsat 5-mincrements
at distances
from 100to 120m. These
testresultsindicated:{I} no significantly
differentperformance
{p < 0.05}
betweenthebelugawhaleandbottlenose
dolphinat thefivetestdistances,
{2}bothanimalsdifferentiallyreportedthreeof the fivetargets,independentof targetdistance,and {3}the performance
of bothanimalsat 120m
rangedbetween60% to 90% correctdetectiondepending
onwhichtarget
waspresented
at 120m. Theremaybe severalreasons
why bothanimals
differentiallyreportedthreeof the targetsat rangesbeyond100m, irrespeetiveof absolutedistance:{l} variabletargetstrength,{2}the mannerin
whichthe targetsweresuspended
plusrotationalmotionaboutthe suspensionpointmayhaveinducedtargetechovariability,and(3}for targets
under100m, targetecholevelswerelargeandboththebelugawhaleand
bottlenosedolphinwere able to differentiatethe signalfrom the backgroundnoise.Beyond100 m, subtlefeaturesof the targetsdetermined
their detectibility.On two targets,the salientfeatureswere apparently
unavailableat rangesbeyond100m, and differentialdetectionoccurred.
Becausethe rangedifferences
weresmall, the significanttarget feature
that wasabsentwasnot solelya functionof sphericalspreadingloss.
3.-05
LLT. Bottlenose
dolphin(Tursiopstruacatus):
Differencein thepatternof
interpulseintervals, Ralph H. Penner and Charles W. Turl (Naval
Ocean SystemsCenter, Hawaii Laboratory,P.O. Box 997, Kailua, HI
96734}
$74
J. Acousl.Soc.Am.Suppl.1, VoL74, Fall 1983
uncertaintyrelationin communicationtheoryandenablesusthereforeto
link bioacoustics
with mathematicalphysics.The signalsapproachthe
theoreticallowerboundfor the productof the time durationand frequency bandwidthandcouldthereforebedesignated
as"smalltime-duration
bandwidth"signals.They are thus well suitedas a classof elementary
optimal time-frequencysignals.The frequencyrangeof interestin the
firstdescribed
classof eetaecansonaris situatedat a dominantfrequency
below100kHz, whilein thePhoeaenaand Commerson
groupthisdomi-
nant valuegoesup to around120kHz. The latter thusenablingthose
smallanimalsto resolvespatialdifferences
in their habitatup to an order
of magnitudeof nearlya centimeter.
3:35
LL9. A qualitative model of the dolphin sonar. James W. Fitzgerald
(Mystic Marinelife Aquarium,Mystic, CT 06355 and B-K Dynamics,
Inc., New London, CT 06320}
By meansof a complex,functionalanatomy,the bioacoustic
apparatusof thedolphinenables
himtooperatefourseparate
sonarsystems
more
or lesssimultaneously,
usingsomeof theanatomical
components
in common.Thesesystems
are:{l} a broadband
high-frequency
{• 30-150 kHz}
echolocation
"attack "sonar,with a narrow( • I 0') forward-lookingbeam
pattern,thatisusedfor thelocationandtrackingof suchtargetsasfoodfish;{2}a broadband,
low-frequency
{ < 30 kHz) echolocation
"search"
sonar,witha broad{• 120}forward-looking
beampattern,thatisusedfor
orientation and intruder detection;(3} an audio-frequency{•0.2-15
kHz},frequency-contoured
"communication"
sonar,with a substantially
nondirectionalbeampattern,that is usedfor communicatingwith other
dolphins;
and,finally,{4}a wideband
{0.15-150kHz},binaural"listening"
sonarthatisusedasthesonarreceiverforall threeof thepreceding
active
sonars,aswell asa passivelisteningsystemfor targetdetection,bearing;
andclassification.
It isshownthat echolocation"clicks"originatingin the
larynx,whichenterthemelonthroughthe closednasalplug,aretotally
internallyreflected,radiatingonly from the forwardend, and form the
attacksonar.A logarithmicspiralof theform R = ,4 exp[{-- tantic}t•],
S74
Effortsto experimentally
demonstrate
echolocation
in Californiasea
lions,Zalophuscalifornianus
[W. Evansand R. Haugen,Bull. So. Cal.
Acad. Sci.62, 165-175(1963);R. J. Schusterman,
Psych.Rec. 16, 129136(1966)]andin greyseals,Halichoerus
grypuslB. SeroneeandS. Ridgway,in ,4nimalSonarSystems,
pp.991-993(1980)]havebeenunsuccessful. However,similarstudies
onpolarpinnipeds
havenotbeenconducted
previously.
No studies
haveinvestigated
thepotentialfor ultrasonic
vocalizationsin pinnipeds.
Echolocation
in polarpinnipeds
hasbeensuggested
because
oftheirhighlydeveloped
vocalabilities
andtheirneedtofindfood
andnavigateduringthedarkaustralwinter[G. Kooyman,Ant. Res.Ser.
11,227-261 (1968);J. Thomasand V. Kuechle,J. Acoust.Soc.Am. 72,
1730--1738(1982)].This presentation
will summarizeobservations
and
evidencethat indicatesthe presence
of echolocation
in polar pinnipeds
andreporttheproduction
of ultrasonic
vocalizations
by a captiveleopard
seal(Hydrurgaleptonyx).
Clicks,buzzes,andfrequency-modulated
chirps
wereproducedwith peakfrequencies
from 4 to 164kHz, but generally
where/•½is the criticalangle,fitsthe shapeof the melon.For the open
nasalplugcondition,
echolocation
"clicks"fromthelarynxpropagate
up
the nasalductinto the premaxillarysac,whichactsasa "bubble"transducer for the search sonar. The source of the whistle-like communicative
phonations
isidentified
aslip-modulations
excited
byexhaust
airexpelled
fromthepremaxillary
sacintothevestibular
sac.Experimental
confirmation, drawnin part from the bioacoustic
literatureon Odontocetes,
is
proffered
in support
of theprincipalqualitative
features
of thisnewmodel.
3:50
LL10. Echolocationin Harbour seals:Mayhe they can do it after all.
Deane Renouf(Departmentof Psychology/Marine
Sciences
Research
Laboratory, Memorial University of Newfoundland,St. John's,
Newfoundland,
A IB •X9, Canada)
between50 and60 kHz. This studydemonstrates
the importanceof inves-
Thoughthereisindirectevidence
to indicate
thatvarious
species
of
tigatingultrasonicvocalizations
in all pinnipeds
and impliesthat polar
pinnipeds
maybethebesttestgroupfor echolocation.
sealsarecapable
ofsomeformofecholocation,
all previous
attemptsat an
experimental
demonstration
of sonarcapacities
havemetwithnegative
results.I haveobtainedthe followingcircumstantial
evidence
that Harboursealscanecholocate:
(1) During threebreedingseasons
I haveob-
servedapparently
healthyblindadultharboursealsincluding
females
which have successfully
raisedpups.(2) When visualcuesare reduced,
4:20
harbour seals make click vocalizations similar to those of animals which
LL12. Seal blindfolded discrimination: Echolocation not proven in
are knownto echolocate.
{3)They are ableto find live fishin total dark-
HMichoeru$•'.r'pus.
B. L. Seronee
andS.H. Ridgway(Code514,Naval
OceanSystems
Center,SanDiego,CA 92152)
hess,
producing
clickswhiledoingso.(4)Onesealtrainedtoretrievea ring
whichhe firsthad to find in a 10-m-diamtank performedas well in the
dark as in daylight,but eliekedonly whenhe couldnot usevision.I
A four-year-old
femalegraysealfromIcelandwastrainedto wearan
obtaineda morerigorousdemonstration
of HarboursealsonarwhenI
opaque
elastic
bandthatblocked
vision.
Echolocation
capability
wasevaluatedin twoexperiments:
(1)Thesealwasrequiredtoretrieveanair-filled
plasticring20cmin diameter
placedat randomin a 5X 1m section
ofa
wasable to train an animal to discriminatebetweentwo visuallyidentical
ringswhichdifferedin acoustic
impedance.
Whentheacoustical
propertiesof theringsweremadeequal,theanimalwasnolongerableto distinguishbetweenthem.Very faint singleor doubletclickswererecorded
duringtheanimal'sperformance,
andit is suggested
that quietdistinct
signals
mayhavebeenappropriate
in anenclosed
tankwhentheobjects
to
bediscriminated
weresuspended
closeto theenclosure's
walls.The reasonswhythetrainingprocedures
usedin thisdemonstration
weresuccess-
10-mredwoodtank.(2)Thesealwasrequiredtodetectthefiatsurfaceofa
25-cmstyrofoam
diskasopposed
to theedgeof thesamedisk( - 30 dB
targetstrength),
placedrandomly
oneithersideofa divider.Withoutthe
blindfold,
theseal'sringretrievalratewas100%witha latencyof 3.8s.In
427 blindfoldedtrialstherewere99% correctresponses,
but latencyin-
creased
to 6.5s.Headscanning
movements
wereobserved
onabouthalf
ful are discussed,
and the limitationsof the conclusions
which can be
the blindfolded trials and click trains were recordedon about 10% of the
drawn from such results are outlined.
trials observed.In the secondexperiment,the blindfoldedseal ap-
proached
thedividerandmadeachoice
abouttargetlocation
(rightorleft)
at least1.5m away.Correctresponses
in a session
neverexceeded
65%
andaveraged
46% on617trials.Withouttheblindfold,theseal'sperformancewasalmost100%.Thegraysealmakessoundunderwater
butdoes
not appearto usethe clicksfor echolocation
in anywaysimilarto the
demonstrated
capabilities
of dolphins.
4:05
LLll. Incidental evidencefor echolocationin polar pinnipeds.Jcanettc
A. Thomas, Frank T. Awbrey, and Sheldon R. Fisher (Hubbs Sea
World ResearchInstitute,1700SouthShoreRoad,SanDiego,CA 92109)
THURSDAY
AFTERNOON,
10 NOVEMBER
1983
SENATE/COMMITTEE
ROOMS, 1:00 P.M.
SessionMM. UnderwaterAcousticsV: SignalProcessingI (Prtcis-PosterSession)
Arthur B. Baggeroer,Chairman
Massachusetts
Cambridge,Massachusetts
02139
Chairman's
Introductian--l:00
Invited Papers
1:05
MM1. Broadbandsignal selectionand generationfor channel sounding.T. G. Birdsall •University of
Michigan,262 CooleyBldg., Ann Arbor, MI 48109I
Two classes
of signals
andapplications
areconsidered.
The T class,for deepwaterworkwhereray pathsare
anappropriatemodel,requiresa processed
outputwaveformthat isa shortpulsewith zeroamplitudebeyonda
$7S
Societyof America
smallneighborhood
of the peak.The F class,for shallowwaterwork wheremodetheoryis an appropriate
model,or for multioctavework wherepropagationvariessignificantlyacrossfrequency,requiresa definite
powerspectrum.Althoughrelated,the two typesof requirementare differentin practice.Appropriatesignal
processing
that balancessignal-to-noise
ratio and resolutionwill be discussed;
it is called "factor-inverse
matched-filtering."
A specific
measureof spectralflatness,
togetherwith in-bandfractionalpower,arecombinedto yield a signalefficiencymeasure.Emphasisis placedon continuousperiodicsignals.The T-class
signalsto be discussed
are binary,digital,phase-modulated
by m sequences;
variationsare augmentedm
sequences
andfrequencymodulation.The F-classsignalsto bediscussed
arelinearFM anda particulardigital
discreteFM signalcalledPDFM.
1:30
MM2. The importanceof correlators.G. Clifford Carter {U.S. Naval Underwater SystemsCenter, New
London,CT 06320)
A lutorial reviewof generalized
crosscorrelatorsand their importanceto passivesonarsignalprocessing
will bepresented.
A discussion
oftheeffects
bandwidth,andintegration
timeaswellasmultipathandmultitargetinterferences
will beincluded.The presentation
will emphasize
broadbandaspectof correlationprocessing
includingdegradations
experienced
by narrow-bandcomponents.
Fundamentallimitson performance
will be
discussed.
ContributedPapers
1:55
MM3. Broadbandsignalprocessing
in communication
systems.Stanley
L. AdamsIHarrisCorporation,
P.O. Box37,Melbourne,FL 32901)and
MichaelH. Brill [Science
Applications,Inc., 1710GoodridgeDrive, P.
O. Box 1303,McLean, VA 22102)
The broadbandcharacteristics
of the underwateracousticpropagationchanneldetermineboththeapproachto communicating
andthe performartecwhichcan be achieved.This paperpresentsa detailedbroadband characterization
of the channel and uses this characterization
to
describeapproaches
to communication.Performancehoundsare calculatedand comparedto channelcapacityresults.
1:59
MM4. Wideband, frequency-domainbeamformingfor coherent signal
processing.
Mark E. Weber •Code5160, Naval ResearchLaboratory,
Washington,.
DC 20375)and RodneyHeisler{Walla Walla College,
CollegePlace,WA 99324I
Coherentdetectionprocessors
for sonar(e.g.,matchedfiltersfor activesystemsl
requirecontinuous
timeseriesasinputandhaveconventionally beenassociated
with delay-and-sum
time-domain
beamformers.
As
an alternative,we haveextendedfrequency-domain
beamforming
techniquesto retainthecoherence
of wideband
signals
andhavedemonstrated
efficientsoftwarefor computing
continuous
time-series
beamsfor flexible
postprocessing.
Using computer-generated
"acoustic-array"
data, the
beamformerwasshownto preservethe envelope,spectrum,and correla-
tionproperties
of signals
whileyieldingneartheoretical
performance
in
reducingbeamside-lobe
levels.Advantages
overa conventional
delayand-sumbeamformerare:{1}eliminationof the needfor highinputsamplingratesto achieveacceptable
beampatterns--thefrequency-domain
approachisinsensitive
to thesampling
rateprovidedit exceeds
the{bandpass}Nyquistrate;{2}reductionof high-beamside-lobe
levelscausedby
malfunctioning
arrayelements--the
•sponseof missing
arrayelements
is
readilyestimatedin the frequencydomainby interpolatingfrom the spectra of neighboring
sensors;
{3}minimization.
of hardwarerequirements-all stagesof signalprocessing
{bandpass
filtering,holefixing,
beamforming, time-linereconstruction,
and matchedfiltering}canbeefficientlyperformedin a generalpurposearray processor.
Extendingprevioustime-spreadwork by the presentauthors[J.
Acoust.Soe.Am. Suppl.I 73, SI 1 {1983)],thefrequency
spreading
of an
acousticsignalreflectingfroman oceanbottom{inthe presence
of source
andreceivermotion}iscomputed
usinga simplegeometric-acoustic
model. In that model,a ray reflectsspecularlyfrom eachbottomfacet,and
arrivesat the receiverif and only if the positionand slopeof the facet
providethe requisitespecularpath. The modelprovidesa connection
betweentheexpectedpowerfluxinto thereceiveraperturefroma particular facet and the slopedistributionof the bottom {assumedconstantin
depth}.For a cw signal,the frequencyspreadcan becomputedby histogrammingin Q = {f-fo}/fo theexpectedrelativeenergyfroma gridof
bottomfacets.{Here,fois the frequencyemittedat the source,andf is the
frequencyof the receivedsignal.}The quantityQ dependsonly on the
positionof the facet,range,depth,and sourceand receivervelocities:it
doesnotdependonfo,solongastheraypathsareindependent
offrequency, asin the presentmodel.In fact, the expossionfor Q is the time derivativeof delaytimefora broadband
signal,aswellashavinga narrow-band
interpretation.Computedfrequency-spread
curvesare presented
for severalsource/receiver
geometries.
Because
relativeenergyvsQis a function
of thechannelandnotof thesentsignal,it mayhelpto connectthebroadbandscatteringfunctionwith the expecteddistributionof powerin time
and frequencyfrom an input powerimpulse.
2:07
MM6. Spread signal processing.Andrew C. Callahan (Raytheon
Company,SubmarineSignalDivision,Portsmouth,RI 0287I)
The signalprocessing
of broadbanddataoftenresultsin signalswhich
arcstillspread
overa regic;n
of parameters,
suchas,frequency,
Doppler,
delay,etc.It isof greatinterestto determinethe possible
gainsachievable
by the inclusionof all signalcontributions
into the formationof a region
statistic.This is formulated into the analysisof distribution mixtures
whichis referredto asspreadsignalprocessing.
To determinethe potential gainsin thisapproach,a particularexampleof signalplusnoiseand
noisedistributionswcrc analyzed for detectionperformanceas a function
of signalleveland thefractionof signalsamples.Simulationresultsindicate an improvementover both the greatestsampleand constantfalse
alarm rate statisticsfor intermediatevaluesoftbe signalsamplefraction.
2:11
2.-03
MMS. Frequencyspreadsof broadbandsignalsreflectingfrom a random
surfnee.Michael H. Brill {ScienceApplications,Inc., 1710 Goodridge
Drive, P.O. Box 1303, McLean, VA 22102},Xavier Zabal {TRW, 7600
ColshireDrive, McLean, VA 22102), and StanleyL. Adams (Harris
Corporation,Box 37, Melbourne,FL 32901)
S76
MM7. A study of the stutistical propertiesof broadbandsignals.Fred
W. Machelland Clark S. Penrod(AppliedResearchLaboratories,
The
Universityof Texasat Austin, Austin, TX 78712-8029)
A commonassumptionin the processing
of broadbandacousticsignalsis that the underlyingprocesses
are Gaussian.AlthoughGaussian
Societyof America
$76
processes
arisenaturallyintheoceanacoustic
environmen
t, anothermotivationfor theGaussian
assumption
isthedesirefor analyticallytractable
resultsand simplealgorithms.In this paper,a broadbandpropagation
modelisusedto analyzethestatisticalproperties
of randomsignalspropagatedin a deepoceanenvironment.
In particular,measurements
of the
first-orderprobabilitydensityfunctionsassociated
with the sourceand
receivedsignalswill be presented
for severalsource-receiver
configurations.Thesemeasurements
provideinsightintothe appropriateness
of a
Gaussian
assumption
in broadbandprocessing.
They alsoillustratethe
effectsofacousticpropagation
mechanisms
onthestatisticalstructureof a
signal.Measurements
of correlationfunctions
arepresented
to showthe
effectsof multipathpropagation.[Work supported
by theOfficeof Naval
Research.]
mateof the background.
The spatialnormalizationhigh-pass
filtering
effecthasbeencalculatedfor a varietyof normalizationschemes
for linear
andcirculararrays.In general,theattenuation
of thefilteris6 dB/oct at
frequencies
muchsmallerthanthedesignfrequency
of thearray.Specific
frequency
response
curvesarepresented,
andtheramifications
to broadbandenergydetectionare discussed.
Theseincludemodifications
to the
designof the Eckart filter,and the reducednoisebiaseffectsfrom anisotropicremoteshipping.
2:27
MMll. Techniquesfor isolatingresonancesin experimentallyobtained
broadband acoustic echoes. S. K. Numrich, N.H.
Dale, and L.
R. Dragonette(Code5132, Naval ResearchLaboratory,Washington,
2:15
MMg. A precisionmethodof determiningwide-bandwidth
pulsedelayin
highly dispersivemedia. Herbert R. Carleton and Howard Austerlitz
(Collegeof Engineeringand Applied Science,SUNY at StonyBrook,
StonyBrook,NY 11794)
Thehighattenuation
of certainclasses
of materialsresultin extensive
distortionof thetransmitted
pulseducto dispersion.
A systemhasbeen
developcA
whichenables
themeasurement
of theattenuationandphaseof
highlyabsorbrive
materialsoverthe frequency
rangeof 0.1 to 20 MHz.
Usinga high-speed
dataacquisition
system
andadedicated
computer,
the
delayanddispersion
component
of the FFT transmission
spectrumare
separately
computed
by usinga seriesof Hilberttransforms
of thespectrum. The minimumdelaycomponentis firstcomputedand subtracted
fromthephasespectrum•
Theresultingphasedataarcthenusedtodeterminethepuredelaycomponent
to a highdegreeof accuracy.Experimen-
DC 20375}
Theoreticaldescriptions
of thescattering
behaviorof solidandhollow
elasticbodiessubmerged
in waterhavebeengivenin termsof the form
functionof the body.Thesecomputations,usuallycarriedout for a wide
rangeofka or frequencies,
constitutea broadbandanalysisof the target's
response.
Whenperformedin spherical
or cylindricalgeometries,
theresultsof thecomputation
canbeseparated
intotherigidandpurelyelastic
(or resonance}
terms.Techniques
havebeendeveloped
for performing
similarseparations
in experimentally
obtainedechoesfor elastictargets.
Of particularinterestare the responses
from boundedfinitebodiesfor
whichnoanalyticalmodelexists.Illustrationswill includebackscattered
returnsfromsolidandhollowtargetsnotamenableto analyticalsolution.
In the caseof the hollowtargets,platewavesgeneratedby the incident
soundwill beidentifiedusingthesebroadbandmethodsof targetinterrogationandanalysis.
tal resultswill be presentedon both modelsystemsand on materialswith
2:31
attenuations
ashighas 100dB/cm anddispersion
ashighas20%.
MM12.
ß 2:19
Performance of a broadband cross correlation detector. Peter
S. Tong (PlanningSystemsIncorporated,7900 WestparkDrive, Suite
600, McLean, VA 22102}
MM9. Determinationof the broadbandspectrafor saturatedparametric
source
function.
Themodeldeveloped
issimilarin principle
tothatofH.
Merklinger[J.Acoust.
Soc.Am.54, 1760-1761
•1973)],
except
thatthe
Crosscorrelatingtheoutputsof two spatiallyseparated
sensors
isone
wayto implement
a broadband
passive
detectorandbearingestimator.In
theabsence
of targets,thecorrelationfunctionwill benearlyzerofor all
delays,andin thepresence
of a target,thisfunctionwill peakat thedelay
corresponding
to thetargetbearingprovidedthe targetis motionless.
If
thetargetismoving,thesignalreceived
at thetwosensors
will experience
differentamountsof time compression,
and as a resultthe correlation
functionwill not reachitspeakvalue.Exactexpressions
for thisdegradationareobtainedin termsof targetgeometry,targetvelocity,signalfrequency,bandwidth,and coherentintegrationtime. Theseexpressions,
althoughadequate
for performance
computation
in a givensituation,are
toocomplexfor systemtrade-offstudies.Greatlysimplifiedexpressions
arederivedin thispaperwhichgivevaluableinsightintotherelationships
of themanyvariables
andaremoresuitablefor system
designandevalua-
ad hocestimateof thenonlinearsourcefunctionisreplacedby an integral
tion.
sonars.
R.J. Wyber
•1(Applied
Research
Laboratories,
TheUniversity
of
Texasat Austin, P.O. Box 8029, Austin,TX 78712-8029)
The determination
of the propagation
of a finiteamplitudewaveby
Burger's
equation
iswellknown.
,Application
ofthissolution
toparametricsonars
generally
involves
modeling
aplanewaveinthenearfield
anda
spherical
waveinthefarfield.
Thetransition
between
these
regions
isnot
welldefinedandgenerally
involves
an arbitrarychoiceof a transition
region.
To avoidthisrequirement
andtoallowthesolution
fora broadbandparametric
sonartobeextended
tothefiniteamplitude
case,
a model
hasbeendeveloped
based
ontheapproximation
thatthenonlinear
losses
in the fundamentalare due entirelyto the work doneon the nonlinear
oftheprimaryintensity.
Thissolution
isextended
toallowforbroadband
source
signals
upto l-octbandwidth.
A solution
isobtained
forthespectrumofthetotalpowerin theprimarybeam,whichisindependent
ofthe
cross-sectionalarea of the beam and is thus valid in both the nearfieldand
farfield.,I The author is on attachment from R. A. N. ResearchLaborato-
ries,P.O. Box706,Darlinghurst,Australia2010.
2:23
MM10. Spectral high-passfiltering effects of broadbandspatial
normalization.
Robert Peri (Bolt Betarickand Newman,Inc., 1300N.
17thStreet,Arlington, VA 222091
Broadband
energydetectionisdependent
upona reliableestimateof
thenoisebackground.
The energyat theoutputof a beamof an acoustic
array is usuallycomparedto the meanenergyof its neighboring
beams,
and a detectionis declaredif a largediscrepancy
exists.This processof
spatialnormalization
isequivalent
to a high-pass
filterwhichattenuates
thosespectral
components
whicharesubstantially
smallerthanthedesign
frequency
of thearray.Thiseffectarisesbecause
of thesubstantial
beam
overlapat lowerfrequencies
whichprecludes
a totallyindependent
esti-
$??
J. Acoust.Soc.Am.Suppl.1, Vol.74, Fall1983.
2:35
MM13. A processingsystem for acousticreciprocal transmission
experiments.
H. Nguyenand H. A. DcFcrrari (Divisionof Ocean
Engineering,
Roscnsteil
Schoolof Marineand Atmospheric
Science,
Universityof Miami, Miami, FL 33149-1098)
Broadband
signalssuchaslinearmaximalpseudorandom
sequences
(LMPRS}findmanyapplications
inacoustic
remote
sensing
in theocean.
Wc havedesigned
a system
whichbothtransmits
andreceives
LMPRS
entirelyundermicroprocessor
control.Timingof theexperiments,
generationsof the transmitted
signals,and coherence
samplingof the reccivedsignalareaccomplished
witha low-power-consuming
RCA 1802
processor.
Parameters
of theexperiment
canbcsetbysoftware
making
possible
a varietyof experiments
withouthardwaremodifications.
The
system
isbatterypowered
andisdesigned
tooperate
forperiods
ofmonths
at sea.Threesystems
havebeenconstructed
foracoustic
reciprocal
transmission
experiments
in theFloridaStraitsandarenowbeingtested.
The
system
willbedescribed
alongwithpreliminary
results
fromexperiments.
[Worksupported
by ONR andNOAA.]
Societyof America
S77
2'.39
MMI4. Bandlimited cross correlation in a multipath environment:
Simulation study results. Peter D. Herstein, Helen M. Steinberg,
Bernard F. Cole, and Henry Weinberg {Naval Underwater Systems
Center,New London,CT 06320}
The techniqueof intersensor
crosscorrelationof acousticsignalsis
usedto obtainsuchinformationas the spatialcohenriceof the environmentor the positionparametersof a broadbandsource.In general,acoustic energypropagates
from a sourceto a sensoralongmultipleraypaths.
However,cross-correlation
performance
is frequentlyanalyzedin terms
of a singlewavefront(planar)model.For the planar model,the signal
receivedat eachsensoris approximated
as the sumof the delayedand
attenuatedsourcesignalplusuncorrelatedGaussiannoise.This enables
the useof performance
criterionbasedon receiversignal-to-noise
ratios.
Extensiveanalysisof cross-correlation
performance
underthe assumptionof the planarmodelhasbeenreported[G. C. Carter,IEEE Trans.
Acoust.Speech
SignalProcess.
ASSP-29{3}
{1981}].In thisp,"per,modelingof thecrosscorrelationbetweentwo sensors
isextendedto analyzethe
situationofa bandlimited
signalpropagating
in a multipathenvironment.
Usingthe genericsonarmodel{H. Weinberg,NUSC TD 597IC), a representative
deepoceanconfiguration
wassimulatedin whichthepropagation wasdominatedby four first-orderbottombouncetype rays.Results
are presented
asfunctionsof{a}therangeandbearingof thesource,and {b}
tbe verticaltilt of thebaseline
of thesensors.
It is shownthat multipath
effectscanprofoundlyeffectthe levelof the normalizedcross-correlation
peak.Signal-to-noise
ratio at eachsensoris found to be an inadequate
estimatorof correlationperformance
for this typeof multipathenviron-
ment.[Thisworkwassponsored
by the NavalSeaSystems
Command,
Washington,DC.]
atedon twosetsof data.The firstsetwascomprised
of nineindependent
underwatertransientsources.
The percentof correctrecognitionof SIGNET in that evaluationrangedfrom 93 to 98. The seconddata •et was
froma strongimpulsiveseismicsource.The percentofcorrectrecognition
was 97. The mathematical
foundation of SIGNET
was also used success-
fullyasa basisfor a multiplesource
identification
technique.
[Worksupportedby ONR/EnvironmentalSciences.]
2:51
MMI7. Passivesourcerangingby usingmodefiltering and modephase
comparingin waveguide.E. C. Shang,C. S. Clay, and Y. Y. Wang
{Departmentof Geologyand Geophysics,
Universityof WisconsinMadison,Madison,WI 53706}
The conventionalbeamformingtechniquecouldnot beusedfor source
locatingin waveguideowing to the modal interferencestructureof the
field.In this papera newmethodof passivesourcerangingin a layered
waveguidehasbeenproposed.
The mode-filtering
processor
wasusedto
processthe field data of a verticalarray in order to obtain individual
modes.
Thesourcerangeinformation
canbeextracted
bymeasurement
of
threeindividualmodephases.
The sourcerangewasexpressed
in termsof
the "modeinterference
distance"
as following:
r = LoD• + d%; Ar•i
----DO{6•0/2rr),where
L,•isacertain
integer;
5q•
oisthephase
difference
of
theith modeandthejth mode;Dr is the"modeinterference
distance"
deftnell.
by:D,j = 2rr/(k,- kj);k, isthewavenumber
oftheithmodegivenbya numerical
modecode.Theinformation
ofLo canbeestimated
by
meansofcomparingthephaseoftbejth modewith anothermode,sayruth
mode,andthenL• wasestimated
by solvingthe following
equation:
(5•,•/2rr)
= Fractional
part{ ( D,•/D•,,) [L,•+
2:55
2:43
MMI5.
Energy partitioning and optical-to-acoustic conversion
efficiencyduringlasergenerationof underwatersound.Allan D. Pierce
(Schoolof ME, GeorgiaInstituteof Technology,Atlanta, GA 30332)
Two mechanisms(thermoacoustic
and ablative)are consideredwith
regardto how muchopticalenergyis eventuallytransformed
into sound.
The analysisof the former beginswith a fluid dynamicanalysisof the
generationof entropyand acousticmodalfieldstakinginto accountviscosityandthermalennduction.
The acousticmodalfieldsatisfies
theWestervelt-Larsoninhomogeneous
waveequationwhile the entropymodal
field satisfiesa transientheat conductioncquationwith similar source
term. The derivationdemonstratesthat the Westervelt-Larson.equation
is validundermuchbroadercircumstances
than waspreviouslyasserted
byBozhkovand Bunkin.The bulk of theabsorbedopticalenergygoesinto
theentropymode,but the acousticportioncanbeenhancedif thespatial
andtemporaldependence
of theenergydeposition
resembles
a solutionof
the wave equation,suchthat initially generatedwavesare continually
pumpedby the source.An upperlimit to lbe conversion
efficiencyis of
order(fi /pcp•pma,
, where
fi iscoefficient
ofthermalexpansion
andp•,•x is
maximumattained(by sourcepumping)acousticpressurein the source
region.Ablationgenerates
soundbecause
of therecoilforceactingon the
surfacewhenevaporatedmaterialjetsoff;the corresponding
acousticradiationefficiencyis estimatedusinga modelproposedby Bunkinet al.
[JETP Lett. 13, 341-343 (1971}].[Work supportedby ONR.]
MM18. Models of fluid structure interactions to optimize acoustics
performanceof sonar systems.JacquelineLarcher, Jean-Marc Parot,
and Jean-PaulBerhaultISoci6t6METRAVIB, BP 182, 69132 Ecully
Cedex 2, France)
In sona•systems,
theinteractionof transducer
elementswith theinner
dome cavity and the boundarylayer with the dome structureaffectthe
overall acousticperformanceof the systemin termsof aberrationsand
self-noise.Simple mathematicalmodelshave beenderived to represent
both phenomena.For acousticaberrationsresultingfrom coupling
betweenthe transducerand the acousticcavityplusdomestructure,an
analyticnumericalmodelhasbeenusedto identifysignificanttechnological parameters
controllingthe performance.
A statisticalenergeticmodel
describes
couplingbetweenthehydrodynamic
boundarylayer,thedome
dynamicstructuralbehaviorand the inner sonarcavity. Experimental
data havebeencollectedon full scaleand modelsonarstructuresrepresentingrealisticexcitationand loadsconditions.Resultsof theoretical
modelsand experimentaldata show good agreementon the effectsof
cavity modesand area massfor acousticaberrationsand of domestructural dynamicpropertiesfor hydrodynamicself-noise.
2:59
MM19. A comparisonofbreadbandsonardiscriminationbetweenhuman
listenersand a filter bank model.DouglasW. Martin and Whirlow W.
L. Au (Naval OceanSystemsCenter,P.O. Box 997, Kailua, HI 967341
Broadband sonar discrimination capabilities of human listeners as a
2.'•7
MMI6. Pattern recognitionby meansof a hybrid adaptiveautoregressive
processingsystem. Bonnie Schnitta-lsraei IKLD Assoc., Inc., East
HamptonFieldOffice,94 PantigoRoad,E. Hampton,N¾ 11937}
An automaticpatternrecognitionalgorithm,consisting
of eventdetection, featureextraction,and a decisionprocess,was developed.The
completeprocessing
systemwaslabeledSIGNET. The featureextraction
aspectof SIGNET formulatedtheautoregressive
IAR} coefficients
froma
hybrid adaptiveAR algorithm in combinationwith a weightedlinear
thresholdelementinto a linear prediction residual{LPR}. The structure of
the data sequencewas then identifiedby extractingthoseLPR segments,
which establishedcvent type boundaryphenomena.SICINET was evalu-
$78
J. Acoust.Soc. Am.Suppl.1, Vol. 74, Fall 1983
functionof signal-to-noise
ratiowerecomparedwith theconstant-Qfilter
bank modelof Chestnut,Landsman,and Floyd [J. Acoust.Soc.Am. 66,
140-147(1979}].A 48-s pulse(122-kHz peakfrequency,39-kHz 3-dB
bandwidth)was usedto collectechoesfrom aluminum, glass,and bronze
cylinders.Discriminationexperimentswere performedin pairs,aluminum-glass,hollow-solidaluminum,and aluminum-bronze.A modified
method of constants with the noise levels randomized
in ten-trial blocks
and the signalstime-expanded
into audiofrequencies
were usedin the
humanexperiments.
Thirty contiguous
filterscoveringa frequencyband
of 50 to 200 kHz wereusedin the constant-Qmodel.The humanlisteners
performedsignificantly
betterthanthecomputermodel,requiringat least
5 dB lesssignal-to-noiseratio at the 75% correct threshold.Listeners
reportedthat dominantcuesoccurredin the time domain.
S78
3:03
isticsarecomplicated
andfrequency
dependent.
Typicallytheresponse
is
reducednear grazingincidence.When a beam is formedfor maximum
response
in a selecteddirection,increasingthe apertureto includeelementsfor whichtheselectedbeamdirectionisneargrazingisinefficientin
increasing
array signalgainand may actuallyleadto a lossin signal-tonoiseratio.The arraygaindependence
uponapertureanglefor cylindrical
and sphericalarraysis presented
for parametricfamiliesof effectiveelementdirectivities.Both uniformand optimumshadings
are considered.
Resultsarepresented
in theformof parametriccurveswhichcanbeused
in systemdesigntradeoffs.
MM20. Dependenceof array gain on aperture angle for cylindrical and
spherical
arraysofdirectional
sensors.
HenryCoxandJ.MichaelSteele
(BoltBeranekand NewmanInc., 1300North 17thStreet,Arlington,VA
22209}
When receivingarraysare placedon air-backedstructuresin water,
the effectof the structureor baffleis to alter the response
of the hydrophonesfromtheirfreefieldcharacteristics.
The exactresponse
character-
THURSDAY
AFTERNOON,
I0 NOVEMBER
SUNSET ROOM, 1:30 P.M.
1983
Joint Meeting of Standards Committees S1 and S3
The activitiesof Sl will bediscussed
first,proceeding
to mattersof interestto bothSI andS3,andconcluding
with S3 activities.
Meeting of StandardsCommittee S1 on Acoustics
T. F. W. Embleton, Chairman S1
NationalResearchCouncil,Divisionof Physics,Montreal Road, Ottawa, Ontario,K1A OR6, Canada
StandardsCommitteeS1, Acoustics.Workinggroupchairswill reporton their progress
in the preparationof
standards,
methods
of measurement
andtesting,
andterminology
in physical
acoustics,
eleftroacoustics,
sonics, ultrasonics,and underwatersound.Work in progressincludesmeasurementof atmosphericabsorption,
noisesources,
noisedosimeters,
integrating-averaging
sound-level
meters,andrevisionandextension
of sound
levelmeterspecifications.
Opendiscussion
of committeereportsis encouraged.
Meeting of StandardsCommittee S3 on Bioacoustics
W. A. Yost, Chairman S3
NationalScienceFoundation,SensoryPhysiology
& Perception,Washington,
DC 20550
StandardsCommitteesS3, Bioacoustics.
The currentstatusof standardsunderpreparationwill be discussed.
In additionto thosetopicsof interestincludinghearingconservation,
dosimeters,
hearingaids,etc.,consideration will be givento newstandardswhichmightbe neededoverthe nextfew years.
THURSDAY
AFTERNOON,
10 NOVEMBER 1983
DEL MAR/HELIX/SANTA
FE ROOMS, 2:00 to 5:20 P.M.
SessionNN. Musical AcousticsVI: Music Perception and Cognition
Diana M. Deutsch, Chairman
Centerfor Human InformationProcessing,
Universityof California,San Diego,La Jolla, California92093
Chairman's
Introduction--2:00
Invited Papers
2:05
NNI. Dieboric listening to musical sequences:Relationship to hemisphericspecialization of function.
Diana Deutsch(Centerfor Human InformationProcessing,
Universityof California,SanDiego,La Jolla,CA
92093)
S79
$79
It isgenerally
assumed
thatpatternsofearadvantage
in dichoticlisteningreflectgreaterinvolvement
of the
hemisphere
contralateralto the preferredear. This assumption
is criticallyreviewedwith respectto musical
materials.A setof experimentsis describedwhich demonstratethe presenceof a left-right anisotropyin the
perceptionof frequencycombinations.
When two frequencies
are simultaneously
presentedin a sequential
setting,perception
of thesefrequencies
issuperiorwhenthehigheristo the rightandthe lowerto theleft than
whenthe higheris to the left and the lowerto the right. Localizationis alsomoreaccuratewhenthe higher
frequencyisto therightandthelowerto theleft.Thesephenomena
areshownto giveriseto apparentpatterns
of ear advantage,whosedirectionmay vary dependingon such factorsas overall error rate and listening
strategy.Suchapparentear advantages
shouldnot be takenasreflectinggreaterinvolvementof the contralateralhemisphere.
Implicationsfor patternsof ear advantagereportedfor speechmaterialsarealsodiscussed.
[Work supported
by NIMH.]
2:3S
NN2. Neuropsyehology
of music:A erltieal reviewof pastwork and future perspectives.
OscarS. M. Marin
(Departmentof Neurology,GoodSamaritanHospitaland MedicalCenter,Portland,OR 97201)
Localizedbrainlesionsmayresultin disordersof musicperception,recognition,reading,or mayalter vocal
or instrumentalperformance.
Amusiasappearin this way to be disordersin .thefield of musicequivalentto
thoseencountered
in aphasias,
agnosias,
or apraxiasin theareasof language
andspeech,visualperception,
and
generalmotorskills.Thus,amusias
posethesameproblems
withrespectto hemispheric
specialization,
and
localizationof function.The relationship
betweennervousstructureandfunction,brainlocalizationor specializedbrainprocessors
to a particularbehaviordependslargelyon the cognitivestructureand characteristics
of
thesystemon whichsuchbehaviorisbased.Thus it depends,for instance,on howconstant,stable,or universal
thecognitive
system
is;it depends
onthesensory
modalities
onwhichit isbased,onitsrequirements
forsensory
perceptualanalysis,on its highercognitivecodesor categories,on its useof informationstoragesystems,
syntacticalgorithms,and linkagesto othersystems.In lightof thesefactors,a reviewof theclinicalliteratureof
thevarioustypesofamusiaswill bepresented.
Parallelisms
or contrasts
with equivalentdisorders
ofspeechand
language,and visualperceptualdisorderswill be discussed.
3.-05
NN3. Relativeand absolutepitch perceptionby birds.StewartH. Hulse (Departmentof Psychology,The
JohnsHopkinsUniversity,Baltimore,MD 21218)
Europeanstarlings{Sturnusuulgaris)
weretrainedto discriminate
a classof rule-based,
fourtoneascending
pitchpatternsfroma comparable
classofdescending
pitchpatterns.Thena seriesof transfertestsexaminedthe
birds'abilityto maintainthe discriminationundervarioustransformations
of the originalpitchstimuli.The
birdsperformed
wellwhenshiftsin toneheightoccurredto novelexemplars
withintheoriginalpitchtraining
range,but not when shiftsoccurredto novelexemplarsoutsidethat range.When informationabout the
directionof pitchchangewasreducedby shortening
thepatterns,thebirdscouldsolvethediscrimination
on
thebasisof thefirsttwo tonesin a pattern,althoughperformance
improvedaspatternlengthand,therefore,
amountof informationincreased.
The sameseriesof transfersshowedthat in producingaccuratediscrimination thebirdswereusingpitchcuesbasedon bothan absoluteand relativeperceptionof pitch.The data have
implications
for a comparative
studyof informationprocessing
in pitchperception.
