bluuebunny/crossref_metadata_2025 huggingface dataset:
Examples of ray-theory solutions for two-dimensional sound speed profiles
Authors: White D.
Published: November 2005

In an earlier paper [“Exact Ray-Theory Solutions for Two-Dimensional Velocity Variation,” J. Acoust. Soc. Am. 51, 117(A) (1972)], a class of transformations was presented which shows for “closed form” solutions for the ray trace equations when the sound speed belongs to a particular set of functions, the set depending on the transformation, which may vary with both depth and range. In this paper the intensity equation is presented for this class of transformations. Two examples of transformations from this class are given. For each, a ray diagram for a particular sound speed profile is shown. For one of these examples, two typical North Pacific sound speed profiles separated by a distance of 676 NM were used to obtain a sound speed profile approximating an ocean sound speed field. For this profile a plot of propagation loss versus range is also presented.
Distribution of the Vibration Amplitude and of the Energy Density over Complex Vibratory Systems
Authors: Skudrzyk E. J.
Published: November 2005

The geometric mean between the maxima and the minima of the frequency curve of the velocity amplitude of a vibrator is independent of the damping, and equal to the amplitude of the wave that propagates from the driver to the boundaries. It is described by the characteristic admittance and is a simple function of the mass of the system and the narrow-band average of the frequency difference between successive resonances. Discontinuities in the density function of the resonances generate an imaginary part that exceeds the real part only if the forced frequency is close to the frequency of the discontinuity. The characteristic admittance is independent of the energy dissipation; in contrast, the energy density is a function of the energy dissipation. The energy density is composed of that of the outgoing wave and that of the reverberant vibration field; it can be computed by methods standard in reverberation theory. Measurements with noise bands always lead to a determination of the energy density, because of the incoherence of the phases of the noise components. The theoretical predictions are compared with experimental results for plates and cylindrical shells.
Relation of Descriptive Phonetics to Research in Speech Communication
Authors: Peterson Gordon E.
Published: November 2005

This paper does not report experimental results but is intended to consider some of the more general objectives of research on speech communication. The conversion of physiological and acoustical measurements on speech to discrete units is one of the fundamental purposes of speech research. There is a substantial number of physiological parameters and of values within these parameters which are significant in the various languages of the earth. Descriptive phonetics provides a discrete symbolization for the numerous sounds which may be produced by the human vocal mechanism and which are significant in spoken language. An unambiguous and relatively complete system of phonetic notation is essential to experimental research on speech communications. The symbols may be specified by the phonetic parameters and parameter values, and each symbol should denote a unique set of phonetic parameter values. This is not true of phonemic symbols, however, since different tokens of the same phonetic type may serve as members of allophones of different phonemes.
Dynamic Articulatory Model of Speech Production
Authors: Henke William L.
Published: November 2005

A dynamic articulatory model of speech production is described. From a discrete phonemic input, it generates a continuous description of the configuration of the articulatory mechanism in a midsagittal section. The model is divided into a “state” and “operators,” which act as agents for modifying the state by trying to manipulate it (i.e., responding articulatory structures) toward abstract “goals.” This bifurcation allows many of the constraints of the real system to be included in the model in a natural manner. By this means, the contextual effects of connected speech can be generated by less ad hoc methods than usually required by other schemes of speech modeling and/or synthesis. The present model concerns itself only with vowels and stops, but it is felt that the general methodologies are applicable to all speech sounds. A motion-picture film of model action, as simulated on a large time-shared computer system, is shown. [Work supported in part by the U. S. Air Force Cambridge Research Laboratories, Office of Aerospace Research, and by Project MAC, and MIT research program sponsored by the U. S. Department of Defense.]
Speech Synthesis by State Simulation
Authors: Rabiner Lawrence R.
Published: November 2005

A new method of speech synthesis is proposed. Each phoneme is characterized by a state. The specification of a state involves specifying steady-state positions of three formants, a frequency region around these formants, and a partial description of the state of the vocal tract while producing the given phoneme. This partial description includes the features of nasality and voicing. The input for this method is a string of phonemes with provisions for stress marks and punctuation. The output is a sequence of control signals appropriate for generating speech on a serial terminal-analog synthesizer. The control signals that must be generated include three formants and their respective bandwidths, a complex pole-zero pair for nasals, a complex pole-zero pair for the fricatives, pitch, and amplitudes of noise and voicing. Speech is generated by proceeding from state to state by a mathematical equation. A state is considered to be reached when the formant values are within a specified region around the target values for the state.
Some Relations between Articulator Movement and Motor Control in Consonant-Vowel-Consonant Monosyllables
Authors: MacNeilage Peter F. , De Clerk Joseph L. , Silverman Sidney I.
Published: November 2005

