bluuebunny/crossref_metadata_2025 huggingface dataset:
Acoustic radiation from a thin plate with fluid loading discontinuity
Authors: Pierucci M.
Published: October 2005

In many underwater acoustic problems, a very compliant coating is applied to the surface of a structure. The presence of this coating will tend to insulate the structural vibrations from fluid loading interaction. The problem of an infinite thin plate, half with fluid loading interaction and half without, represents the discontinuous fluid loading condition that a partially coated structure will experience. The split boundary value problem has been solved by the Wiener—Hopf technique. Radiated intensities and directivity patterns have been calculated and compared to that of a thin plate with homogeneous fluid loading. In a previous paper [M. Pierucci, J. Acoust. Soc. Am. 60, S115 (A) (1976)] a similar problem with the structural vibrations assumed to be governed by the membrane equation was presented.
A community noise code. II. Does it work?
Authors: Bounds S. E. , Garbak J. A. , Mendelsohn E. S. , Peppin R. J. , Whelan J. H.
Published: October 2005

An A-weighted community noise code was developed for Montgomery County. The code requires a single number noise measurement for enforcement. This paper describes the procedure used and the experience of the County in enforcement since the code became enforceable. Although no legal tests have come up since the code became effective (1 October 1976), it appears that there may be some trouble should it come to court. Description of these possible problems will be discussed.
Psychoacoustic performance in children: a developmental study
Authors: Maxon A. B. , Hochberg I.
Published: October 2005

This study investigated the development of psychoacoustic behavior in normal children between 4 and 12 years of age. Three psychoacoustic tasks—difference limen for intensity (DLI), difference limen for frequency (DLF), and temporal integration—as well as pure tone sensitivity were evaluated among groups of children aged 4, 6, 8, 10, and 12. Results showed (a) significant increase in pure tone sensitivity, (b) significant decrease in DLI size and (c) significant decrease in DLF size between 4 and 12 years. The configurations of the functions were similar to those of normal adults, and approached adult values with increasing age. The threshold-duration functions for temporal integration were similar to adult norms—10 dB threshold shift for every decade change in duration—but fell at increasingly lower intensity levels—dB SPL—between 4 and 12 years. In general, there was an improvement in psychoacoustic performance with increased age. The data were also reconstructed with reference to a predicted performance model.
Correction of deviant timing patterns in deaf children's speech using computer techniques
Authors: Osberger M. J.
Published: October 2005

Research has shown that deaf children typically distort the temporal patterns of speech. Data obtained by John and Howarth [Lang. and Speech 8, 127–134 (1965)] indicate that incorrect timing patterns may have a detrimental effect on the intelligibility of deaf children's speech. However, the results of this study have not demonstrated the individual effects of phonemic and timing errors on speech intelligibility. The present paper is a progress report which describes the techniques used to correct deviant timing patterns in deaf children's speech. Six sentences produced by six deaf children have been selected for manipulation using digital speech processing techniques. The 36 utterances have been segmented on a phoneme-by-phoneme basis using an interactive computer facility that allows for segmentation simultaneously by ear and by eye from a visual display of the waveform. The same sentences produced by normal hearing children also have been segmented in order to obtain normative duration values. Adjustment of the segment duration has been accomplished by adding or subtracting whole pitch periods from steady-state portions of the phonemes. Using a six stage approximation procedure, the deaf children's speech has been processed so as to systematically approach the timing patterns typical for normal hearing children. [Research supported by PHS Grant NS 09252.]
Nasalization as a style marker in Persian
Authors: Kahn M. , Ordubadi A. , Bernstein J.
Published: October 2005

Nasal output in informal (conversation) and formal (read, paradigms) Persian were sampled from a fairly homogeneous population of Iranian speakers. Measurement was accomplished by recording the output of a small accelerometer placed on the noise. The peaks on the accelerometer out-put were then compared to the raw speech wave. Overall degree and quantity of nasalization was measured across speakers and compared with similar measurements obtained for hearing adult speakers of English, from Stevens et al. [Speech Hear. Res. 19, 2 (1976)]. Then nasalization was contrasted within each speaker's repertoire of styles. Styles were objectively labeled by appearance of particular lexical items and phonological substitutions. Particular attention was paid to the substitution of postvocalic nasalization for a non-nasal alveolar stop, e.g., the morpheme −i:d→−ĩ:. Oddly enough, this phonological change has seemingly evolved in absence of any original motivating nasal consonant.
Segment and word durational correlates of syntactic boundaries in Italian
Authors: Nespor Marina A. , Allen George D.
Published: October 2005

Major syntactic boundaries are marked in many languages by pauses, but the acoustic phonetic correlates of these pauses differ from language to language. The majority of languages, including English and Italian, signal pauses by lengthening the prepausal segment(s), syllable(s), or word(s). In Italian, however, certain syntactic boundaries satisfying a “left branch” condition on the structural description of the sentence are marked by events following the boundary. In northern Italian dialects, the word immediately following the boundary is shortened; in central, southern, and insular dialects, the initial consonant of the second word following the boundary is lengthened. These three phenomena, prepausal lengthening, immediate postpaudal shortening, and lengthening of the initial consonant of the second word after the pause, are not incompatible, and may in fact be manifestations of one rhythmic principle. Examples of the post-boundary phenomena, their syntactic conditions, and their phonetic correlates will be discussed. [Supported in part by NSF Grant No. BNS74-02513.]
Temporal control of medial stop consonant clusters in English
Authors: Westbury John R.
Published: October 2005

