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Jan 1972

Volume 51, Issue 1A, pp. 1-157

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Natural Resonant Frequencies of an Oblate Acoustical Resonator

C. T. M. Chang

J. Acoust. Soc. Am. Volume 51, Issue 1A, pp. 1-5 (1972); (5 pages) | Cited 1 time

Online Publication Date: 11 Aug 2005

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Natural resonant frequencies of oblate acoustical resonators with either perfectly soft or perfectly rigid boundaries are calculated by locating the zeros of Rmn(1)(−ih, iξ) and Rmn(1)′(−ih, iξ). These frequencies are normalized to those of the corresponding modes of a spherical cavity with the same volume and presented for various ratios of major to minor axes.

Calibration of Condenser Microphones under Increased Atmospheric Pressures

William G. Thomas, Mack J. Preslar, and Joseph C. Farmer

J. Acoust. Soc. Am. Volume 51, Issue 1A, pp. 6-14 (1972); (9 pages) | Cited 2 times

Online Publication Date: 11 Aug 2005

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The sensitivity and frequency response characteristics of type‐L standard laboratory microphones were measured with an electrostatic actuator at surface and at 12 different levels to 31 atm absolute (ATA) in a hyperbaric chamber. The microphones were measured in compressed air and a helium‐air environment, with and without the capillary pin. In addition, one microphone remained at a depth of 31 ATA for 24 h to measure its stability under pressure. Results indicated a loss in sensitivity in compressed air and helium‐air as a function of pressure. In a compressed‐air environment a resonant peak occurred at 4000 Hz, which shifted to 8000 Hz in the helium‐air environment. The microphones showed extremely close agreement between compression and decompression, between different pressurizations, and between different microphones. Also, there was no change in sensitivity over a 24‐h period of pressurization at 31 ATA. Calibration data at several pressures are given.

Noise Reduction in Propeller Fans Using Porous Blades at Free‐Flow Conditions

Robert C. Chanaud

J. Acoust. Soc. Am. Volume 51, Issue 1A, pp. 15-18 (1972); (4 pages)

Online Publication Date: 11 Aug 2005

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Experiments were conducted on propeller fan blades at free‐flow conditions to determine the noise reduction associated with the use of rigid porous materials as the blade material in lieu of solid material. The results suggest that significant sound reduction can be achieved with no loss of pumping efficiency when the pitch angle is increased from normal.

Refraction and Attenuation of Sound by Wind and Thermal Profiles over a Ground Plane

Anthony R. Kriebel

J. Acoust. Soc. Am. Volume 51, Issue 1A, pp. 19-23 (1972); (5 pages) | Cited 1 time

Online Publication Date: 11 Aug 2005

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There is a significant excess attenuation of sound traveling downwind within a typical turbulent shear profile due to the downwind refraction and spreading of the sound rays. This attenuation is in excess of that due to absorption by turbulent eddies, spherical spreading, and ground reflection. When the source and receiver are both located on the ground, the excess attenuation of the directly transmitted sound due to refraction is predicted to be uniform at −11 dB beyond a short range downwind of the source until a shadow zone is reached at a much longer range. This predicted excess attenuation decreases markedly with the elevation of the source and receiver, particularly at short range. There can be an indefinitely large number of reflected rays transmitted to a receiver downwind of a ground‐level source, and the shallow reflected rays which skip off the ground a large number of times may have little excess attenuation, since they travel through the laminar sublayer where the velocity gradient is constant. There are several caustics formed downwind of a ground‐level source. The results show that wind can easily cause anomalous recording of the sound‐pressure level from freeways, airports, and other urban noise sources.

