bluuebunny/crossref_metadata_2025 huggingface dataset:
The design of a quiet automobile cooling fan
Authors: Gray Leslie M.
Published: October 2005

Recent emission control regulations, combined with higher temperature engines, have resulted in automobile cooling fans which run-on for a period of time after the engine has been turned off. Because of the annoyance presented to the consumer, the noise produced by these “after-run” fans has become important to the automobile manufacturer. This paper reviews the development of a radiator cooling fan for use on the 1981 Chrysler K-body vehicle. Noise control techniques developed for the design of quiet marine propellers were adapted to cooling fan design. A fan was designed and built which is over 8 dBA quieter and 20% more efficient than the fan which had been selected by Chrysler as optimum for this vehicle. Limitations in the design of this fan due to the fan material, the power available, and airflow restrictions are reviewed. A comparison of the costs and benefits of custom fan design to the costs of the more usual selection process is presented.
Alternative procedures for acquiring acousto-optic data for computerized tomographic evaluation of sound fields
Authors: Cook B. D. , Laflin J. R. , Gaumond C. F. , Dardy H. D.
Published: October 2005

The principles of computerized transverse tomography can be applied to acousto-optic data for evaluation of local sound pressure. One numerical technique involves building the two-dimensional Fourier domain associated with the decomposition of the sound field into plane waves. Data acquired in one manner allows building this domain along radial spokes which is not readily convenient for numerical processing by digital FFT algorithms. In this paper we present an alternative data collection procedure which allows building the Fourier domain in a rectangular format which is compatible with two-dimensional FFT algorithms. Moreover, with this new method, it is possible to evaluate the pressure along a line for a limited set of data using only a one-dimensional FFT.
PVF2 phase shifters and modulators for fiber-optic sensors
Authors: Koo K. P. , Carome E. F.
Published: October 2005

A number of different fiber optic sensors that utilize optical interferometric detection techniques have been devised by various workers. The sensitivity of these transducers is dependent on the relative phase of the interfering optical beams and it is convenient to employ piezoelectric elements to vary the length of the fiber interferometer arms to control the relative phase. We have conducted an extensive study of the use of the PVF2 thin film elements for such applications. Typically these consist of 25-μ-thick, 1-cm-wide, 10-cm-long uniaxially stretched PVF2 strips attached to single mode optical fibers with epoxy adhesives. Data are presented on the sensitivity, linearity, frequency response, and other relevant characteristics of these devices. [Work supported by ONR.]
The evaluation of fiber-optic levers in the design of optical hydrophones
Authors: Cuomo Frank W.
Published: October 2005

Fiber optic levers, which can be effectively used to detect modulations in a light beam reflected from a vibrating target, have been proven useful in several applications including shock and vibration measurements [R. O. Cook and C. W. Hamm, J. Acoust. Soc. Am. Suppl. 1 64, S79 (1978)] and calibration of acoustical elements [F. W. Cuomo, J. Acoust. Soc. Am. Suppl. 1 64, S80 (1978)]. This paper presents an evaluation of fiber optic levers as potential devices for underwater sound detection. Emphasis is given to their relative performance as optical hydrophones of the noninterferometric type and the evaluating parameters include sensitivity, minimum detectable pressure, dynamic range, and frequency response. It is found that dual element design configurations can be utilized to achieve higher sensitivities and signal to noise discrimination.
Multimode optical evanescent-wase acoustic sensor
Authors: Beasley J. Donald
Published: October 2005

An acoustic sensor using evanescent optical coupling between multimode optical fibers has been successfully demonstrated to have a detector shot-noise limited sensitivity at a sound pressure level of about 50 dB re 1 μPa/(Hz)12. The bandwidth of the sensor is dc to 8000 Hz. Construction of the device is described, along with a theoretical description of its operation compared to observed performance.
Altitudinal differences in the call note intensities of the treefrog, Eleutherodactylus coqui
Authors: Narins Peter M. , Hurley Daniel D.
Published: October 2005

Peak sound levels were measured of the two-note advertisement call of male treefrogs (E. coqui) from populations at two altitudes in the Puerto Rican rain forest. The measurements were made at 50 cm directly in front of a calling male using a one-third octave filter with center frequencies of 1000 and 2000 Hz corresponding to the frequencies of the first (Co) and second (Qui) call notes. Body sizes were also measured. It was found that snout-vent lengths of males from the high site (700 m) were significantly greater (P < 0.001) than those of males from the low site: (350 m). Body size was then correlated with the intensities of the Co and Qui notes in the two populations. At the high site, larger males produced more intense Co and Qui notes than smaller males. At the low site, Co note intensity was proportional to body size but Qui note intensity was independent of it. The high site population with its larger males, produced a mean Co note intensity of 92 dB SPL vs 84 dB SPL for the low site population. In contrast, the Qui notes of males from the two sites were similar in average intensity (97 dB SPL for the low site vs 100 dB SPL for the high site). It is known that the density of calling males is greater at the low site than at the high site. Since the Co note is used by males to indicate their calling location to other males, we suggest that frogs from the low site produce a less intense Co note to accommodate their higher population density.
Effects of speaking rate on vowel identification
Authors: Johnson Thomas L. , Strange Winifred
Published: October 2005