Inferences are often made from cinefluorographic records and from electromyographic records of speech about the underlying mechanisms of articulatory control. Inferences from cinéfluorograms have the disadvantage that one cannot always distinguish between the contribution to articulator position of direct motor control and mechanical properties of the articulators (e.g., their inertia). Inferences from myographic records have the disadvantage that one cannot always tell what muscles are being activated and what movements are occurring. Consideration of both cinéfluorograms and electromyograms from the same subject avoids, to some extent, these disadvantages. This paper reports a study of both indices recorded from the same subject (on different occasions) during the production of 36 CVC monosyllables formed by every combination of initial and final consonants /b/, /d/, and /g/ and the syllable nuclei /i/, /u/, /æ/, and /ɔ/. Some illustrations of typical relations between muscle contraction and movement are given. Particular attention is given to context effects on articulator position and their relation to preceding and following articulator positions. Possible principles underlying these effects are discussed. [Investigation supported in part by the National Institute of Dental Research, National Institutes of Health, U. S. Department of Health, Education, and Welfare, and by the U. S. Army Electronics Command.]
Electromyographic-Cinéfluorographic Investigation of Velar Function during Speech Production
Authors: Lubker James F. , Curtis James F.
Published: November 2005

Cinéfluorographic films of velar movement were made simultaneously with surface electromyographic recordings of velar muscle contraction during the production of selected syllables and sustained vowel and nasal phonemes. The data were analyzed to determine (1) the extent of variation in velar position during the production of various phonemes in relation to alterations in duration and phonetic context; (2) the extent of variation in velar electromyographic activity during the same speech utterances; and (3) the extent to which velar elevation and electromyographic activity covary during the production of sustained vowel and nasal phonemes and during alterations in duration and phonetic context. These data are discussed in relation to the hypothesis, advanced by certain investigators, that the velum acts in an all-or-none (ON-OFF) fashion.
Pattern of Air Flow out of the Mouth during Speech
Authors: Lane H. L. , Catford J. C. , Oster R. , O'Donnell F. E. , Rand T.
Published: November 2005

Since the 19th century, kymographic recording of total air flow out of the mouth has been used to diagnose the varying durations and degrees of constrictions of the vocal tract during speech. The present project attempts to introduce a second dimension to recordings of air flow out of the mouth—namely, cross-sectional area of flow—on the hypothesis that this will reflect changes in the location and cross-sectional shape of constrictions of the vocal tract. Consequently, the findings are pertinent to automatic speech recognition and allied objectives. The procedures included the development of a matrix of 64 hot-wire anemometers and associated circuitry, where output is sampled and digitized for computer processing. Computer programs permit storage, averaging, transposition, normalization, and matching of flow patterns, as well as sustained CRT display and numerical readout. The patterns associated with various sounds and then within- and between-speaker variance are reported.
Acoustic Features in the Manner Differentiation of Korean Stop Consonants
Authors: Weitzman Raymond S. , Han Mieko S.
Published: November 2005

In Korean, a three-way distinction in both the manner and place of articulation serves to differentiate nine stop-consonant phonemes: namely, the aspirated stops /ph/, /th/, and /kh/; the lenis stops /p/, /t/, and /k/; and the fortis stops /P/, /T/, and /K/. While the acoustic features correlated with place of articulation have been extensively studied, those involving the three-way manner differentiation of Korean stops have been inadequate, including the recent claim that the voice onset time is a sufficient cue for making these manner distinctions. The results of our spectrographic studies, a series of tape-cutting and -splicing experiments, and listening tests indicate that two acoustic factors are necessary to make the three-way manner differentiation: (1) the timing of the voicing onset that divides the stop series into two classes—aspirated stops (/ph/, /th/, /kh/) and unaspirated stops (/p/, /t/, /k/, /P/, /T/, /K/); and (2) the quality of the voicing onset that differentiates the lenis stops from the fortis stops.
Approach to Computer Speech Recognition by Direct Analysis of the Speech Wave
Authors: Reddy D. R.
Published: November 2005

A system for obtaining a phonemic transcription from a connected speech sample entered into the computer by a microphone and an analog-to-digital converter is described. The following features of the system are believed to be new: direct input of the speech signal to the computer without filters or spectrographs; the procedures for segmentation and pitch extraction; the procedure for prosodic parameter determination; and many procedures for phoneme classification. About 30 sounds of 1- to 2-sec duration were analyzed on an IBM-7090-PDP1 disk system. Correct identification of many vowel and consonanted phonemes was achieved for a single cooperative speaker. The time for analysis of each sound varied from 40 to 75 sec. For example, the sentence, “John has a book,” resulted in a phoneme string output “J AA M AE Z EH (B D G) U K.” The results encourage continuing the approach with a more powerful computer to achieve real-time recognition.
Digital Analysis of Impulsive Noise
Authors: Lang William W. , Maling George C. , Taylor W. A.
Published: November 2005