3:35
NN4. Music of the animals. Edward C. CartercUe and Carl ShipIcy (Departmentsof Psychologyand
Physiology,
andTheBrainResearch
Institute,UniversityofCalifornia,LosAngeles,
405HilgardAvenue,Los
Angeles,CA 90024)
We examinethe questionand somepossibleanswersof whetheranimalsmake and appreciatemusic.We
takeasthematerialof musicsuchaspects
aspitch,intensity,timbre,texture,harmony,frequencymodulation,
and durationas well as rhythm whichisjust the interactionof all theseaspectsin structuredpatterns.Our
answeris that a lot of God'schillungot rhythm.
4:05
NN5. Perception of rhythmic structures. I_ J_ Hirsh (Washington University and Central Institute for the
Deaf, St. Louis, MO 63110)
The concernof auditoryresearchwith pitch and spectrumhasled to an emphasison individualphoneroes
in speechandon notesin music.Eventhesequentialpropertiesof transitionsin speechor of melodyin music
haveemphasized
changes
in spectrum.While rhythmicstructuresoftenareaspects
of suchpatterns,theymay
be studiedin a "pure" form. The rhythmicgroupingreportedsincethe late 19th centurywasan interesting
observation,but did not leadmuchfurther. Also, early studieson listeners'hearingof rhythmicpatternsmay
havebccnmuchaffectedby an imitative,tappingresponse,
accompaniedby characteristics
of a motor system.
Seashore,
in histestof musicalaptitudes,
studiedrhythmicperception
througha same-different
procedure
but
did notexploitthetechniquetowardnotionsof stimuluscomplexity,or goodor easystructures.
Whethersuch
patternpropertieswill accordwith Martin'ssyllabicstructures,
or Garner'sgroupsof runsandgaps,remains
to be workedout by studieson recognitionand discrimination.Data from a studyalongtheselineswill be
discussed.
[Work supported
by NINCDS.]
S80
d. Acoust.Soc.Am.Suppl.1. VoL74, Fall1983
Societyof America
$80
4:35
NN6. The role of anralizatlonin pitch or tonality recognition.'6/. Dixon Ward (HearingResearch
Laboratory,
University
of Minnesota,
2630University
AvenueSE,Minneapolis,
MN 55414)
PreviOus
research
[E.Terhardt
and
W.D.Wa/'d,
J.Acoust.
Sac.
Am.72,26-33
(1982)]
has
shown
that
most
trainedpianists
cantellwhena particular
selection
fromBach's
"Well-Tempered
Clavichord"
hasbeenshifted
upwardordownward
in keyfromtheoriginalsignature,
performing
at a levelsignificantly
bette•thanchance
evenwhenthistransposition
is onlyonesemit.This resultimpliesthat thesepersons
posses
someform of
absolute
pitch,or absolute
tonality,eventhoughtheyclaimlittleor no abilityto nameisolatedpitches.The
desreeto whichthisrecognition
process
depends
on anralization{anticipation
of howthe excerptshould
sound)arisingeitherfromtheoral announcement
of thecorrectkey that precedes
eachexcerptor from the
(untransposed}
visiblescoreon the answersheetwasexaminedby removingthesecues.Performance
declined
slightlybutremained
abovechance,
indicating
thatauralization,
whilehelpful,isnotessential.
Sounless
there
isa"best"keyforanygivenpianocomposition,
andBachunerringly
choseit, thesepianists'
recognition
of
transposition
wasbasedat leastpartlyon long-term
memoryof theexcerpts
asheardin theoriginalkey.
[Research
supported
bytheBryngBryngelson
Communication
Disorders
Research
Fund.]
ContributedPaper
$:05
the failureto generalizeis duc to the simultaneous
activeprocessing
of
pitch or the inabilityto makegeneralizations
from simplefrequencies.
Four wildcaughtadult starlingsweretrainedto peckat a lit keyonly on
trials duringwhicha 2000-Hz tonewasabsent.Oncediscriminationwas
achieved,probeswereintroducedeveryother session
atp = 0.50 to determinegeneralization
from 1000to 4000Hz. Findingsare in agreement
with earlierwork, usinga PayJovian
procedure,whichindicateda range
constraintfor frequencies
[J. E. Trainer,"The auditoryacuityof certain
birds,"unpublished
doctoraldissertation,
CornellUniv.(1946}],butalso
showthat theconstraintis interactivewith the processing
of relativeand
absolutepitchinformation.
NN?. Frequencygeneralization
ennstrained
by pitchprocessing
in the
European
starling?
JeffreyCynx(Department
of Psychology,
The $ohns
HopkinsUniversity,Baltimore,MD 21218)
Earlier work with pitch processing
hasshownthat the Europeanstar-
ling (Sturnusvulgaris}--unlike
humans•failsto transferlearnedpitch
discriminations
outoftheoriginalfrequency
range(S.Hulse,J.Cynx,and
J. Humpal,"Effectsof shiftin pitchcontexton serialpitchperception
in
birds,"in preparation}.
The p•sent workwasundertaken
to determine
if
THURSDAY
AFTERNOON,
10 NOVEMBER
1983
CHAMBER ROOM, 2:00 TO 5:00 P.M.
Session00. Engineering AcousticsV: Transients
Peter R. Stepanishen,Chairman
Departmentof OceanEngineering,Universityof RhodeIsland,Kingston,RhodeIsland 02881,
Chairman's
Introduction---2:00
Invited Papers
2.'05
OO1. The physicsofacoustlctransients.MiguelC. Junger(CambridgeAcousticalAssociates,
Inc., 54 Rindge
AvenueExtension,Cambridge,MA 02140}
Many if not most soundfields,whethernatural or man-generated,
desirableor objectionable,
are too
transitoryto beapproximated
with steady-state
solutions.Furthermore,transientpulsesareusedincreasingly
to explorethe frequency
dependent
characteristics
of waveguides,
geological
formations,andecho-ranging
targets.This shiftsthe burdenfrom effectivelysteady-state
measurements
at variousfrequencies
to signal
processing
of transientsignals,an evolutionfacilitatedby today'scomputercapability.In spiteof theirimportance,transients
areeffectivelyignoredin standardtextbookswith theexceptionof applicationorientedfields
suchasroomacoustics
andloudspeaker
theory.This reviewpaperdealswith basicphenomena
associated
with
impulsively
accelerated
anddecelerated
boundaries.
Transientradiationloadingandfarfieldsaredescribed
for
planarandconvexpulsegenerators.
Energypartitionbetweenincomp•ssiblenearfieldandacousticfarfieldis
illustrated.Finally, requirements
are formulatedfor theequivalence
of transientand cw scatteringmeasurements.
2:30
002. Time domain methodsof investigatingacoustictransientphenomenain arrays. P. $tepanishen
(Departmentof OceanEngineering,
Universityof RhodeIsland.Kingston,RI 02881)
S81
106thMeeting:AcousticalSocielyof America
A reviewof linearacoustictransientphenomena
in activearraysis presented.
Suchtransients
occurasa
resultof the finitebandwidthof the elements,the time delaycausedby the propagationeffectsin the medium,
and acousticinteractioneffectsamong the elements.The characteristicsof acousticradiation from a time
dependent
monopolcanddipolesources
arefirstdiscussed
to addresssuchphenomena.
Theseresultsarc then
extendedto distributedsourceswherethe importanceof edgeeffectsis clearlyobservedanddiscussed.
Retard-
edpotentialmethods
to accountfor theeffectsofboundaries
onthetransientacoustic
fieldarethenpresented.
Suchmethodsledto thedevelopment
of impulseresponse
techniques
of evaluatingacoustictransientphenomena.The impulseresponse
techniqueis discussed
in detailand numericalresultsare presented
to illustrate
transientacousticpressurefieldand elementinteractionphenomena
in activearrays.
2:55
003. Transient effects in acousticscatteringand radiation problems.G. C. Gann•urd (Naval Surface
WeaponsCenter,R43, SilverSpring,MD 20910)
We considerexamplesof acousticradiationandscatteringproblemsthat wehaveworkedout overthe years
wheretransienteffectsare investigated.In chronologicalorder, we firststudythe soundradiationemittedby
{multipole)pointsources
of varioustypes,undergoing
accelerated
motionsalongvariousrectilinear,circular,
orhelicoidalpaths.Changes
in sourceacceleration
resultsin anemission
ofa transientburstofradiation,andin
a "headlight" effect, that we have quantitativelyexaminedby techniquessimilar to thosedevelopedby
J. Schwinger
for accelerated
electrons.
We thenanalyzethescattering
of a sound5-pulseincidenton a rigid
sphere.Whenthetransientpulsehitsthesphere,it givesit itsmomentumandmakesit undergoan impulsive
acceleration
in thesamedirectionby radiationpressore.
The so-calledKirchhoffsolution[G. R. Kirchhoff,
Mechanic(Teubner,Leipzig,1883-one
hundredyearsago!)3rd.ed.,pp.316-320]for theradiationfieldfroman
impulsivelyaccelerated
sphereisshownto exactlycoincidewith thefirst-ordertermsof thecompletescattered
fieldexpression
that wehaveobtainedvia the Resonance
ScatteringTheory(RST).This exhibitsveryenlighteningconnections
betweentransientsolutionsof radiationand scatteringproblems.
3:20
004. Transient acoustic sources. John V. Bouyoucos,David E. Nelson, and Roger L. Selsam
(Hydroacoustics
Inc., P.O. Box23447,Rochester,N¾ 14692)
The characteristics of several different classesof transient, underwater acoustic sourcesare set forth and
compared.Two relativelynewsources---the
watergunandimplodingpistonsource--arecomparedwith more
well-established
explosivedevicesand air guns.Characteristics
examinedincludespectralfeatures,efficiency
of energyconversion,peaksourcelevels,size,weight,and depthdependence.
In addition,the performance
advantagesand limitationsof the varioussourcetypesin multi-sourcearraysis discussed.
ContributedPapers
3:45
00•. Transientsoundradiationfrom a clampedcircularplate•Impulse
responsemethod. Adnan Akay and Michael Latcha {Mechanical
EngineeringDepartment,WayneStateUniversity,Detroit, MI 48202}
A theoreticalanalysisof transientsoundradiationfrom a clamped
circularplateisobtainedusinga pressure
impulseresponse
method.The
vibrationresponse
of theplateto a transientpointforceis obtained.The
modalpressure
impulseresponse
functionsfor the platearcderivedfrom
the Rayleighsurfaceintegralandnumericallyconvolutedwith themodal
accelerationresponse
of the plate.The impulseresponsefunctionsare
closelyrelatedto the modeshapesand the geometryof the problem.They
relatethespatialdomainto thetemporaldomainof the pressure
waves.
The pressure
impulseresponse
waveforms
aregivenfor a numberof plate
modesandthe changes
in thewaveformswith distancefrom the plateare
shown.Soundradiationdueto forcedandfreevibrationsof the plateare
discussed.
The resultsarecomparedwith thoseobtainedbydirectnumerical integrationof the Rayleigh surfaceintegral and the experiments.
[Work supportedby WSU and NSF.]
purposeof thesetechniques
is to generateadditionalsurfacevibration
dataat regions
ofsparse
observations
andin between
gapsofexistingdata
to obtainsmoothsurfacevibrationdata. The developmentof the interpo-
lationtechniques
isbasedontheequallyspaced
datapointsandthemethod
of
undetermined coefficients, given
by
the
a.{O,O)=a.{x,y)-{k•x+k2y+k_•x-•+k4xy+k•y•),
equation,
where k•,
k•,k•, k4,andksare thecoefficients
neededfor thebestfit of thecurvein
order to relate the unknown surfacevibrationa.O,O) with the known
surfacevibrationa.{ x,y). An expression
for the relativeerror has also
beenderived.This expressionprovidesinformationabout the vibration
distributionover the fiat surfaceand henceaboutthe applicabilityof the
interpolationtechniques.
The resultsof theapplicationof thesetwointerpolationtechniques
basedonanavailablesetof testdataarereportedhere,
andarecompared
withthemeasured
soundpressure
levelsin thefarfield.
"Present address:
C. F. BraunandCo., ChemicalEngineering
Department, 1000 South Fremont Avenue, Alhambra, CA 91802.
4:15
007. The Rayleigh distanceand geometricnearfield size for nonplane
soundradiators. Herbert L. Kuntz (Hoover Keith and Bruce Inc., 9730
Town Park, #108, Houston,TX 77036},Elmer L. Hixson(Department
006. Interpolation techniquesfor soundradiation predictionfrom a fiat
of ElectricalEngineering,The Universityof Texas,Austin,TX 78712),
vibrating surface. Pranab Saha,'• and Allan D. Pierce (School of
MechanicalEngineering,GeorgiaInstituteof Technology,Atlanta, GA
and William W. Ryan, Jr. •Harding University, Searcy,AR 72143}
30332)
In an attemptto developa modelof flat surfacevibrationsto make
accuratefarfield sound radiationpredictions,two interpolationtechniques{12-pointformulaand24-pointformula)havebeendeveloped.
The
S82
The geometricnearfieldof a finiteacousticradiatoristheareaaround
the radiator wherethe soundpressureleveldoesnot follow sphericalor
cylindricalspreading.
The geometricnearfieldhasbeenstudiedextensively for circular and rectangularpistonradiators.The Rayleighdistance
D = kaZ/2, where4 = 2•rf/c, f is the frequency.
c is the sound
S82
speed,anda is half thelargestdimension,
hasbeenusedto approximate
the sizeof the geometricnearfieldof planeradiators.We foundthat, for
variouslyshapedradiators,theRayleighdistanceisusefulin approximatingthegeometric
nearfieldsize.As with planeradiators,we foundlarge
SPLchanges
with radialdistancein thegeometricnearfield.Oneimplicationisthat in noisyenvironments,
wheretheSPL arounda largemachine
theacoustic
radiation.Jetstabilityof thedrivingmechanism
isdiscussed
relativetothenormalmodeofvibrationof thehemisphere.
Thebemispherical displacements
are presentedas a sumof resonantmodesand forced
modeswhichare in turn employedin a parametricstudyof optimizing
acousticoutput.Resultsincludeanalysisof resonantvibrationmodesand
predictionof acousticradiationin both the nearfieldand the farfield.
Experimental
dataarecomparedwith themodelandfutureexperiments
may, necessarily,
bemeasuredin the nearfield,the soundpowercontribution to the soundfieldcan be grosslyunderestimated.
Knowledgeof the
nearfieldsizemay be usefulin industrialsituationsfor determiningthe
validityof soundpowerestimates.[Work supportedby the U.S. Coast
are presented.
4:45
Guard.]
009.
Diffraction at a fixed point on a fluid-loadedplate. R.
V. Waterhouse
andF. S. Archibald{DavidTaylorNavalShipR&D
Center,Code 194,Bethesda,MD 20084I
4:30
008.
At thelastmeeting,sometheoretical
resultswerepresented
for the
nearfielddiffractionpatternformedby planebendingwavespassinga
fixedpointona thinelasticplatein vacuo.Thiscaseisa goodapproximationto a metalplatein air, but not to a metalplatewith waterononeor
bothsides.
Thelattercaseisof interest,
forexample,
whentheplaterepresentsthe hull of a ship,andin the presentwork the previousanalysisis
extendedto this case.The fluid loadingaddsa third dimensionto the
problem,asnowsomeof theacoustic
energyistransferred
fromtheplate
to thewater.Theexpression
for thesoundpressure
contains
a complicatedintegralwhichmustbeevaluated
numerically.
The integralcontainsa
fifthdegreepolynomial
in thedenominator,
thefiverootsof whichcontributefivepolesto the integrand.
Tow-powered low-frequency sound source. H. C. Sehau, A.
L. Van Buren (Naval Research Laboratory, Uoderwater Sound
ReferenceDetachment,P.O. Box 8337, Orlando, FL 32856),and F.
J. Radosta(Embry-RiddleAeronauticalUniversity,DaytonaBeach,FL
32014)
A novelmethodfor productionof low-frequency
soundfrom a submergedrigid bodywith a clampedgas-filledhemispherical
membraneis
discussed.
The deviceisdrivenhydrodynamically
throughthe motionof a
shipor othertowingvehicle.Analyticalmodelsare developed
for the
devicewhichincludesbothbendingand membranetheoriesfor the shell
deformations
with the inclusionof the pressures
from thedrivingjet and
THURSDAY
AFTERNOON,
Session D. Architectural
10 NOVEMBER
1983
CALIFORNIA
ROOM, 1:30 TO 4:35 P.M.
Acoustics II: The Technical Committee on Architectural
Acoustics
V. O. KnudsenDistinguishedLecture
William J. Cavanaugh,Chairman
CavanaughTocciAssociates,
18 Main Street,Natick, Massachusetts
01760
Chairman's Introduction---l:30
Invited Paper
1'35
DI. Somerefieetiona
onroomaeousties.
Cyril M. Harris(Columbia
University,NewYork, NY 10027}
Thispaperreviews
selected
aspects
of thefieldof roomacoustics,
emphasizing
thecontributions
of V. O.
Knudsenandhiscloseassociates
andformerstudents.
TheworkdonebytheauthorwithKnudsenin establishingso-called
"optimum"reverberation
timecurvesfor "Acoustical
Designing
in Architecture"
isdiscussed.
Finally,theauthordescribes
whatheconsiders
themostimportantunsolved
problem
in roomacoustics
and
givessuggestions
for an approachthat maybe usefulin its solution.
SessionPP. ArchitecturalAcousticsVI: RoomAcousticalDesign,Assessment,
Modeling,and Simulation
R. LawrenceKirkegaard,Chairman
R. L. Kirkegaard
andAssociates,
125Everest
Road,Lombard,Illinois60148
ContributedPapers
2:35
PPI. An auditoriumdesignbaseduponsubjectivelyoptimalacousticsfor
The Washington Center, Olympia, Washington, USA. Yoichi Ando
(Faculty of Engineering, Kobe University, Kobe, Japan) and
Dennis Noson (Noson & Associates,2605 East Lynn Street, Seattle, WA
981•2)
Reeentlyd•velopedacousticaldesigncriteria,derivedfrom an exhaustive
programofsubjeetive
testingat KobeUniversityandtheUniversityotG•Sttingeo,
haveb•n appliedtotheacoustical
design
ofTheWash-
S83
ington Center, a multipurposeperformingarts facility in Olympia,
Washington,
USA. In response
to the programmatic
emphasis
on highquality acousticsfor orchestralmusic,the architecturalconfiguration
progressed
from a wide, single-balcony
schemeto one that is narrower
with two balconies.
The acousticaldesigneffortwasconcentrated
on the
size and shape of wall reflectors,room asymmetry, and diffusing elements.The first reflectiontime delay, binaural dissimilarity,and total
energyof the soundfield were predictedwith a computermodelof the
auditorium.Adjustments
weremadeto the shape,cheekedby computer,
andsynthesized
into thearchitecturaldesign,arrivingat optimumvalues
for selected seat locations.
S83
3:35
2:50
PP2. Comparisonof acousticexperienceof studiorecordingsand live
concerts.
Alexandra
G. Sotiropoulou
andDavidB. Fleming(University
College,London,England
andTechnical
University
of Athens,Athens,
Greece}
It hasbeencommonin recentyearsto userecordedmusicin theinves-
tigationofsobjective
qualities
ofconcerthallacoustics.
Theobjectof this
paperistocompare
experimental
results
fromrecorded
music
evaluations
and live concertevaluations.A listof 54 oppositelabelsdescribingacous-
ticqualitiesof concerthallswereusedat thepolesof bipolarratingscales
in the evaluationof studiorecordings.
The rawjudgmentswereanalyzed
by factoranalysisand five independentfactorswere produced,namely
body,clarity,tonalquality,extent,and proximity.The validityof these
resultswas then testedin the environmentalcomplexity of live concert
conditions.
To thisend27 scales
wereevolvedto represent
thepreviously
obtained factors and were used at three live concert evaluations. Four to
fiveindependent
factorswereproduced
depending
on theconcertsituation. Four of thesefactors,namelybody,clarity,tonalquality,and proximityhadalsopreviously
emerged;
twofactorswhichemerged
onlyin the
liveconcertswerespaciousness
and intimacy[A. G. Sotiropoulouet aL,
Proe. Inst. Acoust.,Edinburgh{1982}].Theseresultsshowthat thereare
independent
setsof acousticqualities(factors)commonto thestudiorecordingsusedin thisstudyand to live concerts.
3:05
PP3. Cliff Temple Baptist Church:Acousticsfor worshipand recording.
Russell C. Campbell (General Dynamics, Fort Worth, TX and
Departmentof Physics,Texas ChristianUniversity,Fort Worth, TX
76129)and RichardJ. Lysiak(Departmentof Physics,TexasChristian
University,Fort Worth, TX 76129)
Cliff TempleBaptistChurch,locatedin Dallas,Texas,pridesitselfon
itsexcellentmusicfacilitieswhichare notonly usedfor worship,but also
for recordingRCA's DallasSymphonyseriesof digitalRed Sealalbums.
Reviewers
suchas David Hall [StereoRev.46, 76 (1981)]havehighly
praisedthe acoustics
of Cliff Temple,as well deservedaccordingto this
study.Four typesof objectivedata consistingof noisemeasurements,
echograms,reverberationplots,and characteristicspectra,are usedto
determinesoundfieldcharacteristics
presentin thehall. Usingwidedynamicrangeanalysistechniques
JR.Campbelland R. Lysiak,Bull. Am.
Phys.Soc.28,200(1983)]greatlyenhanced
themeasurement
ofacoustical
parameters,
givinginsightinto thesubjectively
perceivedsuperbacoustical qualities.The objectivedata is then appliedto subjectivecategories
whichare usedfor comparison
of Cliff TempleBaptistChurchwith other
facilities.
JR.Campbell,M. S. thesis,
TexasChristianUniversity(1983}.]
3:20
PP4. Determining the necessarynumber of reflectionsfor an accurate
image source simulation of room acoustics.Lawrence E. Zagar and
JamesK. Thompson (Mechanical EngineeringDepartment, Louisiana
StateUniversity,BatonRouge,LA 70803)
Previousattemptsat usingimagesourcecomputermodelsto determinesoundpressures
in roomsor largeenclosures
havehadmixedresults.
PP5. Music performanceacousticsand room shape:An investigation
employingan imagesmodelof roomacoustics.NicholasA. Edwards
(ArtecConsultants,
1no.,254SeventhAvenue,New York, NY 10001)
Criticallisteners
oftenobservethat rectangular
(shoebox)roomshave
"betteracoustics"
for musicthanfanshapedroomsof similarsize.In this
paperweexamine
therelationship
between
roomshapeandsomephysical
aspects
of soundfieldsin the room.The tool for our analysis
hasbeena
geometricacoustics{images)modelimplementedon a microcomputer.
Three-dimensional
impulseresponses
havebeencomputedfor somesimple fan-shaped,reverse-fan-shaped,
and rectangularrooms. Various
meansof graphicaldisplayareusedto pointout thosetrendsin thetime
andspacedistributions
of theimpulseresponse
thataretiedto thefundamentalshapeof the room.Lateralizationof the soundfieldand development of the reverberantfield are two acousticalprocesses
in particular
that havetheir rootsin the architectureof thespace.Drawingon the past
two decadesof researchinto the influencethat the directionof arriving
soundhason listenerperceptions
andpreferences
for music,weidentify
linksbetweenthe "sound"of a room and its shape.
3:50
PP6. Mathematical and computationalissuesin the deeonvolutionof a
finite-length wavelet from a room impulse response under noisy
conditions.JohnP. WalshIArtec ConsultantsInc., 245 SeventhAvenue,
New York, NY 10001, and Artec/Ars Nova Research, 230 West 15th
Avenue,Vancouver,CanadaVSY IX9}
The theoreticalandcomputational
issues
whicharisein thedesignand
useof algorithmsfor digitalaleconvolution
are discussed.
Derivationof
room impulseresponses
from measurements
madeusingsourcesignals
whichdo not exhibitdelta functionbehavior,undernoisyconditionsimposedby both the ambientconditionson-siteand finite precisionin the
applicationof thedeconvolution
filter,form the focusof the paper.The
genealogy
of thesemethodsin the literatureof time seriesanalysis,geophysicalsignalprocessing,
anddigitalimagerestoration
is described.
4:05
PLY/. Acoustics of coupled spacesrelative to assisted reverberation.
Bruce E. Walker (Consulting and Research in Acoustics, 2659
TownsgateRoad, Suite 101, WestlakeVillage, CA 91361)and Ludwig
W. Sepmeyer(ConsultingEngineer, 1862 Comstock Avenue, Los
Angeles,CA
Onemethodof providingvariablereverberation
in an auditoriumis to
coupleit electroacoustically
with an auxiliaryreverberation
room.Parametersavailablefor controlof the compositecharacteristics
include
microphoneand loudspeaker
locationsin both spaces,the reverberation
timein bothspaces,
andthegainof thecouplingamplifiers.By solvingthe
coupleddifferentialequationsrepresenting
a simplifiedmodelof the arrangement,it wasfoundthat a varietyof decay"shapes"rangingfrom
concave(ratedecreasingwith time) to convexcouldbe realized.Reverber-
ation time couldbe variedover a greaterthan two to one range,while
maintaininga "desirable"straightcharacteristic.Resultsof computer
simulationsfor steady-stateand transientexcitationswill be displayed.
One evident feature of these studies is that the maximum number of reflec-
tionssimulatedfromeachroomsurfaceis critical.An investigation
was
conductedusingmeasureddata for three roomsand computersimulations to evaluatevariousmeansof predictingthe necessarynumber of
reflectionsfor accuratemodeling.Schemeshave beenpresentedin the
literature for predictingthe necessarynumberof reflectionsfor specific
levelsof accuracy.Thesetestshaveindicatedthat suchformulasare highly inaccurate.There havealsobeenremainderformulaspresentedin the
literaturefor correctingcomputationswith a limited numberof reflections.The remainderformulascurrentlyavailablewerefoundtobeunable
to accuratelycompensatefor model errors in analyzingactual rooms.
Where others had indicateda maximum of only three or four reflections
needbe considered,theseinvestigatorsfound that as many as 40 reflections may sometimesbe required.More typically, ten to 20 reflections
from eachroomsurfacemustbe modeledfor acceptable
results.The requirednumberof reflections
wasfoundto bea complexfunctionof room
size,roomproportions,and the distributionand amountof absorption.
S84
4:20
PP8. The decayof soundin roomswith amplificationsystems.Eugene
T. Patronis, Jr. {Schoolof Physics, Georgia Institute of Technology,
Atlanta, GA 30332}and Ted Uzzle (Altec LansingCorporation,Box
3113, Anaheim, CA 92803}
The regenerativebehaviorof soundreinforcementsystemsaffectsthe
soundleveland interactswith the reverberafivcdecayof soundin enclosuresin which they operate,in ways not previouslydescribed.For a
system of loop gain .4(s)B(s), the sound levels will be
--201og[!--A(s•BIs)]ldB ) above those predicted by classical
feedforwardmethods.After the sourceofsoundto beamplifiedisshutoff,
the regenerativeloop will continue producingsound, and will take
P/-- 57.6 log[.4(s}B(s}](s}
todecay60dB,wherePis theregenerative
path
length(m).Methodsfor calculatingandmeasuringthedecayingloop,by
itselfand in combinationwith the room'sreverberation
time,are given.
S84
THURSDAY AFTERNOON, 10 NOVEMBER 1983
GOLDEN WEST ROOM, 1:00TO 3:05 P.M.
SessionQQ. Psychological
Acoustics
V: BinauralHearingandLateralization
JudyR. Dubno, Chairman
HeadandNeckSurgery,
MedicalCenter,University
of California,LosAngeles,
California90024
Chairman's
Introduction--l:00
ContributedPapers
1:05
QQ1. Binauralinteractionin hearingimpairedlisteners.Kaigham
J. Gabriel(Research
Laboratory
of Electrouics,
MIT, Cambridge,
MA
02139)
Thebinauralhearingabilities
offoursensori-neural
losslisteners
were
testedin fourexperiments:
(1) interauraltimediscrimination,
(2) interauralintensitydiscrimination,
(3}interauralcorrelation
discrimination,
whose
negative
slopes
growmoreshallow
withincreasing
rate.When
sensitivity
wasmeasured
forcomposite
signals
madeofclickswhose
centerfrequencies
were4and6kHz,or4,5.2,6,and7.2kHz,theslopes
ofthe
functions
weresimilarto thesingle-frequency
conditions.
However,the
intercepts
forthetwo-andfour-frequency
stimuli
weredecreased
byfactorsofapproximately
• and2,respectively,
relative
tothecase
ofsingle
frequencies.
These
datademonstrate
thattherate-dependent
saturation
of
binaural
information
previously
shown
tooperate
withinfrequency
chan-
and(4)binaural
detection
experiments.
All testswereconducted
oneach
nels[E.R.HafterandR.H.Dye,J.Acoust.
Soc.
Am.73,644-651
(1983}]
subject
using
third-octave
bands
ofnoise
centered
at250,500,1000,
2000,
doesnotaffecttheintegration
ofinformation
across
channels.
[Supported
and4000 Hz. "BinauralAudiograms"canbe obtainedby plottingthe
ratioof normaldiscrimination
jndsto measured
discrimination
jndsver-
by NIH.]
susfrequency
ona log-logscale.
In general,
thefrequency
dependence
of
binauralhearingloss,sodefined,
appears
unrelated
to thefrequency
de-
pendence
ofhearing
lossasmeasured
bycurrent
monaural
audiometric
techniques.
Furthermore,
impairments
ofinteraural
timediscrimination
areindependent
of impairments
in interaural
intensity
discrimination.
Finally,theMLD alonewasnotrelatedtolossofinteraural
timeorintensitysensitivity.
Two of the subjects
testedshowed
elevated
NoS•rand
NoSothresholds,
poorinterauraltimeandintensity
discrimination
buta
"normal"MLD. [Worksupported
byNIH GrantNS10916.]
2:05
QQ4. The extensionof binauralcrosscorrelation
modellingby a
mechanismof lateral inhibition. Werner Lindemann (Lehrstuhl ftir
allgemeine
Elektrntechnik
und Akustik,Ruhr-Universitfit,
D-4630
Bochum,Postfach102148,West Germany}
To modelthestationary
anddynamicbehaviorof thebinauralsystem
wepresent
anextension
ofthewell-known
binaural
crosscorrelation
modelswhichisbasedon a lateralinhibitionmechanismalongthe crosscorre-
lationaxis. The runninginterauralcrosscorrelation
is calculatedby
1:25
QQ2. A generalmodification
for modelsof binauralinteraction,
K.
J. Gabriel,H. S. Colburn,P.M. Zurek,and N. I. Durlach(Research
Laboratory
of Electronics,
MIT, Cambridge,
MA 02139)
Although
manystudies
havedemonstrated
therelationship
between
lateralizationand binauraldetection,currentmodelsof binauralinterac-
tionareunable
topredict
performance
inbothtaskswiththesamesetof
valuesfor themodelparameters.
By incorporating
a mechanism
which
low-pass
filters(averages)
interaural
timeandintensity
differences
intoa
simple,
narrow-band
modelof binaural
interaction,
results
frominter-
counting
spike
coincidences
infrequency
bands.
Theresulting
neural
activitydistribution
is fedintothelateralinhibition
mechanism.
The required
EEandEl gates
canbecombined
indifferent
waystooptimize
the
performance
ofthemodel.A widefieldof psychoacoustic
lateralization
andlocalization
datacanbeexplained
veryeffectively.
Forexample,
in-
teraural
phase
aswellasinteraural
leveldifferences
areevaluated
inorder
to modellateralizationaswell astime-intensitytrading.For nonstation-
arysignals
themodel
canexplain
thelawofthefirstwavefront
andrelated
psychoacoustic
effects.
Themodelparameters
arematched
to thepsychoacoustic
databy choosing
optimaltimeconstants
of thespikefiring
process,
thespikecoincidence
window,
andtheinhibition
mechanism.
auraltimeandintensitydiscrimination
testscanbeusedto predictcorre-
Somemodelresultswill bepresented
graphically
in theformof "neural
activitypatterns."[Work supported
by the DeutscheForschungsge-
lation discriminationand NoS•r detection results.Evidencefor such a
meinschaft.]
low-pass
mechanism
hasmostrecently
beenreported
byGrantham
and
Wightman
[J.Acoust.
$oc.Am.72, 1178-1184
(1982)].
Forbothnormal
listeners
andhearing-impaired
listeners
witha varietyofdifferent
losses,
thepredictions
oftheaugmented
modelsuggest
thatbinaural
hearing
in
correlationdiscrimination
andNoS•rdetectiontaskscanbecharacterized
by a listener's
sensitivity
to interaural
timeandintensity
differences.
[Worksupported
by NIH GrantNSI0916.]
1:45
QQ3. Lateralization of clicks based on interaural time: Additivity of
information across frequency. Elizabeth M. Wenzel and Ervin
R. Hafter (Department of Psychology, University of California,
Berkeley, CA 94720)
Sensitivityto interauraldifferences
of time wasmeasuredfor trainsof
I to 32 (n)clickspresented
at ratesof 400 or 200 per second.The center
frequencies
of thebandpass
clickswereeither4, 5.2,6, or 7.2 kHz. As in
earlierresearch,plotsof log thresholdversuslog n producedfunctions
S85
J. Acoust.
Soc.Am.$uppl.1, Vol.74, Fall1983
2:25
QQ5. Envelope-based
lateralizationof low-frequency
waveforms.
Leslie
R. Bernstein(Department of Psychology,University of Illinois,
Champaign,IL 61820) and Constantine
Trahiotis (Departmentof
SpeechandHearingScience
andDepartmentof Psychology,
University
of Illinois,Champaign,IL 61820)
Severalrecentinvestigations
suggest
that listeners
eithercannotor do
not useinterauraltemporaldisparities(ITDs) in the envelopeof low-
frequency
waveforms
in lateralization
tasks[G. B. Henning,J. Acoust.
Soc.Am. 68, 446--453(1980);G. B. Henningand J. Ashton,HearingRes.
4, 185-194(1981);G. B. Henning,HearingRes.9, 153-172(1983)].Listenersin thosestudiesmay havebeenunableto processtheseITDs princi-
pallybecause
of thetypesof stimulipresented.
We employed
anacoustic
pointingtaskin whichlisteners
variedtheinterauralintensitive
difference
of a 500-Hz narrow-bandnoise(thepointer)sothat it matchedthe intra-
cranialposition
of a second,
experimenter-controlled
stimulus
(thetarget).Targetstimuliweresinusoidally
amplitude-modulated
tonescen-
106thMeeting:
Acoustical
SocietyofAmerica
S85
teredon 500 Hz or I kHz, and modulatedat 25, 50, or 100Hz. Targets
werepresented
with eithertheentirewaveformdelayedor with onlythe
envelope
delayed.
Ourresults
suggest
thatdelaysoftheenvelope
doaffect
thelateralpositionof our low-frequency
targets.However,theenvelopebasedcuesappearto interactwith thoseprov/dedby the fine-structure
whichappearto bedominant.
2.'4•
To understand
the existence
of the binauraledgepitch [Klein and
Hartmann.J. Acoust.Sec.Am. 70, 51-6111981
}] appears
to requirecentral lateralinhibitionin the humanauditorysystem.We havelookedfor
thiseffectin centralmaskingexperiments.
Usingthebinaural-edge
noise,
whichcreatesthe binauraledgepitch,as a musket,we foundpulsation
thresholds
for sinetonesin two frequencyrangeswherethebinauraledge
pitchexists.We furtherfoundmaskingleveldifferences
usingthe same
pulsationthresholdtechnique.Theoreticallythe differencebetweenthe
binaural-edge
thresholds
andtheMLD thresholds
shouldshowthepeak
and valleysignatureof lateralinhibition.No suchstructurewasfound.
We suggest
that this negativeresultdoesnot excludethe possibility
of
QQ6. A searchfor centrallateral inhibition.W. M. Hartmann
central lateral inhibition, but that the time courseof central lateral inhibi-
(Department
of Physics,
Michigan
StateUniversity,
EastLansing,
MI
tionmakesthepulsationthresholdtechnique
an inappropriate
meansfor
observingthe effect.[Work partiallysupportedby the NIH, grant NS
17917.1
48824and Institut de Rechereheet COOrdination
Acoustique/Musique,
31 rue SaintMerri, 75004, Paris,France)
THURSDAY AFTERNOON,
FORUM
10 NOVEMBER 1983
ROOM, 1:30 TO 4:50 P.M.
SessionRR. PhysicalAcousticsV: RayleighWaves, Leaky Waves,etc.
Bernhard R. Tittmann, Chairman
ScienceCenter,RockwellInternational 1049 CaminoDosRiog ThousandOaks, California 91360
Chairman's
!ntroductio•l'..10
ContributedPapers
1:3•
RRI. Quantitativeanalysisof pulsedpseudo-Rayleigh
waves.J. H. M. T.
van der Hijden {Schlumberger-DollResearch, P.O. Box 307,
Ridgefield,CT 06877}
Acoustic
pseudowaves
(leakywaves}
alonga planeinterface
arcstudledin thespace-time
domain.AnalysisoftheGrecn'sfunctionasderived
bytheCagniard--de
Hoopmethodallowsa quantitative
description
ofthe
propagation
of a pseudo-Rayleigh
pulsealonga fluid/solidinterface.
Afterapplying
theCagniard-de
HOOp
methodtheanswer
hastheformof
a convolution
oftheinputsignalof thesourcewiththeexplicitlyobtained
space-time
Green'sfunction{"system's
response"),
whichclearlyshows
Contradicting
experimental,
approximate
theoretical,
andnumerical
resultshavebeenreportedin the literatureby severalauthors[L. M.
Martel et al., Bull. Seisin.Sec.Am. 67, 1277-1290(1977}]on Rayleigh
wavetransmission
coefficientpasta stepchangein elevation.In this pa-
per,reciprocity
for bothwavepropagation
directionacross
a stepisdemonstratedexperimentallyusinga new ratio techniqueeliminatingerror
sources
introduced
fromelasticwavegeneration,
coupling,anddetection.
Two-dimensional
ultrasonic models were used to obtain the data. The
each featureof the time behaviorof the acousticquantitiesat different
experimentaltransmission
coefficientmeasurements
are comparedwith
otherpublishedresults.The ratio of stepheightto Rayleighwavelength
teatedrangedfrom 0.159-1.33. The effectof stepheighton the interferenceof the transmittedwave componentsis examined.The conversion
betweenRayleighand shearwavesat the stepplaysan importantrole in
locationsand their dependence
on the materialparametersinvolved.
Fromananalyticstudyof thespace-time
Green'sfunctionforthereflect-
Sudbury,MA 01776.
thetransmission
coefficient.
'j Present
address:
Sohoquest,
P.O. Box584,
ed pressure
a quantitative
description
of the pseudo-Rayleigh
phenomenonhasbeenderived.This includesa conditionwhich limits the range
of existence
andan equationfor thetravelspeed.A pseudo-Rayleigh
factor whichdetermines
the relativestrengthof the phenomenon
is defined
andthedecayofpulsed
wavemotionalongtheinterface
isstudied.
Using
thisfactorit •comcs clearwhythepseudo-Rayleigh
waveisverystrong
at a water/steel interface,while it doesnot exist on, e.g., a water/ice
interface. Numerical results will be shown.
RR2. Rayleigh wave transmissionreciprocity past a step change in
elevation.
Jacques
R. ChamueP
j (TheCharlesStarkDraperLaboratory,
Inc., 555Technology
Square,Cambridge,
MA 02139)
S86
2:05
RR3. New ultrasonicmodelingfindingson Rayleigh wave propagation
andtheirimplications.
Jacques
R. Chamuel
a•(TheCharles
StarkDraper
Laboratory,Inc., 555 TechnologySquare,Cambridge,MA 02139)
The presence
of unexplained
largeattenuation
of low-frequency
componentsand inverteddispersion
of Rayleighwavescrossingthe oceancontinentmargin,the TibetanPlateau,and the Iranian Plateauare exampiesof complexunsolvedproblemson Rayleighwavepropagation
across
verticalboundaries.In this paper,new ultrasonicmodelingfindingson
Rayleighwavepropagationacrossstepchangesin elevationusingtwoand three-dimensional
modelsare presentedexplainingthe previously
Societyof America
S86
mentionedphenomena.Laboratoryseismicultrasonicmodelingresults
on Tibet are presented
matchingactualfielddata.Physicalinsightsinto
thecauseof theinverteddispersion
andattenuationareobtainedfromthe
reportedresults.Implicationsof the new findingsindicatethe need to
reconsider
thecurrentocean-continent
margin,theTibetanPlateau,and
the Iranian Plateaucrustalstructuremodels.Oppositeto the currentbeliefof thepresence
of a low-velocityhigh-damping
layer(possibly
partially molten)near30km belowthesurfaceof theTibetanPlateau[P. Birdet
al., Nature 266, 162-163 (1977);W. P. Chen et al., J. Geophys.Res.g6,
5937-5962 (1981);K. Y. Chun etal., Bull. Seisin.Soc.Am. 67, 735-750
(1977)]the newreportedfindingssupportthe author'sconceptof a solid
lowattenuationsolidcrustalstructure.A briefdiscussion
on liquid/solid
interfacewavespropagationpasta stepchangein elevationwill followthe
Rayleighwaveresults.
a•Present
address:
Sonoquest,
P.O. Box584,Sudbury, MA 01776.
