Apr 8, 1976 - L. C. Stewart, Wilbur D. Larkin, ... J. R. Franks (Speech and Hear- .... Bowling Green State University, Bowling Green, OH 43403) and R.
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job exposure to steadystatenoise.[Workpartiallysupported by a Rockefeller Foundation Grant.] 3:15
FF6. Observed temporalsummation effectsfor lingualvibrotactile
S69 cies.The advantages soughtin this device,comparedto previousdevices,are (a) the deafpersondoesnot haveto integratesignalsfrom more than one senseinto his perceptionof voice pitch and (b) the deviceis wearable,makingpossiblea closerrelationshipbetween speech-therapy sessions and everydaycommunication.Preliminary experimentalresultswill be reported,and therewill be a demonstration.
thresholdmeasurements. Kal M. Telage(Departmentof Speech
Pathology andAudiology, IthacaCollege, Ithaca,NY 14850), DonaldJ. Fucci, and Robert Blackmon(Lindley Hall, Ohio University, Athens, OH 45701)
Investigations usingmechanical stimulation to measure lingual thresholdsensitivityhaveresultedin conflictingassumptionscon-
cerningthenatureof underlyingneuraltransducers. A basicquestion concernswhether or not exteroceptivetouch receptorsin the
lingualsurface summate energyin response to displacement of tissues.Thisstudytestedthe hypothesisthat thesereceptorswould demonstratetemporalsummationasa functionof pulseduration time. The stimulusunit included an audio oscillator, frequency
counter,electronicswitch,intervaltimer, amplifier,and electromagnetic vibrator. The measurement unit consisted of an accelerometer,
cathodefollower,microphoneamplifier,andvacuum-tubevoltmeter.Vibrotactilelingualtresholdsfor 250 Hz wereobtainedfor
fourgroups of normalspeaking adultsubjects usingrespective pulse durationtimesof 50, 100, 200, and 400 msec.Peakvalueswere recorded in millivolts and converted to dB re one micron rms. Tem-
poralsummation wasobserved up to 200 msecreachingan asyml> tote around400 msec.Findingssupportedthe positionthat tactile transducers in mucoustissuesrespondto vibratorydisplacements in the samewaysaspressurereceptorsin other cutaneoustissues. 3:30
FF7. Vibrotactile frequencyfor encodingspeechparameters.M. Rothenbergand R. T. Verrillo (Departmentof Electricaland Computer Engineeringand the SensoryResearchInstitute, SyracuseUniversity, Syracuse,NY 13210)
Frequencyof vibrationhasnot beenwidely usedasa parameter for encodingspeech-derived informationon the skin.Whereit has beenused,the frequenciesemployedhavenot necessarily been compatiblewith the capabilitiesof the tactilechannel,and no determination was made of the information transmitted by the frequency
variable,asdifferentiatedfrom other parametersusedsimultaneously, suchas duration,amplitudeand location. However,severalinvestigatorshaveshownthat differencelimensfor vibrationfrequency may be smallenoughto makestimulusfrequencyusefulin encoding a speech-derived parametersuchasthe fundamentalfrequency.In the studiesreportedhere,measurements havebeenmadeof the frequencydiscrimination ability of the finger,thenateminence,and forearm,usingboth sinusoidal andpulsedwaveforms.Stimulusconfigurationsincludedthe constantfrequencyvibrationsusedin previousexperimentsaswell asfrequency-modulated (warbled)stimulus patterns.The frequencyof a warbledstimuluswasdesignedto havea temporalvariationanalogousto thosefound in speech.The resultssuggest that the fundamentalfrequencycanbe displayedon the skin asa vibratory frequency if recodedinto a frequency range closelymatched to the skin'scapability.