Passive Sonar Processing for Noise with Unknown Covariance Structure

W. S. Liggett, Jr.

J. Acoust. Soc. Am. Volume 51, Issue 1A, pp. 24-30 (1972); (7 pages)

Online Publication Date: 11 Aug 2005

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Passive processing is interpretation of the noise and noise like signals received by an array of hydrophones. Our model assumes that there is an important noise component about which very little is known, that the data are stationary, that a long data sample is available, that signal wavefronts are planar, and that the response of the array to plane waves is known. We propose a processor and compare it with high‐resolution frequency‐wavenumber spectrum analysis. Let F̂ denote an estimate of the spectral density matrix, and let H denote any spectral density matrix that corresponds to a noise field composed of uncorrelated plane waves. A reasonable estimate of the spectral matrix of the signals and ambient noise is a value of H for which F̂‐H is positive semidefinite and trace H is maximized. The rationale for this estimate is closely related to a rationale for the estimate obtained by high‐resolution frequency‐wavenumber spectrum analysis (which is also called adaptive beamforming). The difference is that the former extracts the contribution from all directions at once, whereas the latter extracts the contribution from each direction separately. The former estimate rejects more unwanted noise than the latter.

Application of Monopulse Tracking Techniques to Passive Linear Arrays

C. A. Roberts and A. G. Favret

J. Acoust. Soc. Am. Volume 51, Issue 1A, pp. 31-37 (1972); (7 pages)

Online Publication Date: 11 Aug 2005

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This paper considers the bearing estimation performance of a monopulse processor for passive linear arrays. The variance of the bearing estimator for this process is derived and compared with computer simulation results for different integration times and input signal‐to‐noise (S/N) ratios. The simulation results illustrate how and why the bearing estimate degrades for very poor S/N ratios or very short integration times.
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Comments on “Application of Conformal Mapping and Variational Method to the Study of Natural Frequencies of Polygonal Plates” [J. C. M. Yu, J. Acoust. Soc. Amer. 49, 781–785 (1971)]

Patricio A. Laura and Evelina Marinelli

J. Acoust. Soc. Am. Volume 51, Issue 1A, pp. 38-38 (1972); (1 page)

Online Publication Date: 11 Aug 2005

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Some of the results obtained by Yu are compared with values obtained by other investigators. In the case of a square plate, Yu's results are approximately 8% higher than the exact values.

Comments on “Speech Analysis and Synthesis by Linear Prediction of the Speech Wave” [B. S. Atal and S. L. Hanauer, J. Acoust. Soc. Amer. 50, 637–655 (1971)]

Edward A. Flinn

J. Acoust. Soc. Am. Volume 51, Issue 1A, pp. 38-38 (1972); (1 page)

Online Publication Date: 11 Aug 2005

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References to publications on linear prediction theory are suggested to complement those given by Atal and Hanauer [J. Acoust. Soc. Amer. 50, 637–655 (1971)].
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Eighty‐Second Meeting of the Acoustical Society of America (A)

J. Acoust. Soc. Am. Volume 51, Issue 1A, pp. 79-157 (1972); (79 pages)

Online Publication Date: 11 Aug 2005

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back to top Session A. Speech Communication I: Perception
Contributed Papers
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Separate Speech and Nonspeech Processing in Dichotic Listening (A)

Ruth S. Day and James C. Bartlett

J. Acoust. Soc. Am. Volume 51, Issue 1A, pp. 79-79 (1972); (1 page)

Online Publication Date: 11 Aug 2005

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Temporal order judgment (TOJ) in dichotic listening can be a difficult task. Previous experiments that used two speech stimuli on each trial (S/S) obtained sizable error rates when subjects were required to report which ear led (TOJ‐by‐ear). When subjects were required to identify the leading stimulus (TO J‐by‐stimulus), the error rate increased substantially. Apparently, the two speech stimuli were competing for analysis by the same processor, and so were overloading it. The present experiment used the same TOJ tasks, but presented a speech and a nonspeech stimulus on each trial (S/NS). The error rate was comparable to that of S/S for TO J‐by‐ear, but did not increase for TO J‐by‐stimulus. This would be expected if the speech and nonspeech stimuli are being sent to different processors, each of which performs its analysis without interference from the other. The interpretation of the data given here is consistent with the results of standard identification experiments reported elsewhere: when asked to identify both stimuli on each dichotic trial, subjects made many errors on S/S, while performance was virtually error‐free on S/NS.
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Is the Left Hemisphere Specialized for Speech, Language, or Something Else (A)