2:20
RR4. Reflection of narrow ultrasonic beams at fluid/solid interfaces.
Finn B. Jensenand Henrik Schmidt (SACLANT ASW Research
Centre, 19026La Spezia,Italy)
The reflectionof ultrasonicbeamsneartheRayleighanglefor a fluid/
solidinterfaceisa well researched
subject.Existingtheories,however,are
all approximate
withlimitations
suchasbeamwidth
largecompared
tothe
wavelength,
lossless
media,parallelbeamsof particularshape(Gaussian),
etc. A new numericalmodelhasbeendevelopedto solvethe reflection
problemwithoutanyof theabovelimitations.
Thistechnique
isbasedon
the fast-fieldsolutionto the waveequation,and solutionscan now be
obtainedfor anybeamwidth,andfor parallel,diverging,and converging
beams.Furthermore,due to the numericalefficiencyof the computer
code,pulsed-beam
solutions
can be generated
in reasonable
time using
Fouriersynthesis
of the time signals.Computationalresultsare presented
crack faces.The systemsof integralequationsare solvednumerically.
Substitution
of the dislocation
densities
into appropriaterepresentation
integralsyieldsthe reflected
and transmitted
surfacewaves.Reflection
andtransmission
coefficients
areplottedversustheangleof incidencefor
variousvaluesof the wavelength,and versusthe wavelengthfor various
valuesof the angleof incidence.A criticalangleof incidence,whichdependson thematerialproperties
of thesolid,hasbeenobserved.
Beyond
thisanglenomechanical
energyisradiatedintothesolidbybodywaves.
3:05
RR7. Eigenrays and eigenmodesfor source-excitedpropagationin
layered multiwave media. I. T. Lu, L. B. Felsen, and A. Kamel
IDepartment of Electrical Engineeringand Computer Science,
Polytechnic
Instituteof New York, Route110,Farmingdale,
NY 11735)
Couplingof wavespecies
at interfaces
andboundaries
in a medium
composed
of planemultiwave
layerscreates
a proliferation
of rayfields
evenafterrelativelyfewmultiplereflections.
Thisinhibitsa raytreatment
of propagation
fromsourceto observer.
The difficultymaybeovercome
by diagonalizing,
in a planewavespectralrepresentation
of theGreen's
function,thereverberation
matrixF descriptive
of theboundarycoupling.
The resulting
eigenvectors
of F represent
combinations
of theoriginalQ
wavespecies,
to bereferredto aseigenrays,
which,exceptfor multiplica-
tionbytheeigenvalue
Aq,q = 1... Q,remain
unaltered
afteronecomplete
reverberation.
Thus eigenrays
maybe tracedthroughsuccessive
reverberationslike ordilmryraysin a single-wave
medium.This featurealso
permitstheoriginalmultiwave
Q x Q matrixproblem
to bedecoupled
intoa sequence
ofscalarproblems.
Conventional
eigenmodes
aregeneratedfromeigenrays
byimposing
self-consistency
(Aq= 11afteronereverberation.Alternativerepresentations
aregivenfor themultiwaveGreen's
functionby useof thesenew concepts.[Work supportedby National
ScienceFoundationandONR AcousticsBranch.]
forvarious
beamconfigurations
reflected
at water/steel
andwater/aluminumoxideinterfaces,
andthe resultsarecomparedwith availableexperi-
3:20
mental data.
RRS. Parametric acoustic conversion in ocean sediments. Suk
WangYoon(Applied
Research
Laboratories,
TheUniversity
ofTexasat
2:35
RRS. Observationsof backwardleaky Lainõwavesin plates.Michel de
Billy,a)LaszloAdler(Department
of WeldingEngineering,
OhioState
University,Columbus,OH 43210),and G6rard Quentin(Groupede
PhysiquedesSolides,Universit6Paris,Paris7, France)
We havepreviouslyreported[J. Acoust.Soc.Am. 72, 1018-1020
(1982)]that a finiteultrasonicbeamproduces
backwardleaky-Rayleigh
wavesfrom liquid-solidinterface.ThesebackwardpropagatingleakyRayleighwavesareof muchloweramplitudesthan the forwardoneand
observedwith a singletransducerin pulse--echo
mode.The objectiveof
thispaperis to reportthe observation
of backwardpropagating
leakyLamb wavesin platesimmersedin water. [ForwardpropagatingleakyLambwaveswerepredicted
andobserved
by PIona,Pitts,andMayer,J.
Acoust.Soc.Am. 59, 1324(1976).]Several
symmetrical
andantisymmetrical Lamb modeswereidentifiedin brassand stainless-steel
platesby
measuring
the criticalangleat whichthe backreflectedsignal(to the
transmitter)is maximum.Backwardpropagatingleaky-Lambwavesare
alsoobservedwith a secondtransduceron the transmittingsideof the
plate.Themeasured
dispersion
curvesarein goodagreement
withtheo-
Austin,Austin,TX 78712-8029)and ThomasA. Griffy (Departmentof
Physics,
The Universityof Texasat Austin,Austin,TX 787121
The interactionof acousticwavesfroma parametricacousticarrayat
a water-sediment
interfacehasbeenstudiedtheoretically.
This investigationwasmotivatedby theobservation
of betterpenetration
of acoustical
energyinto sediments
usinga parametric
acoustic
arrayratherthana
conventional
sourceIT. G. Muir, C. W. Horton,St.,andL. A. Thompson,
J. SoundVib.64, 539(19791].
In orderto treatthenonlinear
interaction
of
soundwavesin a sediment,theinhomogeneous
elasticwaveequationfor a
solidwassolved.One effectof the nonlineartermsin this equationis the
couplingof compressional
andshearwaves.The separation
of thecouplingeffectis shown.The primarywavesfrom a parametricsourceare
expected
to exciteStoneIcywavesalongthe water-sediment
interface.
TheStoneIcy
wavesareassumed
toserveasa sourceforparametric
acoustic conversion
in the sediment.The analyticsolutionsof the inhomogen-
eouswaveequationare spherical
wavesmodifiedby an angulardependencein theamplitude.[Worksupported
by ONR.]
3:35
reticalpredictions.
')Alsoat GroupdePhysique
desSolides,
Universit•
RR9. Numerical simulation of acoustic propagation at a fluid. solid
Paris, Paris 7, France.
interface.Curt Randall (Schlumberger-DollResearch,Ridgefield,CT
06877I
2:S0
RR6. Reflectionand transmi•ion of obliquelyincidentRayleighwaves
by a surface-breaking
crack. Y. C. Angel and J. D. Achenbach
(Departmentof Civil Engineering,The TechnologicalInstitute,
NorthwesternUniversity, Evanston,IL 60201)
Reflection,transmission,
and scatteringof Rayleighwavesthat are
obliquely
incident
ona surface-breaking
crackareinvestigated.
Theformulationof the problemhasbeenreducedto two systems
of singular
integralequations
of thefirstkindfor thedislocation
densities
across
the
$87
Propagation
of acousticpulsesin the neighborhood
of the interface
betweenfluid and solidhalf-spaces
is investigated
numericallyusingthe
finitedifference
technique.
Thesolidhalf-space
maybehomogeneous,
or
it maycompriseseveraldistinctsolidsof differingacoustical
properties.
The solid-solidinterfacemay havearbitrary orientationwith respectto
the fluid-solidinterface.Plotsof the displacementfieldsclearlyillustrate
the wavefronts,headwayes,and surfacemodesnear the fluid-solidinterface.In thecaseof theinhomogeneous
solid,reflection,transmission,
and
modeconversions
at the solid-solidinterface,and subsequent
interactions
with the fluid-solidinterfacegiverise to a multiplicityof decaypulses.
Societyof America
$87
incidence,
theantisymmetric
familyof modesarenotexcited.In addition,
sharpchangesin the FIoquetwavecoefficients
occur,known as the
Wood'sanomalies,as the frequencyof the angleof incidenceis swept.
Theoriginandphysical
significance
of eachofthesedecaypulses
is.made
evidentby the diplacement
fieldplots.
3:80
4:20
RRI0. Acoustic modes in a thin rigid cylinder with periodic gaps. S.
K. Chang (Schlumberger-DollResearch,Box 307, Ridgefield,CT
RRI2. Acousticwavesalonga fluid-filledboreholewith a concentricsolid
layer. S. K. Changand A. H. Everhart{Schlumberger-Doll
Research,
P.O. Box307, Ridgefield,CT 06877}
06877•
Axisymmetricacousticmodesin a thin rigid cylinderwith periodic
gapsimmersedin a fluid are studied.The gapsare circularslotson the
circumference
of the cylinder.The displacement
potentialin the fluid is
expressed
in termsof the FIoquetwavesin the cylindricalgeometry.A
Galerkin'smethodis appliedto formulatethelinearequationsin relation
to the boundaryconditionson the cylinderand in the gaps.The modal
wavenumbers are the location of the zeroes of the determinant
Transientacousticwavesin a fluid-filledcylindricalboreholewith a
concentricelasticsolidlayerare complicatedby acousticmodesthat resuitfromthepresence
of thesolidlayer.A realaxisintegration
technique
[TsangandRadar,Geophys.
44, 1706-1720(1979}]is usedto compute
waveformsexcitedby an isotropicpointsourceplacedon the axisof the
hole.It isevidentthatdispersive
acousticmodesarean importantfeature
of theelasticwavepropagation
for thisconfiguration.
Thereareat least
four classes
of modescausedby the solidlayer:the StoneIcymode,which
issometimes
referredto asa tubewave•thecompressional
modes,caused
of the
matrix in the complexwavenumber
plane.The zeroesare foundby a
Newton-Raphson
iterativemethod.For an axisymmetric
acousticfield,
the modesare leaky waves.It was found that theseleaky wavesare fast
wavesthat havea phasevelocityfasterthan the soundwavesin the ambientfluidmedium.Sinceenergycanleakoutof thestructure,theseleaky
wavesareall attenuativein the axialdirection.Longergapsincreases
the
modalattenuationsinceit is moredifficultto trap the wavesin the struc-
by compressional
wavereflections
in the solidlayer;the shearmodes,
causedby shearwavereflections;
and the hybridmodes,due to mode
conversions
at the interfaces.A studyof the dispersion,attenuation,and
residueof themodesprovidesan explanation
for mostof thefeaturesin
ture.
the waveforms.
4:05
4:35
RR1 I. Scatteringof acousticwavesby a periodicarray of elasticstrips.
A. Sezginerand $. K. Chang(Schlumberger-Doll
Research,Box 307,
Ridgefield,CT 06877)
Thescattering
of a timeharmonicplanewavein a fluidincidentonan
infiniteperiodicarrayof thin elasticstripsis studied.The stripsarecoplanarandperpendicular
to theplaneof incidence.
Theacoustic
displacementpotentialin the fluid is expressed
as a Floquetwaveexpansion.
Mindlin'stheoryof the bendingof thin platesis appliedto relatethe
pressure
difference
across
theelasticstripstothemotionofthestrips.The
shearandbendingcomponents
of thestripmotionareexpanded
in trigonometricbasisfunctions,
suchthattheshearforceandbendingmomentare
zeroat the edgesof the strips.The expansion
coefficients
are solvedfrom
thelinearequations
obtained
byapplyingthemethodofweighted
residualsto theboundaryconditions
on thestripsandin thegaps.Anomalous
reflectionis observedwhenthe incidentwavefrequencycoincideswith
thetransverse
resonance
frequencies
of thestrips.Resonance
frequencies
are observedin closepairs,corresponding
to the strip resonantmodes
with a symmetricand an antisymmetric
displacement
profile.At normal
THURSDAY
AFTERNOON,
10 NOVEMBER
RRI3. Farfield deeomgosition
of acousticwaveformsin a fluid-filled
borehole.AndrewL. Kurkjian (Schlumberger-Doll
Research,Box 307,
Ridgefield,CT 06877}
In acoustic
welllogging,a transientacoustic
sourceisplacedwithina
mud-filledboreholefor the purposeof excitingrefractedcompressional
andshearwavesin thesurrounding
formation.We modelthedownhole
environmentby an infinitefluid-filledcylindersurroundedby an infinite
solidformation.An isotropicpointsourceis placedon theaxisof thehole
andan exactsolutionfor thefieldin theholeisobtainedin thefrequencywavenumber
domain.Space-timewaveformsareobtainedby numerical-
ly transforming
this solution.The waveformsconsistof compressional
and shearrefractedwavesplusmodes,whichare guidedby the hole.In
thispaperwe numerically
computetheseindividualcomponents
of the
field.The modesare obtainedby locatingpolesand evaluatingresidues.
The refractionsare obtainedvia numericalbranchcutintegrations.A vertical branchcutis usedwhich convergesrapidly but only givesaccurate
results in the farfield.
GARDEN
1983
ROOM, 1:30 TO 4:39 P.M.
SessionSS. SpeechCommunication
V: PhonemicPerception
John J. Ohala, Chairman
Department
of Linguistics,
Unioersity
of California,
Berkeley,
California
94720
Chairman's
Introduction•l'.30
ContributedPapers
Russianvowelshasbeenreportedby Chistovichand her colleagues.
Syr-
1:35
SSI. Perceived eritleal distancesbetweenF I-F0, F2-F 1, F3-F2.
Ann
K. SyrdalandH.S. (}opal(CallletCenter,University
ofTexasat Dallas,
1966 !nwood Road, Dallas, TX 75235}
A criticalspectral
distance
of 3 to 3.5criticalbands(bark}between
firstandsecond
formantfrequencies
in simplified
two-formant
synthetic
$88
J. Acoust.
Soc.Am.Suppl.1, VoL74, Fall1983
dal[J.Aeoust.Soc.Am.Suppl.171,S105[1982}]transformed
fundamental
frequency
andformantfrequency
valuesfromnaturallyproduced
AmericanEnglishvowelsinto Bark valuesfrom whichthreedistancemeasures
were calculated:F I-F0, F2-F 1, andF3-F2. Her proposedauditorymodelof vowelperceptionreducedbetween-speaker
variabilityand provideda perceptually
basedquantitatively
definedlink betweensome
acoustic
andphonetic
features.
In thepresent
series
ofexperiments,
sever-
106thMeeting:
Acoustical
SocietyofAmedca
S88
al synthetic
two-vowelcontinuawereconstructed,
eachwith a varying
mesetonesto date[M. S. Han, U.S.C.Studiesin thePhonology
of Asian
frequencyparameterwhichcrosseda criticaldistancein eitherof the 3-
LanguagesVII (1969};M. S. Hah and K-O. Kim, J. Phonet.2, 223-232
bark difference dimensions. Critical distances over the 3-bark difference
(1974)].Thepresenttestutterances,
unlikethoseof previous
studies,
were
selected
onthecriterionofphonotactic
representativeness.
Han'scanonicalrepresentations
ofthetones'F0 patterns
arecorroborated
inthecaseof
monosyllables,
with littleeffectfromsegmental
composition.
Disyllables
involvingsonorantconsonants
at the syllablejuncture,however,do not
haveF0 patternsthataresequences
of twocanonicaltrajectories.
TheF0
patterncharacteristics
of thesesignalsarediscussed.
dimensions,
estimatedby phonemeboundariescalculatedfrom vowel
identification
tests,will becompared
witheachotherandwithprevious
estimates.
Someeffectsof durationonthephoneme
boundaryestimates
of
criticaldistancewill alsobediscussed.
[Worksupported
by NIH].
1:47
SS2. A perceptually based approach to F0
characterization.
Philip Lieberman,Bill Katz, Roger Zimmerman,Allard Jorigroan,
and Mark Miller (Department of Linguistics,Brown University,
Providence,RI 02912}
While researchers
applyingquantitativetechniques
to the characterizationof intonationpatterns[W. E. CooperandJ. M. Sorensen,
FundamentalFrequency
inSentence
Production
(Springer-Verlag,
Berlin,1981)]
haveclaimed
success
i.nrelating
phenomena
suchasF0 "resetting"
tothe
presence
of syntacticboundaries
[J. Breckenridge
andM. Y. Liberman,
"The declinationeffectin perception,"unpublished
manuscript,Bell
Laboratories
(1977}],thisprocedure
hasbeenconfined
to a highlylimited
corpusof short,simple-declarative
readsentences.
The degreeto which
thesemodelscan be generalized
to spontaneous
speechhasrecentlybecome the subjectof controversy[N. Umeda, J. Phonet. 10, 279-290
(19821].We thereforeexamineda corpusof spontaneous
and readspeech
with theintentof findinga quantitative
characterization
whichcouldbe
appliedacrossspeakingconditions.To this end, we analyzedthe data
usingthe "topline"modelingprocedure,aswell aspeak,valley,and allpoints rms lines, computedby linear regression.In simple-declarative
clausesand sentences,
the "topline" model performedadequately.The
all-pointsrmslinealsoperformedwellandcapturedthegreaterdegreeof
varianceoccuringin spontaneous
speech.Given this result,and for rea-
sonsof computational
simplicity,
wefeltthatanall-points
rmslinewas
superiorin characterizingthe data. This rms model is consistentwith
auditoryprocessing
models.
2:23
SS5. Measuresof i•honationtypesin a natural language.Paul L. Kirk
(Departmentof Anthropology,CaliforniaStateUniversity,Northridge,
CA 91330), Peter Ladefoged, and Jenny Ladefoged (Phonetics
Laboratory,LinguisticsDepartment,UCLA, Los Angeles,CA 90024)
Using a Kay digital spectrograph,
three typesof analysis(spectrograms,powerspectra,and waveforms}
wereusedto investigate
different
phonationtypesin a singlenaturallanguage
(JalapaMazatec).In addition
to normal voice,this languageusescreakyvoiceand breathyvoiceto
distinguish
words.We recordedfivespeakers
producingcontras
fivevowelsthatwereidenticalin qualityandpitch.Thespectrograms
showedthat
in comparison
with normalvowelsthecreakyvowelshadglottalpulsesat
irregularintervalsand a greateramplitudein the higherfrequencies.
The
breathyvowelsaremoreclearlydistinguished
in theonset,andtheyoften
lackeddiscernible
pulses.We usedpowerspectradisplaysto quantify
phonationtype differences.In creaky vowelsthe amplitudeof the first
harmonicin relationto the amplitudeof the first formant is lessthan in
normalvoice;and in breathyvowelsthe firstformanthad lessintensityin
comparisonwith that of the first harmonic.Waveformsdisplayedthe
irregularitiesin the glottal pulsesand the high degreeof first formant
dampingin creakyvowels.[Work supported
by USPHSgrantNS 18163o2.]
2:35
1:59
SS3. On the mechanismofF0 downdrift in Japanese.William J. Poser
(BellLaboratories,
Murray Hill, NJ 07974andMassachusetts
Instituteof
Technology,Cambridge,MA 02139}
In Japanese,
asin manyother languages,
fundamentalfrequency(F0)
tendsto fall duringthe courseof an utterance.Previousstudiesattribute
thisfall to a singlemechanism:
accentreduction,downstep,
or a declining
tonalreference
line.Data arepresented
showingthattwomechanisms
are
involved.First, sentences
containingonly unaccented
wordswereconstructedin sucha wayasto permitperfectbalancingof segmentalcontent.
Measurements
of bothaverageandpeakF0 on the high tonedsyllablesof
thesewordsshowa small but consistentdecreasefrom left to right. The
contourisapproximately
exponential,
with a sharpdownturnat theend.
Second,therateof fall isgreaterin sequences
of accentednonsense
words
than in segmentally
identicalsequences
of unaccented
words.Similarly,
theF0 peakof a wordof eithertypeis lowerfollowingan accented
word
thanfollowingan unaccented
word,in otherwisematchedutterances.
It is
suggested
that thesefactsare consequences
of the simultaneous
existence
of downstepand declinationin Japanese.
2:11
SS6. Atypical VOT categories in Hebrew and Spanish. Lawrence
J. Raphael(HerbertH. LehmanCollege,CUNY, Bronx,NY 10468and
Haskins Laboratories,New Haven, CT 06510), Yishai Tobin (Ben
Gurion University of the Negev, P.O. Box 653, Beer-Sheva,Israel
84105},and Tovah Most (GraduateSchool,CUNY, 33 West42nd Street,
New York, NY 10036)
Availabledata indicatethat mostlanguagesemploythreecategories
of VoiceOnsetTime (VOT) to distinguishhornorganicstopconsonants.
The threecategories,
voicinglead/shortlag/longlag,aretemporallydiscreteand,in theopinionof someresearchers,
maycoincidewith psychoacousticallypredeterminedregionsof auditory sensitivity.Moreover,
speakersof languageswhich displaya two-wayopposition(i.e.,/ptk/vs
/bdg/) seemto employadjacentVOT categories(e.g.,shortlag and long
lag) and not the extremecategories(i.e., voicing lead and long lag) to
differentiatestopshavingthe sameplaceof articulation.Data gathered
from native(butbilingual)speakersof Hebrewand PuertoRican Spanish
revealthat they commonlyuseeither the extremecategoriesof VOT or
voicingleadanda categoryintermediateto shortandlonglag.Thesedata,
togetherwith thosepreviouslyreportedfor CanadianFrench, Danish,
and Korean,raisequestionsaboutthe specificrelationshipbetweenauditory sensitivityand the determinationof VOT categories
in naturallanguages.[Researchsupportedby NINCDS.]
SS4. Fundamental frequency characteristics of southern Vietnamese
phonetalctonesin toorio-and disyllables.Franz Seitz (Departmentof
Linguistics,Universityof Pennsylvania,
Philadelphia,PA 19104)
Fundamentalfrequency(F0} trajectoriesweremeasuredfor 87 Vietnamesemonosyllables
and 72 disyllables
usinga computerprogramwhich
employsautoregressive
spectralmodelingwith cepestrallybasedperiodicity estimation.The study addressesthe issueof invarianceversuscontext-dependency
of the F0 patternsassociatedwith the five phonemic
tones;variability of pattern as a function of proximate tones,as well as
segmentalcompositionof the utterance,was examined.The findingsare
comparedwith thoseof thedefinitiveacousticphoneticstudiesof Vietna-
S89
2:47
SS7. Percel•tion of height differences in vowels. Peter F. Assmann and
TerraneeM. Nearey (Departmentof Linguistics,Universityof Alberta,
Edmonton,AB T6G 2H1, Canada)
Vowelscontrastingin the phoneticfeatureof heightor openness
are
differentiatedprimarily by changesin the frequencyof the first formant.
Severalhypotheseshave beenproposedto accountfor the perceptionof
thesedifferences.Mushnikov and Chistovich[Sov. Phys. Acoust. 19,
250-254(19731]
argueihatthefrequency
of themostprominentharmonic
$89
in theF 1 regiondetermines
theheightof a vowel.Carlsonet el. [inAuditory.4nalysisand Perception
of Speech,editedby O. Font and M. A. A.
Tatham(Academic,London,(1974}]favoran amplitude-weighted
average(centerof gravity)of the two mostprominentharmonics.
Resultsof
matchingexperiments
will be reportedin whichlistenersselectthe best
vowelmatchalongan F 1 continuumcorres'•onding
to teststimuliwith
modified
amplitude
spectra.
Theeffects
ofF0, number,
andfrequency
of
harmonics
areinvestigated.
Predicted
distances
according
toseveral
modelswill be comparedwith listener'smatches.
Spectraldistancemodels
basedontheexcitationpatternor loudness
densitywill alsobeconsidered.
Resultsaregenerally
consistent
witha localcenterof gravityhypothesis.
[Worksupported
by SSHRC.]
2:5•-3:15
Break
ContributedPapers
3:15
inghighvowel[i] or [u].Preliminary
observations
revealcomplex
pat-
SS8. Vowel allophonesand the vowel-formant phonetic space.
Patricia Keating, Marie Huffman, and Ellen Jackson IPhonetics
Laboratory,Departmentof Linguistics,
terns not totally consistentwith those for English:anticipatory
palatalization
in [sJ']in Japanese
doesnotseemasrobusta process
asin
English.Furthermore,perseveratory
palatalization,i.e.,œs--•œ.f,
andboth
anticipatory
andperseveratory
depalatalization,
i.e.,.fs--•ss,
sœ--•ss,
all of
Throughassimilation
andotherphoneticprocesses,
a language
may
havemoresegments
on the phoneticsurfacethanin lexicalrepresenta-
whicharerelatively
rarein English,
arefoundin Japanese
data.Theresultssuggest
a diffcultyin explaining
theprevious
Englishdatain terms
tion.ConsiderEnglishvowels:nasalized,long,frontrounded,andcentral
of peripheralarticulatorycontrol.
vowelsare all introduced
in derivations.
Conceivably,
then,languages
couldbe muchmoresimilarphonetically
than phonemically;
possibly
theycouldevenfill the phoneticspaceequally.In that case,languages
withfewerphoneroes
wouldhaveto showmuchmorephoneticvariation
perphoneme,comparedto languages
with manyphoneroes.
The alternativesituationwouldbethat languages
with fewerphonemes
wouldleave
partsof thephonetic
spaceunused.
We aretestingthesepossibilities
by
comparingthe F 1-F2-F3 spacefor vowelallophonesin differentlanguages.
Here we reporton two five-vowel
languages,
Japanese
and Russian.Sevenspeakers
of eachlanguagereadwordlistsandfreetext, and
vowelformantsarecompared
across
conditions
andlanguages.
Preliminary resultsindicatethat Japanese,
the language
expected
to showthe
leastvariation,haswidelyseparated
vowelsin wordlists,butfillsup the
phonetic
spacein prose.[Worksupported
by USPHSgrantNS 18163•32
to Peter Ladefoged.]
3:27
SS9.
Problems
with
duration
models: Evidence
from
Chinese.
Ren Hongmo(PhoneticsLaboratory,LinguisticsDepartment,UCLA,
Los Angeles,CA 90024}
Durationsof(1}closure,(2)fricationnoise,(3)aspiration,
and(4}voice
in Chinesesoundsunderdifferentlinguisticconditions
weremeasured
on
oscillominkdisplaysof waveforms.
A setof rulesof percentage
duration
variationwereformulatedto reflecttheeffectsof eachof severallinguistic
factorssuchasdistinctivefeatures,syllablestructures,
wordlengths,tone
andstresspatterns,etc.The notionof "incompressibility"
[I. Lehiste,J.
Acoust.Sec.Am. 51, 2018-2024(1972);D. H. Klatt, J. Acoust.Sec.Am.
54, 1102-1104tl973}], i.e., that durationsresistbeingshortenedunder
combinedshorteningrules,is discussed.
Like English,Chinesevoweldurationsareincompressible
underseveralshortening
rules;unlikeEnglish,
Chineseconsonantdurationsdo not showclearincompressibility.
Two
problems were found in
applying the
formula Dj
= K*(D• - Dmi. + Dmi. [D. a. Klatt, J. Acoust.Sec.Am. 59, .12081221 0976}] in Chinese,one is that Chinesedata showtwo valuesof
"minimumduration"(onedurationsymptomatic
of wordlengtheffects,
anda shorterdurationunderneutraltone);anotherproblemis that different combinations
of shorteningrulesmay resultin differentpowersof
incompressibility
in duration.
3:51
SSll. Vocalicferment transitionsare integratedwith noncontiguous
fricativenoises.D. H. Whalen(HaskinsLaboratories,
270 Crown St.,
New Haven, CT 06510)
Natural-speechfricativenoisesfrom fricative-vowelor vowel-frica-
tire syllables
wereeditedsothatthenoisestartedoutaseitherIs]or [•] and
endedup the otherfricative.The overalldurationof the noisewasheld
constant,
andtheproportions
of thetwopartsvaried.Thevocalicformant
transitions
supported
thephonetic
category
ofonepartofthenoiseor the
other. With both initial and final fricatives, the transitionsreducedthe
amountof noiseneeded
to identifya fricativeasbelonging
to thecategory
of the transitions.
Thuseitherthetransitions
wereintegrated
with noncontiguous
acoustic
cues,or thetransitions
hadcuevalueonlywhencontiguouswiththeappropriate
fricativenoise.A furtherexperiment
placed
thesameeditednoises
betweentwovocalicsegments,
andsubjects
identifiedtwo fricatives.The perceived
orderingof thefricativeswasoftenthe
reverse of the order of the noises themselves when the transitions were in
theopposite
order.It thusappears
thatthetransitions
areintegrated
with
noncontiguous
acousticcues.[Worksupported
by NIH.]
4:03
SS12. Noisesegmentand vocaliccuesof Frenchfricatives.George
P. McCasland(4045BaltimoreAvenue,C3, Philadelphia,
PA 19104)
A fricative identification test was administered to native French
speakers.
Teststimulihad beeneditedfrom naturallyspokenfricativevowelutterances:/s,
œ,f,
0 / -/i,a,u/. See[J.Acoust.See.Am. SuppL1
70,S33(1981};
and73,S30(1983}]forPriorusewithEnglish
andSpanish
speakers.
Theresults
indicated
thatbothnoisesegment
intensity
andspectrum weremajoracousticcuesfor the Frenchfricatives.Thesecueswere
redundantfor the/f/, eitherlow intensitynoiseor nonsibilant
spectrum
sufficed.
A muchweakercuedueto theoriginalfricative,sibilantor nonsibilant, of the vocalicportionof the editedsyllablesmustbe taken into
account.By comparison,
Delattrehadconcluded
usingsyntheticspeech
stimuli[Phonetica
18,198-230(1968)]thatnoisespectrum
wasnecessary
and noiseintensitywasredundantascuesfor all Frenchfricatives.Results
implicatethe specificlanguage
experience
of the subjects,
e.g.,French
3:39
SS10. An aeoustlcstudy of Japanesecoronal frleative dusters resulting
from vowel devoieing.Haruko Kawasaki {36-513 RLE, and Center for
CognitiveScience,MIT, Cambridge,MA 02139)
Earlier studies[S. Shattuck-Hufnagel,V. Zue, and J. Bernstein,J.
Acoust.Sec.Am. Suppl.164, S92(1978},V. Zue andS.Shattuck-Hufnagel,Proc.9th ICPS 2, 215(1979)]examiningEnglishfricativeclusters[s.f]
and [.rs]acrossword boundaries(e.g., in "gas shortage"and "tunafish
sandwich")showedthat the directionofassimilatorypalatalizationispredominantlyanticipatory:[sœ]oftenbecomes[Lf], but [œs]doesnot. This
study investigatesthe cross-linguisticvalidity of such a tendency.Four
speakersof standardJapanesecasuallyspokesentences
containingfricativeclusters[œs]
and[s.f]resultingfromdevoicing/deletion
of aninteryen-
S90
J. Acoust.Sec.Am.Suppl.1, Vol.74, Fall 1983
lacks/0/; theimpactof naturalor syntheticspeech
assources
of stimulus
materials; and phonetic perception.Haskins Laboratorieson NICHD
ContractNIH-71-2420 washelpfulin the preparationof stimulusmaterials.
4:15
SS13. Portuguesenasalized vowelsand nasal consonants:Their relation
to following consonants.Edith M. Maxwell (36-511 Speech
CommunicationGroup, Massachusetts
Institute of Technology,
Cambridge,MA 02139)
Pilotspectrographic
resultsindicatethatBrazilianPortuguese
demonstrates
a relationship
similarto thatfoundin Englishbetweensyllabic
nucleus
durationandthevoicingcharacteristic
of a followingobstruent:
Societyof America
$90
vowelslengthenbeforevoicedobstruentsand shortenbeforevoiceless
obstruents.Also, a nasalconsonantin Portugueseactsin conjunction
with a precedingvowelasa syllabicnucleus;for example,if in a syllabic
nucleusa voweldoesnot showthe durationexpectedbeforea givenobstruent,the nasaldurationcompensates,
and viceversa.New data from
sixspeakers
of BrazilianPortuguese
derivedfromcomputer
analysis
will
bepresented
whichconfirmthepreliminaryresults.Theacoustic
characteristics
of nasalized
vowels
andnasalconsonants
in Portuguese
will also
bedescribed,
aswellastheextentto whicha prenasalvowelisnasalized
The difference
betweenphonemically
nasalvowelsand vowelsnasalized
because
theyareadjacentto a nasalconsonant
(e.g.,[l•v] IS, "wool"vs
[p•nv] pane,"cloth")will alsobediscussed.
THURSDAY
coarticulation
Haven, CT 06511-6695}
Acousticdata from Swabill(a Bantulanguagewith a five-vowelsystem)revealinterestingdifferences
in the extentanddirectionof vowel-to-
vowelcoarticulation
ascompared
withotherlanguages.
Utterances
were
VpV disyllables,
includingall combinations
of thefivevowelswith stress
on the first vowel,recordedby a nativespeakerof Swahili.Two major
results
emerged
fromtheanalysis:
(i)Previous
research
onotherlanguages
hasshownvowel-to-vowelcoarticulatoryeffectsacrossthe consonantto
berestrictedto the vocalictransitions.
The presentdatarevealsystematic
vowel-to-vowel
coarticulatoryinfluencewhich extendsinto the steadystateportionof thetransconsonantal
vowel.{ii)A second
importantcrosslinguisticdifferenceis foundin examiningthe relationshipbetweenthe
magnitude and direction of these effects.The first vowel, which is
stressed,is found to be moreaffectedby the quality of the secondvowel
than vice versa.In Swahili, then, anticipatoryeffectsof coarticulation
exceed
carryover
effects.
Thisisincontrast
toFowler
(1,981)
inwhich
she
4:27
SS14. Vowel-to-vowel
Sharon Y. Manuel (Haskins Laboratories,270 Crown Street, New
in Swahili.
AFTERNOON,
Rena A.
Krakow
10 NOVEMBER
and
showsstrongercarryoverthan anticipatoryeffectsfor VCVs in English.
[Worksupported
by NICHD.]
1983
CABINET
ROOM, 2:00 TO 3:50 P.M.
SessionTT. Shock and Vibration IV: Damping Techniquesand Materials
Thomas
S. Graham,
Chairma
n
Bolt Beranek and Newman Inc., Union Station, New London, Connecticut 06320
ContributedPapers
2:05
TTI. Transmission,
reflection,andabsorption
of structureborne
noiseby
discontinuitieson a fluid-loaded plate. D. Feit and J. Caspar
(Departmentof ShipAcoustics,David Taylor Naval ShipR&D Center,
Bethesda,
MD 20084)
The propagation
ofstructureborne
noiseovera fluid-loaded
structure
with a numberof discretestructuraldiscontinuities
ismodeled.An analysisispresented
for anelasticplateexcitedbya uniformtimeharmonicline
force; the structural discontinuitiesare each modeledas a translational
(zeromomentimpedance)singledegreeof freedom{SDOF) vibrational
system(mass-spring-dashpot)
attachedto theplate.Waveenergyincident
on the discontinuities
are either reflected,transmittedabsorbedby the
acousticmediumin theformof radiatedsoundwaves,or absorbed
by the
dashpotof the attachedvibrationalsystem.The reflection,transmission,
andabsorption
coefficients
are presented
asa functionof frequencyfor a
bleor incompatible
polymersin polymericnetworksknownasinterpenetratingnetworkpolymers
(IPN's),theyhavethepotentialfor highdamping over a broad rangeof temperaturesand frequencies.In an effort to
understandhow chemicalcompositionand physicalmorphologyaffect
the dampingof thesematerials,a seriesof experiments
involvingvarying
weightratiosof hardblockto softblocksegments,
molecularweightof the
soft block, differentchain extenders,and catalystwere carriedout. The
reaction-injection
molded{RIM) urethanes
werebaseduponpoly{caprolactone)glycols,modified4,4'-diphenylmethanediisocyanate(MDI), 1,4
butanediolor trimethylpropanel,anddibutyltin dilaurate.The dynamic
Young'smoduluswasmeasured
bya resonance
techniquefor eachgroup
of samplesover a rangeof temperatures
and frequencies.
The observed
viscoelastic
propertieswere correlatedwith thermomechanical
transitionsobserved
in differentialscanning
calorimetryanalysis.The potential
of thesematerialsfor usein IPN's in sounddampingapplications
is discussed.
finitenumberof periodicallyspaceddiscontinuities.
The frequencydependence
of thesecoefficients
are affectedby the resonance
frequencyof
theSDOF aswellasresonance
frequencies
associated
withthespacing
of
the discontinuities.
TY3. Comparative measurements on viseoelnstic materials used for
2:20
TT2. Structure-propertyrelationshipsof someRIM polyurethanesfor
potentialsounddampingapplications.
Rodger Capps,LindaM. Martin,
and Eric D. Rustin {Naval ResearchLaboratory,UnderwaterSound
Reference
Detachment,
P.O. Box8337,Orlando,FL 32856)
Polyurethane
elastomers
areblockcopolymers
madeup of relatively
shorturethanehard blocksegmentsseparatinglongerflexiblepolyether
or polyestersoftblocks.Polyurethanes
oftenexhibitmechanicalproperties superiorto conventionalelaatomers.
They also frequentlydisplay
considerable
damping.Whencombinedwith othertypesof semi-compati-
S91
2:35
J. Acoust.Sec. Am. Suppl. 1, VoL 74, Fall 1983
vibration damping. Christian Pillot (lnstitut National des Sciences
Appliqu6esde Lyon, 69621 VilleurbanneCedex,France)and Geoffrey
L. Wilson (Graduate Program in Acousticsand Applied Research
Laboratory, The PennsylvaniaState University, University Park, PA
16802)
In a previouspaperat the 99th meetingof the AcousticalSocietyof
America in Atlanta
in 1980 a new viscoelastometer was described. This
instrumentenablesthe Young'smodulusand lossfactor to be easilyobtainedovera wide rangeof frequencies
and temperatures.The prototype
of thisinstrumentis beingusedin a continuingprojectfor thesystematic
evaluationof the propertiesof a wide varietyof commerciallyavailable
materials.The methodwill be.described
and someexamplesgiven.
2:50
TT4. Measurementof the dampingcharacteristicsof metal matrix
composites
usinga resonant
dwelltechnique.
NancyS. Timmerman(Bolt
BeranekandNewmanInc., 10MoultonStreet,Cambridge,
MA 02238)
The resonantdwell technique,firstdevelol•d by Heine,wasusedto
measurelossfactorsat the fundamental
frequencyof severalcantilever
beamsamples.Nine differentmetalmatrixcomposites
and threeuntilled
basemetalswere testedto studystressand temperaturedependence.
Threetemperatures
andfourstresslevelswereusedin thestudy,andthe
fundamentalfrequencyof all sampleswasbetween100and 200 Hz. The
resultsindicateincreasing
lossfactorwith increasing
stresslevel.Loss
factorsof the composite
materialswerelowerat elevatedtemperature
3:20
•'r6. Narrow-band random responseof a nonlinear oscillator. Huw
G. Davies and Dennis.Nandlall (Department of Mechanical
Engineering,Universityof New Brunswick,Fredericton,N.B., Canada
E3B 5A3)
Themean-square
response
of anoscillator
witha nonlinear
springto
narrow-bandrandomexcitationcanexhibitmultiplevaluesin somefrequencyranges.The randomlyoccurringjumps in levelare similarto the
jump phenomenon
seenin thecaseof a sweptsinusoidal
excitation.The
mean-square
response
ofa Duffingoscillator
iscalculated
hereusingequivalentlinearization.
The excitationis pinknoisepassed
througha firstorder resonantfilter. Triple valuesof the responsecan occurat some
whencomparedwith room temperature,while the lossfactorsof the un-
frequenciesonly when the filter bandwidthis narrower than the oscillator
filledbasemetalswerehigher.[Worksupported
by AMMRC.]
bandwidth. The correct sinusoidal excitation limit is obtained as the filter
3:05
•'TS. Theoretical predictionof sound attenuationin a liquid-filled
rectangularflow duct usinga viscoelastic-fiuid
compositeliner. Sung
H. Ko (NavalUnderwaterSystems
Center,New London,CT 06320}and
LouisT. Ho (DavisW. Taylor Naval ShipResearchand Development
Center,Annapolis,MD 20084)
A theoreticalinvestigation
wasmadeof the soundattenuationin a
two-dimensional,
liquid-filledducttreatedwith a composite
linerconsistingofa viscoelastic
slabanda fluidlayer,whichisbackedby a perfectly
bandwidth
isdecreased.
On theotherhand,themean-square
response
is
wholelysingle-valued
if eitherthefilteroroscillator
bandwidths
arelarge.
The narrow-band
mean-square
response
canbe treatedas a spectrum
level.Integration
of thisleveloverall excitation
frequencies
shows
good
agreement
withtheexactmean-square
response
towhitenoiseexcitation.
Whenmultiplevaluesoccurtheintegrations
usingeitherthe"upper"or
"lower" part of the response
spectrumbracketthe exactvalueand can
hencebeusedto givea crudeestimate
of therelativetimestheresponse
is
at thetwopseudostable
levels.Furtherworktoestimatetheexpected
time
spentat eachlevelisin progress.
[Worksupported
byNSERC,Canada.]
rigid plate. The viscoelasticmaterial is a rubber-like material that has a
lossfactorassociated
with the shearmodulus,and is characterized
by
Lameconstants
andthematerialdensity.
Thefluidlayerof thecomposite
liner is assumedto be lossless
and nondispersive
medium,and is characterizedby thefluiddensityandthespeedof sound.Thefluidcontained
in
the linedduct is assumed
to be inviscidand characterized
by the fluid
densityandthespeedof thesound.The eigenvalue
equationwasderived
3:35
•r7. A novelconcept
for vibrationisolation.