A digital recording of impulsive noise has been analyzed with the aid of a program written for an IBM-7094 data-processing system. The waveform of the impulsive noise is sampled every 32 μsec and digitized by an ADC. The resulting 10-bit data are written on magnetic tape in a format that permits timing pulses to be stored with each data sample. The digitized samples are processed to produce a new tape that is used as the input to a FORTRAN program. The values of the parameters most appropriate for characterizing impulsive noise are determined by the program in conformance with IEEE Recommended Practices for Burst Measurements in the Time Domain [IEEE Publ. No. 257]. The noise to be analyzed by the system can be either the unweighted sound pressure as a function of time, or the output of a filter. The analysis of amplitude and shape variations is completed without manual processing of the data. This method is applied to the noise generated by a card punch.
Noise Source for Acoustical Modeling
Authors: Morse Bonard
Published: November 2005

A new source using intersecting air jets gives high efficiency, concentrated turbulence region, broad directivity, and wide-range spectrum. Design features and confirming calibrations are presented.
General Approach to Forensic Acoustics
Authors: Jablonsky Roy D. , Ward Thomas L.
Published: November 2005

Forensic acoustics is that portion of the science that pertains to, is connected with, or is used in courts of law. The measurement of the acoustic environment of workers alleged to have suffered hearing loss is widely applied. Tentative ratings have been determined [The Relations of Hearing Loss to Noise Exposure, ASA Rept. Z24-X2] for octave-band levels of continuous spectra and sound-pressure levels of pure tones that should not be exceeded in order to avoid permanent hearing damage. As attorneys and insurance adjusters become more knowledgeable and as claims become more complex, other areas must be explored. Persons are frequently required to preceive speech or other signals in noisy environments. Failure to detect required signals may result in accidents that cause personal injury or property damage. Product liability cases may arise as a result of products that fail in such a way as to cause an unusually high noise level. A general approach has been developed for planning the measurement, analyzing the accident, and presenting the data in a form understandable to attorneys, adjusters, juries, and the court.
Electrical Tuning Curves of the Guinea-Pig Cochlea
Authors: Laszlo C. A. , Gannon R. Patrick , Moscovitch David H.
Published: November 2005

Mathematical models of the peripheral auditory system have not so far described the cochlear microphonic (CM) potential. To gather suitable data, measurements were made of the CM potential as a function of frequency at various points along the basilar membrane for constant input sound-pressure level (SPL) at the eardrum. Differential electrodes were implanted in Turns 1 and 3 or Turns 1 and 2 of the cochlea. The exact location of the electrodes was determined from von Békésy's anatomical data and later confirmed histologically. The input was a continuous sine wave, and the frequency range extended from 100 to 9 Hz. The SPL was measured with a probe microphone just external to the eardrum in all experiments. The SPL was kept constant at 60 dB so as to ensure that the CM was in the linear intensity region for all frequencies of interest. The magnitude of the CM output was measured with a narrow-band analyzer. Plotting the CM versus frequency for constant SPL at the eardrum, we established the electrical tuning curves of the guinea-pig cochlea. These electrical tuning curves correspond to the mechanical tuning curves of the cochlea observed by von Békésy.
Spatial Distribution of the Summating Potential of the Guinea-Pig Cochlea
Authors: Honrubia V. , Ward P. H.
Published: November 2005

In the guinea pig, the cochlear-microphonic potentials and the summating potential (SP) have been recorded by means of micropipettes located inside the scala media of each turn of the cochlea. In agreement with the observations of Davis and associates, the polarity of the SP recorded in the first turn is negative for the high frequencies (i.e., 6000 Hz) at low levels of sound pressure. For the lower frequencies (i.e., 900 Hz), the SP is recorded positive before it becomes negative. The lower the frequency, the greater the SPL (sound-pressure level) required to produce a negative SP in the first turn. The SPL at which the SP for low frequencies becomes negative is lower the greater the distance from the oval window. At any point along the basilar membrane the SP is clearly recorded negative and is never positive for frequencies of sound above the ones for which this area is supposed to have the optimum frequency sensitivity for mechanical displacement.
Dependence of the Summating Potential of the Guinea-Pig Cochlea on the Sound Pressure and Duration of Acoustic Stimulation
Authors: Honrubia V. , Ward P. H.
Published: November 2005

The “negative” summating potential as recorded on the first and second turn of the cochlea for high and middle frequencies is linearly proportional to the logarithm of the duration of the sound stimuli within the range of values that have been investigated, from 20 msec to 2 sec. Preliminary calculations of the output-input functions of the potentials for different frequencies in different turns of the cochlea show that its magnitude is linearly related to the strength of the stimulus for middle range of sound-pressure levels. Their slope is higher in each turn for the frequencies near the ones for which this region of the cochlear partition has the maximum amplitude of displacement.
Olivocochlear Bundle: Effects upon Noise-Masked N1 Responses
Authors: Dewson James H.
Published: November 2005