George Papçun, Stephen Krashen, and Dale Terbeek

J. Acoust. Soc. Am. Volume 51, Issue 1A, pp. 79-79 (1972); (1 page)

Online Publication Date: 11 Aug 2005

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Experienced Morse code operators showed significant right‐ear superiority, indicating left‐hemisphere lateralization, for the perception of dichotically presented Morse code letters. No significant lateralization was found for rapid monotically presented Morse code words. Subjects who did not know Morse code did not show significant lateralization when dichotically presented with a set of stimuli which included all Morse code letters; however, they showed a tendency toward left‐hemisphere lateralization with a set of Morse code letters which were restricted in duration and presented at relatively low intensity. Our results show that articulability is not a necessary property of stimuli lateralized to the left hemisphere in dichotic listening; a possible further interpretation is that it is language rather than speech that is lateralized to the left hemisphere.
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Very Brief Short‐Term Memory in Speech Perception (A)

D. B. Pisoni

J. Acoust. Soc. Am. Volume 51, Issue 1A, pp. 79-80 (1972); (2 pages)

Online Publication Date: 11 Aug 2005

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The distinction between categorical and continuous modes of perception has played a central role in discussions of speech perception. Recent findings of Fujisaki and Kawashima [J. Acoust. Soc. Amer. 47, 57 (1970)] suggest that these two modes are not necessarily dichotomous but may be related to the degree to which some brief auditory short‐term memory store is employed during discrimination. The present experiment examined discrimination performance within and between phoneme boundaries using a delayed comparison AX same‐different task. The delay interval between presentations of the standard and comparison sounds varied over a range from 0–2.0 sec for each of four types of synthetic speech stimuli. For steady‐state vowels accuracy of discrimination both within and between boundaries was related to changes in the delay interval. Discrimination of stop consonants remained relatively stable both within and between boundaries. The results suggest that vowels (even as short as 50 msec in duration) are stored differently than stop consonants in auditory short‐term memory. [Research supported in part by grant to Haskins Laboratories from NICHD.]
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Immediate Recall of Conversational Speech (A)

R. J. Jarvella

J. Acoust. Soc. Am. Volume 51, Issue 1A, pp. 80-80 (1972); (1 page)

Online Publication Date: 11 Aug 2005

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Spoken dialogue was systematically interrupted to prompt listeners' recall for one of the final two sentences which they had just heard. Besides change of speaker, three experimental conditions were defined, based on the more immediate speech. These were overt recurrence, implied but linguistically deleted recurrence, and lack of recurrence of critical phrases from the sentences to be recalled. Shared linguistic information in immediate memory by speakers and listeners as they talk is proposed to account for facilitation of recall in the implied recurrence condition. This information is coded to permit the deletion and recovery of linguistic segments in the production and perception of speech. Implications for regulation of the flow of information in conversational speech are noted.
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Auditory Analysis of Time‐Varied Sentential Approximations (A)

D. S. Beasley and T. S. Shriner

J. Acoust. Soc. Am. Volume 51, Issue 1A, pp. 80-80 (1972); (1 page)

Online Publication Date: 11 Aug 2005

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Recent research has suggested that auditory perceptual processing and short‐term memory are interrelated and temporally biased. A recommended manner for investigation of this concept is to co‐vary stimulus duration (SD) and inter‐stimulus interval (ISI) in recognition and recall tasks. The purpose of this study, then, was to investigate the recall accuracy of seven‐word first‐ and second‐order sentential approximations, co‐varying SDs of 200, 300, and 400 msec, with ISIs of 100, 200, 300, and 400 msec. Ten monosyllabic sententlal strings of each order were read by a trained male speaker under controlled experimental conditions. Twelve experimental tapes representing the 12 possible SD/ISI combinations were then manually prepared. One hundred and twenty college‐age normal hearing listeners heard the 20 sentential strings as processed under one of the 12 conditions and were required to recall the seven‐word strings. The results of an ANOVA revealed significant main effects for ISI, WD, and Order, as well as interactions of WD×ISI, and WD×Order. Recall accuracy increased as WD increased, as ISI increased, and as Order increased. The WD×ISI and WD×Order interactions revealed that recall proficiency could be enhanced via a trading relationship between the interacting factors. The results are discussed in terms of their theoretical and clinical implications.
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Memory Effects in Auditory Presentation of Digit Sequences Related to Presentation of Verbal Material (A)