ThomasS. Graham(Bolt
BeranekandNewmanInc., UnionStation,New London,CT 06320}
erties, and the flow velocity. Then, the sound attenuation was obtained
Thispaperdescribes
a novelconceptfor combining
linearsprings
to
synthesize
various
force-deflection
curves
asmightbeusefulforparticular
problems
of machinery
isolation.
(A force-deflection
curvewitha plateau
iseasilysynthesized,
forexample.}
Theconcept
involves
combining
a negativespring,produced
by a standard
springactingagainstleverarms,in
series
andparallelwithstandard
springs.
It issuggested
thatsuchdevices
maybeusefulwheretheuseof rubberformachinery
isolation
isinappro-
usingthe calculatedeigenvalues.
priate.
basedon thetheoryof elasticity,
theacoustic
waveequationin thepresenceof theflowin theduct,theacoustic
waveequation
in theabsence
of
theflowfor thefluidlayerof thecomposite
liner,andpertinentboundary
conditions.
The eigenvalue
equationwassolvednumericallyfor a given
ductgeometry,
thelinerconfiguration,
thecomposite
linermaterialprop-
$92
J. Acoust.
106thMeeting:
Acoustical
Society
ofAmerica
S92
FRIDAY MORNING, 11 NOVEMBER 1983
HAMPTON ROOM, 8:30 A.M. TO 12:05P.M.
SessionUU. Noise VI: Industrial Hearing Conservation
Alice H. Suter, Chairman
SonusCompany,
1501Red OakDrive,SilverSpring,Maryland20910
Invited Papers
8:35
UU1. Hearing conservation:
Regulatorystatusand issues.Alice H. Sutcr{SonusCo., 1501Red Oak Drive,
SilverSpring,MD 209]0)
TheOccupational
SafetyandHealthAdministration
published
thefinaldecisions
on itshearingconserva.
tion amendmenton 8 March 1983.Certainchangesare likely to causeconfusionwhenOSHA personnel
enforcethestandard.Employersnowmustusepersonalmonitoringin cirumstances
whereareamonitoringis
"generally
inappropriate"
unless
theycanshowthat"areasampling
produces
equivalent
results."
Also,OSHA
haschangedthe term "significant
thresholdshift" to "standardthresholdshift," whichsomeindividuals
interpretto meananordinaryor expected
shiftin hearinglevel.Mostchanges
fromtheJanuary1981version
are towardsa performancerather than a specification
approach,whichmay resultin lessrigoroushearing
conservation
practices,
increasing
thelikelihoodthatemployees
will suffernoise-induced
hearinglossbefore
intervention
canoccur.
Consequently,
threecriticalissues
haveemerged.
First,employers
andconsultants
needa standard,practicalmethodof testinghearingprotectorattenuationas it occursin the field.Second,
OSHA needsto deratethe Noise ReductionRating to reflectreal world use,and third, employersneedan
objective
methodby whichto evaluatetheeffectiveness
of theirhearingconservation
programs.
9:05
UU2. Measuring the effectivenessof industrial hearing conservationprograms. Julia Doswell Royster
(EnvironmentalNoise Consultants,Inc., P.O. Box 144, Cary, NC 27511-0144) and Larry H. Royster
(Departmentof Mechanicaland AerospaceEngineering,North CarolinaStateUniversity,Raleigh,NC 276501
The performance
orientationof thehearingconservation
amendmentunderscores
the needto standardize
methodsfor evaluatinghow adequatelyhearingconservationprograms(HCPs) protectemployees'hearing.
Theauthorswill reviewHCP evaluation
procedures
basedonanalysis
of groupaudiometric
datafor exposed
populations.
Techniques
include
comparisons
ofmeanthresholds
forselected
worker
groups
ofhearing
levels
for nonindustrialnoiseexposedpopulations
matchedby raceand sex,calculationof ratesof changein mean
thresholds,andanalysisof thresholdvariabilityin thedatabasetowardbetterhearingor towardpoorerhearing
in baselinecomparisons
andsequentialtestcomparisons.
Acceptablerangesfor the incidenceof definedthreshold shiftshavebeenidentified.Analysisresultsfor additionalindustrialdatabases
will be presented,aswell as
newlydeveloped
approaches
to dataanalysis.
Applyingagecorrections
to individuals'
thresholds
beforecombiningrecordsinto groupdata allowsassessment
of HCPs with feweremployees
by poolingrace/sexgroups
together.Year-to-yearvariabilityin thresholds
for annualaudiograms
hasbeencorrelatedwith daily temporary thresholdshiftsfor employees
wearingdifferenttypesof hearingprotectors.
9:35
UU3. Measurementof employeenoiseexposureSound levelmeterprocedures.
Daniel R. Flynn (National
Bureauof Standards,Washington,DC 20234)
Evenin thiseraof sophisticated
digitalinstrumentation,
thesimplehand-heldsoundlevelmetercontinues
to holditsplaceasa workhorsein themeasurement
of employeenoiseexposure.
The historyof thesoundlevel
meterfor suchmeasurements
isbrieflyreviewedanda summaryisgivenof themajoradvantages
anddisadvantagesofusinga soundlevelmeterforoccupational
noiseexposure
measurements.
Someof theproblems,
perils,
andpitfallsofconducting
suchmeasurements
arehighlighted.
A briefreviewisgivenofaccuracy
requirements
andcalibration
procedures.
Spatialsampling
problems
arebrieflydiscussed.
Theremainderof thetalkconcentrateson temporalsamplingprocedures
for determination
of employeenoiseexposure
associated
with timevaryingnoise;a simpleprocedure
isdescribed
for accurate
measurement
ofnoisedoseusinga hand-heldsound
level meter.
10:05
UU4. Do dosimetersoverestimatecontributionsfrom impulsivenoise?John J. Earshen(Metrosonics,Inc.,
Box 23075, Rochester,NY 14692)
The OccupationalSafetyand Health Administrationpublishedthe finalversionof its hearingconservation
amendment
on 8 March 1983.It statesexplicitlythatcontributions
fromall noise,impulsive,intermittent,and
S93
S93
continuous
mustbeincluded
indetermining
workernoisedose.In additionit isstatedthatmeasurements
must
be madewith instruments
possessing
A-weightingand slowresponse.
Many claimshavebeenmadethat
dosimeters
overestimate
contributions
fromimpulsive
noise(e.g.,defense
submissions
andtestimony
in the
Co!lier-Keyworth
caseandFriendof theCourtsubmission
by Chocolate
Manufacturers
Association).
The
CMA document
presents
results
comparing
theoretical
computation
forwaveforms
havingshortpulsecomponentsto resultsobtainedwith a varietyof dosimeters
currentlyin use.The instrumentreadings
are high
compared
to the theoretical
computations;
thusit is concluded
that dosimeters
overestimate.
This paper
demonstrates
thatdosimeters
complying
withtheOSHAstipulation
toinclude
A-weighting
andslowresponse
donotoverestimate.
Conclusions
reached
in theCMA briefarecriticallyaffected
by ignoring
thedynamic
properties
ofSlowResponse
whenperforming
theoretical
determination
ofpredicted
doseforspecified
pulsed
waveforms.
It hasbeensuggested,
andin several
instances
demonstrated,
thatthediscrepancy
between
computedandmeasured
valuesdisappear
if fastresponse
is substituted.
Mathematical
analysis
of the idealized
dosimeter
transfer
function
verifies
thisconclusion.
It should
benotedthatthediscrepancy
reappears
forpulse
durationoflessthan0.125s.Theissuetoberesolved
isnotoneofinstrument
performance;
ratherit iswhether
the stipulationof A-weightedslowresponse
isjustifiable.
10:35
UUS. Assessment
of the performanceof hearingprotectorsfor hearingconservation
purposes.Elliott
H. Berger
(Acoustical
Engineering,
E-A-RDiv.,CabotCorporation,
7911Zionsville
Road,Indianapolis,
IN
46268)
Ratinghearingprotector
performance
forhearingconservation
purposes
canbemostaccurately
accom-
plished
whennotonlylaboratory,
butalso'fieldperformance
dataaretakenintoconsideration.
Although
standardized
laboratory
testdatahavebeencommonly
available
sincethe1950's(ANSIZ24.22-1957;
ANSI
S3.19-19741,
it is only sincethe mid 1970'sthat significantwork hasbeenconductedin the area of field
performance
evaluation
ofhearing
protectors.
Currently,
anumber
offieldtechniques
areavailable,
including:
real-ear
attenuation
at threshold
and/ormid-line
lateralization
testsusing
actualnoise
exposed
employees
as
subjects,
eitherattheirworkplaces
oratspecial
testclinics;
dosimetry
studies
viaminiature
microphones;
and
temporary
threshold
shiftevaluations
of hearingprotection
usersin noisyindustries.
Theserealworldmethods
will bereviewed
andcontrasted
to thelaboratory
techniques,
andkeypointsillustrated
withrepresentative
data.
ContributedPapers
11:05
UU6. Risk •ssessmentfor populationswearinghearingprotectors.Felix
variesconsiderably.
Advantages
anddisadvantages
of eachmethodisalso
discussed.
Finally,application
of the valuesto on-the-job
situations
will
be discussed.
Z. Sachs(U.S. Army EnvironmentalHygieneAgency,Bldg. E2100,
AberdeenProvingGround,MD 21010)
The considerations
andparameters
underlyingtheassessment
of risk
of hearinglossfor a populationwearingpersonalhearingprotectivedevices(HPD's)areexamined.
A damageriskfunctionfora protected
populationis developed,
and measures
of hearingprotectoreffectiveness
are
defined.It is notedthat the NoiseReductionRating(NRR) formulation
ofprotector
effectiveness
cannot
bevalidlyusedasa population-oriented
measureof hearingprotectoreffectiveness.
In the population-oriented
context,
real-ear
attenuation'
values
forhearing
protectors
obtained
under
user-fitconditionsmustbe used,but the meanvalueshouldonly be reducedby 1/4 to 1/2 of a standarddeviationin orderto providethe requiredstatisticalconfidence.
Finally, somenumericalexamplesof hearing protectoreffectiveness
aredeveloped
usingcomputersimulationakin
to the Monte Carlo method.
! 1:35
UUS. The effect of reduced headband force on the attenuation of muff-
type protectors. Daniel L. Johnson, Charles W. Nixon, and
Mike Skelton(Air Force AerospaceMedical ResearchLaboratory,
Wright-Patterson
Air ForceBase,OH 45433)
The headband
forceof fivedifferentprotectors
wasdecreased
in one-
halfpoundincrements
untiltheforcewaslessthanonepound.Usinga
dummy head,the attenuationwas measuredfor eachvalueof headband
force.Theresults
indicated
thatfourof themuffswererelativelyinsensitiveto a decrease
in headband
forceandlossof 50% of theoriginalforce
resulted in lessthan a 3-dB reduction in the value of•the Noise Reduction
Rating(NRR). One muff,however,wasverysensitiveand a 50% lossin
headband
forceresultedin roughlya 50% lossin attenuation.
To verify
the dummy head results,attenuationwas measuredat selectedforceson
11:20
UU7. Comlmrisonof hearingprotectorsingle-number
rating methods.
LeonardC. Marraccini (U.S. Departmentof Labor, Mine Safetyand
Health Administration,Pittsburgh,PA 15213)
Duringthelasttenyears,variousorganizations
havedeveloped
singlenumberrating methodsfor hearingprotectors.Thesevalueshave been
usedto approximatethe amountof noisereductionobtainedby using
thesedevices.From thehearingprotectorattenuationdataobtainedfrom
theAmericanNationalStandards
Institutetestprocedures,
theorganizationshavemathematicallyarrivedat singlenumberssuchas the "R factor", the "NRR", and "D factor", and so on. These are basedon various
itemssuchasactualnoisespectrums,
pinknoisespectrums,
standard
deviationof theattenuation
data,etc.Thispapercompares
thevarioussingle
numberratingswhichhavebeencalculated
for sixdifferenthearingproteetots,andthemethodsused.As canbe seen,the singlenumberrating
S94
J. Acoust.
Soc.Am.Suppl.1, Vol.74, Fall1983
threehumansubjects.
Althoughthe attenuations
measured
weresome-
whatlessthanthosemeasured
forthedummyheads,
theeffectofchanging headband
forceproduced
similarresults.Whileall protectors
were
unaffected
bya reduction
of one-halfpoundin force,theeffectof greater
reductions
varieddramaticallywith themakeandmodelof the protector.
Apparently,
manufacturers
needtosetguidelines
tailoredto theirspecific
models.
11:50
UU9. Impulse contribution of total worker noise dose. $ohn Erdreich
(NationalInstitutefor OccupationalSafetyand Health, 4676 Columbia
Parkway,Cincinnati,OH 45226)
For severalyearstherehasbeencontroversy
concerning
whetherim-
pulsivenoiseshouldbeincludedin determining
thenoisedoseto whicha
workerisexposed.
Clearly,theimpulsivenoisecomponents
reachtheear
106thMeeting:
Acoustical
Societyof America
$94
andshouldbeconsidered
in determining
hazard.However,recentcourt
rulingsheldthat,sinceappropriate
instrumentation
isnotavailableto the
industrialhygienist
for impulsemeasurement,
thecalculations
andtables
in theOSHA HearingConservation
Amendmentshouldnotincludethis
noise.Howmuchof a difference
doesnotincludingimpulsenoisemakein
thetotaldose?
Measurements
in 14plantsmadewith a 40-kHz bandwidth
FRIDAY
MORNING,
11 NOVEMBER
1983
andeithera 40-dBor a 72-dBdynamicrangewereanalyzedandthetotal
OSHA doseand the OSHA dosefor the impulsesalonewerecalculated.
The impulses
accountfor asmuchas20% of theexposure
time.In this
shortperiod,however,
theimpulsenoiseaccounts
for up to 50% of the
total dose.Eliminatingimpulsesfrom dosecalculationmay resultin'
workerexposureestimates
half of the actualdose.
SENATE/COMMITTEE
ROOMS, 9:00 A.M.
SessionVV. UnderwaterAcousticsVI: Propagation(Pr6cis-Poster
Session)
Ding Lee, Chairman
Naval UnderwaterSystemsCenter,New London,Connecticut06320
Chairman's
Introduction--9:00
ContributedPapers
9:05
VVl. Theoretical method for a range-dependentfast field program.
K. E. Gilbert, W. A. Kuperman, and R. E. Grimm {Naval Ocean
Researchand DevelopmentActivity, Numerical Modeling Division,
NSTL Station,MS 39529}
A fastfieldprogram(i.e.,a Green'sfunctionmethod)is an accurate
and flexiblemeansfor treatingwavepropagationin a range-independent
environment.Until now, however,thereapparentlyhasbeenno theory
for applyingthe methodto a range-dependent
environment.This paper
derives
andappliesa fastfieldmethodfor one-waywavepropagation
in a
range-dependent
environment.The methodisbasedon the solutionof the
ellipticwaveequationfor an arbitraryverticalsourcedistribution.On a
givenrangestep,the verticalsourcedistributionis takento be thefieldat
theendof thepreviousstep.It isshownanalyticallyandnumericallythat
thisapproachdoes,in fact,givethecorrectsolutionfor one-waypropagation in a range-dependent
environment.
Duringthelastdecadethefastfieldprogram(FFP}hasbeenanimportant tool for modelingwave propagationin stratifiedmedia.The earlier
modelsof thistypewerebasedon a solutionof thedepth-separated
wave
equationby meansof the Thomson-Haskellmethod.In this new FFP
modela moredirectandfastersolutiontechnique
isemployed.
Thefieldis
expressed
in termsof unknownscalarpotentials.At eachinterfacethe
boundaryconditionsyield a linear systemof equationsin the Hankel
transforms
of the potentials.Usinga techniquesimilarto theoneusedin
finite-elementprograms,theseequationsare mappedinto a globalsystem
whichis solvedwith an efficientband-solver.
Contraryto theThomsonHaskellmethod,the newtechniquecantreatseveralsourcesand receivers
with one singlesolution.Hence, the field producedby vertical source
arrayscanbedetermined.Evenwith onesourceandreceiverthecomputationalspeedhasbeenimprovedby an orderof magnitude,and pulse
calculationsby meansof Fourier synthesishave becomefeasible.The
featuresof the modelare illustratedthrougha few computational
examples.
9:17
9:09
VV2. Matrix methodfor numericallysolvingthe inhomogeneous
wave
equation.R. E. Grimm, K. E. Gilbert,and W. A. Kuperman(Naval
OceanResearchand Development
Activity, NumericalModeling
Division,NSTL Station,MS 39529)
In recentyears,matrix methods(e;g.,finiteelements,finitediffer-
ences)
havebeensuccessfully
usedtonumerically
solve
theparabolic
wave
equation.
This paperdiscusses
the application
of suchmethodsto the
solution
oftheellipticwaveequation
fora general
verticalsource
distribution. In particular,it is shownthat one-dimensional
finiteelementsare a
convenient
waytoaccurately
reducethedepth-separated
inhomogeneous
waveequationto an easilysolvedsystemof linearequations.
The advan-
tagesof thismethodovermethods
whichusespecial
functions
arethatit
accepts
arbitrarynumerical
profiles
andthatit canbesimplyappliedto
computea range-dependent
"fastfield" solution.In addition,for realistic
environments
withcomplex
stratification,
thecomputation
speed
should
becompetitive
with methodsbasedon specialfunctions.
9:13
VV3. A new fast-field solution to propagation in multilayered solid
environments.Henrik Schmidt (SACLANT ASW ResearchCentre,
19026,La Spezia,Italy}
$95
VV4. Modeling of soundpropagationover Dickins Seamount.Finn B.
Jensen
{SACLANT ASW Research
Centre,19026La Spezia,Italy)
Experimental
dataforsoundpropagation
across
a steepseamount
{14ø
meanslope}wasrecentlyreported[G. R. Ebbesonand R. G. Turner, J.
Acoust.Soc.Am. 73, 143-152(1983}].The broadbanddataexhibita frequency-dependent
shadowing
effectwith a dropin soundleveljustbehind
themountof morethan20 dB at 12.5Hz. An earlierattemptto explain
thesepropagation
featuresusingthe parabolic-equation
techniquegave
promisingresults[F. B. Jensen,W. A. Kuperman,and H. Medwin,J.
Acoust.Soc.Am. Suppl.I 68, S52{1980}].The datahavenow beensubjectedto a detailedmodelingusingbothrange-dependent
ray theoryand
the recentlydeveloped
wide-angled
parabolicequationtheory[D. Lee,
G. Botseas,andJ. S. Papadakis,J. Acoust.Soc.Am. 70, 795-800 {1981}].
It is foundthat the full complexityof the propagationsituationis well
handledbyboththeacousticmodels,andthattheshadowing
isdueto the
cutoffofsteeppropagation
paths(bottom-bounce
paths)bytheseamount,
leavingmainlywaterbornepathsto propagatebeyondthe mount.For
theselatterpathsthe surfacc-decoupling
lossessentially
determines
the
frequencydependence
of the measuredloss.
9:21
VV5. A range reflection parabolic equation. Frederick D. Tappert
(University of Miami, Miami, FL 33149) and Ding Lee (Naval
Underwater SystemsCenter, New London, CT 06320}
Societyof America
S95
Application
of the standardparabolic
waveequationto solvereal
problems
requires
a cleverselection
of thereference
wavenumber
ko.An
extended
parabolic
equation,
earlierdeveloped
[F. D. Tappert,TheParabolicApproximation
Method {Springer-Verlag,
Berlin, 1977},Lecture
Notesin Physics,Vol. 70, pp. 224-287], is re-introduced.
This parabolic
waveequation
hasrangerefraction
capability
andis totallyko-indepen-
However, we choose to solve our three-dimensionalPE by the same
Crank-Nicolsonschemeasusedto solvethe two-dimensionalPE. Using
thisimplicitfinite-difference
schemein conjunction
with anefficienthighperformancepreconditioning
technique,developedat Yale, can produce
an accuratenumericalsolution.[Work supportedjointly by ONR and
NUSC.]
dent.The existingImplicitFinite-Difference
(IFD} modelwasappliedto
testtherangerefraction
parabolic
equation.
Results
compare
favorably
with knownsolutions
for weaklyrangedependent
environments,
butyield
significantcorrectionsfor propagationthroughstrongoceanicfronts.
[Worksupported
by NUSC.]
9:25
W6. HYPER: A hybrid parabolic equation-ray model for highfrequencyunderwatersoundpropagation.Frederick Tappert(University
of Miami/RSMAS, Miami, FL 33149)
Theparabolic
equation
(PE)propagation
modelcontains
all diffraction effects,PE appliesto fully range-dependent
environments,
and PE
hasno upperlimit of validityin frequency.
However,simpleoperation
countestimates
showthat PE executiontimesincreaseproportionalto at
leastthesquare
of frequency,
andthusPE becomes
impractical
to runon
minicomputers
at highfrequencies
{above
about500Hz).Theequations
of
geometrical
acoustics
can be solvedin fully rangedependentenviron-
9'.37
VV9. Applicationof the Yale sparsematrix techniqueto the threedimensionalparabolic wave equation. Ding Lee INaval Underwater
SystemsCenter, New London, CT 06320), Martin H. Schultz (Yale
University,New Haven,CT 06520},and KennethR. Jackson{University
of Toronto,Toronto,Ontario,CanadaM5S IA?}
The Yale Universitysparsematrixtechniqueisan efficientmethodfor
solvinglargesparsesystems
of linearequations
suchasthosethatariseat
eachstepin thenumericalintegration
ofthestiffsystem
ofordinarydifferentialequations
resulting
fromtheapplication
of themethodof linesto
the three-dimensional
parabolicwaveequation.The theorybehindthe
Yale sparsetechniqueand the advantageof usingit for thisproblemare
discussed.
The solutionof a three-dimensional
oceaneddypropagation
problemispresented
asanexample.[Worksupported
jointlybyONR and
NUSC.]
mentswith executiontimesindependent
of frequency,but amplitudesand
phasesarenot reliablebecause
theseequationsdo not containdiffraction
effects.The HYPER (HybridPE-Ray)modelusesonly theray tracepor-
tionof geometrical
acoustics
to locatetheimportantpropagation
paths.
Then HYPER solvesa modifiedparabolicequationin a small region
(decreasing
with increasingfrequency}
nearthe ray pathsand computes
amplitudesand phases.Theoreticalcalcuations
showthat HYPER proridesuniformlyvaliddiffractlyesolutions
in fully rangedependent
environmentswith executiontimesnearlyindependent
of frequency.Thus
HYPER shouldbe practicalto run on minicomputers
at very high frequencies.
9:41
WlO.
Time inversion of acoustic signals with weak dispersion.
L. B. Felsen {Departmentof Electrical Engineeringand Computer
Science,Polytechnic
InstituteofNew York, Route110,Farmingdale,NY
11735)and E. Heyman(Departmentof ElectricalEngineering,
Tel-Arty
University,Tel-Arty 69978, Israel}
Acousticpropagationin a one-dimensional
randominhomogeneous
mediumis considered.
Exactsolutionsof the Dysonequationfor the co-
Wavepropagation
in a verticallyinhomogeneous
oceanexhibitseffective dispersion
althoughthemediumitselfis nondispersive.
Wavedispersion is weak at sufficientlyhigh frequencies.
The resultinglocal plane
wavespectralrepp•entationof a source-excited
soundfieldmay thenbe
invertedexactly to yield the impulsiveresponse.Alternative inversion
techniquesare the Cagniard-DeHonpand the more generalChapman
procedures.Both have limitations which are overcomeby an analytic
functionapproach,
fromwhicheithera generalized
Cagniard-DeHoop
or
the Chapmanformulationsare derivedsystematically
by manipulations
in thecomplexspectralplane.The threemethodsarecomparedandillustrated on caustic-formingmultiple reflectedray fieldsand on refraction
herent field are examined to determine constraints on the correlation
arrivals.
9:29
VV7. Propagationin a one-dimensionalrandom medium. Suzanne
T. McDaniel (AppliedResearchLaboratory,The Pennsylvania
State
University,UniversityPark, PA 16802)
functionof therandominhomogeneities
to insurefiniteresults.The long
rangebehavior
of thecoherent
fieldispredicted,
yieldingan attenuation
dueto scattering
and a modification
of the real part of the propagation
constant.
Approximate
solutions
forthecoherent
fieldarethenappliedto
determinethe incoherentfield. In contrastto resultsobtainedusinga
straightforward
perturbation
approach,thepredictedincoherent
fieldis,
in thiscase,finitein the absence
of attenuation.{Researchsupportedby
ONR.]
9:33
VVS. A wide-anglethree-dimensional
parabolicwaveequation.Ding Lee
(NavalUnderwaterSystems
Center),William L. Siegmann(Rensselaer
PolytechnicInst., Troy NY 12181), and Oregory A. Kriegsmann
(NorthwesternUniversity,Evanston,IL 60201)
Onestraightforward
extension
of thestandardtwo-dimensional
PE to
the three-dimensional
casecanbeaccomplished
by retainingthe angular
derivativeterm. However,a numberof basicquestionsariseconcerning
the derivationof this equationand its domainof validity. We discuss
answers
tothesebasicquestions.
Ouranswers
leadtoformulation
ofa new
wideangie,three-dimensional
partialdifferentialequationwhichmodels
soundpropagation
in the three-dimensional
ocean.This formulationis
achievedby operatortheory.Insteadof straightforward,small-angle
threc-dimensional
PE, the new wide-angleequationis (in principleDa
third-orderpartialdifferentialequation.This third-orderPDE is in an
implicitform, makingits solutionby somenumericalmethodsdifficult.
S96
J. Acoust.Sec.Am.Suppl.1, VoL74, Fall 1983
9:45
VVII.
Intrinsic modes in a wedge-shapedocean. J. M. Arnold
{University of Nottingham, Nottingham, EnglandI and L. B. Felsen
{Department of Electrical Engineering and Computer Science,
PolytechnicInstituteof New York, Route 110,Farmingdale,NY 11735}
By a recentlydevelopedtheoryappliedto propagationin a wedgeshapedoceanwith penetrablebottom[J. M. Arnold and L. B. Felsen,J.
Acoust.Sec.Am. 73 1105119831],
spectralintegralshavebeenderived
that yield,by asymptoticevaluationto lowestorderin the smallbottom
slope,theadiabatic
modes,
wherethesearevalid,butwhichalsodescribe
the previouslyinaceessible
transitionthroughcutoffin upslopepropagation. Thesespectralintegralshavenow beenreexaminedby performing
the evaluationto the next asymptoticorder. It is found that the result
generatedin this manneragrees,to the sameorder of accuracy,with a
directcoupledmodesolutionof theboundaryvalueproblemwhereinthe
adiabaticmodesappearasthe basicelements.Thus, the modeformsgeneratedby thespectralintegralincludelowestordercouplingbetweenadiabaticmodes.We refer to theseuncoupled"more adaptable"modes,which
likewiseapplyin thetransitionthroughcutoff,asintrinsicmodesin order
to distinguishthem from the "lessadaptable"adiabaticmodes.Some
consideration
isgivento still furthergeneralization
of theintrinsicmodes
to furnishuncoupledmodesin a morestronglyrangedependentenvironment.[Work supportedby ONR AcousticsBranch.]
Societyof America
SiN}
9:49
VV12. Acoustic normal modes propagationthrough ocean eddies.
Y. Desaubies,C. S, Chiu, and J. Miller (Departmentof Ocean
Engineering,WoodsHole Oceanographic
Institute,WoodsHole, MA
02543}
Uniformlyvalid asymptoticsolutionsare derivedfor normal mode
propagation
ina slowlyvaryingoceanwaveguide.
Thelimitsofvalidityof
various
approximations
asa function
ofmodenumber,
acoustic
frequency,andrangearediscussed
for realisticoceanenvironments.
In particular, the first correctionto the adiabaticequationsis calculated,which
provides
an approximate
solutionto the coupledmodeequations.
The
The caustics
of shortwavelength
wavepropagation
maybeclassified
accordingto catastrophe
theory.After establishing
thisconnection
the
behavior
ofthetime-dependent
wavefieldduetoanimpulsive
wavein the
vicinityofthegeneral
cuspold
catastrophe
isexamined.
Numericalresults
arepresented
forthefold,cusp,andswallowtail
catastrophes
whichshow
thesmoothvariationof the time-dependent
acousticfieldasthecontrol
parameters
arevaried.Theseresults
vividlydemonstrate
thephenomenon
ofrayfocusing,
showing
thenumberofrayswhichconverge
at eachcatas-
trophe,theresulting
phaseshiftstheyundergo
aswellastheirdecayin
shadow
regions.
Analyticalresults
aregivenwhichdescribe
themostimportantproperties
of thetime-dependent
acoustic
fieldon andat large
distances
awayfromeachof thecuspold
catastrophes.
implicationsfor numericalcalculationof normal modesare discussed.
10:09
9:53
VV13. The uniform WKB normal mode code: Applications to cw nnd
broadbandpropagation.R. F. Henrick (The JohnsHopkins University,
AppliedPhysicsLaboratory,JohnsHopkinsRoad,Laurel,MD 20707),J.
R. Brannan, D. B. Warner, and G. P. Forney (Departmentof
MathematicalScience,ClemsonUniversity,Clemson,SC 296311
The increased
interestin the modelingof underwateracousticsignals
whichare time limitedor possess
significant
frequencybandwidthhas
resultedin a varietyof broadbandpropagationcodes.However,these
codesare typicallylimitedin utility by extremelylongrun timesor in
accuracyby simplifyingassumptions.
The approachtakenhereit to use
uniformasymptoticapproximations
to the normalmodesof the sound
channeltoobtainbothaccuracy
andnumericalefficiency.
Theseapproximationsare basedon the WKB approachbut includecorrectionsfor
modesthat turn near boundariesand near mode turning points.This
uniform WKB model approachleadsto further efficiencies
in multiple
frequencybroadbandor pulsedpropagation.The accuracyof this approachandtheimportanceof thesecorrections
isfirstillustratedfor a cw
signal.Subsequent
examplesshow accurateresultsfor both broadband
and time pulsedsignals.Run time comparisons
showreductionsof two
ordersof magnitudein comparisonto conventionalbroadbandcodes.
VV17. Impulsivewave propagationand the elliptic, hyperbolic,and
parabolic umbilic caustics.Michael G. Brown •Division of Ocean
Engineering,RosenstielSchoolof Marine and AtmosphericScience,
Universityof Miami, Miami, FL 33149-1098)
Thetime-dependent
wavefieldduetoanimpulsive
wavein thevicinity of theelliptic,hyperbolic,
andparabolic
umbiliccaustics
isexamined.
Numericalresultsare presented
whichshowthe smoothvariationof the
time-dependent
acoustic
fieldin thevicinityof all threecaustics.
Analyticalresultsaregivenwhichdescribe
themostimportantproperties
of these
wavefields.Thetime-dependent
structures
of thesewavefieldsarequalitativelydifferentthan thoseassociated
with the cuspoldcaustics.
The
reasonfor thedifference
stemsfromthedifference
in phaseshiftswhich
individual
rayarrivalsundergo
asa resultoftouching
oneofthetwotypes
of caustic(cuspoldversusumbilic).
10:13
VV18. Shallow-oceanfronts:Effectson array performanceand acoustic
prediction of properties. T. H. Rousseau,
• M. J. Jacobson, and
W. L. Siegmann
(Rensselaer
Polytechnic
Institute,Troy, NY 12181)
A parametric model is introducedwhich includesthe location and
9:57
VVI4. On normalmodeattenuation.Gary H. Brooke(DefenceResearch
EstablishmentPacific,Victoria, BC, CanadaV0S 1B0)
The attenuationof normal modesdue to viscous-typeabsorption
lossesin a layeredbottomis examined.A standardperturbational
approachis usedto relatethe modalattenuationcoefficientto the energy
storedand the powerflowin eachmodeand to the intrinsicviscouslossin
eachlayer.As such,themethodisstraightforwardly
appliedto geoacoustic waveguide
configurations
involvingsolidlayers.Numericalexamples
are presentedwhich illustratethe relationshipbetweennormal modeattenuationandenergyconcentration
in the variouslayers.
orientationof a shallow-water
front,aswellasjumpsin soundspeedand
currentacrossit. In orderto investigatefrontaleffectson array performance,a cwpointsourceanda horizontallineararrayof pointreceivers
is
considered.
Theerrorin predicted
source
direction,resulting
froma frontally induceddisplacement
in peakarray output,is examined.Also, it is
shownhow the peakleveland shapeof the main-lobearrayoutputare
degradedsignificantly
by the presence
of a front as a pointsourceap-
proaches
thenearfield.
Finally,twosources
andtworeceivers
areplaced
at known locations on either side of the front. It is shown how travel times
overdirectraysbetween
source-receiver
pairsareaffected
by thevarious
frontalparameters.
A corresponding
system
of equations
maybeinverted
so that travel-timechangescan be usedto predictestimatesfor frontal
geometry and sound-speedand current discontinuitiesacrossa front.
[Worksupported
byONR.] • Present
address:
UnionCollege,
Schenectady, NY 12308.
10:01
10:17
VV15. Abstract withdrawn.
VV19.
Long-range Pacific
acoustic multipath
identification.
John NorthropandRichardC. ShockIcy(NavalOceanSystems
Center,
San Diego, CA 92152I
Acousticsignalsfrom three long-range(500-700 km) transmission
pathsin the NortheastPacificwereexaminedfor multipathstructure.
Soundpropagationalongeachpath encounteredboth differentsoundspeedprovinces
anduniquebathymetrywhich,togetherwith the range
differences,causedcharacteristicpulsearrival patternsat each hydrophonesite.The receivers
wereall on a slopingbottomat depthsbetween
1200and 1400m andthe sourcedepthwasat 450 m in deepwater.Ray-
patharrivalsweremodeledusingIMPULSE,
a newray-theoretical
impulse
10:05
VVI6. Impulsive wave propagationand the cuspoldcaustics.Michael
G. Brown IDivision of Ocean Engineering,RosenstielSchoolof Marine
and AtmosphericScience,Universityof Miami, Miami, FL 33149-1098)
S97
d.Acoust.Soc.Am.Suppl.1, Vol.74, Fall1983
responsecodewritten by oneof us(RCS).This codeusespiecewisecontinuouscubic polynomialsto fit the sound-speed
profile and bathymetric
profile,and Ruuge-Kutta methodsto solvethe ray equationof motion.It
allowsarbitraryray densityin launchangle,and identifieseigenraysby
searchingfor rays whosedepthsbracket the receiverand which were
Societyof America
S97
adjacent
atthesource.
Usingthisprocedure,
wewereabletoidentify
most
acoustics
in the high-frequeacy
limit. The sourcedepthdetermines
the
of the majorpulsearrivalsobservedat eachof the recordingsites.
initial valuesfor the effectivesoundvelocityprofileand itsderivativewith
respectto depth.
10:29
10-.21
VV22. Measurements of transmission fluctuations in the Florida Straits.
VV20. Estimationof mesoscalesoundspeedperturbationsvia underwater
acoustic tomography. Ching-SangChiu and Yves Desaubies
(Department of Ocean Engineering,Woods Hole Oceanographic
Institution,WoodsHole, MA 02543)
The inverseproblemin oceanacoustictomography
corresponds
to the
estimationof the parameters
characterizing
thesoundspeedfluctuations
due to mesoscale eddies from the acoustic travel time data. A determinis-
tic modelof the soundspeedpexturbation
fieldtScis presented.
In the
model&: is assumedto be generated
by a smallnumberof Rossbywaves
andaccounts
for mostof thedatavariance.Thus,6cisdeterminedbyonly
a few waveparameters,
that is the amplitudes,wavenumbers
and phases
of the waves.The forwardproblemof travel time and ray path fluctuationsdue to •c and currentsis studiedby computersimulationsand
resultsare presented.An iterativemethodto estimatethe waveparametersof the nonlinearsystemof the inverseproblemis discussed
andpreliminary resultsin applying it to the data of the 1981 experimentare
presented.
10:25
OceanSystems
Center,Code7222,SanDiego,CA 92152}
Varioussampleeffqctioe
soundvelocityprofiles[E. R. Floyd, J.
Acoust.Soc.Am. 60, 801-809 (1976}]for representative
hypothetical
soundvelocityprofilesare generatedexactlyalbeit numerically.These
various
effectJoe
sound
velocity
profiles
exhibit
theirdependence
uponthe
constantof themotion(i.e.,thevertexvelocity},sourcefrequency,andthe
sourcedepth.Evenfor isotropicsoundvelocityprofiles,theexistsnee
of a
finite velocitygradientis sufficientto inducea constant-of-the-motion
dependence
in theeffectJoe
soundvelocityprofile.Any dependence
upon
theconstantof themotionrepresents
ananisotropic
effectioe
soundvelocity profile.All effectJoe
soundvelocityprofilesexhibitthe vertexpoint
receding
to infinitedepth(flat-earthassumption}
whichmanifests
thenodal characteristic
of the singularityof the nonlineardifferentialequation
thatspecifies
theeffectioe
soundvelocityprofile.The behaviorof thefrequencydependence
manifestsan asymptoticapproachto geometric
MORNING,
Experimentsare underwayon the acousticremotesensingof transport and averagetemperatureof the Florida current.The experiments
employa reciprocaltransmission
geometryto separate
transportandtemperatureeffects.Preliminaryresultsgiveinformationontheacousticvariability and coherenceof transmissionbetweena fixed bottom mounted
sourceand mooredreceiversat rangesof 8, 16, and 24 kin. Statisticsof
fluctuations
for broadbandpulse-liketransmissions
arepresented.
Environmentaldata are usedas inputsto ray and P.E. modelsto intepretre-
sults.[Worksupported
by ONR andNOAA.]
10:33
VV23. Acousticpropegafionof AFAR: Theory and experiment.Stephen
A. Reynolds,StanleyM. Flatt6 ILs SoilsInstitute, P.O. Box 1434, La
Jolla, CA 92038}, Roger Dashen (Institute for Advanced Studies,
Princeton,NJ}, Barry Buehler, and Pat MaciejewskiINUSC, New
London,CT}
We examine the statistics of the second and fourth moments of the
W21. Sampleetacot/resoundvelocityprofiles.Edward R. Floyd •Navai
FRIDAY
H. A. DeFerrari, D. Ko, and P. Gruber (Division of Ocean
Engineering,RosenstielSchoolof Marine and AtmosphericScience,
Universityof Miami, Miami, FL 33149-1098}
11 NOVEMBER
acousticfield measuredat the AzoresFixed AcousticRange(AFAR}.
The resultsarefrom pulsetransmissions
during1973and 1975of several
acousticfrequencies
overtwo volume-refracted
pathsin differentscattering regimes:a 2.9-kingeometricand a 35-kmpartiallysaturatedpath.The
Garrett-Munk internalwavemodelis usedto specifytheindex-of-refraction fluctuations;modelparametersare entirely determinedby environmentalobservations.
Predictionsbasedupon the path-integralformulation [SoundTransmission
througha FluctuatingOcean,editedby S. M.
Flatt6•1979}]comparefavorablywiththeacoustic
observations.
Thearrival timeIphase}
fluctuations
arepredominantly
geometric.Howeverat 35
kin, microrayeffectsin thephasecanbeidentified.The 2.9-kinamplitude
behaviorappearsgeometricalthoughcomparisonis hamperedby a short
time series.At 35 kin, log-amplitudeand intensityfluctuationsare due
largelyto microrayeffects;the powerspectraof log-amplitudeare describedby a singleparametermodelwheretheparameterisrelatedto the
intensitydecorrelationcausedby the microrays.[Work supportedby
ONR, Code 425UA.]
CHAMBER
1983
ROOM, 8:30 TO 11:50 A.M.
SessionWW. Engineering AcousticsVI: Transducers
Daniel Queen, Chairman
Daniel QueenAssociates,5524 w. Gladys•4venue,Chicago,Illinois 60644
Chairman's lntroduetion---8:30
Contributed
Papers
8:35
WWI. Reciprocitycalibrationof transducersin a plane-waveresonator.
Charles L. Burmasterand S. L. Garrett (PhysicsDepartment, Code
61Gx, Naval Postgraduate
S98
J. Acoust.Sec.Am.Suppl.1, Vol.74, Fall1983
In anarticleby Rudnick[J.Acoust.Soc.Am. 63, 1923(I 978)]a procedure for the "reciprocitycalibrationof transducersin unconventional
geometries"was described.The theory presentedby Rudnick hasbeen
testedexperimentallyand extendedto include the effectsof the complianceof nonidealtransducers
on the quality factorof the plane-wave
Societyof America
$98
resonances.
A computer
controlled
system
withautomated
switching
was
designed
andbuilttoacquireandprocess
theresonance
datarequiredfor
9:35
WW5. Noncontacting,acousticvibration sensor.W. G. Richarz, P.
the reciprocitycalculations.
Two reversibletransducers
and one microphoneweremountedin thecylindricalresonant
cavityto allowa six-way
A. Sullivan,andTao Ma IInstitutefor Aerospace
Studies,Universityof
roundrobinself-consistency
checkof the experimental
precision.
The
absolute
accuracyof thesensitivity
thusobtainedis thencomparedwith
the resultsof a conventional
reciprocitytechnique[ANSI S1.10-1966
(R1976)]and/or manufacturers
specifications.
[Work supportedby
ONR.]