The influence of various levels of electrical stimulation of the crossed component of the olivocochlear bundle (OCB) upon N1 responses to clicks presented in various levels of broad-band noise was studied. Equivalent N1 reductions (in microvolts) for click attenuation and for noise masking were titrated with those produced by OCB stimulation. Recordings were taken from the round window. Anesthetized cats with severed middle-ear-muscle tendons were used. The findings are (a) intensity functions and recovery cycles to paired clicks are similar for noise masking and for OCB stimulation and (b) simultaneous delivery of OCB stimulation and noise at three different levels of each yields minor summation of effects at the lowest levels and complete occlusion at the highest. These results are interpreted with regard to central control of receptor events and the attendant implications for signal enhancement through noise reduction within the cochlea. [Research supported in part by the National Science Foundation.]
Responses of Neurones in Cat Cochlear Nucleus to Modulated Tonal Stimuli
Authors: Evans E. F. , Nelson P. G.
Published: November 2005

In decerebrate- and pentobarbitone-anesthetized cats, the extracellular responses of single neurones to frequency-and amplitude-modulated tones have been examined using a LINC computer for on-line stimulus control and response analysis. In contrast to the situation found in the primary auditory cortex (Whitfield and Evans) and in the inferior colliculus (Nelson, Erulkar, and Bryan), the responses of most neurones to modulated stimuli could be simply predicted on the basis of their responsiveness to steady tones tested over a wide frequency range, and of the time course of the responses so obtained. “Off inhibition” was a common finding, and this served to enhance the contrast between the background firing and the responses to repetitive and modulated tones. A small number of neurones, however, gave responses to modulated stimuli that could not be so simply explained. Additional factors were required, particularly sensitivity to change of frequency in a certain direction. These features appeared to be associated with complex steady tone responses in which tonal inhibition was involved, and were more commonly encountered in the dorsal nucleus.
Mechanism of Centrifugal Inhibition by Crossed Olivocochlear Fibres in the Cat
Authors: Fex Jorgen
Published: November 2005

Through intracochlear recordings with microelectrodes in the cat, it has been found that electrical repetitive stimulation of the crossed olivocochlear fibres evokes slow dc potentials. These potentials are positive in the scala tympani and in the organ of Corti and negative in the scala media, in which they reach an amplitude of 3 mV. These findings, together with histological evidence from other investigators, have led to the working hypothesis that the crossed olivocochlear fibres inhibit activity in the auditory nerve by an action on the outer hair cells. [Experiments performed in the Department of Physiology, The John Curtin School of Medical Research, The Australian National University, Canberra, Australian Capital Territory, Australia. The manuscript for this presentation has been written at the National Institutes of Health.]
Electrophysiological Correlates of Binaural Beats in Superior-Olivary Complex of Cat
Authors: Wernick Joel S. , Starr A.
Published: November 2005

Activity of superior olive of Nembutal-anesthetized cats was recorded with bipolar electrodes (100μ 12 mm apart) to a binaural-beat stimulus paradigm. The binaural-beat rate was represented in the recorded activity as a periodicity of the “following” response envelope. A measure of the proportion of this activity that may be considered as physiological interaction, rather than the summation of the two independent monaural responses, was obtained by subtracting, on a CAT computer, responses evoked by monaural stimulation of the two ears from the responses recorded during binaural stimulation. The activity remaining (physiological interaction) resembles an amplitude-modulated sinusoid having a frequency of approximately (f1+f2)/2 and an envelope periodicity corresponding to the binaural-beat rate. The extent of interaction varied with base frequency and intensity, with interaural differences in frequency and intensity, and with the level of anesthesia. This interaction was found only in a discrete region of the medial nucleus of the superior olive. [Work supported by the National Institutes of Health, U. S. Department of Health, Education, and Welfare.]
Detection Characteristics of Two Detectors Based on the Cross Spectrum
Authors: Shapiro Arthur
Published: November 2005

There has been some recent interest in the possibility of using the cross spectrum of the outputs of two hydrophones to effect the detection of signals in background noise. This paper derives and investigates the characteristics of both the cospectrum and the squared modulus of the cross spectrum when used as detectors, and compares them with the standard detector (adds the outputs, squares the result, and low-pass filters). It is shown that the standard detector is superior to the squared modulus of the cross spectrum regardless of noise characteristics and superior to the cospectrum, except for the particular case when the noise is very highly coherent with a phase difference between −π/2 and π/2.
Pressure Field in the Liquid around a Vertically Heaving Sphere
Authors: Paul Erwin W. , Tucker Albert J.
Published: November 2005

The calculation of the pressure field around a periodic vertically heaving sphere half-submerged in fluid of infinite depth is described. To establish the formula for the fluctuating pressure, the forces—which are caused by the heaving body and which depend on the added mass and damping coefficients—must be known. The general expression for the fluctuating force is derived from the velocity potential. Franz converted monopole and dipole expansions to a useful form by introducing certain weighting functions. He further developed an expression for the fluctuating pressure and calculated the resulting pressure directly below the sphere. As an extension to the Franz presentation, the pressure is calculated for different angles from the vertical-heave direction around the submerged hemisphere. The distance from the sphere is taken in the geometrical farfield, but much less than the acoustic wavelength. The plotted weighting functions, pressure components, and average pressure for different angles indicate that they are valid only for restricted-heave frequency regions, which are smaller for greater angles. This is most evident for points on the surface, i.e., for angles near 90°. In the limits of high or low frequency, the classical results are obtained.
Model Study of Acoustic Reflection from a Rippled Water-Sand Interface
Authors: Arcuni P. , Sanders J. V.
Published: November 2005