Measurements were made of closure durations of the eighteen possible voiced-voiceless and voiceless—voiced combinations of /p/, /t/, /k/ and /b/, /d/, /g/ produced medially in isolated nonsense disyllables by three English-speaking males. Preliminary results show that closure durations depend on both voicing and place of articulation of first and second members of such clusters. Mean closure durations were significantly longer (by approximately 20 msec) for voiceless-voiced than voiced—voiceless clusters. Clusters with first-member velars were longer than those with first-member labials and alveolars, while clusters with second-member velars were shorter than those with other second members. Sequences of stops requiring the greatest changes in points of articulation (labial → velar, or velar → labial) were longer than sequences requiring smaller changes in the same direction (labial → alveolar, alveolar → velar, or velar → alveolar, alveolar → labial). Closure durations generally varied inversely with durations of surrounding vowels. Clusters were longest, for example, in the frame /pI__It/, somewhat shorter in/pI__at/, shorter still in /pa__It/, and shortest in /pa__at/. But, durations for like clusters were no shorter in the frame /pI__Id/ than in /pI__It/. These latter findings suggest first that closure durations for medial step clusters are governed extrinsically by a tendency toward isochrony. However, whatever principles lead toward isochrony appear to operate before the rule which results in greater length of final-syllable vowels before voiced stops in English.
Some effects of speaking rate on timing in speech production
Authors: Weismet G. , Ingrisano D.
Published: October 2005

At a previous meeting of the Society, we reported certain effects on speech timing due to emphatic-stress placement within a five-syllable utterance [Weismer and Ingrisano, J. Acoust. Soc. Am. 60, S26(A) (1976)]. The present investigation explores the stability of these effects across two speaking rates for five subjects. Each of the subjects recorded a list of 400 sentences at both speaking rates (conversational and ‘very fast’); the lists contained a randomized arrangement of 4 sentences × 5 emphatic-stress conditions in which each sentence-emphatic-stress combination was repeated twenty times. The time-normalization analysis procedure described in our previous report was used to allow direct comparison of articulatory timing patterns associated with identical phoneme sequences spoken at two distinct rates. Results are discussed relative to the notion of reorganization of articulatory commands with large changes in speaking rate [Gay and Hirose, Phonetiea 27, 44–56 (1973)] or the lack thereof [Lindblom, J. Acoust. Soc. Am. 35, 1773–1781 (1963)]. [Supported by NIMH Grant ♯R03-MH 28705-01.]
An interaction between auditory and oral sensory feedback in speech regulation
Authors: Crary M. A. , Fucci D. , Warren J. A.
Published: October 2005

Investigation into the relative contribution of auditory and oral sensory feedback in speech regulation has received much attention in the last twenty years. Many studies have disrupted one or both of the primary feedback modalities in speech and reported the resulting effects on production. Recently, data has been reported which suggest an interaction between auditory and oral sensory feedback in speech regulation. To investigate further the interaction between the auditory and oral sensory feedback modalities during speech production lingual vibrotactile thresholds were obtained from Ss in the following conditions: (1) before and after speech production with normal auditory feedback, (2) before and after speech production under exposure to auditory masking, and (3) before and after exposure to auditory masking without performing speech tasks. In addition, duration measurements were obtained for selected speech sounds to investigate temporal changes in the articulatory patterns of Ss in the various conditions. Lingual sensory decreases and temporal reorganization were observed only in Ss speaking under auditory masking. These data suggest a balanced interaction between auditory and oral sensory feedback modalities which, when disturbed, results in nonphonemic changes in speech production.
Finite-amplitude acoustic pulse propagation in dispersive thermo-viscous fluids
Authors: McKendree P. S. , Fenlon F. H.
Published: October 2005

We have investigated the propagation of initially square and exponentially decaying finite-amplitude pulses in dispersive thermaviscous fluids via numerical analysis of the appropriate nonlinear acoustic wave equations for liquids containing gas bubbles and for mono-relaxing fluids. In a computer generated film, we begin by exhibiting the degeneration of these simple pulses in a lossless fluid dynamic-steady state solitons and their subsequent collisions during the course of propagation. Viscous absorption and spherical spreading losses are then introduced independently so that their effect in damping soliton structure as it forms, is clearly demonstrated. The example of “solitonlike” formulation in a leggy dispersive fluid which we have included in the film, was chosen to simulate an experiment in a gas liquid medium previously reported In the literature [S. S. Kutateladze, A. P. Burdukov, V. V. Kuznetsov et al., Sov. Phys.—Dokl. 17, 1051–1052 (1973)]. Following this presentation, the physical conditions required to induce “solitonlike” behavior via acoustic pulses in different types of dispersive thermoviscous fluids will then be briefly considered.
Collinear interaction of noise with a finite-amplitude tone
Authors: Webster Don A. , Blackstock David T.
Published: October 2005