The measurement
of vibrationof lightweightstructures
requiresthat
anyloadingduetoa vibrationtransducer
beeliminated.
A noncontacting
displacement
sensor
hasbeendeveloped
toassistin theunderstanding
of
Toronto,4925DufferinStreet,Downsview,
Ontario,M3H 5T6•Canada
I
the dynamicsof lightweightair cushionvehicleskirts.A remotevibration
sensoris requiredto monitorthe unsteadymotionof thesemembranelike
structures.
A low-costacoustic
displacement
sensorhasbeendeveloped.
A piezoelectric
driveraimedat thevibratingsurface;thereflectedbeamis
8:50
detected by a microphone. The motion of the reflector introduces a
WW2. Computerizedmeasurementand analyslsof sonar transducer
equivalent circuit parameters. L. J. $kowronck, D. V. Contc, O.
B. Wilson, and S. L. Garrett (PhysicsDepartment,Code 61Gx, Naval
Postgraduate
Measurements
of the electricaland mechanicalpropertiesof transdueersare of importancein both their designand servicein their evaluation. Followingthe formalismof Hunt [Electroacoustics
(AcousticalSo-
cietyof America,New York, 1982}],theseproperties
canbe determined
by accuratemeasurements
of compleximpedanceor admittancemade
throughoutthefrequencyrangeof interest.Manualcollectionof the necessarydata is tediousand particularlyerror pronefor transducers
with
sharpresonances.
A computer-controlled
system,usingan H-P 85, will
be describedwhichautomaticallyacquiresand plotsthe electricaldata
andcalculates
the equivalentelectricalcircuitparameters,
couplingconstants,andefficiencies.
Sampledatawill bepresented
for piezoelectric
and
magnetostrictive
transducers.
[Work supportedby ONR and the NPS
FoundationResearchProgram.]
"Dopplershift"whichis detectedby a lock-inamplifierwhoseinternal
electronicstransformthis informationinto a signalproportionalto displacement.The resolutionof thesystemisgovernedby thewavelength
of
theincidentbeam,highfrequencies
(fo < 20 kHzI affordingpeakto peak
valuesof the orderof I 0 ram;for largerexcursions
lowerfrequencies
are
used.The systemis sensitive
to changes
in air temperature,
thespeedof
soundfiguringin the Dopplerfactor. In additionthe directivityof the
transducerplaysa role,the resultantamplitudemodulatedsignalaffording additionalsensitivity.The displacementtransduceris readily configuredfromstandardcomponents
foundin manylaboratories
andis ideal
for the detectionof low-frequencydisplacements
(f< 100 Hz). [Work
supportedby the Natural Scienceand EngineeringResearchCounciland
TransportCanada.]
9:50
WW6. Finite elementmethodappliedto characterizationof piezoelectric
ceramics.B. Tocquet,D. Boucher(GERDSM,83140LeBrusc,France),
J. N. Decarpigny,J. C. Debus,and P. Tierce {ISEN, 3, rue F. Ba•s,
59046 Lille Cedex, France}
9:05
WW3.
A wide bandwidth constant beamwidth end-fire array.
Beatriz Ugrinovichand Elmer L. Hixson (Departmentof Electrical
Engineering,
The Universityof Texasat Austin,Austin,TX 78712}
An end-firearray usingfive electretmicrophonesand "bucket-brigade"analogdelaylinesareusedto producethedesiredbeamwidthat 353
Hz. A half-scalemodelis implemented
by addingtwo moremicrophones
and usingthreeredundantmicrophones
to givethe samebeamwidthat
707 Hz. High-passand low-passfiltersare usedin the respectivearray
outputswhich are summedto producea constantbeamwidthover the
octave.Thedesignprocess
isrepeatedto producea constantbeamwidth3octavearray. Predictedand measuredcharacteristics
will be presented.
Finiteelementcomputation
of piezoelectric
transducers
requiresthe
knowledge
of elastic,piezoelectric,
anddielectriccoefficients
ofceramics.
Theseconstants
are generallynot availablefrom the manufacturer,and
even,variationsup to 20% canbeexpectedin theworsecases.The classical experimentalmethod,proposedby Mason, is basedon admittance
measurements
and a completedeterminationof all the materialspropertiesrequiresfiveresonatorgeometries.
An interestingmethod,basedon
anadjustment
offirstmodesof ceramicringswitha finiteelementcode,is
described.
It hasthreeadvantages
overthe Masonmethod.First, it does
not requireparticularresonatorgeometries;
second,the experimental
methodis summedup on a simpleimpedancemeasurement
of the whole
ceramics;and third, the adjustmentis unaffected
by localnonhomogeneity of materials.In this paper,the whole methodis developed.Then
experimental
and numericalresultsarecomparedfor severalceramics.
10:05
9:20
WW4. An improved fiber optic lever transducer. Frank W. Cuomo
(Departmentof Physics,Universityof RhodeIsland,Kingston,R102881
and.NUSC, Newport,RI 02841)
The conceptof a bifurcatedfiberoptictransducerhasbeendescribed
and appliedto the measurement
of pressureand temperature.This approachhas been usedto designlow-frequencyhydrophones
[F. W.
Cuomo,J. Acoust.Soc.Am. 73, 1848-1857(1983)].Thesensitivity
of this
deviceis proportionalto the total numberof adjacenttransmit/receive
fiber pairsusedin the bundle.For goodsensitivitythe transmit/receive
fiber distribution
must be maximized
while the total number of fibers
must be large.This paperdiscusses
an improvedbifurcatedfiber optic
WW7, Computationof a piezoelectricdeep-submergence
transducerby
three-dimensionalfinite element method. B. Tocquet, D. Boucher
(GERDSM, 83140Le Brusc,France),J. C. Debus,andP. Tierce(ISEN,
3, rue F. Bai•s,59046 Lille Cedex,France}
The advantagesof deep-submergence
transducerare well known althoughpracticalsolutionsto solvehigh-pressure
problemsare veryfew.
In this paper,sucha systemis studied.The radiatingareaof the transduceris a ring, on the innerfaceof whichseverallengthexpandermotors
arefixedin a starshape.Everymotoriscomposed
of a ceramicstackanda
tail mass. No mechanical connection is able to transmit exterior static or
transducer
comprising
onetransmit
fiberandtworeceive
fibers,each
dynamicforcesto themotors.This transducerhasmainlytwo resonance
frequencies
whichcanbeused:oneis lower than the resonance
frequency
receivefiberhavinga differentcorediameter.The threefibersare separatedat oneendandcombinedat the distalendin the vicinityof a miniature
of the ring alone,the other is slightlyhigherthan the motor resonance.To
analyzethis transducer,a finiteelementcomputercode(ATILA)hasbeen
reflectivesurfacesensitiveto axial motion causedby minute pressure
changessuchthat any displacement
of the reflectorfrom equilibriumwill
developed.In water,the vicinityof the transduceris modelizedwith 3D
fluid elementsup to an exteriorsurface,the boundaryreflectionbeing
dampedthroughuseof a suitableradiationimpedance.So, in air eigenmodes,transmittingvoltageresponse,
directivitypatterns,and electrical
impedancecan be computed.In this paper,the experimentalresultsobtainedwith a deep-submergence
transducerare comparedwith the theo-
increase or decrease the illuminated
areas of the two receive fibers and will
generatea processed
outputsignalproportionalto this motion.The major
relevantimprovementsover prior designsinclude a probe of minimal
dimensions,
a greatlyimprovedsensitivity,and an outputindependentof
variationsat theinput.
-•99
retical ones.
S99
11:05
10:20
WWS. Responseof an edge-supported,
annular,electretearphone.llenc
WW11. Four accelerometerstructural vibration intensity measurements
J. Busch-Vishniac
(Departmentof MechanicalEngineering,
University
on beams.G. P. Carroll and J. A. Clark (MechanicalEngineering
Department,CatholicUniversityof America, Washington,DC 20064)
of Texas at Austin, Austin, TX 78712}
In manyelectre•transducers,
thediaphragmisheldabovea metalized
backplateby circularridgesmachinedinto the backplate.Suchtransducersmay be thoughtof as a seriesof annularelectrcttransducer
segments,eachof whichhasanedge-supported
diaphragm.In thetreatment
presented
herethebehaviorof an edge-supported,
annular,eleetretearphoneis studiedanalyticallyin a two-stepprocedure.First, the static
diaphragmdeflectionis determined.A stabilitycriterionis developed
which physicallycorresponds
to a limit in the maximumstablestatic
deflection.Second,thediaphragmdynamicmotionis determinedand the
resulting
soundpressure
in theearcanalcalculated.
Usingthismethodthe
linearresponse
anddistortionresponse
maybeseparately
analyzed.Both
tend to increasein levelas the transducerapproachesthe point of static
instability.Experimentalresultsagreewell with the predictionsof the
theory.[Workdonein partat BellLaboratories,
Murray Hill, NJ 07974.]
10:35
WW9. Characteristicsof a particle velocity hydrophonebasedon hot.
film anemometry.Pieter S. Dubbeiday (Naval ResearchLaboratory,
Underwater Sound ReferenceDetachment, P.O. Box 8337, Orlando, FL
32856)
It is desirableto measureparticle velocityin an acousticfield in addi-
tion to pressure.The heat transferinherentin hot-filmanemometryis
mostlya functionof particlemotion.The relationbetweenparticlevelocity and voltageoutputin a harmonichydroacoustic
fieldappearsdifferent
from that in a nonperiodicflow (King's law). For horizontalmotion,the
outputisproportionalto the velocitysquared,with a frequencytwicethat
of theacousticfield.If themotionisvertical,it modulatesthesteadyfreeconvection flow off the film, and a linear relation ensueswith the same
Two accelerometer
measurement
methodsdo not accuratelymeasure
structuralvibrationintensitynearboundaries
for the lowestbeammodes
because
theshearandmoment-related
intensitycomponents
arenolonger
equal.It wasshownby theauthors[J.Acoust.Soc.Am. Suppl.I 73, S33
•i 983)]that thisisa seriouslimitationsinceit isoftenby thelowestmodes
that poweris transmittedthroughcomplexstructures.In thistalk, a four
aceelerometer
spectralaveragingmeasurement
approachoriginallyproposedby Verheij[J. SoundVib. 70, 133-1380980)1will be reviewed.A
method for convenientlyimplementingthis approachwith currently
availabletwo-channel
FFT signalprocessors
will bedescribed
andresults
froman experimental
studyof a beamexcitedtransversely
at oneendand
dampedat theotherendwill be presented.
The experimentalresultswill
also be comparedwith theoreticalsolutionsand with resultsobtained
independently
by holographicinterferometry.[Researchsupportedby
David Taylor Naval ShipResearchand DevelopmentCenter,Washington, DC.]
11:20
WW12. Relationshipbetweenreflectionand transmissioncoefficientsof
a linearpassive
junction.L.J. MagaandG. Maidanik(DavidW. Taylor
Naval ShipResearch
andDevelopment
Center,Bethesda,
MD 20084)
The impulseresponsefunctionof coupled,one-dimensional
dynamic
systemscan be describedin termsof the wavenumbersof the constituent
dynamic systemstogether with the reflectionand transmissioncoefficientsat junctionswhichcouplethe dynamicsystems.The junctionsalso
definethe terminalpositionsof the dynamicsystems.Constructions
of
somesimplebut usefuljunctionsare considered
and the corresponding
reflectionand transmission
coefficients
that can be assigned
to thejunc-
frequency
asthefield.Experimental
resultswereobtainedby meansof a
horizontallydrivenopentroughfor the firstcaseand a verticalinertial
calibratorfor the second.It wasattemptedto correlatethe output,expressedas a Nusseltnumberamplitude,to the relevantdimensionless
numbers:particledisplacement
relativeto sensordiameter,Stokes,Four-
tions are derived. The characteristics of these coefficients and their rela-
ier, andGrashofnumbers.Preliminaryexperiments
showthat an imposed
biasflow improvesthe sensitivityand directionalresponse
of the sensor
[Work supported
by Officeof Naval Research.]
WW13. An acoustic microscopedesignedfor observingthe vocal fold
tissue.Yojiro Inoue,Yuki Kakita, and Minoru Hirano IDepartmentof
10:50
WWI0. An automatedadmittancemeasuringsystemfor electroacoustic
transducers.
ClementinaM. Ruggicroand T. A. Hcnriqucz(Naval
ResearchLaboratory,UnderwaterSound ReferenceDetachment,
Orlando, FL 32856}
A fullyautomated
method
ofobtaining
admittance
loops
ofpiezoelectric transducers
hasbeendesigned
to beutilizedin conjunction
with the
H-P 4192Aimpedance
analyzer.Thealgorithmdetermines
thefrequenciesat maximumand minimumadmittances;the seriesand parallelreso-
nance
frequencies;
theresonance
andantiresonance
frequencies
aswellas
themechanical
qualityfactoroftheelement
undertest.Thecollected
data
areplottedin theformof admittance
loopswithevenlyspaced
points.
This programhasbeenimplemented
successfully
at the Underwater
tionshipwith eachotherare discussed.
11-.35
Otolaryngology.
Schoolof Medicine,Kurume University,Kurume 830,
Japan}
This paperdescribesour newly designedscanningacousticmicroscope(SAM). Our concernis to determinethe mechanical
properties
of
eachhistologicalcomponentof the vocal foldsin normaland varying
pathological
states.Generallyspeaking,the imagesobtainedby meansof
anacousticmicroscope
notonlypresentstructureoftheobjectto beinvestigatedbut also reflectits mechanicalproperties.Our presentSAM has
the followingfeatures.(I) The frequencyof ultrasonicwavesis variable
between100and 200 MHz, causingthe resolutionbetween5 and
(21Logarithmicandlinearconversion
of theimageintensityareavailable.
The imageconvertedby logarithmicfunctioncan covera wide rangeof
mechanicalproperties.131Tilting mechanismis installedto the sample
bedsoasto adjusttheangleof thespecimen.
(4)The imagesstoredin the
digital memorycanbedisplayedon an ordinary videosystem.The structureandfunctionof our newSAM systemwill bedemonstrated
together
SoundReference
Detachmentasa meansto rapidlyobtaintheadmittance
withsomepreliminarydataof voealfoldtissue.[Worksupported
in part
information of various loaded and unloaded underwater transducers and
by ScientificGrant :•:57870103 by the JapaneseMinistry of F_.,ducation,
transducer
elements.
[Worksponsored
byNAVSEA.]
Scienceand Culture.]
$100
106thMeeting:
Acouslical
SocietyofAmerica
Sl 00
FRIDAY MORNING,
11 NOVEMBER 1983
COUNCIL ROOM, 9:00 A.M. TO 12:05P.M.
SessionXX. ArchitecturalAcousticsVII andMusicalAcousticsVII: OrganTechnologyToday
David L. Klepper, Chairman
KlepperMarshallKingAssociates
Ltd., 96 HaarlemAvenue,WhitePlains,New York10603
Invited Papers
9:05
XX1. Comparingthe relativeadvantages
of pneumato-andelectroacoustic
sourcesfor organtoneradiationin
churches.
DanielW. Martin {BaldwinPiano& OrganCompany,Cincinnati,OH 45202}
The varietywhichexistswithinchurcharchitecturaldesign,in liturgicalformsof worship,in the relative
locationof churchorgansand the worshippets,
and evenin the structures
{or lack thereof)whichorgan
buildershaveprovidedin theimmediatevicinityof theorgantoneradiators,suggests
that thereis probably
morethanoneaesthetically
acceptable
meansfor radiatingorgantoneintoworshipspace.Yet someadherents
to thetraditionalmaintainthatthereis onlyoneacceptable
meansfor radiatingorgantone,i.e.,pneumatoacoustic.
Thisanalysis
assumes
(1)thatequivalent
roomacoustics
andtonesourcelocations
areprovidedfor
eitherpneumator-or electroacoustic
toneradiators;and {2}that electricalinputsignalsare providedto electroacoustic
toneradiatorswhichincludethetransient,spectralandmodulationcontributions
to thetonebythe
traditionalair streaminteractionwith a piperesonator.
What acoustical
advantages
anddisadvantages
remain
for the two differenttypesof toneradiationmeans?
9:35
XX2. How computerand electroacoustictechnologyare used to improve musical performancein church
electronicorgans.Duane A. Kuhn {ClassicalOrganDivision,BaldwinPiano& OrganCompany,Cincinnati,
OH 45202}
Recentadvances
in technology
enabletheelectronic
organto approximate
closelythemusicalresources
of
thepipeorganwhileincreasing
thecontrolandflexibilityof thoseresources.
To createa trueensemble
of organ
sounda patentedmultipleoctavegeneratortuningsystemprovidesmultiplefrequencysources
on a givennote
and variancein sourcesbetweendifferent octavesof the samechromatic note, all under masterclock control for
tuningstability.A tone radiationsystemconsisting
of an electroacoustic
pipe array with fifteenindividual
audiochannelsprovidestoneradiationcharacteristics
similarto thoseof a groupof air-blownfluepipes.The
useof a microprocessor
controlledcombinationactionincreases
instrumentreliabilitywhile reducingitscost.
New controlofferedto the organistby this noise-freecombinationactionincludespedalstop-to-manualdivisionregistration,visualidentificationof individualstopsin the crescendo
pedalsequence,
and a newtypeof
division cancel.
10:05
Presentations by Panel of Experts
Participants
Ronald F. Ellis
M.P. Moller, Inc., 403 N. Prospect
St., Hagerstown,
Maryland 21740
Jean-LouisCoignet,Tonal Director
Casavant
FreresLte., C. P. 38, St. Hyacinthe,Quebec,CanadaJ2S 7B2
Manuel J. Rosales
Rosales
OrganBuilders,
Inc., 160Glendale
Blvd.,LosAngeles,
California90026
Lawrence Phelps
AllenOrganCompany,
Macungie,Pennsylvania
18062
S101
Societyof America
Slfil
GARDEN ROOM, 8:30 TO 10:11A.M..
SessionYY. SpeechCommunication
VI: Effectsof Age on Productionand Perception
Patricia K. Kuhl, Chairman
Department
of Speech
andHearingScience.
University
of Washington,
Seattle,Washington
98195
Chairman's
Introduction--8:30
ContributedPapers
8'.35
YYI. The interactionof ageand responseconditionin the useof acoustic
cuesto voicingin final stops.C. Wardrip-Fruinand SharonPeach
(Departmentof Communicative
Disorders,CaliforniaStateUniversity,
LongBeach,CA 90840}
Thedevelopmental
useofvowelduration,finaltransition,
andvoicing
duringclosureascuesto voicingin finalstopconsonants
wasinvestigated,
usingsubjects
ages3 to 6 yearsandadult The stimuliwerealterationsof
eightstop-vowel-stop
words.Thepresentation
ofeachstimulus
itemwas
response
contingent.Therewasevidencethat theadultsresponded
more
to durationcuesthandid thechildren.The response
to spectralcueswas
moresimilarfor the threeagegroups.A comparisonof the response
of
theseadultswith response
of adultsin a previousstudysuggested
that
conditionof response
hada verysignificant
effecton thedirectionand/or
magnitudeof response
to specifictreatments.In theearlierstudythestimuli werepresented
at 750ms.The response
contingent
presentation
of the
stimuliin thisstudyseemedto resultin a verydifferentdecisionstrategy
on the part of the listeners.For example,adult subjects
judgedthe same
stimulusitem voiced(67%} at 750 msISI but voiceless
(62%) underthe
openintervalcondition.Listeners
gavemuchmoredefinitejudgments
underthe fixedintervalcondition,judgingmanystimuliambiguousin the
openintervalcondition.Implications
of thesefindingsfor thedesignand
theinterpretation
of speech
perception
studieswill bediscussed.
We investigated
whetherperceiveddifferences
in stimulusgoodness,
thatis, thedegreeto whicha stimuluswithina phoneme
categoryisconsideredto be a "goodinstance"of the category,predicteddifferential
responses
to thesestimulibyyounginfants.Two pointswerechosen
in an
F I/F2 coordinatevowelspace:onejudgedto bea "good"representative
of the/i/vowel category,the other a "poor" representative,
basedon
adult judgments.Then, variantsweresynthesized
by manipulatingthe
first two formantsin both distanceand directionfrom thesetwo points.
The resulting stimuli formed rings around the "good"
/i/and the "poor"/i/. Thirty-two6-month-oldinfantsweretestedin a
generalization
taskusinga visuallyreinforcedhead-turnprocedure.Half
of the infantswere testedusingthe "good"/i/and its variants,and half
usingthe"poor"/i/and itsvariants.
Results
showed
thatgeneralization
aroundthe "good"/i/was significantly
greaterthanaroundthe "poor"
/i/. Moreover,infant response
patternscorrelatedwith adult subjective
"goodness"
judgments.
9:11
YY4. Chidren'sidentificationof synthesized/r-w/continua for adult
andchildspeakers.
Ralph N. Ohde(Divisionof Hearingand Speech
Sciences,
VanderbiltUniversitySchoolof Medicine,Nashville,TN
37232}and DonaldJ. Shaft (Speech
and HearingSciences
Program,
Universityof Michigan,i i I I EastCatherineStreet,Ann Arbor,Ml
4810•)
8:47
In a recent
study[D. J.ShatfandP.J.Benson,
J.Acoust.
Soc.Am.71,
1008-1015
(1982}],
adultswerefoundto reliablyidentifysynthesized/rw/continua modeledafter adult and child vocal tractsafter one testing
YY2. Vowel normalizationby 3-year-oldchildren.Cathy A. Kubaska
and RichardN. Aslin (Departmentof Psychology,
IndianaUniversity,
Bloomington,IN 47405)
A two-alternativeforced-choiceprocedurewas usedto assessvowel
normalizationin 3-year-olds.The stimuliwereeditednaturaltokensof
[$e]and [n] producedby maleand femaleadultsand maleand female
children. Subjectswere visually reinforcedfor making an appropriate
pointingresponse
to oneof twotelevisions.
Initial trainingof thepointing
response
consisted
ofpairinganadultmale[ze]withonetelevision
andan
adultmale[A]withtheother.After reaching
an 90% correctcriterionon
thetrainingstimuli,subjects
werepresented
withblocksof eightstimuli
(four[•e]sandfour[n]s).The tokensof [n] by the femaleadultand the
childrenhad formantvalueswhich were closerin frequencyto the male
adult's[a:].For subjects
in the constantvowelgroup,all the [a:]swere
assigned
to onepointingresponse,
andall the[A]Sto theother.For subjectsin the mixedvowelgroup,two [a:]sand two [A]swereassignedto
eachpointingresponse.
The constantvowelgroupwasableto categorize
the vowelsappropriately,
despitethe differences
in absolutefrequency;
the mixed vowel groupperformednear chance.Theseresultsprovide
empiricalevidencefor vowelnormalizationin youngchildren.
session.
In order to determinethe stabilityof children'sperceptionof
thesecontinua,wetestedten6-7-year-oldsubjects
with normalarticulation andhearing.After passing
a criteriontestof at least90% correct
identifications
of theend-point
stimuli,eachchildlistened
to randomizations of the stimuli from the adult and child continua on two separate
days.Theresults
showed
nosignificant
difference
in category
boundaries
betweenthetwotestingsessions
for bothadultandchildcontinua.The
childrencorrectlyidentified
thethreestimuliat eachendof theadultand
child continuaat leastat the 95% leveland the categoryboundaryoccurredwithin the threemiddlestimuli.Thesefindingssuggest
that childrenareat leastasreliableasadultsin theirresponses
to variations
in the
F2 andF3 separation
of glideonsetfrequencies
evenwhentheabsolute
frequency
spectrum
ofstimulidifferbya factorof 1.5.[Worksupported
in
partby NINCDS.]
YYS. Acousticanalysisof cry of SIDS infants. John M. Heinz, Rachel
E. Stark, Rosemary Condino, Michele Hege (John F. Kennedy
Institute, 707 N. Broadway,Baltimore, MD 21205},and Alfred Stein-
schneider(NationalSIDS Institute,Atlanta,
Spontaneous
cry recordingswere obtainedfor approximately1700
8:59
infantsbornat theUniversity
ofMarylandHospitalovera 2•-yearperiod.
Wherepossible,
recordings
wereobtainedduringboththefirstandfourth
YY3. The internal structure of vowel categories in infancy: Effects of
weeks of life. Of those infants recorded, four later died of SIDS. For one,
stimulus"goodness."DiAnne L. GrieserandPatriciaK. Kuhl(WJ-10,
Child Developmentand Mental Retardation Center, University of
Washington,Seattle,WA 98195]
recordings
had beenobtainedduringboththe firstand fourthweeks,for
oneonly duringthe firstweek,for oneonly duringthe fourthweek,and
one only at two later times (9 and 14 weeks}.Thirty-secondsamplesof
S102
SI02
continuous,
fully developed
cry wereselected
for detailedanalysisfrom
eachof theSIDSinfantsandfrom50age-matched
controls.
Foreachcry
segment,measures
of duration,intensity,and fundamentalfrequency
wereobtained
andthepresence
or absence
ofa numberofcryfeatures
was
Acousticmeasurements
weremadeof the vowelsin spontaneously
producedwordswith knownreferents.Vowelsweregroupedby targetvowel
intohigh,front {/i/,/i/}, highback{/u/,/U/}, andlow (/o/,/a/). Evidencefor controlof vowelheightwasmeasured
in termsof firstformant
determined.Preliminaryanalysisof the data for the two SIDS infants
frequency
{F 1}cl•ange
overtime.Vowelbacking
wasmeasured
bychanges
insecond
formantfrequency
{F2}.AverageF 1andF 2 valuesandstandard
deviations
off i andF2 weredetertrained
fromharmonic
amplitudes
in
recordedin weekoneindicates
that a numberof the measures
grouptoward the tailsof the distributionsof thesemeasuresfor the controls,while
the data for the two SIDS infants recorded in week four do not show this
narrow-band
pattern.Implicationsof theseresultsand further findingswill be dis-
spectra.Over periodsof 5 months,the averageF i for high vowelsdecreasedwhile the averageF 1 for low vowelsincreased.Also, standard
deviations
for eachvowelgroupdecreased
with age.Controlof backing
wasseenprimarilyin increasingaverageF2 for front vowels.Standard
deviations
ofF2 forbothfrontandbackvowels
decr•
withage.[Work
supportedby grantsfrom the U.S. Departmentof Educationand from
NINCDS.]
cussed.
[Work supported
by NICHD and the AaronStrausand Liilie
StrausFoundation.]
9-.35
YY6. Chameteristies
of redopliented
babblingin 6-8-monthold infants.
RachelE. Stark and Jennifer Bond {JohnF. KennedyInstitute,707 N.
Broadway,Baltimore,MD 21205}
Reduplicatedbabblinghasbeendefinedas sequences
of identicalor
nearlyidenticalconsonant-vowel
syllables.
Thistypeof vocalizafion
appearsquite suddenlyin the premeaningfulutterancesof infantsat 6-9
monthsof age.In the presentstudy,reduplicated
babblingwasexamined
at the timeof its onsetin four infantsof 6-8 months.Computer-assisted
spectrographic
analysiswascarriedoutandamplitudeandpitchcontours
wereobtained.
Measurements
weremadeof syllableandsequence
duration.A speciallydesigned
transcription
systemwasalsoemployedin data
analysis.It wasfoundthat: (I} the timing patternsin reduplicatedbabblingdifferedin specific
waysfromthoseof earliervocalizations;
{2}that a
varietyof vocants[vowel-like)
soundswereproducedwithin a babbled
sequence;
{3}that mannerof articulationof consonantal
{closant)
sounds
variedbut placeof articulationdid not withina babbledsequence.
The
implications
of thesefindingsfor development
of speech
motorskillswill
bediscussed.
[Worksupported
by NICHD.]
9:47
YY7. Developmentof vowel nrticulntion in children. Corine Bickley
(Department of Electrical Engineering and Computer Science,
Massachusetts
Instituteof Technology,Cambridge,MA 02 I
The development
ofclfildren'sabilityto producehighversuslow vowels and front versusback vowelswas examinedin a longitudinalstudy.
FRIDAY
MORNING,
11 NOVEMBER
1983
discrete Fourier transforms and from local maxima in LPC
9:59
YYS. Acoustie ehnracteristits of stop consonantsin the speeeh of
ehiidren. Ralph N. Ohde [Division of Hearing and SpeechSciences,
VanderbiltUniversitySchoolof Medicine,Nashville,TN 37232}
Althoughtherearetheoretical
andpracticalreasons
for studyingthe
acoustic
correlates
ofspeech
sounds
inchildren,fewstudies
haveattemptedto examinecharacteristics
of theirproductibnwhichmaydirectlyvary
asa functionof placeof articulation.Research
onthespectralcharacteristics of stopsin adultshaveshownthat frequencyand amplitudeparametersvarysystematically
andsomewhatinvariantlywith placeof articulation.The purposeof this studywasto determinethe acousticcorrelates
of stopconsonants
in thespeech
of children.Sixchildrenbetween8 and9
yearsrecorded
fiverepetitions
eachof voiceless
aspirated/ph,
th,k•/and
voicedfo,d,g/stopsin combination
with thevowels/i,e,u,o,u/.Spectral
characteristics
of burstonsetsweredeterminedaccordingto LPC analyses.The findingsshowedthat place of articulationsystematically
influeneedthespectralcharacteristics
of stopconsonants.
Averageresonant
peaksfor labialsweregenerallybelow2 kHz, andfor alveolarstheywere
generallyabove2500 Hz. Spectralcharacteristics
of velars,on the other
hand,werehighlyinfluencedby vowelcontext;the resonantpeakswere
high precedinghigh front vowelsand low preceding
backvowels.The
findingswill bediscussed
in termsof theseacousticcorrelatesof placeof
articulationandtheirvariabilityin children'sspeech
production.[Work
supported
in partby NINCDS.]
'
GARDEN
ROOM, 10:15 A.M.
TO 12:20 P.M.
SessionzZ_ SpeechCommunication
VII: ImpairedProductionand Perception
Sandra L Hamlet, Chairman
Department
of HearingandSpeech
Science,
University
of Maryland,College
Park,Maryland20742
ContributedPapers
10:20
configurations
with
and
without
thefirst
formant.
SyntheSis
inthe/el/
environment allowed minimal acoustic differences to cue the contrasts.
ZZi. Procedures
which
altertheintelliglbility
ofvoiced
stop
consonants To maximizethe probabilityof findingevidenceof maskingspreadthe
for hearingimpairedlisteners,M. F. Donnan,J. M. Lindholm,andM.
T. Hannley {Departments of Speech and. Hearing Science and
Psychology,
ArizonaStateUniversity,Tempe,AZ 85287)
To assess
thehypothesis
thatspreadof maskingfromF 1isresponsible
for pooridentification
of voicedstopconsonants
by hearingimpaired
listeners,/bdg/weresynthesized
with burstsand formanttransitionsin
S103
stimuliwerepresented
at levelsbothaboveandbelowthepointof maximuminteiligibility.At nopointon thefunctionwasperformance
without
the first formant better than performancewith the first formant. To inves-
tigateotherwaysin whichtheintelligibility
ofrod/couldbeenhanced,
we
altered,in separatemanipulations,
theamplitudeanddurationat signal
onsetofthecuesforplaceofarticulation.
Increasing
theamplitude
of the
onsetcuesimprovedidentification
accuracyfor/d/but not for fo/or
S103
/g/. In contrast,
increasing
thedurationoftheonsetcuesimproved
identificationaccuracyfor/g/but impairedaccuracyfor/b/and/d/. These
resultsand otherssuggestthat the beneficialeffectsof prolongingthe
onsetspectrum
for/g/resultsnotfrombetterfrequency
resolution
dueto
longerprocessing
time,but fromthecueof durationperse.
obtainedfrom selectedportionsof the Minimal Auditory Capabilities
(MACI Test {includingCID EverydaySentences},
the DiagnosticRhyme
Test,theCaliforniaConsonantTest,andotherlessdifficulttestsdesigned
to reducethe role of specificlanguagelealures.Resultssupportthoseof
the Hochmairson the efficacyof singlechannelimplant systemsfor
speechunderstanding.
[Research
supported
in partby a Biomedical
Re- ß
searchSupportGrant {NIMH}.]
10:32
ZZ2. On improving articulation index predictionsof speechsound
identificationperformanceby the hearingimpaired.ChaslavV. Pavlovic
11.'08
(Departmentof Communicative
Disorders,Universityof Mississippi,
Oxford, MS 386?71 and Gerald A. StudebakerIDepartment of
AudiologyandSpeeCh
Pathology,MemphisStateUniversity,Memphis,
ZZ5. A prototype hearing aid for acoustic coupling of telephoneand
hearing aids. Richard G. Stoker, Marilyn French-St. George, and
Jonathan Brown (Program in Communication Disorders, The
TN 38152•
Pennsylvania
StateUniversity,I l0 Moore Building,UniversityPark, PA
16802)
Predictions
of speechsoundidentification
performance
by hearing
impairedindividualsweremadeusingan articulationindex(AI). The AI
scheme used was one that had earlier been found accurate for normal
hearinglisteners.It wasexpectedthat somesensorinenral
hearingim-
pairedindividuals
wouldexhibitreduced
suprathreshold
speech
processingcapacity,andthattherefore,
theAI procedure
wouldneedto bemodified to aceomodate those effects. To this end we measured several
psychoacoustical
variables(criticalbands.upwardspreadof masking,
temporalmasking,
tuningcurves,etc.}thatmightbeincocporated
intothe
AI formulasto accountfor thedegradedperformance.
Resultsfor eachof
theindividuals
testedwill bediscussed.
[Worksupported
by NINCDS.]
10:44
ZZ3.
Principal
component amplitude compression. Diane
K. Bustamanteand Louis D. Braida IRLE, Rm. 36-749, MIT, Boston,
MA 02 ! 39}
Multiband amplitudecompressionsystemswhich processeach fre-
quencybandindependently
of theothershaveyetto proveadvantageous
for sensorineural
hearingimpairedlistenersover goodlinearamplification systems.Althoughaudibilityis improved,certainspeechcuesare
consistently
degradedby multibandcompression.
Acousticanalysisindicatesthat multibandsystems
whitenthe short-termspeechspectrum,re-
ducingthe spectraldetail.Analysisof speechreceptionerrorssuggests
thatthisdegrades
speech
intelligibility.
Spectral
detailcanbepreserved
by
utilizing the correlationof speechlevels in different frequencybands.
Ratherthan treatingeachbandindependently,
thecompression
in each
channelisa functionof the levelsin all thechannels.One implementation
of sucha systemisbasedona principalcomponent
analysis
of short-term
speechspectra.Compression
of the firstcomponent,
whichcorresponds
roughlyto overalllevel,equalizesthe energyin consonants
and vowels
muchasdoesa widebandcompressor.
Compression
of thesecondcomponent, whichcorresponds
roughlyto spectraltilt, actsas a variablefrequencygaincharacteristic.
The principalcomponent
systemimplementation and measurements
of the propertiesof processed
speechmaterials
will be presented.
10:56
ZZA. Second-languagespeech tests in a deaf patient with cooblear
implant.CarIG. MfillerandCorneliaM. Kemppel{SpecchandHearing
Center,Universityof Denver, Denver, CO 80208•
Some reports of speechunderstandingthrough cochlear implants
have been difficult to evaluate becausetest material in a foreign language
wasnot comparableto the widely usedand highlystandardizedspeech
material in English.Thus the data and their implicationshave not been
widelyaccepted.
To overcome
this,wehaveprovidedpatient"CK" from
theViennese
ImplantProjectwithentensive
Englishlanguage
trainingin
vocabulary,
grammar,andcomposition
with the goalsof evaluatingher
process
of second-language
acquisition
andof corroborating
thesignifi-
Recenttrendsin the telecommunications
industryhaveresultedin an
increasednumberof telephonereceiverswhichare not compatiblewith
the inductioncoilscontainedin many hearingaids.This situationhas
developed
in spiteof effortsbytheFederalGovernment
to legislate
telephone/hearing
aidcompatibility.
Thisprojectwasdesigned
to evaluatea
prototypeheatingaid with specializedfrequencyshapingcapability.In
short,wewishedto discoverif currenttechnologies
werecapableof creating a hearingaid whichcouldbeeffectivelyusedby hearingaid wearersto
understand
speechtransmittedovera telephonewithoutthe useof mag-
neticcoupling.Ten subjects
fromthreedifferenthearinglosscategories:
precipitous
high-frequency
loss,slopinghigh-frequency
loss,andrelatively fiat, severeloss,were tested.Subjectswereevaluatedusingthreetypes
of frequency
shaping:"typicalhearingaid response,"
low-frequency
compensation,and fiat gain condition(up to 40 dB of linear amplification
beyondthat normally requiredfor free-fieldcommunication}.
Subjects
wererequiredto respondto recordingsof the NU-6 WORD LIST presentedin quietandwith 45 dB and 55 dB SPL of competingbackground
noise(multitalkingnoise}.The resultsof this study suggestthat certain
classesof hearingimpairmentmay benefitfrom specializedcircuitry
whichprovidesfrequencyshapingto the telephone
signalsreceivedat the
hearingaid microphone.This techniquehasalsobeenshownto evenbe
effectivein moderateamountsof backgroundnoise,allowingspeculation
that acousticcouplingof hearingaidsand telephones
maybemorerealistic thancommonlythought.
11:20
ZZ6. An approachto telephonecommunication
betweendeafandhearing
persons.Jared .Bernstein,R. Becker, D. Bell, H. Murveit, F. Poza,
and G. Stevens(SpeechResearchProgram,SRI International,Menlo
Park, CA 94025•
It maybe possible
for a deafpersonanda hearingpersonto converse
overthetelephoneusingspecialequipmentonlyat thedeafperson's
endof
the connection.The deafpersondrivesa text-to-speech
converterwith an
efficientkeyboardsystem.The hearingpersonspeaks
sentences
in a wordat-a-timefashion.The wordsare handledat the deaf person'send by a
largevocabularyisolated-word
recognition
systemthat displaysa sentencelatticela sequence
of setsof likelywordsfor eachwordspoken
I. The
deafpersonthentriesto finda sensible
paththroughthe sentence
lattice.
For sucha systemto besuccessful
requiresadequateperformance
in:
humantext generationspeed,12)text-to-speech
intelligibility,{3}human
one-word-at-a-timespeaking,(4• large vocabularyIWR, and {5} human
disambiguation
of sentence
lattices.We reportpreliminaryexperimental
results that bear on requirements [1}, {2}, [3}, and 15};we outline an ap-
proachto {4}, the implementationof which is simulated.Experimental
studiesof{l) and15}arerun ondeafsubjects.
[Thismaterialisbasedupon
work supportedby the NationalScienceFoundationunderGrant ECS8023527.]
11:32
cant Vienneseresultsby usingstandardizedEnglishlanguagetests.Tape-
recordedmaterialwaspresentedsolelythroughelectricalconnectionto
the speechprocessing
electronics
suppliedby the Hochmairgroup(Vienna), therebyrulingout possibleacousticalinput. Stimulationwasdeliveredto a singlechannelelectrode
throughamplitudelimiting,frequency
shaping,andhigh-frequency
pre-emphasis
circuitry.We reporton results
$104
ZZ7. Identification of novelwordsandsentencesusinga tactile vocoder.
B. J. Frost, P. L. Brooks {Department of Psychology, Quecn's
University,Kingston,Ontario, K7L 3N6, Canada),D.M. Gibson,andJ.
L. Mason IDepartmentof ElectricalEngineering,Qucen'sUniversity,
Kingston, Ontario, K7L 3N6, Canada)
Societyo! Amedca
S104
A groupof five anteriorand sevenposterioraphasicpatientswere
recordedfor their vowelproductions
of theninenondipthongized
vowels
of AmericanEnglish[PetersonandBarney,J. Acoust.Soc.Am. 24, 175184{1952}],andcomparedto theproductions
of a groupof sevennormal
speakers.
All phonemic
substitutions
wereeliminated
fromthedatabase.
A linearpredictivecodingprogramwasusedto extractthefirstandsecondformantfrequencies
for eachof thefiverepetitions
of theninevowels.
The voweldurationand the fundamentalfrequencyof pronationwere
alsomeasured.
Statisticalanalyses
revealedthat thedurationandthefundamentalfrequencyfor the aphasics
weresignificantly
differentfrom the
normal subjects.Although there were no significantdifferences
in the
formantfrequencymeans,thereweresignificantly
largerstandarddeviationsfor the aphasicgroup.This greatervariabilitywas considered
as
evidenceof a phoneticdeficiton the part of the aphasicspeakers,
in the
context of preservedphonemicorganization.[Work supportedby
ADAMHA.]
The presentexperiments
arepart of an ongoingevaluationof a tactile
vocoderthat hasbeendeveloped
at Queen'sUniversity.The subjectused
in the experiments
hasnormalhearingand had previouslyacquireda
[actualvocabulary
of 250words.In all experiments
thesubjectandreader
satin adjacentsoundproof
boothswitha windowprovidingvisualcontact
when necessary.
The first seriesof experimentsexaminedthe subject's
abilityto identifywordsthat thesubjecthadnot receivedtactualexperiencewith before.The subjectwasnot awareof thepossible
wordsthat
mightoccuranda givenwordwasonlytestedonce.In thelipreading
alone
(LA} condition39% of the wordswereidentifiedcorrectlycomparedto
69% correctin the lipreadingplustactile vocoder(LV) condition.The
abilityofthesubject
to identifynovelwordswiththetactilevocoder
alone
{VA} wassurprisingand encouraging.