4:00
FF9. Real-timespeechspectrographic display(SSD)with implicationsfor speechtrainingfor the deaf.L. C. Stewart,WilburD. Larkin, and Robert A. Houde (Center for Communications Research,Rochester, NY 14614)
At the Austinmeetingsof the Societywe reportedon work with the VisualSpeechTrainingAid (VSTA), a speechparameterdisplay
[J. Acoust.Soc.Am. 57,518 (A)'(1975)]. TheVSTA demonstrated the utility of a visualdisplayfor trainingstressand eliminationof inappropriatepauses andnasalityin deafspeech.It wassimilarly usefulin displayingvoice-voiceless distinctionsand appropriatepitch rangeandcontoursfor mostdeafspeech.However,the needfor a visualdisplayto reliablyindicatearticulationled us to developa real-timespeechspectrographic display(SSD). The sound-spectrographictype of displayis attractivebecauseit hasadequatefrequency resolutionto displayformantsand fricativesin speech,yet the time resolutionis sufficientto displaystopsand to showvocal-foldperiodicityduringvoicedsounds.The real-timeinstrumentdeveloped producesand storesa frequency-time-intensity displayon a video monitor while the soundis beingspoken.The resultingspeechspectogramcloselyresembles the standard broad-band spectrogram in time, frequency,and grey-scale resolution.Preliminaryevaluations which are highly encouragingare reported. 4:15
FF 10. Effect of heating-aidmicrophonelocationon the intelligibility of hearingaidtransduced speech.J. R. Franks(Speechand Hearing Clinic, Arizona State University, Tempe, AZ 85281), L. L. Feth, and R. G. Daniloff (Department of Audiology and SpeechSciences, Purdue University, West Lafayette, IN 47907) The effect of hearing-aidmicrophone location upon speechintelligibility wasinvestigatedusingten normal-hearing,youngadult listeners.A closed-response-set speechdiscriminationtask was recorded in the presenceof a spatially separatednoise through a hearing aid mountedon a dummyhead.Recordings weremadein both anechoicand reverberantsoundfields (Rt = 0.5 sec).Three experimentallisteningconditionswere employed-microphoneplaced (a) in the top of the hearingaid case;(b) in the bottom of the hearing aid case;and (c) in the auricle,overthe earmold.A fourth condition of ear open with no hearingaid was usedas a reference condition. Results indicated that the location of the microphone does have an effect on the intelligibility of the,speechsignal,and that the effect is dependentupon the characteristics of the soundfield. For both sound fields, the bottom microphone location provided the leastintelligiblespeechsignal.The resultsfor the top and auricular locationsindicated that the speechsignalswere of equivalentin-
telligibility. The highestspeechintelligibilityscoreswereobtained under the reference condition. Reverberation in the sound field
3:45
FF8. Auditoryaid to deafspeakers in monitoringfundamental voice frequencies. E. Villehut(Foundation for HearingAid Research, Woodstock, NY 12498) andM. C. Killion (IndustrialResearch Products,Elk GroveVillage, IL 60007) Profound deafnessis often accompaniedby a lossin frequency-
discriminating ability. Whensuchdeafness datesfrom infancy,the deafpersonmayneverlearnto speakwith the inflectionsof fundamentalvoicefrequencythat arepart of the conventions of language and that contributeto speechintelligibility.Visualand tactiledeviceshavebeenbuilt to help the frequency-insensitive deaf speaker monitor,and therebylearnto control,the pitch of hisvoice.This paperdescribes an auditorypitch-monitordevice,in whichvoicepitchinformationis presented by way of subsonic-frequency, squarewavemodulationsof the low-frequencyportion of speech.The modulationfrequencies trackthe changing fundamentalvoicefrequen-
tendedto reducethe intelligibilityfor all listeningconditions.[This researchwassupportedby a grant from NINCDS.] 4:30
FF11. Multivariateadaptivetestingappliedto the prescriptive fittingof hearingaids.H. Levitt,R. E. C. White,andS. B. Resnick (CommunicationSciencesLaboratory,Doctoral Programin Speech
andHearingSciences CUNY, GraduateSchool,New York, NY 10036) Amongthe problemsencountered in fitting of hearingaidsare (i) measurements of performanceare subjectto significantrandom fluctuations;(ii) subjectstypicallyadaptto the hearingaid, resultingin
gradualdriftsin the optimumparametervalues;(iii) variables interact, therebypresentingcertaindangersif only one variableis manipulated at a time; and (iv) data obtained under carefully controlled conditionsdo not alwayscorrespondto performancein the field.
The simplicialmethod[G.E.P. Box, Appl. Statist.6, 81-101 (1957)]
J. Acoust. Soc. Am., Vol. 59, Suppl. No. 1, Spring 1976
Redistribution subject to ASA license or copyright; see http://acousticalsociety.org/content/terms. Download to IP: 154.127.49.199 On: Tue, 29 Nov 2016 06:15:35
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91st Meeting: Acoustical Society of America
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is a powerful adaptive technique designedfor problems of this type and has been used as part of an ongoingstudy to develop a practical protocol for the prescriptivefitting of a wearablemasterhearingaid. Preliminary trials with five subjectsshowedsuperiorperformance for the fitted wearable master hearing aid than that obtained with the subjects'own aid under comparableconditionsof speechin noise. [Researchsupportedby PHS Contract No. NIH-N01-NS-4-2323.]