The interaction between a low-level band of noise and a finite-amplitude tone has been measured in air in a plane progressive wave tube. Noise bands generally 1–3 octaves wide with center frequencies in the range 0.7–1.2 kHz were used. At the source the tone SPL was in the range 140–151 dB (re 0.0002 μbar); the frequency was either within the noise band or somewhat above. When the tone was absent, the noise propagated as a small-signal wave. When the tone was turned on, however, a strong modulation took place. After a propagation distance of only a few meters, the noise spectrum extended at least 4–5 octaves above the original noise band. Moreover, the spectrum was quite flat. The energy required to extend the noise apparently came from the tone and its harmonics, not the original noise band. [Work supported by NASA, AFOSR, and ONR.]
Simplified, low-cost, efficient, acoustic levitation system
Authors: Apfel Robert E.
Published: October 2005

Recently I have improved apparatus for the acoustic levitation of a drop of one liquid in another, making it practical to build for anyone who has an oscillaior and audio amplifier with response to 50 kHz, a current probe, an inexpensive oscilloscope, and a lead zirconate titanate cylinder of the right size. This piezoelectric cylinder (1.5-in. o.d. and length, 0.125-in. thickness) is epoxied near the center of a foot long piece of standard 30-mm o.d. pyrex tube. A hollow piston with o-ring seal and O. 005-in. diaphragm acts as an excellent bottom, pressure-release reflector of acoustic energy, as is the top air—liquid interface, leading to strong acoustic standing waves at particular resonance frequencies. Optimum frequencies are determined by observing the input current to the transducer as the oscillator is tuned between 47 and 55 kHz, and as liquid and piston levels are adjusted. Benzene droplets in water have been levitated with only a fraction of a watt input to the transducer. More details of this simple system will be described. [Work supported by U. S. Office of Naval Research and NSF, Heat Transfer Program.]
Effects of imperfectly stratified media on geometrical acoustics wave normal constants: 2-D theory
Authors: ReVelle D. O.
Published: October 2005

Using kinematics and geometry, a theory has been developed to obtain cumulative changes in the characteristic velocity k (Snell's law constant) of the wave normal, of the wave normal, and of its heading in two dimensional media (over a flat earth). The specific case studied is that of a steady-state atmosphere whose finite length layers of constant temperature (sound speed) slope at a small angle which is independent of altitude. An explicit expression is developed for determining the nonplane wave parameter (a direction cosine) from atmospheric temperature and wind structure and wave parameters which relies heavily on the well-known one-dimensional results. Changes in k are generally small, but vary with layer thickness and slope. The peak change is maximum at steep angles as the wave, in general, becomes progressively more nonplane. Similar changes in wage heading are also predicted, but with no explicit dependence on layer slope. Applications of the research include reexamination of Rocket Grenade data, etc., and development of a statistical—physical theory of waves in realistic media.
Auditory thresholds and reaction times measured with two procedures in the cat
Authors: Orr J. L. , Moody D. B. , Stebbins W.
Published: October 2005

Auditory thresholds and reaction times were measured in three cats with a two response pedal positive reinforcement behavioral procedure. A cat initiated a trial cycle by depressing a response pedal with each front paw. Depressing both response pedals for 4–6 sec turned on a light to mark the 1.6-sec trial. During a trial, release of one of the pedals was defined as a “Yes” report and release of the other pedal was defined as a “No.” Both correct “Yes” and “No” reports were reinforced with liquid meat food. Thresholds and reaction times were obtained with both discrete trial threshold “tracking” and the method of constant stimuli. With both methods, hald of the trials were blanks in which the tone was not presented. Thresholds obtained with the two methods were in good agreement. The shape of the audiograms was similar to that previously reported [J. D. Miller, C. S. Watson, and W. P. Covell “Deafening Effects of Noise on the Cat,” Acta Oto-Laryngol. Suppl. 176, 1–91 (1963)] and the absolute level was higher. [Work supported by NINCDS.]
Neuroelectrical correlates of categorical speech perception in preschool aged children
Authors: Molfese D. L. , Hess T. M.
Published: October 2005

Auditory evoked potentials (AEP) were recorded for a 500-msec period from the temporal language processing areas of the left (LH) and right hemispheres (RH) of 6 male and 6 female four-year-old children in response to 4 synthetically generated bilabial stop consonants with voice onset time (VOT) values of 0, +20, +40, and +60 msec. AEPs were averaged for each VOT condition and then factor analyzed [Molfese, 1976]. Four factors accounting for 65% of the total variance were extracted. Factor scores for these orthogonal factors were then submitted to a 2(sex) × 2(Hemisphere) × 4 (VOT) ANOVA. In this way, components of the brain-response were identified which reflected the following: (1) sensitivity to VOT changes that crossed the phoneme boundary (F = 11.82, df + 3, 80, p < 0.01), (2) specific RH involvement in the categorical perception process (F = 3.58, df = 3, 30, p < 0.05), (3) sex differences in RH activity (F = 6.24, df = 1, 10, p < 0.05), and (4) general hemisphere differences (F = 8.77, df = 1, 10, p < 0.01). These results support the notion that speech perception is a multidimensional process dependent on mechanisms within both hemispheres. Developmental issues are also addressed.
Continued evaluation of a multipoint electrotactile speech aid
Authors: Sparks D. W. , Kuhl P. K. , Edmonds A. E. , Gray G. P. , Bourgeois M. , Wiedmer B. , Gray J. , Ardell L. A.
Published: October 2005