Theseresultswill be discussed
in
detail.Experiments
testingthesubject's
abilityto recognizeopensetsentences showed an increase in correct identification of over 100% when the
LV conditionwascomparedto the LA condition.
11:44
12:08
ZZS. Identification of words and manner features of speech by two
profoundlydeaf teenagersusinga tactile vocoder.P. L. Brooks,B.
ZZ10.
I. Frost{Department
of Psychology,
Queen'sUniversity,Kingston,
ThomasMurry and Michael Caligiuri (Veterans Administration
Ontario, K71 3N6, Canada}, J. L. Mason, and D. M. Gibson
IDepartmentof ElectricalEngineering,
Queen'sUniversity,Kingston,
Medical Center, San Diego, CA 921611
farmant
characteristics in
Huntington's disease.
The speechof Huntington'sdisease
(HD) hasbeendescribed
with a
varietyof termsincludingslow,hesitant,andstaccatolike,
yetvirtuallyno
datahavebeenpresented
to quantifythesecharacteristics.
Acousticanalysisof thevowelsin HD speech
mayprovideinformation
aboutthenature
Ontario, K7L 3N6, Canadal
Twoprelingually
profoundly
deafteenage
girlsweretaughttoidentify
"live-voice"Englishwordswhilewearinga tactileyoder.To ensurethe
subject's
deafness,
hearingaidswereremovedand earplugsand headphones
carryingwhitenoisewereworn.Thereadersatoutof sightfrom
thesubjectsolipreadinginformationcouldnotbeobtained.Wordswere
of thespeech
output.In thisstudy,twoquestions
wereposed.
(1)Are the
vowelsof HD subjects
differentfrom normalspeakers
as determinedby
the formantclusterpatterns?
(2) Are HD speakers
capableof reaching
vowelformanttargetswhenmorecomplexspeech
utterances
areutilized?
Tensubjects
withHD rangingin agefrom26 to 58yearsoldwerestudied.
Eachsubjectwasaskedto producefourvowelsin isolationandin CVC
introducedtwo or threeat a time until the subjectreachedcriterionon a
50-wordlist.The two subjects
acquireda tactualvocabularyof 50 words
with 21 and25 h of training,respectively.
Immediatelyaftertheseword
identification
tests,experiments
werecarriedout to testthesubject's
ability to identifythe "mannerof articulation"featuresof speech.Subjects
couldidentifywhetherCV's containeda nasal,liquid voicedstop,unvoicedstop,or unvoicedfricativewith accuracies
rangingfrom 75% to
syllables
in whichtheinitialconsonant
waseither/d/or/g/and thefinal
consonant
wasalways/d/. Measurements
off I andF2 weremadeforall
vowelsfrom widebandspectrograms.
The resultsindicatethat the
isovoweltargets,especially
for F2, for HD speakers,
weredifferentfrom
100% correct.
normalF2 values.When comparedto the isovowels,the formantsin the
CVC context reflectedcentralization.The resultssuggestthat formant
trajectories
for the vowelsin HD speechfail to reachnormalisovowel
formanttargets
andthatasthestimulus
complexity
increases,
approximationto normalvowelformantfrequencies
decreases.
[Worksupported
by
11:56
ZZ9, Vowel productionin aphasia.John H. Ryalls (Departmentof
Linguistics,
BrownUniversity,
Providence,
RI 02912)
FRIDAY
Vowel
MORNING,
11 NOVEMBER
the VeteransAdministration.]
CABINET
1983
Session AAA. Shock and Vibration V: Friction-Generated
ROOM, 9:00 TO 11:05 A.M.
Noise
Paul J. Remington,Chairman
Bolt Beranekand NewmanInc., 10 Moulton Street,Cambridge,Massachusetts02238
Chairman's
Introduction--9:00
Invited Papers
9:05
AAAI, Disk brake noisein rail transit vehicles.Lynn L. Faulknerand CharlesW. Rodman(Applied
Dynamicsand Acoustics:Section,
Battcllc'sColumbusLaboratories,Columbus,OH 43201}
A criticalparameter
in themechanism
ofdiskbrakesqueal
isthemanner
inwhichthecoefficient
offriction
changes
asa functionof theinstantaneous
relativevelocity
between
thefrictionmaterialandthebrakerotor.
Substitution
of alternativematerialsfor asbestos
asa frictionmaterialconstituent
hasproducedsquealin some
brakedesigns
butnotin others,leadingto theconclusion
thatoneor moreparameters
notassociated
with
S105
d.Acoust.
Sec.Am.Suppl.1, Vol.74, Fall1903
106thMeeting:
Acoustical
SocietyofAmerica
S105
frictionmaterialcharacteristics
operates
to controlthesquealmechanism.
The probablenatureof theseparametersis reviewedalongwitha description
of experimental
workcarriedout to investigate
thecauseof squeal.
[Work Supported
by US-DOT-TSCandWashington
MetropolitanAreaTransitAuthority{WMATA).]
9:.35
AAA2. Mechanismsfor the generationof railroad wheelsqueal.NicholasR. Dixon and Paul J. Remington
(BoltBeranekand NewmanInc., Cambridge,MA 02138}
Railroadwheelsquealis associated
with rail vehiclesroundingcurvesof smallradii, and it is regardedas
oneof the mostintenseandannoyingnoisemechanisms
on rapidtransitsystems.
This paperreviewsa theory
for thegeneration
of wheelsquealandprovidesexperimental
datafromlaboratoryandfieldmeasurements
that
arecompared
withthetheoretical
analysis.
Squealoccurswhentherailroadwheelslideslaterallyacross
therail
head,andthetheoretical
analysis
shows
thatthefrictionforcesgenerated
by thisslidingcancausesquealif the
coefficient
of frictiondecreases
with increasing
relativevelocitybetweenthewheelandrail. Laboratorymeasurements
of thecoefficient
of friction(p) versusthelateralcreepof a railroadwheelarediscussed
that verify
thedecrease
in p with increasing
wheelrail relativevelocity.A seriesof fieldmeasurements
on severalrapid
transit lines is described that determined the influence of the ratio of curve radius to truck wheelbase on the
occurrence
ofsquealandprovidedgoodagreement
withthetheoretical
prediction
fortheonsetofwheelsqueal.
Methodsof controllingsquealhaveinvolvedspecialdampedor resilientwheels.A recentsurveyof the loss
factordataof specialized
wheels,knownto suppress
squeal,indicates
that lesswheeldampingisrequiredthan
that predictedby the presenttheory.Reasonsfor thisdiscrepancy
are discussed.
10:05
AAA3.Vibrationdamping
tocontrolrailroadwheelsqueal.FrancisKirschnet(TheSoundcoat
Company,175
PearlStreet,Brooklyn,NY 11201)
The squealnoiseradiatedby rapid transit wheelson sharp turns is an importantinstanceof friction
generatednoise.It is causedby the lateral slip-stickfrictional forcebetweenthe wheel and railhead. Noise
controlmethodssuchasrail lubrication,hard facedrails,tunedwheeldampers,and resilientwheelshavedot
beenentirelysatisfactory
from thestandpointof eithercosteffectiveness
or of safety.This paperwill focuson
severallightweight
vibrationdampingtreatments
whichhavebeeneconomical
andeffective
meansof reducing
squealnoise.Severalring and constrained
layerdampingtreatmentswhichmakeuseof efficientviscoclastic
dampingmaterialshaveresultedfromextensive
development
and laboratorytestingprograms.Treatments
rangedfrom 1% to 2% of thetotalweightof wheelsweighing450-800lb. Waysidenoisereductions
of 34 dB
havebeenmeasuredin recentfield testson rapid transitsystems.Thesemeasurements
haveshownexcellent
correlation
withvibrationspectrameasured
in thelaboratoryandconfirmtheeffectiveness
of vibrationdamping in controllingfrictiongeneratednoiseof thistype.
10'.35
AAA4. In-serviceevaluationof dampedsubwaywheels.JeromeE. Manning (CambridgeCo!laborative,Inc.,
P.O. Box 74, Cambridge,MA 02142)
A I-yr in-service
evaluation
ofdampedsubwaywheelsisbeingdoneontheNew York CityTransitAuthority system
aspartof theUrbanMassTransportation
Administration's
UrbanRail NoiseAbatementProgram.
Four typesof dampedwheelsare beingevaluatedto determinetheir effectiveness
in reducingwheelsqueal.
Acousticdataarebeingcollectedthroughoutthe I-yr programto monitortheacoustical
performance
of the
wheels.Data arealsobeingcollectedto deteivninc
thecostof thewheels,includinganyadditionalmaintenance
andinspection.
This presentation
focuses
on resultsobtainedthroughthefirst6 monthsof the I-yr evaluation.
[Worksupported
by theUnitedStatesDepartmentof Transportation.]
$106
$106
FRIDAY MORNING,
11 NOVEMBER 1983
FORUM ROOM, 8:00 TO 11:41A.M.
SessionBBB. PhysicalAcousticsVI: GeneralTopicsIII--Mostly Scattering
Allan D. Pierce, Chairman
School
of Mechanical
Engineering,
Georgia
Atlanta,Georgia
30332
Chairman's
Introduction.•8:00
ContributedPapers
8:05
BBB1. Vsriatlonal method for predictionof acousticradiation from
vibrating bodies. Allan D. Pierce and Xiao-Feng Wu (School of
MechanicalEngineering,
GeorgiaInstituteof Technology,Atlanta, GA
303321
Integralequationformulations
suchasdiscussed
by Chertock,CopIcy,Schenck,
Meyer,Bell,Zinn, Stallybrass,
and manyothers,typically
havenonsymmetric
kernelsandare not easilyrephrasedasa variational
principle.However,a symmetrickerneldoesresultfrom thenormalderivativeof the Kirchhoff-Helmholtzintegral,with the exteriorpointsubsequentlyallowedto approachthe surface,but the integrandthenhasunmanageable
singularities.
A methoddueto ManeandStallybrass
allows
thisintegralequationto berecastintoa usableform(involvingtangential
derivatives
of theunknownsurfacepressure}
andthisversionin turn leads
to a variationalprinciplethat hasconsiderable
promisefor systematic
(Department of Engineering Sciencesand Applied Mathematics,
NorthwesternUniversity,Evanston,IL 60201)
A newmethodisdescribed
for determiningthescattered
fieldfroman
obstaclein the resonantfrequencyregime.The methodis basedon the
assumption
thatthedensityof theobstacle
iseithermuchgreateror much
lessthanthedensityof thesurrounding
acousticfluid.Whenthefrequencyof theincidentwaveisnotcloseto a resonance
frequency
of theobstacle
in vacuo the reaction of the fluid on the obstacle is small. However, this
reactionis importantneara resonance
frequency.We usethe methodof
matchedasymptoticexpansions
to obtaina uniformapproximationfor
the scatteredfield,valid at all frequencies.
It is shownthat the resonant
peakbandwidthisrelatedto theradiationcrosssection,
forsimplemodes.
Multiplemodesarealsoconsidered.
The methodis illustratedby examples.
approximate
solutions
of radiation
problems
in thelowto moderate
ka
regimes.Validity of this formulationis substantiated
by derivationof
knownresultsfor vibratingspheres
anddisks.Numericalresultsfor other
geometries
areexpected
to yieldhigheraccuracythanpreviously
because
onecanincorporate
one'sbest"physicalinsight"in initialchoicesfor the
classof trial functionsfor surfacepressure.If computationsnow in pro-
gress
arecompleted,
theexampleofanoscillating
airfoilwill bediscussed,
with someexpectedclarificationof the anomalousresultsof the Brooks'
experiment.
8:17
BBB2. Acousticscatteringfromabsorbentwedges.Mehmet Marsanand
SabihI. Hayek(Departmentof Engineering
ScienceandMechanicsand
8:41
BBB4. Comparisonof physicalacousticsand geometrletheory of
diffraction predictions for backscatteringby impedance-covered
wedgelikescatterers.D. A. Sachs(Bolt Beranekand Newman Inc., 50
Moulton Street,Cambridge,MA 02238)
Radarscattering
studieshaveshownthatscattering
predictions
based
on physical
acoustics
aregenerally
invalidawayfromspecularly
reflectingdirections.
In thispaper,comparisons
aremadebetween
thepredictionsof physicalacoustics
and the geometrical
theoryof diffractionfor
acousticbackscattering
by impedance-covered
wedgelikescatterers.
Substantialdifferences
are seenin theresultsat anglesof incidencewell off the
The AppliedResearchLaboratory,The Pennsylvania
StateUniversity,
specularly
backscattering
directionwherediffraction
by thewedgeedge
dominates
the return.[Work sponsored
by Naval UnderwaterSystems
UniversityPark, PA 16802I
Center,New London,CT.]
The predictionof thesoundscattered
by impedance
coveredwedgesis
obtainedby useof dualintegralequations.
The impedance
of eachfaceof
thewedgeismodeledasa pointreactingcomplexquantitywhichisindependentof the other face.The solutionwasconstructedas an angular
spectrumto satisfythe boundaryconditions
and Sommerfeld
radiation
condition.The solutionkernel was obtainedexactly and is in terms of
circularfunctions.The solutionof the scatteredpressurewas then obtainedfor farfieldand mid-rangeby useof asymptotictechniques.
This
solutionismuchsimplerthantheonedeveloped
byRussianscientists
[for
example,seeG. D. Malyuzhinets,"The Radiationof Soundby Vibrating
Boundariesof an Arbitrary Wedge,Parts 1 and 2," Soy.Phys.Acoust.1,
152-174, 240-248 (1955}]which was obtainedby a methodsimilar to
Wiener-Hopf techniques.
Thus it iseasierto usehighwaynoiseapplicationsbecauseof its simplicity.The solutionfor the diffractedpressure
exhibitsclearlythe role of the incidentand reflectedshadowboundaries
and showsthere is one minimum in the scatteredfield which dependson
thetwo surfaceimpedances.
For backscattered
pressure,
the solutionex-
hibitstwo minima.In all cases,
thescattered
pressure
becomes
negligible
nearthewedgesurfaces.
[Work supported
by NAVSEA.]
8:29
BBB3, A new approach to resonancescattering in acousticsand
elasticity. A. N. Norris (Exxon Researchand EngineeringCompany,
P.O. Box. 45, Linden,NJ 07036},G. A. Kriegsmann,and E. L. Reiss
S107
J. Acoust.
Soc.Am.Suppl.1,VoL74,Fall1983
8:53
BBB$.Acousticresonance
scatteringby a cylindricalshell.D. Brilla•
andG. C. Gaunaurd(NavalSurfaceWeaponsCenter,R43, WhiteOak,
SilverSpring,MD 20910}
Wepresenta studyof theresonance
scattering
process
thattakesplace
whenplaneacousticwavesare incidenton elasticcylindricalshellsin
water.The analysis
proceeds
alongthelinesdescribed
by usearlier[D.
Brill and G. Gaunaurd,J. Acoust.Soc.Am. 73, 1448-1455I1983}]for
solidelasticcylinders,andextendsit to Ihollow}shells.For aluminumgasfilledcylindricalshellsof variousthicknesses,
weconstructthefamiliesof
zerosin thecomplexk•a • x} planethatgiveriseto theRayleighandthe
whispering
gallerywavescircumnavigating
theshell.Wehaveisolated
the
propermodalshellresonances
from their modalbackgrounds
and we
havegenerated
monostatic
plotsofbackground-supressed
formfunctions
(i.e.,crosssections}
thatagreewellwithrecentexperimental
observations
madeby a team in France.We havenoticedthat as the shellsbecome
thinner,fewerfamiliesat polesseemto offercontributions,
until for very
thin shells,only one typeof circumnavigating
surfacewaveseemsto be
possible.
Finally,by meansof the RST-polediagrams,we havealsostudiedthe moreattenuatedlandlesssignificant}
contributionsof the Franz or
creepingwavesto theoverallresonance
scatteringprocess.
Work continues.a•D. Brill is with the U.S. Naval Academy,Annapolis,MD 21402.
106thMeeting:
Acoustical
Society
ofAmedca
$107
9:05
BBB6. Excitation of anomalous resonances for acoustical scattering
from fluid loadedsolid elastic spheroids.M. F. Werby (Naval Ocean
ResearchDevelopmentActivity, NSTL Station,MS 39529)and Roger
H. HackmanINaval CoastalSystemsCenter,PanamaCity, FL 32407)
Conventionaltheoriesof scatteringfrom fluid-loadedelasticsolids
indicatethat thereis a thresholdin K.4 (K is the wavenumberand .4 some
characteristicdimensionof the object)below which one cannot excite
Rayleighresonances
andfor whichthescattering
behavioris essentially
rigid.However,a systematic
investigation
of acoustical
scatteringfrom
elasticsolidspheroids
reveals
thatanomalous
behavioroccursforscatteringin an angularregionoffthe axisof symmetry.it wasfoundthat this
behavioris morepronounced
for higheraspectratioobjectsandthatthe
anomalous
form functionsshiftdownin K.4 with increasing
aspectratio.
Furtherinvestigationrevealedthat thisbehavioractuallycorresponded
to
the excitationof surfacedisturbances
corresponding
to standingwaves
followinga spheroidalpath.We thusrefer to themas spheroidalresonances,which are similar in natureto Rayleightype resonances.
Suchresonances
canonlyoccurfor elongatedobjectsabovea certainaspectratio
and are most stronglyexcitedat specificangles.Theseresultswill be
presented.
9:17
BBB7. Rigid scatteringfrom fluid-lnadedobjectsfor highaspectratios.
M.F. Werby {NavalOceanResearchand DevelopmentActivity, NSTL,
Station,MS 39529)
We performa systematic
studyof acousticalscatteringfrom rigid
fluid-loaded
spheroids
withaspectratiosrangingfrom 10to 30 usingthe
coupled
high-order
T-matrixformulation
developed
forhigh-aspect
ratio
problems.
Thekl/2 rangewillbefrom6 to50,wherek isthewavenumber
and/is thelengthof thespheroid.
Until recentlyit hasnotbeenpossible
to
explorethisregionof interest.Of particularinterestis the monostatic
miningtheparameters
of therepresentation
aredescribed.
Someof these
procedures
havebeenimplemented,and resultsare shown.A simplified
descriptionis developedfor the caseofa circularlysymmetrictransducer
whichpermitsa significant
reductionin computation.Forwardandbackward propagation
of the radiatedacousticalfieldcanbe performedusing
Fourier transform methods.This characterizationis very effectivefor
analysisof scatteringproblems,particularlywhen they are expressedin
the T-matrixformalism.An exampleisshownfor normalincidencebackscatteringfrom a layeredviscoelastic
half-space.
9:53
BBB!0. Scatteringof elasticsurfacewavesby a semi-infinitefluid-filled
crack. W. M•hring (Max-Planck-lnstitut fiir Str•mungsforsehung,
]•ttingcrstr. 4-8, D 3400,G•ttingen,FederalRepublicGermany)
Wave momentum
considerations lead to the conclusion that scatter-
ing problemsinvolvinga fluid-filledcrack Inormalstressand displacementcontinuous,
vanishingtangentialstress)shouldbe in manyrespects
simplerto salvethan similarproblemswith a zero-stress
crack.To illustratethis,an elastichalf-space
with a semi-infinite
fluid-filledcrackparallel to the free surfaceand extendingto the left is considered.Incident
surfacewaves,both from the left and from the right are assumed.The
Wiencr-Hopf techniqueis usedto determinethe reflectedand transmitted surfacewavesfor differentfrequencies
and differentvaluesof Poisson'sratio.It is foundthat, in termsof thenormalfree-surface
displacement,scatteringislargerfor wavesincidentfrom the left.The methodcan
be extendedto a semi-infinitefluid-rifledcrack in an elasticlayer. The
solutioncanalsoserveasa startingpointin well-knownefficientmethods
to calculatethe scatteringof elasticwavesby a finitecrack or by a finite
sizedconnectionbetweentwo elasticlayers.Similar resultsfor zero-st•ss
crackshaveapparentlybeenobtainedonly in symmetricalconfigurations.
10:05
angular
distributions.
In thisregionthereisa proliferation
ofnullsdueto
thevariationof pathsfromdifferentpointsof thescattererto thepointof
detection.
Theoriginofthefirstandsubsequent
nullscanberelatedto the
aspectratioof the objectby an expression
derivedfromclassical
wave
arguments.
Resultswill bepresented.
BBBII. Sound scatteringand radiation from a thin rod in a viscous
medium. Wen H. Lin and A. C. Raptis (ComponentsTechnology
Division(308),ArgonneNational Laboratory,Argonne,IL 60439)
Sound waves incident on a thin elastic rod whose radius is smaller than
the wavelengthof the incident sound induce flexural and uniform
compressional
oscillations
in the rod. Theseelasticoscillations
againradiate sound waves into the fluid medium and affect the scattered waves.
BBBS. The isolationof physicalmechanisms
associatedwith acoustical
scattering from submergedelastic spheroidal and spherical shells.
M. F. Werby {Naval Ocean Research and Development Activity,
Numerical Modeling Division, NSTL Station,MS 39529) and Roger
H. Hackman{NavalCoastalSystemsCenter,PanamaCity, FL 32407)
Acousticalscattering
fromsubmerged
spheroidal
andsphericalelastic
shellsexhibitsvariedbehaviorover a broadrangeof K`4 {K is the wavenumberand.4 the largestdimensionof the object).This behavioris com-
plicateddue to reflections
from the innersurface(exceptfor very thin
shells)resultingin a very pronounced
interferencephenomenon
between
theinternalandspecularreflections
aswellaseffectsfromtheresonances,
A generaltheorybasedon elastodynamics
that accountsfor all these
mechanisms
isperforceverydifficultto employcomputationally.
In addition,someK.4 regionsdo not includeall themechanisms
andthusa more
simplifiedtheorycouldbe used.Thus,if onecandevelopa procedurethat
can accountfor the individualmechanismsseparatelyconsiderableprogresswill bcmadein solvingthe overallproblem.We proposeto developa
theorybasedon an orderingprocedurethat will allow oneto isolatethe
variouseffects.Severalassumptions
and schemeswill be examinedand
comparedto solutions
of theexactproblem.
9:41
BBB9. Angular spectrumcharacterizationof acousticaltransducers.
RichardK. Johnson
(IREX, 69 SpringStreet,Ramsey,NJ 07446)
The transmitting
andreceivingresponses
of an acoustical
transducer
in a fluid are characterizedusingthe angularspectrumof planewaves
representation.
Nearfieldand farfieldcalibrationprocedures
for deter-
$108
This synopsis
presentstheoryof soundscatteringby, andacousto-clastic
vibrations of, a thin elastic unbound rod in a viscousfluid. The shear
viscosityof the fluidwasconsideredin thesolutionsto the boundmy-value
problemsconcerningthe soundscatteringandthe elasticresponse
of the
rod. Resultsshowthat the scatteredcompressional
wavesconsistof the
rigid-rodscatteringof compressional
wave,a monopolarwavedueto the
uniformpulsating
of therod,anda dipolafwaveduetotheflexuralvibration of the rod.The scatteredviscouswavesconsistof the rigid-rodscattering of viscouswave and a dipolaxwave due to the flexural vibrationof
the rod. Acoustic resonances occur when the effective inertia force of the
rod balancesthe stiffnessforce of the rod. The fluid viscosityand the
scatteringof soundgive riseto radiationdampingfor the rod vibrations
and affectsignificantlytbe acousticresonances.
10:17
BBBI2. Selective observationof elastic body resonancesby using long
pulses to excite a ringing responsein the body. S. K. Numrich,
W. E. Howell, and H. UberalP• {Naval Research Laboratory,
Washington,DC 20375)
An elasticbodysubmerged
in waterwill ringwheninsonifiedbysound
whosefrequencyisthe sameasoneof theresonances
of that body.Correspondence
hasbeenestablished
between
thesenormalmoderesonances
of
the bodyand the individualcircumferential
wavespredictedby creeping
wavetheory.Insonifyingthetargetwith a relativelylongsinusoidal
pulse
resultsin a seriesof superimposed
responses
consistingof the specular
reflectionanda seriesof creepingwavesarrivingaftersuccessive
circumnavigationsof the body. Echoes,both analyticallyand experimentally
Societyof America
S108
obtained,fromsphericaltargetswill beusedto identifytheproperties
of
the resonanceringingand associatethe superimposed
echoeswith the
resonance
poles
thatcanbepredicted
theoretically.
alAlsoatTheCatholic
Universityof America,Washington,DC 20064.
10:29
BBBI3. Effects due to elantie responseof some simple bodies on
eoherently processedbroadband echoes. C. F. Gaumond, S. K.
Numrich, and L.
R. Dragonette(Naval ResearchLaboratory,
As an approximationunderwatertargetsare sometimes
modeledas
point scatterers.However, broadbandechoesfrom elasticbodiesof finite
extentcanbemodulated
bycircumferential
orinternal
elastic
waves.
This
modulation
causes
theechoes
tobetemporally
broadened
andmorewidely distributedon a cross-ambiguity
plot.The extentof theseelasticeffects
on pulsewidth,coherence,
andambiguitywill beshownfor severalcases
of solid and hollow bodies.
BBB16. Intensityfluctuationsof wavespropagatingin a randommedium.
Alan R. Wenzcl (Naval Ocean Researchand DevelopmentActivity,
Code 340, NSTL Station,MS 39529)
A theoreticalanalysisof the wavefieldradiatedby a pointsourcein a
one-dimensional
randommediumis presented.
The analysisis basedon
thequasi-Rytovmethod,andincludesbothmultipleforward-scatter
and
multiple backscattereffects.An approximateexpressionfor the meansquarefluctuatingintensityisderivedunderconditions
of a weaklydissipatiremedium.This expression
showsthatat low andintermediate
frequenciesthe intensityfluctuationsare a maximumat the sourcepoint,
decreasing
exponentiallywith distancefrom the source.Thesefindings
are in qualitativeagreement
with analyticaland numericalresultsobtainedby Kohler and Papanicolaou
[J. Math. Phys. 15, 2186-2197
(1974}].At highfrequencies,
however,thisexpression
showsthat, under
certain conditions,the intensityfluctuationsreach a maximum at some
positivedistancefromthesource,decreasing
monotonically
withdistance
in eitherdirectionfrom this maximumpoint.Theselatter resultsare in
qualitativeagreementwith observations
of intensityfluctuations
of optical wavespropagating
in the loweratmosphere.
[Researchsupportedby
NORDA.]
10:41
BBB14. Mixed-mode acoustic glory: Model
11:05
and experimental
verification.Kevin L. Williamsand Philip L. Marston(Departmentof
Physics,
Washington
StateUniversity,Pullman,WA 99164)
Scatteringfrom largeelasticor fluid spheresis enhancedalongthe
backwardaxisdue to a weakfocusing.The effectof diffractionon this
axialfocusingwasshown[P. L. MarstonandD. S. Langley,J. Acoust.
Soc.Am. 73, 1464-1475(1983)]to removean unphysicaldivergence
of
scattered
pressure
predicted
by elementary
ray acoustics.
Our previous
modelof this "acousticglory" of elasticsphereswascompleteonly for
transmitted
waveswithinthespherewhichwereeitherall longitudinal
(L)
or all shear(S).Thesecontributions
wereseparatedby measuringthe
backscattering
of shorttoneburstsfrom a glassspherein waterhaving
ka•457. Measuredpeak-to-peak
pressures
weretypicallywithin 5% of
predictions[P. L. Marston,K. L. Williams,and T. J. B. Hanson,J.
Acoust.Soc.Am. 74, 605-618 (1983)].In the presentresearchwe completethetheoryfor thecaseof mixed-mode
gloriesin whichthereis at
]east one L to S or S to L mode conversion due to reflection. A novel
calculationshowsthe focalparametersare iodcpcndent
of permutations
ofthemodesequence;
however,
thecontributions
to thescattering
depend
onsequence.
Measured
mixed-mode
pressures
(fromtheaforementioned
sphere)
arewithin5% of thepredictions.
[Worksupported
byONR. Mar-
11:17
BBB17. Scatteringfrom gratingsof high aspectratio complianttubes
embedded in an elastomer. Ronald P. Radlinski and Robert S. Janus
(NavalUnderwaterSystems
Center,New London,CT 06320)
An improvedformulationfor normalincidentplanewavescattering
from gratingsof complianttubesembedded
in a viscoclastic
layerimmersedin fluidis presented.
Approximations
to boundaryconditions
at
theinterfaces
between
theinterstice
andcompliantclements
areeliminatedby treatingtheinterstice
asa viscoelastic
platewhichhasthematerial
properties
of thepolymermatrixmaterial.Thecomplianttubesarctreatedastwo structurallyandacoustically
coupledplateswith endconditions
whichcorrespond
to thosefor thevibrationalmodesof a highlyeccentric
ellipticalshell.Conditions
on normaldisplacement,
normalstress,
and
tangential
displacement
relatethecompliant
platesandviscoclastic
plate
boundaries
to the surrounding
viscoelastic
layers.Comparisons
of the
insertionlossfor gratingsin fluid and gratingsin viscoelastic
layersin
fluid will be shown. Limitations of the analysiswill be discussedand
calculations
will becomparedwith experimental
data.
stonis an Alfred P. S1oanResearchFcllow.]
11:29
BBBIS, Precisionmeasurementsof the reflection coefficientand of the
10:53
BBBIS. Ultrasoundpropagationand scatteringin randomlydistributed
particles.
Jofi.
oC. Machado(COPPE/UFRJ,
Department
of Biomedical
Engineering,
C. P. 68510,RiodeJaneiro,Brazil),Rubens
A. Sigelmann,
andAkira lshimaru(Departmentof ElectricalEngineering,
University
of Washington,Seattle,WA 98195}
This paperdealswith experimental
and theoretical
investigations
aimedat increasing
thebasicunderstanding
of theinteraction
of acoustic
waveswith randommedia.The rangesof frequencyare 0.85-3.0 MHz
and 5.0-6.0 MHz. The randommediumconsistsof a suspension
of polystyrenespheres
(meandiameter0.589ram,standarddeviation0.066ram}
in a solutionof waterandsugar.For differentconcentrations,
experimental resultsfor attenuationand pulsebroadeningfor transmission
and
backscattering,
andattenuation
asa functionof thereceiving
anglefor
transmission
only are presented.In the rangeof 0.85-1.1 MHz, the total
scattering
crosssectionof the particlesdepends
on the lSth powerof
frequency.
Thisdependence
isdueto the roleof shearwavesinsidethe
particles.
The powerspectrum
densityof a burstof sinewaveback-
acousticimpedanceof materialsin water filled tubes.E. J. Skudrzyk
(Applied ResearchLaboratory,The PennsylvaniaState University,
University Park, PA 168021
The reflectioncoefficient
andtheacousticimpedance
of materialscan
be measuredin tubeseitherby monitoringthe amplitudeand phaseof
reflectedsinusoidallymodulatedpulses,or by determiningthe resonance
frequencies
andthedampingobserved
fora continuously
excitedstanding
wave.The pulsemethodhasthe advantageof isolatingthe errorscaused
by thetubeconstructional
arrangement,
whilethestandingwavemethod
integratestheseerrorswith the propertiesof the test probes.The tube
itselfaffectsthe experimentalresultsdue to vibrationsthat travel in the
wall and are coupledinto the water,by additionaltubevibrationsthat
occurat itsendsandby reflection•causedbydiscontinuities
andsupports.
Also, the transducers
will be consideredin detailand the effectsof damping.In thispaper,thebehaviorof themeasuring
tubewill beanalyzedand
recommendations
will be madefor the designof trouble-freetesttubes.
[Sponsored
by NAVSEA O5H andbytheOfficeof NavalResearch
(Code
479).]
scatteredfrom the randommediumis measured.The experimentaland
theoreticalresultsagreewell. The complexpropagation
constantof the
coherentwavein the mediumwith largeconcentrations
of particlesis
measured.It deviatesfrom thosepredictedfor a low-densitymedium.For
the theoreticalcalculations,the sizedistributionof the particleswascon-
sidered.
[Worksupported
byCNPqin BrazilandtheU.S.Army Research
Officeand theOfficeof Naval Research.]
S109
11:41
BBB19. Abstract withdrawn.
Societyof America
S109
SUNRISE ROOM, 9:00TO 11:50A.M.
Session
CCC.Psychological
Acoustics
VI: HearingImpairment;
Applied
Acoustical
Analysis
Donald D. Dirks, Chairman
HeadandNeckSurgery,
MedicalCenterUniversity
of California,
LosAngeles,
California
90024
Chairman's Introductionre9:00
ContributedPapers
9:05
CCC1. Patterns of phonemeidentificationerrors in cooblearand eighth
nervedisorders.
Maureen HarmIcy(Departmentof SpeechandHearing
Science,ArizonaStateUniversity,Tempe,AZ 85282)
The purposeof thisstudywasto determinewhetherpatternsof phonemeidentificationerrorsdifferas a functionof signalpresentation
level
amonglistenerswith eachlearand retrocochlearauditory disorder.An
analysis
of thespeech
intclligibilityperformance
of 15patientswith confirmedeighth nervedisorderwasconducted,usingconfusionmatrices
derivedfromresponses
toa monosyllabic
wordlist.Thesameanalysis
was
conducted
on theresponses
of a groupof 15patientswitheachleardisor-
ders,matched
totheretrocochlear
groupforageandaudiometric
configuration.The resultsindicatedthat: (1) vowelerrorswcrcmarcprevalent
andvarieddirectlywith increasing
stimuluspresentation
levelin theretrocochlear
group;and(2)consonant
errorsdidnotdifferin typeorrelative
frequencybetweenthetwo groups,norwastherea level-dependent
effect.
Theseresultsare supportedby closed-setvowel identificationtestsand
thusdo not appearto bean artifact of opensettesting.Vowel errorsmay
accountfor a majorpartof thespeech
"rollover"phenomenon
typicalof
retrocochleardysfunction.
10:05
CCCA. Temporal processingin cochlearimplants.Robert V. Shannon
{ColemanLaboratory,HSE-863,Universityof California,SanFrancisco,
CA 94143)
Psychophysical
experiments
wereconducted
to assess
the temporal
processing
of patientswith multichannel
cochlearimplants.Threshold
and suprathreshold
temporalintegrationweresimilarto normals,with
integration
timeconstants
of 100-200msand50-100ms,respectively.
Gap detectiondecreasedfrom 60 ms near thresholdto 1-2 ms for loud
stimuli,similarto normals
at highfrequencies.
Forwardmasking
decreasedas the delayof the signalfrom the maskerwasdecreased,
with a
timecoursesimilarto or slightlylongerthannormals.All of thesemea-
suresindicatethattemporalintegration
andadaptation
in implants
are
similarto normals,
indicating
an intactcentralmechanism.
Onemajor
difference
between
implants
andnormals
wasin thesensitivity
to details
of the temporalwaveform.Normalshearlittle or no differenceasa functionof phasewithin a complexwaveform,but the samestimulicancause
largeperceptual
differences
forimplantpatients.
Implications
forimplant
processor
designareconsidered.
[Worksupported
by NIH.]
9:20
10:20
CCC2. Hearingaid usingan emphasized
speechfor hearing-impaired
subjects.
HidenobuHarasakiandShinjiOzawa(Facultyof Science
and
Technology,
Keio University,3-14-1,Hiyoshi,Kohoku-ku,Yokohama
223 Japan),Hiroshi Oho, and ToshisadaDeguchi (Departmentof
Educations,
Tokyo(•akugeiUniversity,
Koganei-shi,
Tokyo,Japan)
A new hearingaid whichemphasizes
the phoneticfeaturesof mono-
syllables
issuggested
in thispaper.In vowelpartsofspeech,
weapplied
a
digitalfilteringtechnique
toa formantemphasis.
The 101ordertransversal filter emphasizes
formantfrequencies
( + 10- + 30 riB).This filter
enabledus to reducemisrecognitions
of/i/and/e/,
/u/and /o/ for
hearing-impaired
children.To emphasize
consonant
parts,threeemphasismethods
areexperimented
anddiscussed.
Oneisanemphasis
ofamplitudesin consonant
part,thenextisa durationexpansion
of nasalconsonant,andthelastisan insertion
of silence
between
stopconsonants
and
the followingvowels.The combinations
of thesemethodswerealsoex-
perimented.
Theresults
of theseexperiments
showed
a distinctimprovementin therecognition
ratioof monosyllables.
9:35
CCCS. Electrical stimulationof the auditory nerve in man: Dynamic
range as a function of stimulus duration. Mark White (863-HSE,
Universityof California,SanFrancisco,CA 94143)
Psychophysical
testswith implantedsubjects
indicatethat responses
to short durationelectricalstimuli (similarin duration to transitional
segments
in speech)
exhibitverynarrowdynamicranges,on theorderof
6-10 dB;whereasresponses
to longerdurationstimulicanexhibitconsiderably larger dynamic ranges,on the order of 17-40 dB. A specialized
formof compression
thatcompensates
for thisvariation
of thesubject's
dynamicrangemaybeuseful.A verysignificant
amountof compression
is
essentialbecause
of thenarrowdynamicrangeelicitedbyelectricalstimuli in thesesubjects.We haveinvestigateda setof"split-spectrum,"multichannelspeechprocessor
configurations.
Thesespeechprocessors
have
beendesigned
to compress
thewidedynamicrangeof theacoustic
environmentinto the verynarrowdynamicrangeof the implantrecipient.A
setof compression
systems
havebeencompared
to determine
whichstrategiesofferthemosteffectivecontrolof stimulusamplitude.[Work supported oy NIH and Hearing Research, Inc.]
CCC3. Calculation of the external-ear directional filter function of the
KEMAR manikin. R. E. Davis, S. Koshigoc, and A. Tubis
(Departmentof Physics,PurdueUniversity,WestLafayette,IN 47907)
In order to assessthe quantitativereliability of tbe calculationof
sounddiffraction by the external car using the boundary-integral-equa-
tion methodIS. Koshigoeand A. Tubis,J. Acoust.Sac.Am. Suppl.I 73,
S76 (1982)],wc calculatcthe directionalfilter functionfor the KEMAR
manikinexternalear. The calculationsarc basedon the assumptions
of
blocked
meatus
conditions
andtheembedding
of tbeexternal
earin a
planerigidbaffle.[Work supported
by NSF.]
Sl10
J.Acoust.
Soc.Am.Suppl.
1,Vol.74,Fall1983
10:35
CCC6. Gap detection in sensori-neuraland simulated hearing
impairments. Mary Florentine
(133FR,
Communication
Laboratory, Northeastern University, Boston, MA
Research
021151 and
Seren Buus (413MU, Auditory Perception Laboratory, Northeastern
University,Boston,MA 021151
The minimumdetectablegapMDG in a low-passIf,. = 7 kHz I noise
was measuredmonaurally as a function of level in listenerswith normal
106th
Meeting:
Acoustical
Society
ofAmerica S110
hearing,
hearing
impairments
of primarilycochlear
origin,andimpairmentssimulated
by masking.
Thelistener
judgedwhichof twointervals,
markedbylights,contained
thegapandamodified
BUDTIF procedure
wasusedtomeasure
theMDG. Theresults
fornormallisteners
agreewith
previousdata.Resultsfor sevenimpairedlisteners
indicatethat in most
cases
theirMDGs dependon theirhigh-frequency
thresholds.
For example,at highlevels,
onelistener
witha low-frequency
impairment
hadnearly normalMDGs, whereas
listeners
with high-frequency
impairments
showedenlargedMDGs. Mostof the reductionin temporalacuitycould
be producedby presenting
a normallistenerwith a maskingnoisespec-
and3.5kHz.Forthenormallisteners,
thespeech
wassetto70dBSPLand
thenoiseto 80dBSPL.For theimpairedlisteners,
thelevelswerechosen
toyieldbetterthan95%discrimination
intheeasiest
condition,
butpoor
discrimination
in themostdifficultcondition.
Bothgroups
of listeners
showed
thepoorest
performance
whenthenoisewascentered
at 2.5kHz.
Asthenoise
moved
awayfromthiscritical
region
performance
improved
forbothgroups,
butmorerapidlyforthenormallisteners.
Theseresults
indicate
thattheimpaired
listeners'
reduced
frequency
selectivity
may
contribute
totheirdifficulty
ofdiscriminating
speech
innoise.
[Supported
by NSF and NIH.]
trallyshaped
to simulatetheaudiogram.
However,for twoimpairedlistenerswithalmostidentical
audiograms,
onelistener's
performance
could
be simulatedwell by maskinga normal ear, but the other'sMDGs were
worsethan the simulationby a factor 1.5at the high levels.Theseresults
indicatethat temporalacuity,perse,maybereducedin some,but not all,
impairedlisteners.[Work supportedby NIH Grant RR07143and the
RSDF of NortheasternUniversity.]
10:50
CCC7. Diffraction limitations on sound-imagingexperiments for
hearing-aidedlisteners.George F. Kuhn (VibrasoundResearchCorp.,
10957EastBethanyDrive, SuiteJ, Aurora, CO 80014)
It had beenproposedby Bauer [J. Acoust.Soc.Am. 33, 1536-1539
( 1961}]thattwo loudspeakers
of differentsourcestrengths
in thehorizontal planecouldbe usedto producea virtual soundimage,locatedat other
than the actual source location. It is shown here that, due to the diffrac-
tionof soundby thehead,thisparticularmethodproduces
simultaneous
andinterdependent
interauraltime (ITD) and leveldifferences
(ILD). The
particular1TDsand ILDs producedby Bauer'smethoddo not generally
correspondto a uniquespatiallocationand thereforeproducepotentially
conflictinglocalizationcues.This difficultyisaggravated
by unbalancing
thehearingaidgainsor theirphaseresponse.