A model experiment was performed to measure acoustic reflection from a rippled sand surface using a pulse-echo system employing electrostatic transducers over the frequency range 100–350 kHz. The ripple wavelength of 1.23 cm was slightly greater than the longest acoustic wavelength, and it had an amplitude-to-wavelength ratio of 1/10. Boiling of the sand to remove entrapped air was essential before the scattering effects of the ripples could be observed. The angles of propagation of the scattered spectra are found to agree with the theoretical prediction within ±2°. The amplitudes of two orders of the scattered spectrum were measured at an incident angle of 45° and compared to the theory for the limiting condition, where the ripple wavelength is very much larger than the acoustic wavelength. Agreement was excellent for the spectral reflection, but was not as good for the first-order reflection. [Work supported in part by the U. S. Office of Naval Research and the Bureau of Ships.]
NASA General-Purpose Program for Structural Analysis
Authors: Butler Thomas G.
Published: November 2005

In order to facilitate communications among NASA agencies and between aerospace companies and NASA agencies on related structural analyses, a standardized digital program is being sponsored by NASA. Its main features are solution by finite-element technique, either force or displacement method, modular for ease of updating, independent of make of digital equipment, no limitation to size of problem, standardized input-output, and frequent entry-exit points. Static, dynamic, and random solutions are available. The program will feature many automatic features and checks, but in no way does it preempt the wishes of the analyst.
Interconnection of Structural Systems by Use of Immittance Concepts
Authors: On Frank J.
Published: November 2005

The problem of describing a complex structural system subjected to a dynamic environment so as to consider the information available about its individual subsystems is treated. An approach is presented that involves the formulation of immittance matrices and interconnection equations wherein force-equilibrium and motion-compatibility conditions, implicitly imposed, have equivalence to physical connections at the interfaces. Characteristic values of the interconnection matrix are shown to correspond to critical frequencies of the composite system as observed at the interconnections. This method differs from that of the transmission matrix method in that the constituent systems need not be serially connected in tandem and that the composite system may be formulated without regard for the relative number of interconnections between the constituent systems. Mechanized on electronic computers, this method of interconnection may provide an additional means of solving highly complex problems that, when attempted by other methods, may exceed the capacity of the computer. In environmental testing, the method provides sound basis for performing subassembly testing, which may obviate the demand for increasingly large complex environmental test facilities of future generation aerospace systems. Recommendations for further required investigations are made.
The Magnitude of Cochlear Microphonics Elicited by Noise and by Pure Tones
Authors: Mainen Michael W. , Glackin Robert , Warfield Dickens , Elder James
Published: November 2005

Cochlear microphonics were recorded from round-window electrodes in ten cats. The ears were stimulated alternately with broad-band noise and with pure tones in the frequency range 200 to 8000 Hz. The sound-pressure level (SPL) of the pure tone was matched in intensity to the SPL of the same frequency component within the noise, after correcting to a one-cycle bandwidth. Results showed that the cochlear input-output curve with noise was generally similar in shape to that produced by pure tones. However, noise was seen to suppress microphonic output at all frequencies tested. The tone-noise response ratio was both frequency- and intensity-related. Suppression of the noise response was greater with increasing stimulus intensity. Suppression was greater at frequencies above 800 Hz and was broadly related to cochlear sensitivity. Overload occurred at lower SPL's with noise stimulation than with pure-tone stimulation. [Research supported by grants from the National Institutes of Neurological Diseases and Blindness and an anonymous donation to the Division of Otolaryngology.]
The Longitudinal Distribution of the Cochlear Microphonic (CM) Potentials Inside the Scala Media of the Guinea Pig's Cochlea
Authors: Honrubia V. , Ward P. H.
Published: November 2005

The cochlear microphonic (CM) potentials were recorded in each turn of the cochlea for sound stimuli between 3000 to 300 Hz, and the longitudinal distribution of the potentials were determined. For every frequency, the envelope of the CM was steeper on the side toward the base than that on the side toward the apex of the cochlea. The envelope of the CM for high frequencies had larger slopes than did the envelope for the low frequencies. This was true both on the proximal and distal sides of the maximum of the envelope. The magnitude of the slope is a linear function of the logarithm of the sound's frequency. The receptive fields of the cochlea for the sound stimuli used showed that at the level of the maximum sensitive points a given magnitude of CM (i.e., 1 mV) was obtained for all the frequencies with approximately the same sound-pressure level (i.e., 70 dB).
Auditory Sensitivity of the Mongolian Gerbil (Meriones unguiculatus)
Authors: Finck Alfred
Published: November 2005