Carl E. Bronell

J. Acoust. Soc. Am. Volume 51, Issue 1A, pp. 80-80 (1972); (1 page)

Online Publication Date: 11 Aug 2005

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Two experiments investigated accuracy of recall for digit sequences of length 7 and 10 which were presented with other verbal material. In study 1, subjects listened to a complete recorded message before attempting to recall the digit sequence imbedded in the message. Study 2 required that subjects only “listen to as much of the message as you need….” More errors were made when recall was delayed by additional verbal material. When 10 digits were presented, but only 7 were required to be recalled, error rates were higher than when 7 digits were presented. Requiring the subjects to reorder the digit sequence before recall increased error rate. Systematic effects of alternative message phrasings were observed on both error rate and listeners' subjective evaluation of relative difficulty. Error rates in the two studies were generally similar.
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Relation of the Verbal Transformation and the Phonemic Restoration Effects (A)

C. J. Obusek and R. M. Warren

J. Acoust. Soc. Am. Volume 51, Issue 1A, pp. 80-80 (1972); (1 page)

Online Publication Date: 11 Aug 2005

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The purpose of this investigation was to examine the relationship postulated between illusory changes of repeated words (“Verbal Transformations” or VTs) and illusory presence of phonemes replaced by noise (“Phonemic Restorations” or PhRs) [R. M. Warren and R. P. Warren, “Auditory Illusions and Confusions,” Sci. Amer. 223, 30–36 (1970)]. Separate groups of 20 subjects each were presented with one of four taped variations of the repeating stimulus word magistrate: (1) stimulus intact; (2) speech sound /s/ removed and replaced with 100‐Hz octave band noise; (3) syllable “gis” removed and replaced with 100‐Hz octave band noise; (4) speech sound/s/removed and replaced with a silent gap. When PhRs are evoked, most VTs involve the restored portion of the word, suggesting the usefulness of PhRs combined with verbal reorganizations in listening to speech in the presence of noise. Other effects of PhRs upon VTs were found. Implications of these results for mechanisms of speech perception are discussed.
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Perceptual Confusions between Four‐Dimensional Sounds (A)

J. C. Webster, M. M. Woodhead, and A. Carpenter

J. Acoust. Soc. Am. Volume 51, Issue 1A, pp. 80-80 (1972); (1 page)

Online Publication Date: 11 Aug 2005

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Are meaningless sounds learned and identified in a speech mode? Sixteen sounds were generated differing on four dimension, each having two values. These were: the source waveform contained either all harmonics or odd harmonics; the fundamental frequency was either 90 or 142 Hz; there were either one or two formant frequency regions; and the formant(s) was (were) either low, 600 (and 1550) Hz or high, 940 (and 2440) Hz. Twenty‐four listeners identified these sounds. Fewer confusions were made between sounds (1) as the number of dimensions on which they differed increased, and (2) as the dimension(s) changed, from formant number to ferment frequency region, to fundamental frequency, to source waveform. Similarly, fewer confusions were made between sounds whose formant frequencies and fundamental frequency were in a fixed ratio than between those with the same formant frequency. In essence fixed ferment sounds were more often called the same sound than were fixed ratio sounds. The data fit a hypothesis that classification was made on a generalized “pitch” dimension.
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Click Perception in Sentences as a Function of Mode of presentation and Handedness (A)

D. Cyr, R. Daniloff, and R. Berry

J. Acoust. Soc. Am. Volume 51, Issue 1A, pp. 80-81 (1972); (2 pages)

Online Publication Date: 11 Aug 2005

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Eighteen right‐handed and eighteen left‐handed young normal listeners identified the location of clicks embedded within sentences. The sentence‐click stimuli were presented monotically and dichotically to right and left ears; subjects wrote down click location with a slash mark on the sentence. Results indicate no significant difference in correct location of clicks (for either right‐ or left‐handed listeners) as a function of mode of presentation, monotic or dichotic, to either ear, i.e., no laterality effect. Size of target (click on correct syllable, correct word, but not for word and/or word boundary) significantly affected correctness of location for right‐ and left‐handed subjects. Left‐handers were generally more accurate in over‐all click location on word and syllable sized “targets.” There is also evidence of a handedness by mode of presentation interaction. Results are discussed in terms of models of speech perception and laterality‐handedness effects.
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Is Vowel Perception Non‐Euclidean (A)