At the 92nd meeting of the Acoustical Society of America, we reported preliminary data on vowel and stop and nasal consonant recognition using our multipoint electrotactile speech aid (MESA). Speech tokens were presented to artifically deafened adults who were required to identify the tokens in three conditions; tactile presentation, visual presentation, and tactile plus visual presentation. This report will be an update on our continuing evaluation of the speech transmission capabilities of the MESA. Specifically, we have extended our tests to fricatives, stops in final position, vowel recognition across talkers, segmental and suprasegmental features within a sentence context, and, finally, connected discourse. While the MESA demonstrates excellent resolution for certain speech features, we will discuss m-difications of the MESA designed to enhance its transmission of those features not well resolved.
Velocity as vibration for measurand machinery condition analysis
Authors: Misialek R. F.
Published: October 2005

The paper presents the argument for using vibration velocity rather than acceleration or displacement as the measurand to more readily assess rotating machinery health and maintenance requirements. Also presented are the techniques used and the inherent advantages.
Improved acoustic system for auditory research
Authors: Sokolich W. G.
Published: October 2005

A closed acoustic system, based on the principles of lumped-element and transmission-line acoustics, has been developed for use in acute physiological experiments on small mammals. Through the appropriate utilization of a high-quality push-pull electrostatic earspeaker (Stax, SRX), a low-impedance sound source having a relatively flat frequency response and a bandwidth of over 30 kHz is obtained. The output impedance of the source is increased by means of a lumped acoustic resistance in order to match the characteristic impedance of a uniform delivery line. The characteristic impedance of the delivery line is selected so that acoustic stimuli are propagated from the source to the eardrum without the introduction of substantial amplitude and phase distortion. Sound near the eardrum is coupled to a 12-in. precision condenser microphone through a high-impedance uniform probe line that is terminated in its characteristic impedance over the range of higher sound frequencies. When electrical equalization of +6 dB/octave is applied above 3 kHz, the frequency response of the sound monitor is flat to within ±2 dB over a 30-kHz bandwidth.
Vocal tract area function determination in the presence of spatially varying loss: Further developments in inverse scattering
Authors: Resnick J. R. , Heinz J. M.
Published: October 2005

A reflectance formulation of the acoustic inverse-scattering method of measuring vocal tract area functions has been developed. We arrive at a partial differential difference equation in which the pressure and area of the vocal tract appear as unknown functions. Such a formulation has several advantages. First, the vocal tract model may include a spatially dependent loss term whose magnitude need not be proportional to area. Second, the solution of the equation evolves in space and time, thereby leading to a recursive computational procedure. The relationship between this approach and the integral equation method in the lossless case is developed in terms of the Riemann function for the underlying Webster equation. [This work was supported in part by an NSF predoctoral fellowship and an Institutional National Research Service Award No. 5T32GMO57.]
Digital simulation of the telephone
Authors: Schmidt C. E. , Rabiner L. R. , Berkley D. A.
Published: October 2005

Recently a large number of systems have been proposed for speech communication which operate over both wide-band channels and standard telephone connections. To investigate such systems it is useful to be able to simulate the telephone as well as the other speech processing parts of the system. Thus, we have investigated a simple digital network which, to a first order, simulates the properties of both the standard carbon microphone, and the telephone transmission system. The simulation consists of a combination of nonlinear distortion, noise addition, and bandpass filtering. The parameters of the simulation were manually adjusted to provide optimum matches to several telephone links. To evaluate the method, two formal tests were made. In one, listeners were asked to identify which of a pair of utterances was an actual telephone line recording. In the other, listeners were asked to judge similarity between an actual telephone recording and the simulation. Results indicate that for some sets of simulation parameters the similarity between the simulation and the actual telephone line was high. Recordings will be played to demonstrate these results.
Alphabetic process for cueing readers of natural languages to speak four dimensions of sound in speech has been constructed
Authors: Robson Ernest , Robson Marion
Published: October 2005

The four dimensions of this notation are presented visually: fundamental frequency, duration, intensity, and silence (slide No. 1). The application of this code to the IPA is shown (slide No. 2). Tests on relative graphic prominence of cues are demonstrated (slide No. 3). The role of orthogonality (independence) in notational systems is discussed.
Acoustic propagation through an analytic eddy using the parabolic approach
Authors: Baer Ralph N.
Published: October 2005