The Mongolian gerbil is native to the region of the Gobi Desert. The gerbil cochlear and vestibular elements are unusually well exposed for study and experimental investigation. This report depicts several features of the gross and microscopic anatomy of the gerbil and describes its auditory sensitivity by the cochlear-potential method. Criterion cochlear potentials (0.5 μV) range from 50 dB at 200 Hz to 60 dB at 30 000 Hz. In the regions of 1000 and 4000 Hz cochlear sensitivity is seen at 15 and 0 dB SPL, respectively. Comparisons are made between gerbil cochlear responses and responses from other small rodents. [Research supported by the National Institutes of Neurological Diseases and Blindness, U. S. Department of Health, Education and Welfare.]
Creeping-Wave Analysis of Acoustic Scattering by Elastic, Cylindrical Shells
Authors: Uginčius Peter , Überall Herbert
Published: November 2005

The Sommerfeld-Watson transformation is applied on the normal-mode solution of a plane wave being scattered by an infinite, elastic, cylindrical shell immersed in a fluid and containing another fluid. The resulting residue series is generated by poles that are the complex zeroes of a six-by-six determinant. These zeroes are found numerically by an extension of the Newton-Raphson method for complex functions. It is found that besides the infinity of the well-known Franz's zeroes there exists a finite number of additional zeroes, which generate generalized Rayleigh and Stonely waves. These latter zeroes owe their existence solely to the elastic properties of the scatterer; they disappear in the limits of zero or infinite rigidity. Scattering cross sections are presented for various elastic and geometric parameters of the shell.
Effect of Transducer Size, Shape, and Surface Sensitivity in the Measurement of Boundary-Layer Pressures
Authors: White Pritchard H.
Published: November 2005

The measurement of a random-pressure field by a transducer of finite size is subject to error because the transducer senses the spatial average pressure over its face rather than a point value. Methods of correction for this effect under certain conditions have been developed earlier; however, many important parameters of the system have been neglected. The present study shows the effect of various boundary-layer parameters, as well as the shape of the transducer upon the measurement error. It is concluded that no general “true”-size correction factor exists, but that an estimate must be made for each particular situation. The effect of nonuniform surface sensitivity of the transducer is also considered. This factor brings about an effectively smaller transducer size, but also can lead to serious errors in cross-correlation analysis.
An Analysis of Perceptual Confusions in Identification of Dichotically Presented CVC Syllables
Authors: Shankweiler D. , Studdert-Kennedy M.
Published: November 2005

Earlier studies with synthetic speech have shown that the method of presenting pairs of competing syllables dichotically yields reliable differences in the accuracy of recognition of material presented to the left and right ears. Contrasting consonants, presented in consonant-vowel (CV) syllables as minimal pairs, are more accurately identified from the right ear than from the left. A significant right-ear advantage was not found when steady-state vowels were presented in isolation. Since there are a number of possible explanations for this difference in perception of vowels and consonants, further experiments were performed using “real speech” with vowels in syllabic context. The results were essentially the same as in the earlier experiment—consonants were significantly better identified from the right-ear channel; vowels gave no consistent lateral differences. These results point to a genuine difference in the mode of central processing of consonants and vowels. An analysis of the matrix of confusions was carried out in order to discover what feature information is retained and what is lost in listening to syllables presented dichotically.
Relations between Prosodic Variables and Emotions in Normal American English Utterances
Authors: Huttar George L.
Published: November 2005

Relations between a speaker's emotional states and some acoustic prosodic variables of his speech were investigated experimentally. The speaker's emotional states, as reflected in 30 utterances, were evaluated by 19 subjects on nine semantic differential scales. The utterances were also evaluated for pitch, loudness, and speed. Durational, fundamental-frequency, and amplitude characteristics of each utterance were measured. Linear correlation coefficients were computed between the acoustic variables and the listeners' judgment of the speaker's emotional states. Significant correlations were found between some of the acoustic variables (e.g., maximum fundamental frequency) and the judgments of some types of emotion. Higher correlations were found between the acoustic variables and judgments of degree of emotion. Correlation coefficients were also computed between judgments of emotion and judgments of prosodic features. Many of these correlations were significant, and higher than the correlations with the acoustic variables. The possibility of regular, but nonlinear, relations between acoustic prosodic variables of speech and perceived emotion was also investigated.
The Relative Contribution of Visual and Auditory Components of Speech to Speech Intelligibility under Varying Conditions of Frequency Distortion
Authors: Sanders Derek A.
Published: November 2005