It appearsfromthestudyby
A. Nabelek,T. Letowski,and D. Mason[J. SpeechHear. Res.23, 670687 {1980}]that aidedlistenerspositionthesoundimageon thebasisof
interauraltime differences.
The role of interauralpressureleveldiffer-
ences
onthepositioning
ofsound
images
couldnotbeestablished
unambiguouslyfrom thesedata.
11:20
CCC9. Changesof tinnitus pitch after monauralexposureto a 1000-Hz
pure tone. I. M. Young and L. D. Lowry (Department of Otolaryngology,
Jefferson
MedicalCollegeof ThomasJefferson
University,
Philadelphia,PA 19107}
A subjectwith tinnitusof 10000-Hz pitch equ!valentin the left ear
and no tinnitusin the right ear wasexposedin the left ear to a continuous
pure tone 2000 Hz, 107dB SPL, for 10 min. This exposureresultedin
permanenttinnitusin bothearswith similarpitchof 10000Hz. Whenthe
left ear wasexposedto a continuous
puretone1000Hz, 123dB SPL, for
21 min, tinnitusdisappeared
temporarilyfrom stimulatedear but was
heardin thenonstimulated
ear.In theleftear:6• h afterstimulation,
tinnitusreappearedas a mixture of multiple pitches;51 h after stimulation, tinnituspitch changedto 4100 Hz, 3 dayslater to 5800 Hz, 5 days
later to 8700 Hz, and 48 days later to the original 10000 Hz and has
remainedtheresince.In the nonstimulated
right ear:After stimulation,
tinnituspitchwas7500-8500 Hz for 7 days;thereafter,tinnitushasbeen
fluctuatingbetween8500-9500 Hz; tinnitusdid not return to the pre-
exposure
pitchof l0 000 Hz until about9 weeksafterexposure.
Differencein recoverybetweentwo earswascomparedwith our previousstudies of 125-, 250-, and 500-Hz stimulation.
11:35
CCC10. Diagnosis of childhood respiratory diseasebasedon acoustical
analysis.ElizabethB Slawinska(Departmentof Psychology,University
of Calgary,Calgary,Alberta, T2N 1N4, Canada}
Diseasesof the respiratorypathwaysare oftenassociated
with a nar-
11:05
CCCS. Masking of the/da/-/ga/distinction in eoehlearimpairment.
Soren Buns, Joanne L. Miller, and Bertram Schaff (Psychology
Department,NortheasternUniversity,Boston,MA 02115)
Discriminationbetweentwo 300-mssynthesizedsyllables,/da/and
/ga/, presented
in the middleof a 900-msnarrow-bandnoise,wasmeasuredin threenormalandsixcochlearlyimpairedlisteners.The segmental distinctionwasconveyedby the frequencyof the initial burstand the
rowingof therespiralory
channel.Differentdiseases
arecharacterized
by
a welldefinedlocusof theconstriction.
Theoreticalanalyses
suggest
particular acousticalcharacteristics
whichcan aid in diagnosis.Predictions
include(al a shift in spectraldensityto the higherfrequencyrange,due
jointly to an enlargednoisesourceand the constrictedrespiratorychan-
nel, in tonsiliris;(b}specificrelationsbetweenthe acousticalpressure/
murmur at inspirationand expiration,in congenitalstridor;tcJseveral
/ga/the transitionstartedaround 1.9 kHz and roseto its steady-state
noisesourcesgeneratinglarge high-frequencyamplitudes,in acutesubglottallaryngitis;(d)stridorduringinspirationif theconstriction
isin the
neckor during expirationotherwise,with the narrowingof the traches.
Thesetheoreticalpredictions
are developed
and thentestedwith experimentaldataobtainedfrom 500children,including50casesof tonsilitis,47
value of 2.5 kHz and for/da/it
started around 3.0 kHz and fell to 2.5 kHz.
The narrow-band noises were 300 Hz wide and were centered between 1
cases
ofcongenital
stridor,30cases
ofsubglottal
laryngitis,
and24cases
of
narrowingof the traches.[Work supportedby AHFMR and NSERC.]
form of the third-formant transition, which was 50 ms in duration: For
$111
d. Acoust.Soc.Am.Suppl.1, Vol. 74, Fall 1983
$1 '11
FRIDAY
AFTERNOON,
11 NOVEMBER
1983
HAMPTON
ROOM, 2:00 TO 5:05 P.M.
SessionDDD.-Noise VII: Measurement, Evaluation, and Control
GeorgeC. Maling, Jr., Chairman
IBM Acoustics
Laboratory,C18/704, P.O. Box 390, Poughkeepsie,
New York 12602
Chairman's
Introduetion---2:00
ContributedPapers
2:05
DDDI, A note on the acousticsof a duet •th a wall treatment of axially
imrtitioned porous material. S. W. Rienstra (National Aerospace
LaboratoryNLR, P.O. Box 153,8300AD Emmeloord,The Netherlands)
Considered
istheproblemof soundpropagation
througha cylindrical
ductwith a walltreatmentconsisting
of a layerof porousmaterial,usually
fixedbya segmented
structure.The mathematical
problemisoneof sound
fieldsin the duet and in the layer coupledby conditionsof continuity
acrossthe interface.So, in general,the layer is not locallyreactingand
cannotbe represented
by an impedanceof the wall. As a resultcalculationstendto bequitecomplex.However,in thepresentpaperit isshown
that if the porouslayerissegmented
byan axialarrayof annularpartitions
with a smallenoughpitch,the couplingof the fieldssimplifiesin sucha
waythat theconditionof continuityreducesto a boundarycondition,per
circumferential
modesimilarto that of a pointreactingliner.Sothenthe
porousmaterialis characterizedby a circumferentialmodenumber-dependentimpedanceof the duct wall. Consequently,
all the well-establishedtheoryfor soundpropagationin ductswith uniformwall impedanceisapplicable
from hereon.
rudderof thejet trainer.The specimens
weresubjected
to thesameexcitationof thejetsof theengines.
The durationof testings
wereaccumulated
to the sameperiodin which the first crackwasdetectedon the aircraft
(100h}.Testsshowedthat improvement
couldbeachievedby introducing
intermediatesupportin the form of a spacerbetweenthe skinsof the
panel,or by increasing
thenumberofstiffeners
or ribs,or byjustenlarging
the rib flangesand addingonemorerivet row. Initial tensionof the skin
alsohad a bettereffect,for example,applyingair pressure
betweenthe
skinsproducedsuchtension.Alternativelythe reductionin skin stiffnesses
causedbyjet temperaturehadan adverseeffect.Extensivetheoretical calculationsfor panelinstabilitiesundervarioussupportconditions
weremade.There wasa closerelationshipbetweenthe staticbuckling
modeand the modecausingacousticfatiguefailure.'• Previously
a researchworker at Departmentof Researchand Development,Helwan
AircraftFactory,Arab Organizationfor Industry,Egypt.
2:50
DDIM. Annoyanceto advancedturbopropaircraft flyover noise.David
A. McCurdy INASA Langley Research Center, Mail Stop 463,
Hampton, VA 23665}
2:20
DDD2. The effect of grazing flow on the impedance of Helmhnltz
resonator. Nghiem-Minh Nguyen-Vo, and Peter A. Monkewitz
(Mechanicsand StructureDepartment,Universityof California,Los
Angeles,CA 90024I
A theoreticalmodelfor the acousticimpedanceofa Helmholtzresonatorwithgrazingflowispresented
forthecaseoflow-excitation
frequency andamplitudeandmoderategrazingflow machnumber.The analysis
is basedon the two-dimensional
linearizedinvicidequationof motion.
The methodof matchedasymptoticexpansions
is combinedwith the
C•reen'sfunctiontechniqueto solvethe boundaryvalueproblem.It is
shownthat the vorticitygeneratedby soundincidenton a rigid bodyis
"carriedaway"by thegrazingflow.This resultsin a transferof acoustic
energyto the one associatedwith vorticaldistribution.The acousticim-
A laboratoryexperimentwasconductedto quantifythe annoyanceto
advancedturbopropaircraft flyovernoise.A computersynthesissystem
wasusedto generate45 realistic,time-varyingsimulations
of propeller
aircraft flyovernoisein whichthe harmoniccontentwassystematically
variedto representthe factorialcombinations
of five fundamentalfrequenciesrangingfrom 67.5 to 292.5 Hz, threefrequencyenvelopeshapes
representinghelicaltip Mach numbersof 0.63, 0.73, and 0.78, and three
toneto broadbandnoiseratiosof 0, 15,and 30 dB. In the experiment,64
subjects
judgedtheannoyance
of recordings
of the45 synthesized
flyover
noisespresented
at D-weightedsoundpressure
levelsof 70, 80, and90 dB
in a testingroom which simulatesthe outdooracousticenvironment.
Analysesof thejudgmentsexaminetheeffectson annoyance
of thediffereneasin the harmoniccontentof the flyovernoises.The annoyancepredictionabilityof variousnoisemeasurement
procedures
andcorrections
is
also examined.
pedanceobtainedagreeswell with experimental
resultsavailablein the
literature.[Researchsupportedby NASA.]
3.•5
2:35
DDDS. Alternative concept for aircraft interior noise control. Curtis
DDD3.Acoustic
fatiguefailureofaircraftcomponent.
SabryF. Girgis
a•
(Department of Aeronautics, Faculty of Engineering, AI-Fateh
University, Tripoli, Libya)
Rudderskincrackswerenoticedon the lower part of mostaircraftsof
oneseries.The seriesof aircraftweregroundedfor rudderrepair.Investigationsweremadelateranda permanentsolutionto overcomethisfailure
wasdevised.The stresses
that causefailure dependon the dynamiccharacteristicsof the paneland on the externalexcitation.The dynamiccharacteristicswere determinedby groundresonancetests,in the form of
resonantfrequencies
and modeshapes.The externalexcitationwasdueto
intensesoundpressuregeneratedby thejetsof engines.The excitationof
both lurbulentboundarylayer and vortexeffectsare at low level.Equivalentspecimens
of therudderpanelwereconstructed
butwith thedifferent
designapproaches.
Specimens
were installedon elasticmountingsand
hingedto rigid framesin a similarmannerto the lower part of aircraft
$112
I. Holmer IE-A-R Division,CabotCorporation,791! ZionsvilleRoad,
Indianapolis,
IN 46268)
Cuerenttechnologyfor aircraft interior noisecontroldependson the
useof weightedbarriersand absorbinglayersto controlnoiseradiation
into the cabinenvironment.This ignoresthe presenceof structureborne
flankingpathsto interiorstructural/decorativesurfaceswhichcontribute
significantly
to the totalcabinnoiseIcyel.An alternativeapproachis to
employstructuraldampingwith (orwithout)vibrationisolationto reduce
noiseradiated.This concepthassignificantpotentialfor reducingtreatmcntweight,because
it canmakeuseof the weightof deeorativesurfaces
foracoustic
functions.
In thispaper
•vereview
theresults
ofa flighttest
demonstration
programfor thisdampedtrim panelconcept.The treated
aircraft (a 12-14 passenger
business
jet) exhibitedequalor lower noise
level• to that achievedwith weighted-layertreatmentswith more than a
40% reductionin the weightof acousticalmaterialsused.
$112
3-20
DDD6. Vibroaeonstic
habitabilityof spacestations.
DavidG. Stephens
(NASA LangleyResearch
Center,Mail Stop463,Hampton,VA 23665)
The predictionand controlof noiseand vibrationis essential
in the
designand operationof futurespacestationsto ensuremaximumcrew
efficiency
andutilization.On a numberof previousspacevehicles,noise
andvibrationlevelshaveexceeded
designspecifications
andhaveevoked
crewcomplaints,particularlyin the areasof sleepand communication,
thussuggesting
the needfor bettervibroacoustic
predictionand control
techniques.
In othercases,adversereactionshaveresulteddespitedesign
specifications
beingmet whichsuggests
that earthbaseddesigncriteria
maybeinadequate
for spaceapplications.
A technology
programisbeing
formulatedto developprediction
methods
andcontroltechniques
for use
in the designand operationof spacestationsto ensureacceptablevibroaconsticlevelsfor bearing,communication•
performance,
comfort,and
sleep.The goalsinclude:accuratevibroacoustic
predictionand assessment modelsfor spacestationdesign;criteria for assessing
the effectsof
differentspacestationcrewexposurelevels;and newtechniques
for controlling the vibroacoustic
environmentwithin a spacestation.
3:35
DDD?. Quallfleatlon of a bemi-•nechoic room for sound power level
determination.
Bart L. Burkewitz(E-A-R Division,CabotCorporation,
7911ZionsvilleRd., Indianapolis,
IN 46268}
As part of E-A-R's technicalexpansionprogram for its noiseand
vibrationcontrol laboratory,an interim hemi-anechoicroom has been
addedto the facilities.Consistentwith collectionof qualityacousticdata,
specialacousticenvironments
needto beunderstood.
To accomplish
this,
ANSI StandardS1.35-i 979, "PrecisionMethodsfor the Determinationof
sented.The formulationisdeveloped
asan aid for thedesignof experimentsand experimental
procedures
for measuringthe performance
of
blankets.
The interpretation
of dataacquiredin suchexperiments
istreated in somedetail.A simplifiedanalyticalmodel,whichhas the gross
featuresof the pressure
fieldbeneatha convecting
turbulentboundary
layer,isutilized.Thisserves
toillustrate
thetrendsthatcanbeanticipated
in dataandto illustratethe effectsof undesireable
straypressure
fields.
Somelimiteddatawereacquiredin a quietturbulentpipefacilityandare
treatedwith the developedformalism.Significantfeaturesin the data are
briefly discussed.
4:20
DDDI0.
Water-flow-induced tones associated with resonant fluctuations
of a free floodingcavity.S. A. Elder (PhysicsDepartment,U.S. Naval
Academy,Annapolis,MD 21402}
A towed-modelapparatusdesignedto studynonresonantwater-flow-
inducedcavitytoneswasfoundto exhibitstrongfixed-frequency
oscillalion at certainspeeds.
Stationaryensonification
of themodelbymeansof a
J9 projectordisclosed
sixapparentresonances
in therange0-200 Hz, five
of whichcouldbeexcitedbyflowoverthecavity.Aecelerometer
measurementsof thecavitywall vibrationareconsistent
with thehypothesis
that
the acoustic oscillation is due to fluctuations in the chamber cross section.
The strongest
modewasfoundto occurat a Strouhalnumberpredictable
by a formulapreviously
derivedfor air pipetones.
[Work supported
by
Naval SeaSystemsCommandGeneralHydromechanics
ResearchProgram,administered
by the David W. Taylor Naval ShipR & D Center,
Bethesda,MD.]
Sound Power Levels of Noise Sources in Anechoic and Hemi-Anechoic
Rooms," was selectedas both a tool to guidestudy of the room and a
documentation
procedureto provideassurance
to subscqnent
recipients
of results
oftestsperformed
intheroom.Thispaperwill discuss
thespecific testprocedures
usedto qualifytheroomunderthestandard,dataanaly-
sistechniqu•used,andtheidiosyneracies
involvedin performing
testsof
DDDI1, Measured and predicted features of the quasisteady wall
pressurefield beneathturbulentspotsin a laminar boundarylayer. Fred
C. De Metz (i 1815JelltenAvenue,GranadaHills, CA 91344}
Themeasured
features
ofthequasisteady
components
ofthewallpres-
this type.
3:50
DDDS. Documentprinter sourcenoiseeontrolmA casehistory. Daniel
T. Lilley (E-A-R Division, Cabot Corporation,7911 Zionsville Road,
Indianapolis,IN 46268)
Noisereductionof at least17<lBA-weightedsoundlevelwasobtained
on a multi-function,dot matrix documentprinter by incorporationof
damping,vibration isolation,and modificationof the acousticalpaths
withinthemachine.This resultwasachievedwithoutthe useof sophisticatedmeasurement
andanalysistechniques,
butby consideration
of basic
principlesofstructuraldynamics,applicationof appropriatematerialsin
conjunctionwith minor designmodifications,
and attentionto detail.
Method of measurement
was per ANSI S1.29-1979,"Method for the
Measurementand Designationof NoiseEmitted by Computerand Bust-'
hessEquipment."Emphasisis givento the importanceof usinghighly
dampedisolationmaterialswhichpermitlargeimpedance
mismatches
at
structuralattachmentsiteswhilemaintainingintegrityof staticconnections.A discussion
of noisesourcesand treatmentapproachfor eachis
provided.
4:05
DDD9. Turbolentboundarylayer beneathblankets:Measurementsand
interpretations.F. E. Geib and G. Maidanik (David Taylor Naval Ship
Researchand DevelopmentCenter,Code 1942,Bethesda,MD 20084)
An analytical formulation of the performanceof a blanket asa spatial-
temporalfilter for turbulentboundarylayer pressurefluctuationsis pre-
S113
4:35
surefieldbeneathnaturallyand artificiallygenerated
turbulentspotsin a
laminar boundarylayer are comparedwith thosecalculatedfrom structural modelsbasedon the large-scalemotionswithin the spots.Contrasts
reportedin the literslureconcerningwhetherthe wall pressuredisturbanceduringspotpassage
is initially negativeor positiveand the spatial
distributionof the spot'swall pressurefield are discussed[Cantwell,.
Coles,and Dimotakis,J. Fluid Mech. 87, 641•72 (1978};Mautner and
Van Atta, J. Fluid Mech. 11g, 59-77 {1982}].
4:50
DDDI2. Correlation of flight effectson centerlinevelocity decay for
cold-flowacousticallyexcitedjets. Uwe H. von Glahn (NASA Lewis
ResearchCenter,Cleveland,OH 44135}
Acousticexcitationcaninfluence
thelarge-scale
shearlayerstructure
ofjet flow,thereby
causing
thejet centerline
velocitytodecaymorerapidly. This phenomena
hasnumerouspracticalapplications,
suchas the reductionofjct/fiap impingement
velocityin orderto reduceflapstructural
loadsfor under-the-wingSTOL aircraftconcepts.In the presentpaper.
cold-flowcenterlinevelocitydecaydata obtainedwith acousticexcitation
of thejet exhaustflow are correlatedwith and without flight effects.Initially, static data are correlatedin terms of a new acousticparameter
involvingthe thresholdsoundlevelneededto initiateacousticexcitation
of thejet plume.It isshownthat for a givenflightspeed,thesameacoustic
excitationparameteris valid as that developedfor the static condition.
.Finally,
anaerodynamic
flighteffects
parameter
isincluded
to correlate
the staticand flight centerlinevelocity decaydata with and without acoustic excitation.
S113
FRIDAY
AFTERNOON,
11 NOVEMBER
Session EEE. Architectural
1983
Acoustics VIII
COUNCIL
and Musical
Acoustics VIII:
ROOM,
Architectural
1:30 TO 4:45 P.M.
Acoustics for the
Organ
Ewart A. Wetherill, Chairman
Bolt Beranekand NewmanInc., 21120 VanowenStreet,CanogaPark, California91303
Chairman's Introducfion•l:30
Invited Papers
1:35
EEEL Architectural acoustiesfor the organ. Robert B. Newman (Bolt Beranek and Newman Inc.,
Cambridge,MA 02238}
Organsareusedin manysettings:
churches,
concerthalls,recitalhalls,andevenpracticerooms.An organ
maybeusedasa soloinstrument,asaccompaniment
to a chorus,or aspartofan orchestralcnsemble.
Thereisa
widerangeof apprupriate
acoustics
for theauditoriumaswellasplacement
of theinstrumentandperformer
with relationto theaudience
andto theotherperformers.
Thesematterswill bediscussed.
2.-O5
EEE2. l•eliminry
observationsof the influenceof caseworkof pipe orgmtson room acousticalfields.
BertramY. Kinzey,Jr. (Department
of Architecture,Universityof Florida,Gainesville,
FL 3261l)
A studioorganwasbuiltfor theUniversityof Floridasothatitscasework
canenclose
thepipeworkexcept
fortheopenfrontor beremovedto permitpipestobefree-standing.
Thesoundofpipesin variouslocations
was
recordedat a numberof pointsin theroomwith andwithoutthecasein place.The universityorganistrecorded
the sameBach preludeand fugueusingidenticalregistrationwith and without caseenclosure.Data are
presented
showingthecomparative
spectralanalysis
ofselected
noteswithandwithoutcasework.
Professional
musicians
wereaskedto pickthecasedanduncased
examples
of therecorded
preludeandfugueandgivetheir
reactions.Generally,the soundwith the casein placecontainedlouderlowerharmonicsrelativeto higher
pitchesthansoundfrom free-standing
pipes.Musiciansreadilydifferentiated
betweenthe easedand uncased
examplesof the preludeandfugueandobserved
a betterblendingof encasedhigh-frequency
noteswhichwas
lackingfor free-standing
pipes.
2:20
EEE3. Roomacousticsfor organs.BertramY. Kinzey, Jr. (Departmentof Architecture,Universityof
Florida, Gainesville,FL 32611}
Traditionalcriteriaof veryreverberant
environments
for organmusicare cited.Theseare comparedto
suchconsiderations
assmallinstruments
in smallspaces
vslargeronesin largevolumes.
Theneedforclarityin
theauditionof thepolyphonic
literaturefortheorganisdiscussed
andcompared
to therequirement
of speech
intelligibilityin churches
wheregoodacoustics
forbothmusicandspeech
area goal.All thefactorepregented
relativeto acousticalenvironmentsfor organsindicatethe needfor a broaderrangeof criteria than organists
andorganbuildersandotherstypicallyaccept.
2:35
Presentationsby Panel of Experts
Participants
Daniel W. Martin
BaldwinPianoand OrganCompany,1801 GilbertAvenue,Cincinnati,Ohio
45202
Ronald F. Ellis
M.P. Moller,Inc., 403N. Prospect
Street,Hagerstown,
Maryland21740
Sl 14
J. Acoust.Sec. Am. Suppl.1, VoL 74, Fall 1983
$114
Jean-LouisCoignet
Organier-expert
for theCityof Paris,France,CasarantFreresLte., C. P. 38, St.
Hyacinthe,Quebec,CanadaJ2S 7B2
Manuel J. Rosales
Rosales
OrganBuiMers,
Inc., 160Glendale
Blvd.,LosAngeles,
California90026
Duane A. Kuhn
Classical
OrganDivision,
BaldwinPianoandOrganCompany,
1801GilbertAvenue, Cincinnati, Ohio 45202
LawrencePhelps
Allen OrganCompany,Macungie,Pennsylvania
18062
ContributedPaper
3:35
EEE4. Electroacousticassistanceof parish churchorgan music. R.
L. Prater,F.W. Christie,andC. Stockbridge
(AmericanBellInc., E. D.
& D., Holmdel, NJ 07733)
Whentheneworganist
at St.George's-by-the-River
churchin Rumson,NewJersey
complained
thathisgreatest
effortsat fillingthechurch
nave.Wemeasured
anaverage
reverberation
timenear1.5s(measured
in
thirdoctavebandsupto 8 kHz),9bserved
inefficient
coupling
of sound
energy
fromthepipeorganchamber
viathechancel
tothecongregation,
dueto locationof thesoleacoustic
feedhighin thesidewallof thechancel.
Toaugment
theacoustic
coupling
amicrophone
waspositioned
infrontof
theorganchamber,
andthesignal
wasdigitally
delayed
by82ms,amplified,and fed into a pair of powerfulloudspeakers
positioned
high and
attempted
to quantifythisfeelingandexplorelow-costremedies.
The
against
therearcorners
ofthenave.Thisproduced
a substantial
increase
in soundlevel( > 6 dBover3 octaves}.
Bothweandtheorganist
foundthe
naturalcharacter
of thepipeorganwith thismildelectroacoustic
assist
church is of modestsize, a 8.1 X9.6-m chancelarea and a 19.7X 17.8-m
quitegratifying.
with music seemedfutile becausethe reverberationtime was too low, we
3:50 to 4:45
Panel Discussion
FRIDAY
AFTERNOON,
11 NOVEMBER
GARDEN
1983
ROOM, 2:00 TO 5:07 P: M.
Session
FFF. SpeechCommunication
VIII: SpeechPhysiology
andTiming
Peter J. Benson,Chairman
ITT-DCD, 10060CarrollCanyon,SanDiego,California92131
ContributedPapers
2:05
FFFI. Electroglottographic
andacousticwaveforms
of voiceonsetin
stutterers.Gloria J. Bordenand Thomas Baer (HaskinsLaboratories,
New Haven,C-q'06510)
Thefirstfewglottalpulses
in thestuttered
andfluenttokens
ofvoiced
utterances
bystutterers
wereanalyzed
andcompared
withtheinitialvoice
pulses
inthesame
utterances
bynonstutterers.
Signals
analyzed
werethe
patterns
oftenaccompanied
stuttering
episodes,
withidiocyncratic
strategiesrevealed
forbreaking
thestuttering
block.Theenvelope
forthefirst
EGG cycles
differed
fromnormalforsomestutterers.
Someof thesevere
stutterers
showed
patterns
of gradualbuildupof EGG amplitude
aftera
block,whereasthe mild stutterersand normalcontrolsshoweda more
abruptenvelope.
Whenfluent,all speakers
hadEGGswithabruptenvelopes
anda morestable
openphase
foreachcycle.
EGGactivities
willbe
relatedto theiracoustic
correlates.
[Worksupported
by NIH.]
impedance
changes
acrosstheglottisduringvoiceinitiationvia eleetrog-
Iottography
(EGG)andtheacoustic
waveforms.
In single-cycle
analysis
2:17
of vocalfold vibration,normalspeakers
evidenced
abruptdecrease
in
impedance
withincreasing
vocalfoldcontact,
anda moregradualincrease
in impedance
asthefoldsopened.
Stutterers,
whenperceived
as
fluent,followed
thesamepatternasnormals.
Extremely
aberrantEGG
$115
J.Acoust.
Soc.Am.Suppl.1,VoL74,Fall1983
FFF2. An aerodynamics•udyof stopswith differentphonationtypes.
SarahN. Dart and PatriciaA. Keating{Phonetics
Lab, Departmentof
Linguistics,
UCLA, LosAngeles,
CA 90024}
106thMeeting:
Acoustical
Society
ofAmerica
Sl 15
Measurements
weremadeof intraoralair pressure
and oral airflow
duringtheproductionof stopswith differentphonationtypes.The sounds
investigated
includeKoreanlenisand fortis,and Hindi voicedand murmured,stops.An aerodynamic
modelwasusedto simulatepossible
articulationswhichcouldproduceair flowsandpressures
likethoseobserved.
For example,higherintraoralpressure
andloweroralflowwerefoundfor
functionand/or utterance,and in the coordinationof muscleactivity
patternsfor anyparticulargesture.[Research
supported
by a grantfrom
the NationalInstituteof Health (NS-10424).]
3:05
Koreanfortisascompared
to lenisstops.Thisdifference
followsfroma
simulateddifferencein vocaltract wall tenseness.
Furthermore,the right
shapeof intraoralpressurecurvescan be simulatedwith a differencein
subglottalpressures.This analysis-by-synthesis
approach,combining
physiological
measurements
andarticulatorymodeling,providesnewinsightsinto differences
in phonationtypes.[Work supported
by USPHS
grantNS 18163-02to PeterLadefoged.]
2:29
FFF3. Controlof rate and movementdurationin speech.David J. Ostry,
Kevin G. Muhall, and Avraham Parush(Departmentof Psychology,
McGill University,Montreal, QuebecH3A lB1, Canada)
This paperprovidesevidenceon the controlof rate and movement
duration in speech.A computerizedpulsed-ultrasound
systemwas used
to monitorseparatelytonguedotsummovements
and laryngealgestures
duringthe productionof CV and CVCVC sequences.
The kinematicsof
tongueandiaryngealmovements
wereanalysed
bypartitioning
theloweringgestureof thetongueandboththeabductionandaddution gestures
of the vocalfoldsto give estimatesof displacement,duration,and maximum velocity.For botharticulatorsthe ratioof themaximumvelocityto
the extentof the gesturewasfoundto vary inverselywith the durationof
themovement.
The findingsuggests
thata singlefunctionmightaccount
for a wide rangeof changesin the duration of individualgestures.The
controlof movement
rateanddurationthroughtheregulationof biomechanicalcharacteristics
of speecharticulatorsis discussed.
2:41
FFF4. Ultrasonic orientation methods for tongue scanning. Sandra
L. Hamlet (Departmentof Hearingand SpeechSciences,
Universityof
Maryland,CollegePark, MD 20742)
Real-timeultrasonicimagingof the tonguepresents
a problemin verificationof the orientationof the scan,especiallywhendetailedmeasurementsareto bemade,or replicationof measurements
isattempted.Ultrasonicallyidentifiable
landmarksmaybefreeto move(e.g.,hyoidbone)and
thuspresentan inherentlyunstablereference.A reviewandevaluationof
variousorientationtechniques
is presented,including(I) useof external
facialfeaturesfor transducerplacement,(2) useof ultrasonicallydistinguishableanatomy,{3•placementof oral markersor probes,(4}adoption
of standardspeech
andspeech-like
gestures.
[Work supported
by NIH.]
FFF6. Vibratory patterns of the vocal folds during pulse register
phonation. Robert L. Whitehead, Dale E. Metz, and Brenda
H. Whitehead(NationalTechnicalInstitutefor the Deaf, P.O. Box9887,
Rochester,NY 14623}
In a previous
paperJR.L. Whiteheadeta!.,J.Acoust.Soc.Am. Suppl.
I 73, S47(1983}]we reportedthat duringa singlevowelsampleof pulse
registerphonation,eachvibratorycycleof the vocalfoldsconsisted
of
eithera doubleor triplepulsingmotionpriortoachieving
complete
glottal
closure.Thecurrentpaperpresents
dataon twoadditionalvowelsamples
obtainedon thesamefemalesubjectphonatingin pulseregister.Glottal
area-timefunctionswerecalculated,usinghighspeedlaryngealfilms,for
35 consecutive
cyclesfromonefilm andfor 33 consecutive
cyclesfrom the
other.The resultsfromthefirstfilmindicatedthateachvibratorycycleof
thevocalfoldsconsisted
of a singleopening/closing
gesturefollowedbya
lengthyclosedperiod.The resultsfrom the secondfilm indicatedthat
eachvibratorycycleconsisted
of a doubleopening/closing
vocalfoldpatternfollowedby thelengthlyperiodof closure.Fromourdata,it appears
that one of the physiological
descriptorsof pulsephonationis that of
multiple, as well as single,vibratory patternsof the vocal folds. [Work
supportedby U.S. Departmentof Education.]
3:17
FFF7. Stability analysisof the humanvocalcords.CharlesThompson,
J.Wallace Grant, andSharonA. Starowicz(Departmentof Engineering
Science and Mechanics, Virginia Polytechnic Institute and State
University,Blacksburg,VA 24061)
A mathematicalmodelwill be presentedto describethe behaviorof
the vocalcordsduringthe productionof speech.The modelfor the folds
consists
of two-hinged
gateswhichserveto modulatetheflowthroughthe
glottis.The degreeof flow modulationis relatedto the angulardisplacementof thegates.Equationsgoverning
themechanical
motionof thegates
arederivedbysatisfying
conservation
of massandmomentum
across
the
glottis.The introduction
of acoustic
impedance
of thevocaltractserveto
couplemechanical,acoustic,andfluiddynamicelementsof themodel.A
linearstabilityanalysiswill bepresented
detailingtherangeof mechanical
constantsfor whichthe motionof the gatewill becomestable.It is shown
that stability of the gate motion is not dependenton the trans-glottal
pressuredistributionbut on the acoustic-mechanical
interaction.
3:29
FFFS. Differential negative resistancein a one-massmodel of the larynx
2:53
FFF5. Jaw muscle activity for speech and nonspeechgestures.
Michele Gcntil and Thomas Gay (Department of Oral Biology,
Universityof ConnecticutHealth Center,Farmington,CT 06032)
The activity patternsof the mandibularelevatormusclesystemwere
investigated
for speech
andnonspeech
gestures
for thepurposeof determiningthe possibilityof nenromuscularspecializationfor speechin relation to other mandibular functions. Intra-muscular wire electrodes were
placedinto the sevenmudesof themandibularsystemandthe anterior
belly of the digastric.The activityof thesemuscleswasrecordedalong
with a time varyingmagnetometervoltagethat corresponded
to the dis-
placement
of thejaw in twoandthreedimensional
space.Thesesignals
wererecordedfrom threeadult AmericanEnglishsubjectsduringthe
productionof speechat differentratesand for nonspeech
gesturesthat
includedbordermovements,
functionalopening-and-closing
and mastication.Resultsindicatedthatjaw spacefor speechisthe mostrestrictedof
any mandibularfunction,jaw movementsfor speechare generallyproducedby the most simplemuscleaction patternsand individualdifferencesexistin theselection
ofa givenmuscleor musclesystemfora specific
S116
d. Acoust.Soc. Am. Suppl.1, VoL 74, Fall 1983
with supraglottalresistance.William A. Conrad (30 W. 71 Street,New
York, NY 10023)
The steadyflow calculationsof Conrad [Conferenceon Physiology
andBiophysies
ofVoice,Iowa(1983)],showthatthelarynxcanmanifesta
differentialnegativeresistance,
i.e., translaryngeal
pressure
candecrease
as flow rate increases. These calculations
were based on the one-mass
modelofFlanaganandLandgraf[IEEE Trans.AudioElectroacoust.
AU16, 57-64 (1968}]with addedsupragiottalresistance.
If the springacting
on themassischangedfromlinearto nonlinear,thedifferentialnegative
resistance
becomes
boundedby two regionsof positivedifferentialresistance.As nonlinearstiffnessincreases,
differentialnegativeresistance
disappears.The one-massmodel plus supraglottalresistancecan be describedas an N-type, flow-controlled
nonlinearresistance,
QNLR. It is
well knownin electronicsandelsewherethat a QNLR in a seriesresonant
circuit can transformde powerto osci!latorypower[e.g., Ph. le Corbei!ler,Proc. Inst. Elec. Eng. 79, 361-378 (1936}].The systemcan be
usefullyanalyzedin termsof vander Porsequationwhichgivestheoscillationcondition,the frequency,rateof build-up,limitingamplitudeand
efficiency.The analysisshowsthat differentialnegativeresistanceis a
necessary
conditionfor oscillation.
Sl 16
3:41-3:55
Bre•k
ContributedPapers
3:55
FFF9. Durational characteristicsof vocal and subvocalspeech.Bruce
L. Smith and JamesHillenbrand (Speechand LanguagePathology,
NorthwesternUniversity,2299 SheridanRoad, Evanston,IL 60201)
In an attemptto investigateissuesrelatedto speechtiming,adult sub-
jectswereaskedtoperformtwotasks.Theyproduced
a numberofdisyllabicwordsandphrases
orally,andtheyalso"thought"thesamewordsand
phraseswithoutvocalizingthem.Someof the stimuliwereeasyto pronouncele.g., "baseball"),while others were more difficult (e.g., "wrist
watch"}.Subjects
repeatedeachstimulus20 timesin succession
asrapidly
and as accuratelyas possible.Durationsof vocaland subvocalproductionswere measuredby havingsubjectstap the spacebar of a computer
terminaleachtime theysaidor thoughtthe word.Measurements
of intertap intervalssuggest
that stimuliwhichweremoredifficultto pronounce
vocally(indicatedby longerinter-tapintervals}werealsomoredifficultto
producesubvocally(r = 0.86}. However,subvocaldurationsaveraged
about15% shorterthanoral productions.
Thesefindingsappearto support modelsof speechproductionwhichproposethat speechsegments
havetemporalcharacteristics
associated
with themat theabstractorganizationallevel,but the resultsalsoseemto showoutput-leveleffectsas
well.
4:31
FFF12. Computationof mappingfrom muscularcontractionpatternsto
formantpatternsin vowelspace.Y. Kakita (KurumeUniversitySchool
of Medicine, Kurume, Japan) and O. Fujimura (Bell Laboratories,
Murray Hill, NJ 07974}
In previouspapers[J. Acoust.Soc.Am. Suppl.1 62, S15(1977);
in
Frontiers
ofSpeech
Communication
Research,
editedby B. Lindblomand
S.Ohman(Academic,London,1979)],pp. 17-24,wedemonstrated
thata
three-dimensional
staticmodelof the tonguecanbe usedto explainsome
basiccharacteristics,
in particularan insensitivity
of the formantpattern
of the vowel[i] to changes
in the magnitude
of musclecontraction
force
overa widerangewhenan appropriate
setof muscles
is used.We have
implemented
a computerprogramto computesystematically
the mapping relationbetweenvariouscombinations
of musclecontractions
and
theresultantformantfrequencies
in thevowelspace.Muscularmodeling
fordifferentvowelsarebeingexperimented
basedonavailableanatomical
andphysiological
data,inparticularthosereported
byK. Hondaetal. [J.
Acoust.Soc.Am. Suppl.172, S103(1982)].Eventually,aftertheworkby
M. V. Mathewset al. [J. Acoust.Soc.Am. 63, 1535(1978)]on mapping
betweenareafunctionsandformantpatterns,thiswouldillustrateinherent characteristics
of the inverserelationsfrom F patternsto muscular
patterns
forvowels.
Uniqueness
problems
willbediscussed
withquantita4:07
FFFI0. Acoustic characteristics of flap productions by American
English-speaking children and adults. Robert Rimac and Bruce
L. Smith(Speechand LanguagePathology,NorthwesternUniversity,
2299 SheridanRoad, Evanston,IL 60201)
Acousticcharacteristics
of underlying,intervocalic/d/ and/t/ flaps
produced
by a numberof childrenandadultswerestudiedto determine
whetherchildren'sflapsshowedsimilar propertiesto their other speech
segments
whencompared
withadults'productions.
Closuredurationsof
flapsandotherconsonents
anda numberof voweldurations
weremeasuredusinga laboratorymini-computer
system.Contrasts
suchas"pudding/putting"and"writer/rider"produced
in a carrierphrasewereelicited usingpicturessothat no auditorymodelwouldbe availablefor the
children.Preliminaryresultsshowedthat flapsfrom underlying/d/were
about10% longerin durationthanflapsfromunderlying/t/for boththe
childrenandadults.Althoughstressed
vowelspreceding
underlying/d/
flapswerelongerindurationthanthosepreceding
underlying/t/flaps
for
bothgroups,thiscontrastwassubstantially
greaterfor the adults.It was
alsoobserved
that flapdurationswereapproximately
40% longerfor the
children than for the adults, while the durations of the children's vowels
andnonflapconsonant
productions
weremorecomparable
to the adult's
durationsfor thosesegments.
tive examples.
4:43
FFF13. Componentsof lingual and labial articulation. Jan Edwards,
Katherine S. Harris (Graduate Center, CUNY and Haskins
Laboratories, 270 Crown Street, New Haven, CT 06510}, and
Betty Tuller(CornellUniversityMedicalCollege,Ithaca,NY 14853and
HaskinsLaboratories,270 Crown Street,New Haven, CT 06510)
One problemin speechproductionresearchis that it is difficultto
relate muscleactivity in individual articulatorsto the resultingmovements.In largepart, thisis because
movementof any givenarticulatoris
highlydependenton movementof connected
structures.Both tongue
bladeandlip movements
containa component
dueto jaw movementin
additionto a componentthat reflectsmuscleactivityof the tongueor lip.
Usingdata obtainedby the x-ray microbeamsystem[Kiritani et al., J.
Acoust.SOC.
Am., ( 1975)],tonguebladeandlip movements
wereseparated into thesetwo components.
Dynamiccharacteristics
of tongueblade
articulationof/i/and/a/and
labial articulationof/p/were examined
acrossmultipletokensof two to four syllablenonsense
utterances.The
timingof lip andtonguebladearticulationsrelativetojaw raisingfor/p/
andjaw loweringfor/i/and/a/is
influencedby surroundingphonentic
contextand syllablestress.It wasfoundthat the lip and the tongueblade
compensate
for somebut notall of thevariations
in inter-articulator
timingandpositioning.
[Worksupported
by NINCDS.]
4:19
4:55
FFFll. Effects of phrasing and word emphasis on transitional
movements•Location and stability of tongue blade iceberg patterns.
O. Fujimuraand W. R. Spencer(BellLaboratories,
Murray Hill, NJ
07974)
In previous
ASA meetings,
it wassuggested
thatcertainmovements
of
an articulator that is crucial for both CV and VC identities were often
observedunaffectedin their nearpeakpartsas stablefragmentaltime
functions,evenwhenlargevariationin otherportionssuchasvowelportionswasintroducedby prosodiccontrol.By an automaticprocedure,we
haveidentifiedthe partsof demisyllabic
transitionsthat are likely to be
stableundermanipulationof phrasingsuchas(21 + 2}X 3 vs21 + (2X 3},
and contrasfiveemphasesplacedon differentwordsin a sentencesuchas
"It's 9 8 11 Brooks Drive." The data were obtained by the computer
controlledx-raymicrobeamsystemat the Universityof Tokyo [Kiritani,
Itoh, andFujimura,Acoust.Soc.Am. 57, 1516-1520(1975)],andpertain,
in thispaper,to theverticalpositionof a metalpelletplacedon thetongue
blade.