A method for improving the agreement between solutions of the (exact) Helmholtz and the (approximate) parabolic equations by means of simple corrections to the latter has been previously reported [J.A. DeSanto, J.S. Perkins, and R.N. Baer, J. Acoust. Soc. Am. 61, S12(A) (1977)]. Using a computer program based on this algorithm and an analytic sound-speed field model [R.F. Henrick, W. L. Siegmann, and M.J. Jacobson, J. Acoust. Soc. Am. 61, S11(A) (1977)] for an ocean region containing an eddy we perform several numerical experiments. It is found that by placing a sound source near the eddy center the character of the acoustic field as a function of range and depth changes dramatically even for relatively weak eddies. This is true at several frequencies. For fixed source and receiver configurations there are changes in the received pressure field often exceeding 20 dB as the eddy traverses the region of transmission.
Acoustic fluctuations on the space and time scale of large ocean eddies
Authors: Clark J. G. , Dominijanni L. , Adams S. L.
Published: October 2005

As a rule, ocean acoustic propagation over several hundred kilometers, the space scale of a large eddy, will be by multipath. Also, in general, the multipath will be sufficiently complex that interference effects will introduce difficulties in relating cw propagation fluctuations to environmental processes. However, recent analytical and experimental results from a test of several months duration demonstrate that these difficulties can be overcome by a proper selection of source and receiver depths in the water column. The test results are at a frequency of 206 Hz and the range between source and receiver is in excess of 500 km. Quantitative results on acoustic transmission fluctuation will be presented on all time scales from a few minutes to several months.
Tone glides and ear advantage for pitch
Authors: Whittaker R. G.
Published: October 2005

A replication of the Efron-Yund study [R. Efron and E. W. Yund, Neuropsychologia 12, 249–256 (1974)] was accomplished and findings were in close agreement with those of the original investigators: When subjects receive dichotic stimulation by steady-state tone bursts of equal intensity but differing frequency, pitch extraction of the resulting chord is usually dominated by the frequency going to one ear resulting in an ear advantage for pitch. A series of linearly rising tone glides was constructed with center frequencies equal to the values used for pure-tone testing, and substituted into the design so that the glides went to the nondominant ear. For most subjects, the effect is to decrease the observed ear dominance and the degree of change is predicted by the amount of frequency change of the glide stimulus. An interpretation invoking the activation of receptor cells tuned to changes in acoustic stimulation is developed.
Comparison of a phase random multipath model to ocean acoustic fluctuation data
Authors: Hamblen W. R.
Published: October 2005

As part of a study of ocean acoustic fluctuation, the probability densities for amplitude rate and phase rate are predicted from a phase random model. The amplitude rate density is discovered to be Gaussian, the phase rate density is discovered to be a unique bell-shaped curve. Both depend upon the ocean parameter ν2, the single-path mean-square phase rate. ν2 is shown to be the only parameter of importance. Data obtained by the Woods Hole Oceanographic Institution are analyzed and compared with the predicted densities. Experiments conducted at 220 and 406 Hz over a 250-km range near Eluethera reveal values of ν2 on the order of 10−3 sec−2. The agreement between the data and the predicted densities is excellent. [Work supported by ONR.]
Distribution of surface-generated noise in a stratified ocean
Authors: Kuperman Wm. A. , Ingenito Frank
Published: October 2005

A theoretical model for the statistical distribution of surface-generated noise in a stratified, laws medium has been developed. The model is strictly wave theoretic, with the source of the surface noise taken to be a plane of statistically distributed monopoles. Expressions for the intensity depth profile and spatial correlation function of the noise in the water column are derived. An important result is that the correlation function is spatially nonstationary in the vertical, due to the inhomogeneity in the vertical structure. Sample calculations in shallow water environments indicate that the velocity profile and bottom properties are important in determining the structure of the correlation function. In the companion paper these correlation functions are used to predict conventional and optimum array gains in detecting shallow water sources. For this application the wave theoretic model is necessary to accurately represent both the noise field structure and the propagation of the noise signals.
Scattering of elastic waves from spherical and cylindrical inclusion in a solid medium
Authors: Flax Lawrence
Published: October 2005

Differential and total cross section are computed for the scattering of a plane longitudinal wave from spherical or cylindrical isotropic elastic inclusion embedded in another isotropic elastic medium. The inclusion and/or the medium may be absorptive. The dependence of the scattering cross section on ka (k is the longitudinal wave number in the host material and a is the radius of inclusion) over the range 0–50 is computed for various media. The effect of the elastic constants of both host and inclusion material on the frequency dependence of the cross section will be examined.
Diffraction by blunt and coated edges
Authors: Eisler Thomas J. , Taylor David W.
Published: October 2005

The edge of a rigid wedge is surrounded by a thin coating whose density and sound velocity differ from those of the ambient medium. The scattering of an incident plane wave is expressed by means of an integral equation which is solved by literation. The method is also applicable to a rigid coating, whose configuration is equivalent to a rigid wedge with a slightly blunted edge. The solution is expressed as the well-known rigid wedge solution plus a small perturbation. The perturbation is found to be proportional to the quantity ka raised to a power which depends on the wedge angle, where k is the incident wavenumber and a is a length typical of the radius of curvature of the coating at the edge. Let the interior wedge half-angle be Ω The power of ka is found to be π/(π−Ω) for 0⩽π/2 and 2 for π/2⩽Ω<π.
Effects of exposure-pattern differences on TTS and hair-cell destruction in the chinchilla
Authors: Ward W. Dixon , Turner Christopher W.
Published: October 2005

