The time course of vowel context effects Howard C Nusbaum and James Sawusch Citation: The Journal of the Acoustical Society of America 67, S53 (1980); doi: 10.1121/1.2018271 View online: https://doi.org/10.1121/1.2018271 View Table of Contents: https://asa.scitation.org/toc/jas/67/S1 Published by the Acoustical Society of America peak glottal opening during the devoiced vowel is larger when a fricative either precedes or follows it, and smaller when the vowel is surrounded on both sides by single or geminated stops [Work supported by NINCDS and BRSG.] controlled variations of glottal opening [Work supported by NINCDS and BRSG.] a) Also: Lund University, Lund, Sweden b)Also: University of Tokyo, Tokyo, Japan a) Also: University of Tokyo, Japan b)Also: Lund University, Sweden 5:00 V16 The time course of vowel context effects Howard C Nusbaum and JamesR Sawusch(Department of Psychology,State University 4:48 of New York at Buffalo, Amherst, NY 14226) V15 Scaling of glottal opening A L6fqvist,a) T Baer, and H Yoshiokab) (Haskins Laboratories, 270 Crown Street, New Haven, CT 06510) Laryngeal control mainly occurs along two dimensions One involves the longitudinal tension of the vocal cords and is used for F0 control Speakers can normally exert very fine-graded control in this dimension, and it is usedextensively for linguistic purposes.The other dimension is that of abduction-adduction, involved in the control of phonation type, voicing, and aspiration From published records, it appears that more than two or three distinct degrees of glottal openingare rarely used during speechproductionin different languages The present experiment was designed to clarify the control of glottal abduction-adduction and examines how many degreesof glottal opening speakers can produce consistently under various static and dynamic nonspeech and speech conditions Glottal opening was monitored simultaneouslyby a fiberscope and a transillumination system Preliminary results indicate that without training and visual feedback subjects can only produce gross abduction and adduction gestures and are unable to make finely THURSDAY MORNING, 24 APRIL 1980 At previous meetingsof the Society we presented evidence for the existenceof two different perceptualmechanismsmediatinganchorinducedcontrasteffectsfoundwith vowels Extra presentationsof an [i] endpoint to subjectsidentifyingan [i]-[I] seriescausedchanges in sensitivity Anchoring with [I] produced criterion shifts which were dependent on the availability of auditory memory Since [i] and [I] differ in tenseness,intrinsic duration in natural speech, and acoustic status (point versus nonpoint), the differences in perceptual effects of these vowels cannot be ascribed to any one factor To explore the role of these variables in vowel context effects, a number of different vowel series from different parts of the vowel space have been examined using a successive contrast paradigm In this procedure, a context vowel is presented first, followed at varying temporal intervals by a test vowel Results obtainedusingthis procedureprovide new evidenceconcerningthe perceptual mechanismsunderlying vowel anchor effects Further, the pattern of these results obtained with different vowel series have important implications for theories of vowel perception [Work supported by NSF and NIMH.] BALLROOM SOUTH, 9:00 A.M TO 12:00 NOON Session W Noise V: Vehicle Noise and Noise Propagation Robert D Bruce, Chairman Bolt Beranek and Newman Inc., 50 Moulton Street, Cambridge, Massachusetts 02138 Contributed Papers 9:00 W1 Urban light motor vehicle noise levels at close-in distances for a worst casesituation Gale R Hruska (U.S Environmental Protection Agency, Region V Noise Program, 230 S Dearborn Street, Chicago, IL 60604) and Kent C Williams (U.S Environmental Protection Agency, Region IV Noise Program, 354 Courtland Street, N.E., Atlanta, GA 30308) Effective motor vehicle noiseenforcement in many urban areas can only be accomplishedif measurementsare made relatively close to the vehicle To help define reasonable enforcement levels, in situ sound level measurements were recorded in four geographical locations for 8307 light weight motor vehicles accelerating from rest or near rest To insure a "worst case" situation, the microphoneswere positioned at 3.81 m from the centerline of travel and 27 to 46 m from the initial point of acceleration The data were partitioned into three "acceptable" vehicle classesand one class which included all vehiclesjudged to have had defective or modified exhaust systems, or had been unreasonably driven Analysis of the data shows that the "unacceptable" vehicle distribution has a mean sound level at least $53 J Acoust Soc Am Suppl 1, Vol 67, Spring 1980 dBA greater than those obtained for all of the "acceptable" classes Relations between the posted speed limits and the mean values of the observed sound levels were obtained 9:15 W2 Vehicle passbysoundlevel time histories.J S Bradley (Faculty of Engineering Science, University of Western Ontario, London, Ontario, Canada N6A 5B9) An earlier study of particular vehicles of various types [ J S Bradley, J Acoust Soc Am Suppl 65, S66 (1979)], indicated that vehicles are directional radiators of sound in the horizontal plane and that the assumption of a point source was incorrect The present investigation extended the work to include an analysis of a large number of vehicle passby time histories for various vehicle types to determine how representative the particular results were Average passby time histories were computed for five different vehicle classificationsand compared to predicted values Results showed deviationsfrom a point sourcemodel and varied with vehicle 99th Meeting: Acoustical Society of America $53 ... effects of these vowels cannot be ascribed to any one factor To explore the role of these variables in vowel context effects, a number of different vowel series from different parts of the vowel. .. 5:00 V16 The time course of vowel context effects Howard C Nusbaum and JamesR Sawusch(Department of Psychology,State University 4:48 of New York at Buffalo, Amherst, NY 14226) V15 Scaling of glottal... mechanismsunderlying vowel anchor effects Further, the pattern of these results obtained with different vowel series have important implications for theories of vowel perception [Work supported