trained subjects.Further experimentswith up to 20 all-passfilters showedthat for group-delaycurveswith multiple maxima and minima the limit of perceptibility has a value of about 0.6 msec (peak to valley) for trained subjects. 5:00
FF 13. Speechaudiomerryvia boneconduction.B. Edgerton,J. L. 4:45
Danhauer,and T. Barnard(Department of SpeechCommunication, BowlingGreenStateUniversity,BowlingGreen,OH 43403) and R. Beattie(Departmentof Speech,Long BeachState,Long Beach,CA
FF12. Audibility of groupdelaydistortions.J. Blauert(RuhrUniversit/it, 4630 Bochum, Germany F.R.) and P. Laws (Gesamthochschule,4100 Duisburg,Germany F.R.)
We report upon exemplary measurementsof group-delaydistortions as induced into electroacoustical transmission by the fact that earphonesand loudspeakersare not necessarilyminimum phasesystems. Additional psychoacousticaltests showedthat the measured distortions are on the order of the limit of perceptibility or exceed this limit. The limit of perceptibility of group-delaydistortions de-
pendsstronglyupon the kind of signal,the shapeof the group-delay curve, and the state of training of the subjects.For short sound pulsesand group-delaydistortionsas producedby second-orderallpassfilters we found in diotic presentation,with one all-passat frequenciesbetween1 and 4 kHz, a limit of group-delayperceptibility between 1 and 2 msecfor untrained subjectsand 0.4 msec for
THURSDAY,
90808)
This study was designedto determine (1) valuesfor SRT's obtainedvia bone conductionusingthe NU cassetterecording,(2) the relationshipbetween BC PTA's and BC SRT's for normals, (3) shortterm reliability of BC SRT's, and (4) characteristicsof articulation functionsfor spondeesobtainedby BC and by AC. An averageBC
SRT wasdeterminedfor 50 normallyhearingyoungadultsusing mastoidplacement.While relationshipsbetween BC PTA's and BC SRT'swere not in agreementwith thoseindicatedby earlierinvestigators,the averageSPL valuesfor the BC SRT's were. Test-retest reliability for BC SRT's wasvery high. A comparisonof articulation functions indicatesthat the perception of speechas a function of intensity doesnot differ significantlyfor air or bone conducted transmissionsystems.
8 APRIL 1976
FEDERAL ROOM, 2:00 P.M. ß
SessionGG. SpeechCommunicationVI: SpeechAnalysis Thomas H. Crystal, Chairman
Institutefor DefenseAnalyses,Princeton,New Jersey08540 Invited Paper 2:00
GG1. Vocal-tractdeterminants of resonance frequencies andbandwidths. G. Fant [Departmentof SpeechCommunication,Royal Instituteof Technology(KTH), S-10044 Stockholm70, Sweden]
This,isa reviewof recentyears'development of the theoryof vocaltransmission focusingon the spatialdistributionof energy,resonance bandwidths,perturbationsin areaand in lengthdimensions with applicationsto nonuniform scalingof vocal-tractdimensions,and discussions of "resonancecavity"relations.In additionto the well established influenceof the vocal-wallimpedanceon the tuningof very low F1 resonances, thereare alsoindicationsthat F1 of [a]-type vowelscouldbe significantlyinfluencedby the tuningof the vocal-wallmassshuntwhich,accordingto our measurements, shouldbe heavierin the regionof the lower pharynx than anywhereelse.New measurements of the closed-trac. t resonanceand bandwidthfor malesand femalesare reportedand alsosomeobserveddifferencesin male-femalecavity sizeand shape.
Contributed Papers 2:24
GG2. Uniquenessof articulationsdeterminedfrom acousticdata. Lloyd Rice and Peter Ladefoged(PhoneticsLaboratory, UCLA, Los Angeles,CA 90024)
Whatis the minimumsetof acousticdatathat determinesa unique shapeof the vocaltract?This dependsin part on the degreeof accuracywith whichthe vocaltract shapeis to be specified(the number of points on the surfaceof the vocal tract that are determined), in
part on the kind of acousticdata (whether both frequenciesand bandwidthsof the formants are known), and in part on the constraintsthat are imposed on the possibleshapesof the vocal tract, so that only potentially observableshapesare considered.We assume that the degreeof accuracyrequiredinvolvesspecifying18 points along the vocal tract, and that the articulatory constraintsare those that have been observed in non-nasalized vowels. We then show the
extent to which we can determine the shapeof the vocal tract, givenonly two or three formant frequenciesand no bandwidth information.
J. Acoust. Soc. Am., Vol. 59, Suppl. No. 1, Spring 1976
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