Twenty normal-hearing young adults were tested to establish speech discrimination loss under three conditions of sensory input and four conditions of frequency filtering. The speech material used comprised phonetically monosyllabic words from C.I.D. Auditory Test W-22. The speech sample was presented under the following sensory input conditions—(1) vision alone, (2) audition alone, (3) vision and audition simultaneously. The frequency spectrum of the speech was varied by a filter system to produce the following bandwidths—(1) unfiltered, (2) 500 Hz low pass, (3) 2000 Hz high pass, (4) 500–2000 Hz bandpass. The results indicate that the mode of presentation, frequency-filter bandwidths, and interaction of mode presentation and frequency-filter bandwidths all effect speech discrimination. Greater dependency on visual clues was evidenced as auditory distortion increased. The data were found to be significant at the 0.0001 level of confidence.
The Effects of High-Cutoff Filtered Noise Upon the Intelligibility of Different Speech Materials in a Closed-Response Set
Authors: Busch A. C. , Eldredge D.
Published: November 2005

House, Williams, Hecker, and Kryter [J. Acoust. Soc. Am. 37, 158–166 (1965)] have pointed out that while the Modified Rhyme Test (MRT) is a highly repeatable, stable test, its only drawback is that it is less capable than open-format tests of discriminating among highly intelligible communications systems. An experiment was performed to determine whether the discrimination function of the closed-response format would be altered by the introduction of different speech materials into the closed-response sets. The MRT and a 9-choice nonsense-syllable, closed-response test were administered to subjects under five types of high-cutoff filtered noise to 1500 Hz, 2120 Hz, 3000 Hz, 6800 Hz (speech-shaped), and 6800 Hz (flat Gaussian)—at six S/N ratios. The results indicated that a significant increase in the discrimination function resulted from the 9-choice nonsense materials but that no real differences resulted in the slope of the function. Both the MRT and the 9-choice test showed the same effects relative to each other and between noise types.
Studies in Auditory Search
Authors: Davis Julia
Published: November 2005

A previous paper presented at an ASA meeting (June, 1966) treated auditory search, involving the identification of syllables embedded within sentences. Results indicated relationships among lengths, syllable positions, word class in which syllables were embedded, and search time and accuracy of search. This paper extends the previous treatment and examines specifically several aspects of auditory search. Search time for the conditions in which syllables are present and absent were examined. Correct responses were always associated with shorter response latencies when the syllable was present; when the syllable was absent, search time for correct and incorrect responses were similar, with no consistent trend emerging. Examination of word class within which target syllables were located indicated that accuracy was poorer and search time longer for modifiers than for nouns, verbs, and connecting words. Although accuracy was similar for the latter three, time of search varied, indicating that search time may be a precise measurement for studies of this nature, and that the auditory processing of language may be greatly dependent on grammatical word class. Theoretical concepts relative to the possibility of different levels of language processing and the rôle of immediate memory in recall in the task of auditory search is discussed.
Acoustic Nonlineartry of an Orifice
Authors: Ingard Uno , Ising Hartmut
Published: November 2005

The acoustic nonlinearity of an orifice in a plate has been investigated by measuring simultaneously the oscillatory-flow velocity in the orifice and the acoustic-pressure fluctuations producing the flow. The relation between the pressure and velocity amplitudes, which is linear at sufficiently low pressures, is found to approach a square-law relation at large velocity amplitudes. By evaluating the phase relationship between the fundamental-harmonic components of pressure and velocity, the acoustic-orifice impedance is determined. In the square-law region of the pressure-velocity relation the resistive component of the orifice impedance dominates and is proportional to the velocity amplitude. This method of measurement, which is particularly useful at high amplitudes, is supplemented by measurements of sound transmission and frequency response of the orifice plate so that an impedance curve can be constructed over an extended range of amplitudes. An analogous program of measurements has been carried out to study the influence of a superimposed steady flow on the acoustic-orifice impedance. Finally, as an application of the results obtained, the absorption characteristics of resonator absorbers for high-intensity sound are discussed. [This work was supported in part by the U. S. Navy Office of Naval Research.]
On Predicting Fluctuating Pressures at a Wall Beneath a Turbulent Boundary Layer
Authors: Ailman C. M.
Published: November 2005

The purpose of this paper is to present graphs, nomographs, and simple equations to aid in predicting the characteristics of the fluctuating pressures that cause steady-state dynamic environments during transonic and supersonic atmospheric flight. The source of these pressures is the turbulent boundary layer over the external surface of the vehicle. Such a boundary layer may be well-behaved (undisturbed and slowly growing) or disturbed by local static-pressure gradients or external profile variations. The basis for the engineering prediction techniques contained herein is entirely empirical (approximately 20 documented references) since the limited theoretical treatments available today are too restrictive in their applications. Data are presented for many conditions and situations in the Mach number range from .6 to 5.0. Extrapolation of axisymmetric or two-dimensional results to three-dimensional problems by means of static pressure studies is discussed.
Nonlinear Bubble Oscillations
Authors: Solomon Louis P. , Plesset Milton S.
Published: November 2005