Chinchillas were exposed to 700–2800-Hz noise at 105 dB SPL. Group A was exposed for 10 min on 22 occasions half a week (3 or 4 days) apart. Group B was exposed on a “factory” schedule: 22 10-min exposures given on Monday through Friday for a month. Group C received a 220-min exposure on a single day. Median TTS's 60 min after exposure, at 1, 2, 4, and 8 kHz, were 10, 12, and 66 dB, respectively. The median number of missing outer hair cells (MOHC) was 59, 99, and 54, respectively; two control animals had 51 mud 60 MOHC. There was no relation between individual differences in TTS and in cochlear damage. Apparently chinchillas can experience a single very severe TTS (more than 60 dB an hour after exposure) with no measurable haircell damage, but a moderately severe exposure, repeated daily without time for complete recovery between exposures, can produce measurable damage. The relative susceptibility of chinchilla and man will be discussed. [Research supported by the National Institute of Neurological and Communicative Disorders and Stroke, Public Health Service.]
Electrophysiological and morphological observations of electrolytically lesioned chinchilla cochleas
Authors: Ferraro John A. , Lim David J.
Published: October 2005

Electrolytic lesions were produced in chinchilla cochleas with the method described by Ferraro and Dallos [Arch. Otolaryngol. 101, 312 (1975)]. This procedure involves passing a current of 1–3mA, at an approximate frequency of 5 MHz, for a controlled amount of time between a differential pair of recording electrodes located in a particular cochlear turn. Cochlear microphonic responses were recorded immediately before lesioning and for a period of from one to three hours after lesioning. The cochleas were then perfused with glutaraldehyde, dissected out and prepared for scanning electron microscopic examination with the Murakami technique [Arch. Histol. Jpn. 36, 189 (1974)]. A localized region of destruction of cochlear partition elements located between the electrode tips, progressing from outer to inner hair cells and supporting structures was observed. Cochlear microphonic data and corresponding scanning electron photomicrographs of lesioned cochleas are presented. [This research was supported in part by grants from the Graduate School, and College of Social and Behavioral Sciences, Ohio State University.]
Frequency-position maps for the chinchilla cochlea
Authors: Eldredge D. H. , Miller J. D. , Bohne B. A. , Clark W. W.
Published: October 2005

Frequencies of tones are mapped on to distances along the organ of Corti by associating behaviorally measured threshold shifts with areas of histologically observed damage. Individual differences in the lengths of the cochleas are normalized by expressing distance in percentage of the total length and then converting to a standard length of 18.4 min. Useful points from at least 17 ears studied at CID along with similar data of Ryan and Dallos collected at Northwestern University are used to construct the map. It appears that distance in mm plotted against log frequency can be approximated by locating 1.6 kHz at the middle of the basilar membrane and moving about 2.5 mm for each octave change in frequency. In contrast to the familar maps of cat and man, there is a suggestion that the slope (mm/log/f) is greater in the apical half and less in the basal half of the cochlea. [Supported by NS 03856 and NS 01791.]
Speech synthesis by hand and by rule for use in perceptual studies
Authors: Klatt Dennis H.
Published: October 2005

A computer-simulated formant synthesizer will be described that provides a flexible method of generating synthetic speech with precisely controlled acoustic characteristics. The output can be used to study systematically the relative perceptual importance of different acoustic cues to phonetic contrasts. Listings of a machine-independent FORTRAN program for specifying synthesizer control parameter values as a function of time are available along with the FORTRAN synthesizer software. Documentation, including preliminary rules for consonant-vowel synthesis, is under development. Since hand synthesis of lengthy material is very tedious, a program useful for the generation of sentence-length utterances to study prosodic variables and segmental perception in sentence contexts is also under development. A synthesis by rule program is used to lay out preliminary specifications for all control parameters. The rule program makes parameter files that can be modified easily by hand before waveform generation. The user can also intervene early in the rule process and, e.g., modify segmental durations before parameter contours are drawn automatically. These programs are valuable additions to experimental techniques such as using pieces of natural speech or vocoder-modified natural speech because it is possible to test perceptual results under conditions where the stimulus is known precisely. [Supported by an NIH Grant.]
Recognition of tonal sequences derived from traditional triad structures
Authors: Killam Rosemary N. , Lorton Paul V.
Published: October 2005

The effect of reordering pitches comprising traditional triads into all possible tonal sequences was measured on subject perception and confusion of triad qualities. Seventeen musically trained subjects participated in the study, which was conducted on the PLATO computer system, using computer-accessed sound source. Stimuli consisted of equal numbers of all four triad qualities, randomly presented in all possible arrangements of tones. Sequences used 512-Hz tone as lowest pitch (with exception of two-thirds of augmented triad tonal sequences, which were based at semitone's interval from 512 Hz). Stimuli were presented at 0.2 and 0.1 sec/pitch, with additional simultaneous triad presentation to control for S's variability in quality recognition. Previous studies of perception of tonal sequences [W.J. Dowling, Percept. Psychophys. 9(3B), 348–349 (1972), and J.B. Davis and J. Jennings, J. Acoust. Soc. Am. 6l, 534–541 (1977)] lend support to theories of S use of auditory imagery in recognition tasks. Current study measured effect of order of intervals produced by tonal sequences on S accurate recognition of triad quality, with resulting implications of S's use of pre-existent auditory pattern imagery.
Bubble noise measurement facility
Authors: Mathews T. C. , Paladino D. J. , Taylor David W.
Published: October 2005