Dale Terbeek and Richard Harshman

J. Acoust. Soc. Am. Volume 51, Issue 1A, pp. 81-81 (1972); (1 page)

Online Publication Date: 11 Aug 2005

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In continuation of an experiment described previously [D. Terbeek and R. Harshman, J. Acoust. Soc. Amer. 50, 147(A) (1971)], judgments of perceptual similarity and difference for 12 natural vowel sounds were obtained from native speakers of Turkish and Swedish. These new data, like the earlier data from English, Thai, and German subjects, were analyzed using the PARAFAC multimode factor analysis method [R. Harshman, UCLA Working Papers in Phonetics No. 16 (1970)]. The resulting perceptual spaces are roughly interpretable in terms of traditional vowel descriptions, but certain difficulties remain. The results for the five languages tested, together with results reported by other investigators, were subjected to several further types of analysis. The patterns which emerge suggest that the function relating perceived distances between vowels to their positions along underlying perceptual dimensions is non‐Euclidean in two ways. First, the perceptual dimensions do not lie orthogonally to one another, implying that they are related in meaning. Second, they interact nonlinearly, producing a curved space, an effect which causes the extraction of an uninterpretable dimension when linear models are used.
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A Reexamination of Reaction Time to Segments and Syllables (A)

J. W. King, M. Hoffman, and R. G. Daniloff

J. Acoust. Soc. Am. Volume 51, Issue 1A, pp. 81-81 (1972); (1 page)

Online Publication Date: 11 Aug 2005

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This study reports subject auditory reaction times to syllables (CVC, CCV, and VCC in construction) and to their constituent segments. A target syllable or segment was located randomly in each of 288 lists each containing 10 nonsense syllables. Stimulus material was presented via earphones to 12 normal hearing subjects who heard the target syllable or segment spoken before each list. Reaction time was measured from the beginning of the target to the depression of the response button by the subject. Response times, false alarms, and misses were recorded from a frequency counter on a data printer. Analysis of data indicated that, within limits, subjects reacted equally fast to syllables of different constructions, given similar durations. Contrary to the findings of Savin and Beret [J. Verbal Learning and Verbal Behavior, 1970], subject response to syllable initial segments was significantly greater than to the entire syllable. Segment response times within a syllable generally increased according to segment position from initial to final.
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Contour Plots of Speech with Subglottal‐Rate Time Resolution Provide New Insight Into Perceptual Cues (A)

J. L. Stewart

J. Acoust. Soc. Am. Volume 51, Issue 1A, pp. 81-81 (1972); (1 page)

Online Publication Date: 11 Aug 2005

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An electronic analog ear having 24 sections has a space‐time pattern that can be converted to a contour pattern in the manner of a “Voiceprint.” Each section signal is half‐wave rectified and low‐pass filtered to 400 Hz so as to retain several harmonies of fundamental voice pitch. Contours are generated with high speed commutation of the 24 section signals, a delay line smoothing device, and a level clipper. The actual experimental system, which is frequency scaled downward by a factor of 20 is described. A number of example patterns are shown for both speech and nonspeech sounds. Cues are revealed which allow the central nervous system to make localization measurements on the basis of envelope periodicity. A voice pitch mechanism is demonstrated which depends upon periodic pattern projections into the cochlea in a manner which is not well described with spectra.
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Radiation from a Spherical Source Eccentrically Positioned in a Fluid Sphere (A)

William Thompson, Jr.