Numerical solutions have been obtained for the motion of a gas bubble in an incompressible liquid when harmonic-pressure oscillations are imposed. The mean pressure in the liquid was taken to be 1 atm and the ratio of oscillating-pressure amplitude A to the mean pressure was given the values 0.2, 0.5, 1.0, and 2.0. The equilibrium bubble radius was chosen to be R0=10−2, 10−3, and 10−4 cm, and the angular frequency of the pressure variations was ω=0.2×105, 0.7×105, and 1.2×105 per sec. The phenomena of bubble “explosion” or “collapse” were found for large A—i.e., 1.0 and 2.0. For the smaller values of A, the bubble radius varied with time within well-defined limits, but nonlinear effects were evident.
Second-Order Fields near a Pulsating Source
Authors: Gould Robert K.
Published: November 2005

An approximately spherical sound field of finite extent is produced in a liquid by a pulsating gas bubble. Observations of tracer particles near the bubble indicate an absence of acoustic streaming (as befits a spherical field) but the presence of radiation pressure. By the use of spherical tracer particles of different densities and compressibilities, comparisons with radiation-pressure theory can be made. At higher sonic amplitudes surface waves appear on the bubble accompanied by acoustic streaming in the nearby liquid. Measurements of the critical amplitude for the onset of these surface waves permit comparison with theory and with Eisenmenger's experimental results for parametrically excited plane surface waves. [This work was supported in part by a grant from the National Institutes of Health, Department of Health, Education, and Welfare.]
The Formation of Liquid Jets during Cavitation Bubble Collapse
Authors: Eller Anthony
Published: November 2005

A cavity collapsing in a pressure gradient or near a rigid boundary will acquire translational motion. A consequence of this motion is that the cavity shape will not remain spherical, and a high-velocity jet of liquid, pointing forward, will form at the rear of the cavity. Descriptions of the cavity shape as a function of time have been obtained by an analysis of the collapse of an empty cavity in an infinite, incompressible liquid when the cavity has an initial translational velocity. This theory is used to compute the time history of jet formation, the velocity of the jet, and the pressure in the surrounding liquid for a range of values of the hydrostatic pressure and of the initial-cavity radius and velocity.
Finite-Amplitude Acoustic Waves in Crystalline Solids
Authors: Thompson R. B. , Wilkinson C. D. W.
Published: November 2005

Acoustic waves at gigacycle frequencies show finite-amplitude effects at relatively low power levels. Such effects have been studied using Bragg diffraction of light from each harmonic of the acoustic wave. In this way, a direct harmonic analysis of the wave was obtained without the need for a calibrated broadband transducer. The crystals studied include Z-cut quartz and MgO. The following effects of finite amplitude waves have been observed in quartz—variation of the attenuation of the fundamental with power level; the presence of the second through fifth acoustic harmonics; and the growth and decay of these harmonics as a function of the distance travelled by the acoustic pulse. This last point assures that the harmonics are generated in the bulk of the solid. Similar effects have been observed in MgO. The experimental observations have been compared with theoretical predictions and estimates of the relevant third-order elastic constants obtained. We are grateful to D. T. Blackstock for the use of his computer program [J. Acoust. Soc. Am. 36, 534–542 (1964)] to obtain the theoretical estimates.
Exact Formula for the Expansion Time of a Deep-Fired Explosion Bubble
Authors: Epstein David
Published: November 2005

To implement theoretical investigation of unusual features of a deep-fired underwater explosion waveform [D. Epstein, J. Acoust. Soc. Am. 35, 800 (A) (1963)], an exact formula giving the dependence of gas-sphere motion on depth is derived. Retaining the noncompressive, nonmigratory description, an expansion-time formula in the form of an infinite series of terms, each formally equivalent to an incomplete beta function, is obtained; the series coefficients are developed in ascending powers of the cube root of the bubble depth. The formula is applied to the bubble-pulse period; for shallow bubbles, the lead term is identified as the Willis formula. But, although at great depth this term contributes merely a fraction of the total expansion time, the entire series combines to yield approximately the period predicted by the z−5/6 law! Hence, the experimental observation [M. Blaik and E. Christian, J. Acoust. Soc. Am. 38, 50 (1965)] that the Willis formula holds to 22 000 ft is supported, but it should be regarded as a semiempirical fit.
Analysis of Response Areas from Single Units of the Auditory Nerve
Authors: Finck Alfred
Published: November 2005

This study approaches the problem of how responses from single auditory neurons may represent the configuration of auditory threshold. Response areas of 164 single units were obtained from the acoustic nerve of the golden hamster. These data were analyzed with respect to the threshold SPL for each of 31 frequencies. The results indicate that the likelihood of obtaining fiber activity in the acoustic nerve differs for different frequency tones. In those regions where the frequency of occurrence of response areas is high, absolute threshold values are typically low. It is suggested that innervation density, as well as absolute sensitivity, may be important features in the representation of the hearing curve at the level of the acoustic nerve. [Research supported by the National Institutes of Neurological Diseases and Blindness, U. S. Department of Health, Education and Welfare.]