A facility has been constructed at the David W. Taylor Naval Ship R & D Center for the measurement of bubble splitting noise. The facility is patterned after the bubble splitting apparatus of Sevik and Park of Pennsylvania State University [M. Sevik and S. H. Park, J. Basic Eng. Trans. ASME, Paper No. 72-WA/FE-32, 1–8 (1972)]. The difference in the new facility is the provision for measurement of bubble splitting noise. In addition to the measurement of sound pressure levels associated with controlled bubble splitting the acoustic capabilities of the facility provide a means for measuring the bubble size distribution under different flow conditions. Flow characteristics of the facility, background noise spectra and bubble noise data are presented.
Sound attenuation measurements over various ground covers
Authors: Bass H. E. , Bolen L. N.
Published: October 2005

Two series of measurements of sound attenuation by various ground covers have been completed. Surface impedance values have been determined for clay soil, sand, and prepared grass fields of various heights. These values were obtained for frequencies from 50 to 2000 Hz. In addition seismic sensors were used to measure the transmission properties of sound into clay soil as a function of the angle of incidence. Results of the impedance measurements are consistent to previous results [J. E. Piercy, T. F. W. Embleton, and L. C. Sutherland, J. Acoust. Soc. Am. 61, 1403–1419 (1977)] with the largest surface effects observed at low frequencies. [Work supported by ARO.]
Attenuation of highway noise by narrow forest belts
Authors: Borthwick J. O. , Reethof G. , McDaniel O. H. , Carlson D. E.
Published: October 2005

Over the last several years highway noise prediction methods have been refined and calibrated for sound propagation over open terrain and interacting with complex physical barriers. However, very little work has been done in the area of traffic noise propagation through bands of vegetation, which most laymen feel offer the most feasible means of reducing traffic din. The lack of research in this area is probably due to the general feeling shared by most acousticians that narrow bands of vegetation adjacent to highways provide little physical noise reduction. This paper briefly describes current highway noise prediction methods as related to vegetative barriers and presents results from a comprehensive study of sound attenuation by narrow forest belts recently conducted at the Pennsylvania State University. Based on extensive field measurements, values of insertion loss are reported for point source, as well as for quasiline source conditions. These results are compared with models currently approved for use in predicting highway noise. In closing conclusions based on data collected are presented along with recommendations for future work in this area. [Work supported by the USDA Forest Service, Northeastern Forest Experiment Station through the Pinchot Institute for Environmental Forestry Research and the Federal Highway Administration.]
Multiphonic tones in the woodwind instruments
Authors: Backus John
Published: October 2005

The orchestral woodwind instruments have evolved to give musical tones having a single definite pitch and a characteristic quality. However, certain unorthodox fingerings and/or embouchure adjustments can result in tones of a quite different character, having perhaps two separate pitches sounding simultaneously, or perhaps a rather indefinite pitch and a “rough” or “beating” quality. Such tones have been named multiphonics. They were investigated as follows: The internal standing wave of a multiphonic tone was picked up by a microphone, supplied with an appropriate probe; the microphone output was recorded on tape. Loops made from this tape allowed the internal standing wave to be reproduced continously for analysis. The input impedance curve of the instrument with the multiphonic fingering was also plotted. It was found that multiphonic tones consist of two independently generated main components, one associated with the lowest resonance of the instrument, and the other with the third or fourth resonance. Furthermore, the higher-frequency component is amplitude modulated by the low-frequency component because of the nonlinearity of the air flow through the reed aperture. This results in two more components whose frequencies are given by the difference and sum, respectively, of the two main component frequencies. Listening tests demonstrated that the ear generally hears the two main components and the difference frequency. [Work supported by the NSF.]
Discharge rates of auditory-nerve fibers in gerbils with damaged cochleas: A two-tone summation effect
Authors: Schmiedt R. A. , Zwislocki J. J.
Published: October 2005

In normal animals discharge rates of auditory-nerve fibers driven by excitor tones at their characteristic frequencies CF's decrease when a second tone is appropriately placed above or below CF. This phenomenon is termed two-tone suppression or inhibition (TTI), and the second tone is termed the inhibitor tone. In gerbils treated with kanamycin or exposed to impulse noise, TTI is absent in a number of fibers [R.A. Schmiedt and J. J. Zwislocki, J. Acoust. Soc. Am. 61, S75(A) (1977)]. Furthermore, some of these fibers have discharge rates in response to excitor tones that increase when a second tone is added at frequencies and intensities normally associated with inhibition. We term this type of response two-tone summation. It most frequently occurs in fibers with both steep rate-level functions and high saturation rates for second tones placed above CF. For second tones below CF summation is associated with tuning curves which exhibit supranormal sensitivity at low frequencies. This summation effect may be relevant to psycho-physical studies of masking and two-tone effects in hearing-impaired listeners [B. Leshowitz et al., J, Acoust. Soc. Am. 59, S2(A) (1976)].
Response of auditory-nerve fibers to sinusoidal amplitude modulation
Authors: Smith R. L. , Brachman M. L.
Published: October 2005