J. Acoust. Soc. Am. Volume 51, Issue 1A, pp. 81-82 (1972); (2 pages)

Online Publication Date: 11 Aug 2005

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Acoustic Radiation from a spherical source eccentrically positioned within a fluid sphere embedded in another fluid is evaluated. This configuration is an idealization of a spherical acoustic lens used as a sound projector. To effect a solution, the translational addition theorem for spherical wavefunctions is used to express series of wavemodes centered at one sphere in terms of modes centered at the other, thereby facilitating the task of satisfying the boundary conditions. Because spherical wavefunctions centered at one point are not orthogonal over the surface of a sphere centered elsewhere, each mode associated with the first sphere couples into every one of the modes associated with the other. Hence, the evaluation of the modal coefficients in the series for the radiated pressure necessitates solving an infinite set of equations. Approximate solutions are obtained by truncating the set to finite size and solving numerically. The source radiation impedance and farfield directivity have been calculated for representative values of the many parameters that characterize the problem, such as wavelength size of fluid sphere and source, relative characteristic impedances and sound velocities of the two fluids, and position and velocity distribution of the source. [Research was supported by the Ordnance Research Laboratory under contract with the U. S. Naval Ordance Systems Command.]
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Some Effects of Water Loading on Turbulence Induced Plate Vibration (A)

W. A. Strawderman and R. A. Christman

J. Acoust. Soc. Am. Volume 51, Issue 1A, pp. 82-82 (1972); (1 page)

Online Publication Date: 11 Aug 2005

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This paper presents the results of a theoretical study of the effects of water loading on a turbulent‐flow‐excited, thin, finite plate. The water loading is defined as the pressure field produced in the water, at the plate surface, as a result of the plate vibration. The propagating component of this pressure field acts in temporal phase with plate resistive forces, and the nonpropagating component acts in phase with plate inertial forces. Thus, water loading may be interpreted as additional inertia and additional resistance of the plate. In an example, comparison of computed, turbulent‐flow‐excited water loaded and in‐vacuo plate vibration spectra revealed the additional inertia to be 1.5–12 times the inertia of the plate alone. The additional resistance was found to be approximately 1% of the critical value of the in‐vacuo plate. The additional inertial and resistive forces caused the “mode” shapes of the water‐loaded plate to differ from the corresponding mode shapes of the in‐vacuo plate.
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Transient Sounds Due to Implosion of Simple Structures under Hydrostatic Pressure (A)

W. T. Reader and G. Chertock

J. Acoust. Soc. Am. Volume 51, Issue 1A, pp. 82-82 (1972); (1 page)

Online Publication Date: 11 Aug 2005

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Experiments have been performed with a small simple structure which is designed to implode under hydrostatic pressure, and to generate sound by such processes as tearing, inrush of water, compression of internal air, and impact. The associated theory predicts the motion and deformation of the structure, and also analyzes the radiated sound as the sum of multipole components. Experiments were conducted at depths of 40, 200, and 500 ft; the structure's motions were measured by accelerometers, and the radiated sound pressures versus time were measured with hydrophones at up to eight locations about the implosion. The measurements are in substantial agreement with the theoretical predictions. In particular, they confirm that the dominant contribution to the sound is simply the monopole component p(R,t) = ρV̈/(4πR), where V̈ is the second time derivative of the volume enclosed by the wetted surface.
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Approximate Model for Predicting Operational Parameters of the Class IV Flextensional Underwater Transducer (A)

James R. Rutledge and L. H. Royster

J. Acoust. Soc. Am. Volume 51, Issue 1A, pp. 82-82 (1972); (1 page)

Online Publication Date: 11 Aug 2005

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An approximate model for predicting operational parameters of the Class IV flextensional underwater transducer is developed. The model combines approximate solutions for the acoustic radiation problem, the forced shell vibration problem, and the electromechanical problem of the piezoelectric stack. The acoustic radiation is approximated by using a source density formulation technique and is coupled to a mathematical model which predicts the vibrations of the shell coupled to the piezoelectric stack. The forced vibration solution of the shell with the acoustical loads included is then combined with the electromechanical equations governing the piezoelectric stack. The model predicts operational parameters which includes the farfield radiation pattern and the stress variations and electrical impedance of the stack.
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