$117
FFF14. The word-position similarity constraint on segmental speech
errors: Further experimental results. StefanieShattuck-Hufnagcl
(Research Laboratory of Electronics, MassachusettsInstitute of
Technology,Cambridge,MA 02139)
In earlierexperimentsit wasshownthat speecherrorsinvolvingthe
interactionof two targetsegments
arcgovernedby a word-position
similarity constraint:
two segments
are morelikelyto interactin an error if
they are word initial then if they are stressed-syllable
initial or simply
syllableinitial. Further experimentshaveshownthat thiseffect( 1) is more
pronouncedfor nonwordsthan for words, suggestingthat the phenomenonarisesduringthecomputationof a short-termrepresentation
of the
unitsof theutteranceratherthanduringlexicalaccess,
and(2)isfoundin
sentencegenerationtasksaswell as in the originaltongue-twisterrepeti-
tiontasks,makingan expla•nation
in termsof memoryconstraints
less
likelyandan accountin termsof productionplanningmorelikely.[Work
supportedby NIH-NINCDS Grant •2 RO I NSO4332 19.]
$117
FRIDAY
AFTERNOON,
11 NOVEMBER
1983
FORUM ROOM, 1:00 P.M.
SessionGGG. UnderwaterAcousticsVII: SignalProcessing(Pr6cis-PosterSession)
Harry A. DeFerrari, Chairman
Rosensteil
Schoolof MarineandAtmospheric
Science,University
of Miami, 4600Rickenbacker
Causeway,
Miami, Florida
33156
Chairman's
Introduction•l:00
Invited Papers
L-OS
GCA•I. High-resolution
beamforming
withoversampled
arrays.CharlesL. Byrne(TheCatholicUniversityof
America,Washington,DC 200641and RaymondM. Fitzgerald(Naval ResearchLaboratory,Code5120,
Plane-wavebeamforming
is interpretable
asestimationof theFourierwavevectorspectrumfromsamples
of the spaticilydependentacousticfield.Becausespaticilylocalizedsourcescontributediscretepeaksto the
wavevectorspectrum,the useof high-resolution
nonlineartechniques(suchas Burg'smaximumentropy
method--MEM) to resolvecloselyspacedsourceshasreceivedmuchattention[Johnson,Proc.1EEE 70{9),
1018-1028{I 982}].Suchtechniques
areexpectedto bemostusefulfor shortarrays,whosedimensions
do not
exceeda few wavelengths,for whichcaseconventionalbeamformingofferspoorresolution.Suchshortarrays
typicallycontaina numberof hydrophones
andthusoversample
thespatialfield;thespacing
betweenadjacent
hydrophones
is lessthan one half a wavelength.When MEM is appliedto oversampled
arrays,spurious
featuresarcoftenproduceddueto theconcentration
of thespectrumwithinthevisibleregionof wavevectors.
Thesespuriousfeaturescanbe eliminatedthroughthe useof a moregeneralhigh resolutionprocedure,the
weighted
reciprocalspectrum
approximation
method[ByrneandFitzgerald,IEEE Trans.Acoust.Speech
SignalProcess.
ASSP-31,276-279 {1983)].
1.-30
GGG2. Signal design considerationsfor long-rangeshipboardactive sonar. Thaddeus G. Bell (Naval
UnderwaterSystemsCenter,New LondonLaboratory,New London,CT 06320}
Ifs long-range
shipboard
activesonaristosuccessfully
covertargetranges
outto thefirstconvergence
zone
at 35 miles,an optimumfrequencyabout3 kHz is impliedalongwith a usablebandapproximating1.5 kHz.
This modestbandhasmanycompetingdemandson its utilizationbesidessignaldesign,someof whichare
subbandallocationsfor: multiple-shipmutualinterference,
increased
data rate, and adjacentsectorcoverage
withoutreverberation
buildup.The basichandsegmentavailablefor signaldesignmustbe usedto copewith
eitherhigh or low Doppler echoesin a combinationof noiseand reverberationinterference.Echoesdiffer
significantly
fromthetransmitted
signalfromspreading
effects
bothin timeandfrequency.
Timespreading
can
beproduced
by multiplepathsandtargetstructure.Frequency
spreading
canbeproducedby targetandown
shipmotion.Reverberation
spectracanbesignificantly
influencedby wavemotion,own shipmotion,relative
bearingof transmission
andbiologicalscatteringresonances.
Selectedsignaldesignoptionsareconsidered
for
copingwiththeforegoing
signalandinterference
characteristics.
Methodsof estiniating
consequent
detection
performanceare presented.
ContributedPapers
1:55
GGG3. Source depth classificationby modal decompositionand
correlation.DeWayne White and StanleyChin-Bing{Naval Research
and Development Activity. Numerical Modeling Division. NSTL
correlationfor replicashavingthe target'strue depth.At present,synthesizeddatacontainingnoisehasbeenusedfor comparisons.
However,the
methodshowspromiseofbeinga usefultoolfor depthlocalization.Exam-
pieswill bepresented
for bothverticalandhorizontalarrays.
Station,MS 39529)
Variousmethodshavebeenandarebeingusedto classifyandlocalize
submarinetargetsusingreal-timeinformationfromacousticsensors.
We
haveinvestigated
anothertechniquewhich utilizesthe environmentand
its variabilityto excludeItheoretically}
all possibletargetdepthsexcept
the correctone.The methodinvolvessynthesizing
the normalmodesusingthebestavailablesoundspeedprofileandgeoacoustic
modelasinputs
to a complexnormalmodemodel.Bothsinglefrequencyand broadband
fieldscanbemodeled.Thesesynthesized
modesaresampledin depth(or
range)
toforma suiteof replicas.
Thesynthesized
replicas
arethencorrelatedwith the roodallydeconvolved
incomingdata havingthe samespatial samplingasthe replicas.The ambiguitysurfaceshowsrelativelyhigh
S118
1:59
GGG4. A comparisonof spatial spectrafrom vertical line arrays of
differentapertureusingmaximumentropymethod(MEM) beamforming.
Mimi Zebrick Lawrence(ODSI DefenseSystems,Inc., 61i0 Executive
Boulevard,Rockville,MD 20852)and Dan J. Ramsdale(Naval Ocean
Researchand Development
Activity,OceanAcousticsDivision,Code
345, NSTL Station,MS 39529•
This studywas undertakento providea preliminaryanswerto the
question
of howaperturesizeaffectsbeamwidth
andresolution
for vertical linearraydatawhichisprocessed
usingthe(MEM) beamformer.
This
Sl 18
wasdoneempiricallyby examining
the(MEM) beamformed
outputof a
nine-element
verticalline array and reducingthe apertureby deleting
hydrophones.
Narrow-bandacousticdata wereprovidedby a cw source
(54Hz) whichwastowedat a nominaldepthof 91 m radiallyawayfrom
thearray.The(MEM) beamformer
wasimplemented
usingtheBurgalgorithm in complexform with averagingperformedoverthe filter coefficients.The spatialspectrum
wascharacterized
in generalby two dominantarrivalswhichvariedin angularseparation
andlevelrelativeto the
background
noise.For arrivalswith highsignal-to-noise
ratiosand large
angular separation,preliminary resultsshowedlittle degradationin
beamwidth
astheaperturewasdecreased
by a factorof two.As theangular separation
betweenarrivalsdecreased
or whenthesignal-to-noise
ratio
decreased,
beamwidthand resolutionwere degradedwhen the aperture
was reduced.
tionlevelsfor thispurposeis found.Whena signalexceeds
the saturation
levelof the A/D converter,spurioussignalswill be generatedat new
frequencies,
whichmay aliasbackuponthebandof interest.When two or
more signalsjointly exceedthe saturationlevel, intermodulationeffects
amongsignalshavingdifferentarrivalanglesmayproducespurioussignalswhicharecoherent
across
thearray.Thesesignals
appearin frequency-wavenumber
spaceasfalsetargets.An analysisanda computersimulation of this effectare presented.
The requirements
on the minimum
acceptablesaturationlevelof the A/D converterare determined.
2:15
GGG8.Interpolationnoisein a hard-limitedbeamformer.
J. W. Young
(Bolt Beranek and Newman Inc., 3065 RosecransPlace, Suite 208 San
Diego, CA 92110)
2:03
GGGS. Re•po•se of a towed•rray to acousticfieldsin shallowwater. M.
J. Buckingham
a•(NavalResearch
Laboratory,
Code5120,Washington,
DC 20375)
An analysisof the response
of a towedarray to the modalfield in
isoveloeity
shallowwaterispresented.
In general,theresponse
consists
of
a coherentsum over all the modes.However, when the sourceis endfire-on
to the array, or in that vicinity,the towingmotionintroducesa certain
amountof rangeaveraginginto the response
to the farfieldradiation.A
criterion is given, in termsof the interferencelength betweenthe two
lowestordermodesin the field,for the degreeofrangeaveragingrequired
to reducethe outputof the array to an incoherent
sumoverthe modes.
This sum is associatedwith a set of virtual sourcesdistributed in azimuth,
eachof whichis associated
with a particularnormalmode.This means
thatsomesignalenergyisrejectedby thearray,whichresultsin a reductionin the signalgain.At thesametimebeambroadening,
or in extreme
casesbeam splitting,arisingfrom the angularspreadof the virtual
sources,
occurs
andthismaygiverisetoa significant
bearing
error.• Currentlyonexchange
fromtheRoyalAircraftEstablishment,
Farnborough,
Hants, UK.
2:19
GGG9. On the useof focusedhorizontal arrays as modeseparationand
source location devices in ocean acoustics-numericalmodeling results
2:07
GGC•.
Beamforming
typicallyrequiressamplingof individualhydrophone
outputsat a rate substantiallyhigherthan Nyquistfor bandpassprocesses.One approachto minimizingthe samplingrate is the useof an
interpolationfilter for reconstruction
of intermediatesamplevaluesJR.
G. PridhamandR. A. Mucci,J. Acoust.Soc.Am. 63,425-434(1978)].In
principle,therequiredsamples
canbedeterminedwithouterrorfromthe
Nyquistratesamplessincethe lattercontaincompleteinformationon the
band-limitedelementsignal.When the elementsignalsare hard-limited,
all amplitudeinformationislostanderrorsareintroducedintotheinterpolationprocess.
Informationin a hard-limitedsignal(HLS) iscontained
in thezero-crossing
times.Basically,sampling
a HLS obliterates
theinformationnecessary
to determineexactzero-crossing
timesbetweensample
values.In this paper,we presentan analysisof the meansquareerror
(interpolationnoise)associated
with estimatingthe valuesof the I•LS at
intermediate
times.We computetheincrease
in beamnoisepowerdueto
this error and showthat this imposesa limit on our ability to perform
adaptivenull steeringwith suchan array.
A look at detection performance for maximum entropy
beamforming.
Arthur J. Collier(Code5122,NavalResearch
Laboratory,
Washington,
DC 20375)
A statisticalinvestigation
of the detectionperformanceof maximum
entropybeamforming
for low levelsignalsisdescribed.
The investigation
wasperformed
fora horizontallinearraywitha half-wavelength
frequency of 500Hz. Bothsparseandfilledarrayconfigurations
wereinvestigated. Realisticmodelsof a deep-waterambientnoisefield and array self-
noisewereusedto definetheexpected
cross-spectral
matrixfor thearray
in a noisefield.Signalsof 60, 200,and400 Hz comingfrom nearbroadside
and near end-fire were considered. The detection statistics were obtained
by generating
samplemeancross-spectral
matriceswith a Wishartdistribution,usingthe Bartlettdecomposition
as implemented
by Smithand
Hocking[AppliedStatistics,
1972].The resultsaresummarized
in ROC
James F. Lynch (Department of Ocean Engineering,Woods Hole
OceanographicInstitution, Woods Hole, MA 02543) and Daniel
K. Schwartz(Departmentof Physics,HarvardUniversity,Cambridge,
MA 02138)
It hasbeenshowntheoreticallythat one can performnormalmode
separation
and sourcelocationusingfocusedhorizontalarrays[J. F.
Lynch,J. Acoust.Soc.Am. (to be published)].
To illustratethis theory,
numericalmodeling
results
aredisplayed
forbothlineandconvexcirculaly curvedarraysin range-dependent
and range-independent
waveguide
environments,
bothin thepresence
andabsence
of sourcemotion.Various
topicsto bediscussed
include:directmeasurement
of modalgroupvelocities from movingcw sourcemeasurements,
determinationof environmentalrangevariations,modeinterference
effectsandray theorymultipath focusing,and the intercomparison
of focusedarray modefiltration
with other standardtechniques,e.g., steering.
2:23
2:11
GGG7. Digitizing effectson noisedynamicrangeand signalspectrain
broadbandarrays.M.D. Green,J. W. Young, and F. I. M. Sullivan
(Bolt Beranekand Newman Inc., 3065 RosecransPlace,Suite208, San
Diego,CA 92110)
Digitizing of the signalsfrom elementsin an acousticarray resultsin
GGGI0. Initial seatest resultsof a multi-hydrophonedigital buoy system
with in-situ Fl:r processingcapabilities.Peter C. King and Peter
D. Herstein (Naval UnderwaterSystemsCenter, New London, CT
06320)
Two majorproblemshavebeenhistoricallyassociated
with self-containedanalogacousticdata acquisitionbuoysystems.
First, analogtape
recordercharacteristicsbound the obtainabledynamic range of the re-
varioustypesof errorsin the beamforming
process.Amongtheseare
quantizationnoise,clippingnoise,spectraldistortion,and false-target
ceiveddata. Second,post-processing
of the data tapesto obtainthe requiredacousticinformation
canbebothtimeconsuming
andexpensive.
generation associatedwith clipping. This paper presentsan analysis of
To addressthese problems, a new buoy has been developedat NUSC.
theseeffectsin the contextof designrequirementsfor a broadbandreceiv-
Acousticdata from eachof eighthydrophonesis digitizedand then fast
Fouriertransformedby the buoy'smicro-processor.
Complexandensembleaveragedspectralresultsare thenwrittenontoa digitalcassette
tape.
ingarray.The arraymustoperateovera specified
dynamicrangeof ambientnoise.A methodisdeveloped
for ensuringthatthesumof quantizationnoiseandclippingnoisewill bekeptat a specified
levelbelowambient
noiseoverthe entireoperatingrange.The optimumselectionofquantiza-
S119
An instantaneous
dynamicrangeof morethan72 dB isavailableoverthe
frequencyband2-350 Hz. The spectralresultsare computedin 2 Hz
Sl 19
increments
and Harmingweightingis used.The first at-seatestof the
systemoccurredin August1983at a deepwaterlocationnearBermuda.
In thispaperwewillpresent
results
fromthaitest.Received
signals
from
stationaryandmovingcw sources
will be emphasized.
[Thiswork was
sponsored
by theSurveillance
Environmental-Acoustic
SupportProject
{SEAS},NavalOceanResearch
andDevelopment
Activity,Code520{C.
E. Stuart,ProgramManager}.]
2-.39
GGGI4. The influence of environment and source motion on broadband
acousticcorrelations:
A nornmlmodeapproach,
Robert Gragg(Applied
ResearchLaboratories,The Universityof Texasat Austin, Austin,TX
78712-8029)
Wedealwitha sourcewhichemitsa broadband
signal$(t }whilemov-
ingthrough
a shallow
{<300m),range-invariant
environment
atconstant
speed,
depth,andbearing.
The received
signalis constructed
fromthe
result[K. E. Hawker,J. Acoust.Soc.Am. 63, 675-681(1979}]for the
$ {t)• e• case.In termsof Fouriertransforms,
2:27
GGGll. Sidelobe level of hyperbolicfrequencymodulated(HFM)
waveforms.
S. I. Chou (Naval OceanSystemsCenter,SanDiego,CA
^
P{r,z,t}•• (S{ca)expl
{ik,{to)
n
92 i 52)
X [ I -- e,(co)cos
0 (t)] Ir -- r,•{t
As largetime-bandwidth
productsareemployedfor the widelyused
LFM (linearfrequency-modulated)
waveforms,
thelossdueto thephase
mismatch
of thepeakoutputof a singlematchedfilterbecomes
excessive
evenfor verymoderatetargetradialspeeds.
HFM {hyperbolic
frequency
modulated}waveformscaneliminatethis loss.An early resulton sidelobe
levelof HFM waveform[J. J. Kroszczynski,Proc. IEEE $7, 1260-1266
{1969}]apparently
haserrorsin itsderivation
in applyingasymptotic
approximation
techniques.
Theonlynumerical
resultprovided
theredidnot
agreewell with the analyticallyderivedresult,despitethe claim to the
contrary.In the presentpaper,newasymptoticresultshavebeenderived
usingintegrationby partsin thecorrectdirection,sothat termsdiscarded
aresmallerthanthequantitybeingapproximated.
Computersimulations
usingseveralsetsof parameters,
includingtheonementionedabove,comparewell with the newanalyticapproximations.
The increased
sidelobe
level of HFM
waveform over that of the LFM
X g../•*
[;,ca,{cod
}1U, [zo,o, {co,t
}]}"
is the signalat r,z,t from a sourceon trajectoryro{t}at depthzoand speech
uo. O(t) is the source-receiverangle, e•(co}=v•/t/•ca}(I,
and
to,,{co,t
) = to- vok,{ca)leos
O{t) -- e, {co}]
isa Doppler-shifted
frequency.
We model subkilohertz-band
signalsin this way for fixed explosive
sources
{SUS)andfor movingnoisesources.
The signalanditsautocorrelationarecomparedwith experimental
data to determinethe importance
of environmentalfactors{grossSVP features,finerSVP details,bottom
attentuationprofile}and sourcemotion{speedand cparange),aswell as
sourceandreceiverdepths.[Work supported
byDARPA TTO andNaval
ElectronicsSystems
Command{Code612}.]
one is much less than
indicatedby the early approximation.
GGGIS. Cross correlation of two hyperbolic-frequency-modulated
{HFM} waveforms.
S. I. Chou{NavalOceanSystems
Center,SanDiego,
2:31
GGG12. Array gain improvementsat low SNR and low frequencyvia
maximumentropybeamforming.Donald R. De1Balzo{Naval Research
Laboratory,
Code5.120,
Washington,
DC20375}
It isfairlywellaccepted
that nonlinearbeamformers
will significantly
improvearrayperformance
for the caseof moderateto highinputSNR
and near the designfrequency.Most applicationsof high-resolution
beamformershave beentarget resolutionand localization,assumingan
initial detectionhas beenmade. This work addresses
array gain at low
SNR for bladeratefrequencies
well belowdesignusinga maximumentropy beamformer{MEB} on a horizontal,bottomedarray. Simulation
resultsshowarraygainimprovements
for theMEB, whencomparedto a
conventionalapproach,that dependon the input SNR and averaging
time.
CA 92152}
In a multi-userradar/sonarenvironment,or in thecaseof a singleuser
but with differentpulsestransmitted,it is important to know the cross
correlationof the waveformsasa functionof time delay.The cross-correlationpropertyof two differentlysweptLFM {linear-frequency-modulated}waveformsisstraightforward
fromtheviewpointof usingthestation-
ary-phase
approximation.
There,asonewaveform's
frequency-time
curve
slidesagainstthe other's,the intersectingangleremainsconstantoveran
interactionintervalin timedelaycorresponding
to thecommonfrequency
intervalof thetwowaveforms.
The picturechanges
vastlywhenthetwo
LFM waveforms
arereplacedby t.woHFM {hyperbolic-frequency-modulated}ones.In this paper,the crosscorrelationover suchan intervalis
established.
Usingexamples,the analyticalapproximationis shownto
comparefavorablywith numericalsimulationresults.The difference
betweentheanalyticandnumericalresultsis furthercharacterized
using
the unity volumeconstraintfor narrow-bandcross-ambiguity
function
which is lesserknownthan the auto-ambiguitycounterpart.
2:35
GGGI3. A ray theory simulatorof a movingbroadbandsource.James
D. RatlilT and Clark S. PenrodlApplied ResearchLaboratories,The
Universityof Texasat Austin, Austin, TX 78712-8029}
A computermodel is describedwhich simulatesand processes
the
timeseriesreceived
froma movingbroadband
source.Ray theoryisused
2.-47
GGG16. Coherent wavefront resolution. Donald A. Murphy {1062
Valencia Mesa Drive, Fullerton, CA 92633•
Resolvingcoherentarrivalsis fundamentallydifferentfrom resolving
to computethe setof eigenraysinstantaneously
valid at eachsourceemissiontimein a rangeinvariantenvironment
characterized
byan arbitrarily
depth-dependent
water-columnsound-speed
profileatop a singlesediment layerwith linearsoundspeedand attenuationprofilesoverlyinga
arrivals from independent sourcesbecausean interference field is created
semi-infinite
homogeneous
substrate.
The received
timeseriesisobtained
by a discretetime domainconvolutionof an arbitrarysourcewaveform
with a setof impulseresponses
whichdependonemission
timeandpropagationpath.Thereceived
timeseries
canbeautocorrelated
or crosscorrelatedto examinetheimpactonbroadband
signalprocessing
dueto environmental(particularlybottominteraction}
effects,sourcemotioneffects
IDopplerandmultipathstructure
evolution},
andthechoiceofsignalprocessing
parameters.
Examplecorrelationfunctionsareshownto illustrate
the effectsof someof thesemechanisms.
[Work supportedby Naval
OceanResearch
andDevelopment
Activity,Code530.]
null of the interference field at its center will resolve the two arrivals for
S120
by the coherentarrivals.This resultsin a fieldwhichis not spatiallystationary.At highsignal-to-noise
ratiosconsiderably
betterresolutionis
possiblethan for the caseof independent
sources.An array whichhasa
aperturesconsiderably
smallerthan expectedby usingthe Rayleighcriterion.The phasedifferenceof the two arrivalsiscriticalto resolutionin tMs
case.Resolutionof this type was observedwith signalswhich were receivedat a fixed array in the deepoceanfrom a singlelow-frequency
sourceover long propagationpathsthroughcomplicatedsoundspeed
structures,thusdemonstratingthe coherenceof the multipathsinvolved.
The coherence
of the verticalmultipathsfollowsfrom thediscretenature
of the arrival structure.In this caseeachmultipathis not appreciably
spreadin arrival angle.
S120
2:51
2:55
GGGI?.Sensitivity
ofa passive
horizontal-tracking
algorithm
toinputJ. Jacobson
(Rensselaer
PolytechnicInstitute,Troy, NY 12181)
GGG18. Eigenvaluedetectionthresholdstatistics.PeterC. Mignerey
(Naval ResearchLaboratory,Code 5120 Applied Ocean Acoustics,
We considerthe passivedeterminationof bearing,range,depth,frequency,andhorizontalvelocityfor a narrow-band
acoustic
sourcewhich
movesat constantdepth.An algorithmfor trackinga movingsourceis
A promising
methodforhigh-resolution
beamforming
onunderwater
arraysis the eigenvector
decomposition
methodwhichrequiresknowledgeof theexpected
noisein orderfor multipleeigenvalues
to occur.[D.
developedandemployed,usinga horizontallineararraywhichistowedat
fixeddepth.The sourceandreceivermovewith constanthorizontalvelocity in the upperportionof a deepoceanand are separatedby relatively
H. Johnsonand S. P. DeGraaf, IEEE Trans. AcousticsSpeechSignal
Process.
30, 638(1982).]It ispresently
notwellunderstood
howto objectivelyseparate
thesignalandnoisesubspaces.
Whenthecorrelationma-
shortrange.Acousticsignalsare presumed
to arrivealongtwo upperoceanraypaths.Thetrackingisaccomplished
usinga newcombination
of
processed
multipathinformationfrom the ray paths,frequencyshifts
froma cw emission,anddirectionalmeaurements
from the lineararray.
The sensitivityof predictionsfor three-dimensional
position,frequency,
becomes
full andthe½igenvalues
spread.Undertheseconditions
theclassification
of eigenvalues
maybemadeusingstatistical
methods.
A Gaussianprocess
wasappliedto thehydrophones
of a ten-element
filledarray
andsamplenoisematricesweregenerated
in themetricof otherindepen-
measurement
errors. P. Bilazarian,
'1 W. L. Siegmann,and M.
and horizontalvelocityare demonstratedfor smallvariationsin environmentalparametersand acousticmeasurements.
Resultsfor a varietyof
source-receiver
configurations
are discussed.
Varianceestimatesof position and motionpredictionsare obainedin termsof input measurement
tricesareestimated
witha finitenumberof degrees
of freedomtherank
dent samplenoisematrices.Probabilitydensitieswere obtainedbasedon
106samples
foreacheigenvalue
andthebroadside
beamof conventional,
maximumlikelihoodandmaximumentropybeamformers.
A comparison
of ROC curvesdemonstrates
sufficientdetectioncapabilityby the eigen-
variances.
[Worksupported
byONR.],I Present
address:
SienaCollege,
value method to allow the establishment of detection thresholds for the
Loudonville, NY 1221I.
objectiveclassification
of eigenvalues.
FRIDAY
AFTERNOON,
11 NOVEMBER
1983
SENATE/COMMITTEE
ROOMS, 1:00 TO 4:35 P.M.
SessionHHH. Underwater AcousticsVIII: Scattering and Noise
Herman Medwin, Chairman
Departmentof Physics,
NaoalPostgraduate
School,Monterey,California93940
Chairman's
Introductionml:00
ContributedPapers
1:05
HHH1. Surfacestatisticsand the spatialcoherenceof surface-scattered
energy.W. A. Kinney (NORDA Code 340, NSTL Station,MS 39529)
and C. S. Clay (Departmentof Geologyand Geophysics,
WeeksHall,
Universityof Wisconsin,
Madison,WI 53706)
The facet-ensemble
method[W. A. Kinneyet al., $. Acoust.Soc.Am.
73, 183-194(1983}]wasusedto determinehow the statisticsof a rough
surfacerelate to the spatialcoherenceof energyscatteredfrom it. Two
The backscattering
from a manganese
nodulefield is studied.The
theorypredictsa dependence
of reflectivity
onacoustic
wavelength,
noduleshape,nodulesizeandnumberof nodules
perunitarea.Firstresults
froma recentdeeptowexpedition(ECHO Leg01, June1983)arepresented. The variabilityof reflectivitywith nodulecoverage
and sizeis discussed
for eachof severalfrequencies
(4.5,9, 28, 60, 110,163kHz).The
acousticdata,obtainedsome70 m abovethe deepseafloor,are compared
with bottomphotographs
andboxcorestakenalongthesamepath.
ideal water surfaces were studied. One had a sawtooth cross section de-
rivedfromthesumof thefirstfourtermsof a Fouriersineseriesrepresen-
1:35
tation. The cross section of the other surface was derived from the sum of
the sametermsbut with eachhavingrandomphase.This resultedin two
surfaces
eachwith the samermsroughness
(0.2 cmI, spatialwavelength
(16cm},andspatialwavenumber
components,
butdifferentcross-sectional shapes.
With eachsurface,theacousticfieldin waterwascomputedat
two receiverlocationsfor both backscatterand forward scatterfor a grazing angleof 35 (with respectto the surfacemean),11210
kHz, and a total
travel distanceof 421 cm. For backscatter,the pressureamplitudesand
coherencevaluesdiffer considerablybetweenthe two surfaces,and the
differences
increase
with increasing
receiverseparation.
For forwardscatter the differences
are muchless.[Work supportedby NORDA.]
1:20
HHH2. Variability of acoustic reflectivity over a manganesenodule
field. F. N. Spiess and Marco M.P. Weydert (Marine Physical
Laboratoryof the ScrippsInstitution of Oceanography,University of
California, San Diego, San Diego, CA 92152}
$121
J. Acoust.Soc. Am. Suppl. 1, VoL 74, Fall 1983
HHH3. Wind- and wave-inducedacousticnoiseat very low frequencies.
A. C. Kibblewhite,
• K. C. Ewans,and D.C. Coup (Departmentof
Physics,Universityof Auckland,Auckland,New Zealand)
Underwater ambient noiseis known to be dependenton the wind.
Severalmechanisms
havebeenproposedto explainthe natureof the transfer of energyfrom the wind field to the acousticnoisefield.Examples
include wind and wave turbulence
and nonlinear interactions
between
surfacewaves,whichgivenriseto manyphonemenu
notpresentin linear
theory.Thisstudyexaminesthesewind-relatedmechanisms
fromthelow
endof the acousticspectrum.Data from a long-termstudyof oceanwaves
and the associated
microseismic
field recordedashorehasproducedevidencehelpfulto the identification
of processes
activein theacousticfield
at somewhathigher frequencies.The uniqueenvironmentunder which
theserecordings
weremadein New Zealandhascontributedto the successof the study.Correlationswith ambient noiserecordedby a shallow
waterhydrophone
werealsomade.'• VisitingScientist,
AppliedResearch
Laboratories,The University of Texas at Austin, Austin, TX 78712-8029.
S121
1:50
2:50
HHH4. High-frequencyacousticsea surfacescatter correlated with
wind and wave measurements.
StevenO. McConnell (Applied Physics
Laboratory, University of Washington, Seattle, WA 98105),
SerhadAtakturk, and Kristina B. Katsaros (Department of
Atmospheric
Sciences,
Universityof Washington,
Seattle,WA 98195)
Backscatterandforward-scattermeasurements
weremadeat frequenciesrangingfrom20 to 50 kHz (principally21 and40 kHz} in LakeWashington.Simultaneous
measurements
weremadeof thewindspeed,stress,
anddirection,andof the largeandsmallscalewaveheightup to frequenciesof 30 Hz. The waveheightsensors
penetrated
the watersurfaceat the
approximatecenterof the areaof ensonification,
allowinga spatiallyas
well as temporally simultaneouscomparisonof scatteringlevels with
waveheight.Preliminaryresultsshowthebackscatter
levelto beabout10
dB lessthanin theopenoceanfor a givenwindspeed.This resultmaybe
due to differencesin near-surfacebubble size density distributions
betweensaltandfreshwater[Scott,Deep-SeaRes.22, 653--657(19751].
2:05
HHHS. AppUeation of the composite roughness model to bottom
bagkscatterlng. Darrell R. Jackson {Applied Physics Laboratory,
Universityof Washington,Seattle,WA 98105},Dale P. Winebrenner,
and A. lshimaru(Departmentof ElectricalEngineering,Universityof
Washington,Seattle,WA 98! 95)
Oceanbottomacousticbackscattering
is modeledas an incoherent
sumof intensifies
dueto interfaceroughness
andvolumeinhomogeneity.
Roughinterface
scattering
istreatedbya version
ofthecomposite
roughnessmodelsimilarto that appliedto theseasurface[S.T. McDaniel and
A.D. Gorman,J. Geophys,Res.97, 4127-4136(1982}].The volumescatteringportionof the modelemploysthe first-ordermultiple-scattering
approximation
includingrefractionand large-scale
interfaceslopes,but
neglects
layering[A. N. Irakin andYu. P. Lysanov,Soy.Phys.Acoust.
27, 212-215 (1981}].The modelis comparedwith data presented
at the
Cincinnatimeeting[J.•. Crisp,P. A. G. Thomas,A.M. Baird,andD. R.
Jackson,
•. Acoust.Soc.Am. Suppl.173, S97(1983)]usingpower-lawfits
to measuredbottom relief spectra.The relativelyslowfall-off of these
spectracauses
thecompositeroughness
modelto besensitive
to the largescalecutoffwavenumber.
[Worksupported
by ONR.]
HHHS. Ocean ambient noise at very low frequencies. Frederick
D. Cotaras, Harold M. Merklinger, and lan A. Fraser (Defense
Research Establishment Atlantic, P.O.
3.'05
Box 1012, Dartmouth, Nova
Scotia,Canada B2Y3Z7}
HHH9. Spectraand limits of boundarywavesat grazingineiclenceover
Ambient noisein the frequencyrange i to 20 Hz wasmeasuredat a
numberof sitesin the North Atlantic. Freelydrifting,surface-suspended
hydrophones
wereused.A digitalradiotelemetrylink wasusedto transmit theacousticdata to an attendingship.It isshownthal the characterof
thenoisein the l-4-Hz rangeis differentfrom that in the 6-20-Hz range.
The distributionof 5-rainaveragesof noisepowerin narrowfrequency
bandsshowssignificantdifferences
in standarddeviation,skew,andkurtosisobservedaboveand below5 Hz. The highcoherence
of noisemeasuredby two independentmeasurement
systems150-300 m apart horizontally givesstrongevidencethat the noisemeasuredin the 1-5-Hz
range was not flow, turbulence,or electricalnoiserelated.There is an
indicationin the data that two noisemechanisms
maybe responsible
for
the noisein the l-5-Hz range;at leastoneof theseis windspeedrelated.
Herman Medwin {PhysicsDepartment, Naval PostgraduateSchool,
Monterey,CA 93940}
rough surfaees. Gerald L. D'Spainf
Emily H. Childs,
'• and'
Previouslywe havepresented
measurements
of thelarge,coherently
scattered,boundarywaveamplitudeand dispersion
for low-frequency
grazingpropagation
overrigidplanes
withrigidhemispherical
orhemicylindriealbosses.
Recentlaboratorystudieswith wedgecorrugations
and
withspherical
roughness
elements,
andfor rangesupto kR = 3000,show
that:{a}thegrowthoftheboundarywaveamplitudeisself-limited;
and
thespectrumof the boundarywaveamplitudeis a functionof the slope
andsizeof thewedgecorrugations.
[Research
supported
by theOfficeof
NavalResearch.]
'} OceanAcoustics
Associates.
3:20
HHHI0. Coherentresponseto a pointsourceirradiatinga roughplane.
2:20
HHH6.
High-frequency scattering from the sea surface. Suzanne
T. McDanid {AppliedResearchLaboratory,The Pennsylvania
State
University,UniversityPark, PA 16802]
Compositeroughness
theoryprovidesone meansof treatinghighfrequency
scatteringfromtheseasurface.In thismethod,thesurfaceis
artificiallypartitionedinto two wavenumberregimesleadingto results
that are dependent
on preciselyhow the surfaceis partitioned.in this
paper,diffractlyecorrections
to the geometricalopticssolutionof the
Kirehhoff integralare derived.The correctionterms,in this case,arise
quitenaturallyfrom an asymptotic
expansion
of the scatteringintegral
and are, hence,not dependenton the choiceof an arbitrary parameter.
Numerical
results are obtained for a Iwo-dimensiona]
surface and com-
paredwithIheresultsofcomposite
roughness
theory.[Research
supportcd by NORDA.]
R.J. Lucas
'• andV. Twersky(Department
of Mathematics,
University
of Illinois, Chicago,IL 60680)
We considera pointsourceof soundexcitinga planarroughsurface,
and write the coherentresponse
as the Sommerfeld-Weyl
integralin
terms
ofthe.reflection
coefficient
(R) forcorrelated
distributions
ofprotuberances(bosses}
on rigid or free baseplanes.The coefficientR and the
associated
angle-dependent
impedancearc determinedby the ensembleaveragedmultiplescatteringamplitude{F} for onefixedbossof revolution, and F is specifiedby its singlescatteredvalue and the statisticalmechanics radial distribution function (p} for impenetrable disks.
Low-frequency
formsin termsofsimpleintegrals
ofp delineate
multipolo
couplingand packingeffectson propagation
and attenuation(arising
from incoherentscatteringaswell asabsorption}
asfunctionsof the fraction {w}of baseplanecoveredby bosses.
Approximations
of the response
integralandcorresponding
plotsare presented
to exhibitthe d•pendence
on w andon otherkeyparameters,
andnear-grazing
aspects
areempha-
sized.
a•Visiting
fromMathematics
Dept.,LoyolaUniversity,
Chicago,
2:35
IL.
HHH7. Comparisonsbetween sinusoidalboundary s•attering theories
and measured data. Diana F. McCaramon {Applied Research
3:35
Laboratory,The PennsylvaniaState University,UniversityPark, PA
16802]
HHHII.
An exactgolutionto scatteringfrom a sinusoidalboundaryhasbeen
presented
by Holford [J. Acoust.SOC.Am. 70, I i 16-1128{1981)].This
solution,and the approximatesolutionsof Kirchhoff,Eckarl, Brekhovskikh, and Rayleighare contrastedwith the measureddata givenby LaCasceandTamarkin[J. Appl. Phys.27 [2](I 956]]for threedifferentsurfaceroughnesses.
Verygoodagreement
isobtainedby theHolfordtheory,
especially
in thelocationof reflection
amplitudepeaksandzeros.
S122
Model of high-frequency ambient noise in coastal waters.
David Dunlap (Bendix Oceanies,15825 Roxford Street, Sylmar, CA
91342}
A computersimulationof Ihe directionaldependence
and level of
intensityof high-frequency
ambientnoisein coastalwatershasbeendeveloped.Many investigatorshave shownthe directionaldependenceof
surfacegeneratednoise.This paperextendsthat work to higherfrequenciesto simulatethebackground
in whichsomeactivesonarsystems
must
S122
operate.Contributionsfrom thermalnoiseand biologicallyproduced
noisearealsoconsidered
in thetotallevels.The surfacewindnoisecomponent is modelledas a variablegeometricpatternof point sourceswhose
densitymay alsobe varied. Initial levelsand bottom reflectioncoefficients
aretal•enfromtheliterature,
andresults
arecompared
withmeasured
data.The noiseintensityispresented
asa functionoffrequency,
depthand
vertical direction.
normaland30øanglesof incidence
versuswindspeed
arepresented.
Profilesof volumescatteringare shownin relationto the watercolumncharacteristics.The bottomscattering,asobservedvia a surface-bottom-surfacepathiscontrolledbysurfaceroughness.
Statisticaldistributionsof the
backscattering
observations
arecomparedwith theRayleighianprobability densityfunction.Theseobservations
clearlyindicatethe potentialof
utilizing the DCP4400/300 to gain usefulinformationaboutseasurface
conditionsand abouthigh-frequency
backscattering
in general.
3:50
HHH12. Measurements of wind-generated noise levels in the Eastern
Indian Ocean.D. J. Kewleyand A. S. Burgess{Departmentof Defense,
WeaponsSystemsResearchLaboratory, Defense ResearchCentre
Salisbury,SouthAustralia}
Recordings
of ambientseanoisemadewith a verticallinearhydrophonearray {VLA} at five sitesin the EasternIndian Oceanhave been
analyzedfor wind-speeddependence.Use is madeof the verticaldirectionaldiscriminationof the VLA to resolvenoisegeneratedat a distance
and locallygeneratedwind noise.The resultsare comparedwith data
fromsimilarexperiments
offtheeastcoastof Australia[A. S. Burgess
and
D. J. Kewley,J. Acoust.Soc.Am. 73, 201-210 (1983}].
4:05
HHHI3. Observationsof scattering at 300 kHz. Lloyd C. Huff and
Robert G. Williams (NOAA, National Ocean Service,6001 Executive
Boulevard,Rockville,MD 20852)
Observations
made
with
a
modified
Ametek-Straza
model
DCP4400/300 Dopplercurrentprofilerduringan experimentto characterize the current measurementperformanceof the DCP4400/300 in a
bottom-mounted,
upward-looking
configuration
affordedthe opportunity to observenarrow-beambackscattering
over an interestingrangeof
environmental
conditions.CTD casts,watersamplesfor particulatedistributions,andwindvelocitymeasurements
weremadeconcurrently
with
the acoustic observations. The functional forms of surface backscatter at
S123
4:20
HHH14.
Sonar estimates of sea floor microroughness.T. K. Stanton
{MarineStudiesCenter,Universityof Wisconsin,Madison,WI 53706}
This paperpresents
an analysisof theeffectsof microroughness
of the
oceanbottomon a sonarsignal.The resultsbestapply to featureswhere
the roughnessamplitudeis lessthan one-quarterof an acousticwavelengthsuchaswith ripples,bedsof rocks,and nodules.The shapeof the
probabilitydensityfunction(PDF} of the echoenvelopeis examinedin
termsof the rmsroughness
and a newparameter,thecorrelationareaof
the bottom.The area is equalto the productof the x andy correlation
distances
alongthe floor.The PDF is shownto beextremelysensitiveto
small changesin the roughness.
Furthermoreby determiningthe rms
roughness
from standardcoherentreflectionmeasurements,
the correlation areamaybe extracteddirectlyfrom the PDF. Thusbothverticalas
well as lateral informationis obtainablefrom sonardata. The technique
canbe usedto discriminatebetweendifferenttypesof bottomsthat may
havethe sameroughness
but differentcorrelationareas,for examplea
floorwith ripplesversusonewith rocksor nodules.The analysiscombines
two approaches:
{1}A generalstatisticalmodelemployingthe Rice PDF
(S.O.Rice,in Selected
PapersonNoiseandStochastic
Processes,
editedby
N.Wax{Dover,
NewYork,!954},
pp.133-294]
and{2}atheory
originated
byEckart[C. Eckart,J. Acoust.Soc.Am. 25, 566-570(1953}].Theanalysisisappliedto sonardatacollected
fromthecontinental
shelfnearCape
Hatteras,North Carolina. The resultsareconsistentwith the knowncharacteristics of the area.
5123'

Final published version

Transcription

Similar documents

Vol 1 Ross A. McFarland Papers - Wright State University Libraries

Computer Aided Engineering of Public Address Loudspeakers