Stimuli consisted of 300-msec-long tones at the CF of the unit under study. The tone bursts were amplitude modulated during their second 150 msec, and SPL was varied with percent modulation and modulation frequency held constant. Response firing rates were obtained from PST and period histograms synchronized to the tone bursts and modulating sinusoids respectively. The period histograms were approximately sinusoidal and response modulation was estimated from the amplitude of the fundamental component of the histogram waveform. When SPL was increased the average firing rate increased and then asymptotically approached saturation, while response modulation increased to a maximum and then decreased. The shape of the response modulation function could be predicted by taking increments along the average rate-intensity function, suggesting that the same saturating nonlinearity limits responses to both constant and modulated stimuli. However, for some units the predicted modulation function had to be shifted as much as 7 dB towards higher intensities in order to match the measured responses. Hence an additional mechanism may be involved which produces a small shift in dynamic range.
Tone and vowel quality
Authors: Zee Eric
Published: October 2005

The study investigates the influence of tone on vowel quality. Speakers of a tone language, Taiwanese, were instructed to produce the vowels, [i], [u], [e], [o], [ɔ], and [a], with two maximally contrasted tones, the high-falling and the low, in terms of fundamental frequency level. In most cases, these vowels are meaningful monosyllabic morphemes in that language. Preliminary results indicate that vowel quality is affected by tone. All vowels except [a] have a higher first formant frequency when they are produced with the high-falling tone. The difference in formant frequency is small but consistent. There are cases in which the vowel is raised if the tone of some lexical items is replaced by a high tone, e.g., in Foochow (Chao, 1933; Yuen et al., 1960; Chen and Norman, 1965; Maddieson, 1975) and a rising tone raises a vowel, e.g., in Lahu (Matisoff, 1973). Our results seem to point in the opposite direction from these cases as the first formant frequency is taken to be inversely related to vowel height. [Research supported by NSF.]
Sentence factors in reading speed: A prediction rule
Authors: Harris Marion O.
Published: October 2005

Give several subjects a list of sentences to read aloud; calculate a reading speed for each sentence as the ratio of phoneme count to total speech duration; normalize these speeds to zero mean; and compare the results. Few sentences will be read exactly at the mean rate. In some cases, different readers' speeds for the same sentence will scatter; in others, all will be close. Are these conditions random or systematic? Sentence speed data were obtained for three sets of material and eight readers. Speeds were plotted against an index number calculated for each sentence. The index number was designed to reflect numbers of words and phonemes; quantities and metric arrangements of (sentence-) stressed and unstressed syllables; some limited aspects of phonological structure of the stressed syllables; pause and pseudopause effects; the presence of recursive units, particles, emphatic stress, and sentence bifurcation. Speed is found to correlate positively with this index; a straight line fits the data well. This type of rule might be used to calculate basic timing patterns in speech synthesis.
Model of word recognition from fluent speech
Authors: Cole R. A.
Published: October 2005

Results of experiments in which listeners detect the occurrence of mispronounced words in fluent speech suggest that (a) whenever possible, an utterance is analyzed syllable by syllable and word by word, (b) the first syllable of a word can be used to constrain recognition of subsequent syllables within that word, (c) words are recognized during the interaction of constraints provided by the input and listeners' use of context, and (d) recognition of a word carries with it the immediate knowledge of phonological, syntactic and semantic constraints on an immediately following word. Each assumption of the model will be examined in terms of the results which led to its formulation.
Acoustical analysis of internal open juncture of VCV utterances
Authors: Baker D. J.
Published: October 2005

The temporal and sound level (voltage) characteristics of VCV nonsense words were investigated. Sixteen consonant sounds /p, b, t, d, k, g, f, v, θ, ƫ, s, z, ∫, ȝ, t∫, and dȝ/ were combined with three vowel sounds /i, a, u/ to form two/syllable nonsense words in which the initial and terminal vowels were the same. Thus, a total of 48 two-syllable nonsense words formed the corpus of the material. Two constraints were imposed: (1) the intervocalic consonant was combined with the first or second vowel and (2) the first or second syllable was stressed. Thus, for each of the 48 VCV words, four stress-juncture patterns were generated (′ V+ CV, V+′CV, ′VC+V, VC+′V). The resultant 192 stimuli were spoken and recorded on tape. Graphic level recordings of the tapes were made on a sound level recorder operating at a paper speed of 100 mm/sec and a writing speed of 500 mm/sec. The resultant sound level recordings were analyzed as to the effect of the stress-juncture constraints on the timing and relative of the two syllables. Several inter- and intrarelationships of the two-syllable productions are discussed.