To examine the role of context in providing temporal information that supports identification of vowels, eleven t-vowel-t syllables were excised from a carrier sentence spoken at both normal and rapid speaking rates by an adult male talker. Separate groups of subjects identified vowels in the syllables presented in the following contexts: (1) in isolation, (2) embedded in the inappropriate rate carrier sentence, (3) embedded in the appropriate rate carrier sentence, and (4) accompanied by the immediately preceding word (“the”) from the rapidly-produced carrier (minimal context). Vowel identification was highly accurate for normal rate targets in all contexts. For rapidly produced syllables were most frequent for syllables in isolation, intermediate for syllables in inappropriate rate and minimal contexts, and least frequent for syllables in appropriate rate context. Most errors in the identification of rapid targets occurred on “intrinsically long” intended vowels. The results indicate that vowels may be incompletely specified in a single syllable of rapid speech, and that the surrounding speech context may provide temporal information necessary for accurate vowel identification. [Work supported by NIMH, NICHHD, NSF.]
Kinesthetic reaction times in the speech motor system
Authors: Cole K. J. , Abbs J. H.
Published: October 2005

Several speech production theorists have cited long-latency RT (reaction times) in the speech musculature as a partial basis for discounting the potential role of afferent feedback. However, these RT latencies, ranging from 120 to 140 ms, have been obtained primarily with auditory and visual stimuli. In the present experiment we were interested in determining the mininal response latency capabilities of the speech control system under optimal learning and stimulus conditions. Subjects were instructed to produce labial closure following a brisk mechanical stretch stimulus applied to the oral angle. In most subjects, the voluntary orbicularis oris (OOI) response consisted of: (I) a marked reduction of “resting” EMG activity, followed in 10–15 ms by, (2) the interference pattern related to activation of OOI. In highly trained subjects, RT latencies from the onset of the stimulus to the onset of OOI activation were frequently as short as 50 ms with a large percentage less than 75 ms. Latencies to the onset of the EMG reduction were correspondingly shorter. These findings will be discussed in relation to (I) comparable “kinesthetic” RT results recently reported in the spinal motor system, and (2) implications for the role of afferent mechanisms for speech motor control. [Work supported by NSF grant 13274.]
The effect of stress and task variation on formant location
Authors: Scherer K. R. , Tolkmitt F.
Published: October 2005

The effect of psychological stress and of different task demands on the frequency, amplitude, and band width of formants in words spoken as part of a word recognition task was studied. Subjects were 39 medical assistants who took part in an experiment on the effect of arousal on speech performance. Subjects had to engage in two types of cognitive tasks with different demands on concentration and mathematical ability and had to describe two types of films, one film on pottery making with low stress inducing potential and one film on a surgical operation. Immediately after each of these tasks, subjects had to read out loud words which were presented at relatively short exposure times (to simulate a word recognition task). Vowels within these words were isolated and formant frequencies, amplitude and band width were measured using linear prediction formant estimation routines. The results are interpreted in terms of the inter-speaker and intra-speaker variability of formant data across different levels of emotional arousal and task demands.
Acoustic characteristics of correctly produced vowels in deaf children's speech
Authors: Osberger M. J. , Levitt H. , Slosberg R.
Published: October 2005

An analysis was performed on the acoustic characteristics of the vowels /i, æ, u/ in several CV contexts in the speech of deaf and normal hearing children. The CV syllables were embedded in sentences, and only those syllables judged by a group of phoneticians to have been correctly produced were analyzed for the deaf children. For all three vowels, there was greater variability among the deaf subjects than among the normal hearing subjects in the frequency location of the first two formants. The average differences in the F1 − F2 plots between the two groups of speakers varied systematically depending upon the vowel produced and the phonetic context in which it occurred. Differences between the two groups of speakers was observed for the F1/F2 ratio as well as for the absolute frequency location of the formants. These data indicate that vowels in deaf children's speech can be correctly identified even though the absolute and relative formant values differ from that of normal hearing speakers. [Research supported by PHS Grant ♯09252 from NINCDS.]
Long-term average speech spectra for normal and hearing-impaired adolescents
Authors: Formby C. , Monsen R. B.
Published: October 2005

Acoustical aspects of the speech of hearing-impaired persons are typically examined over brief periods of time for simple utterances. We were interested in whether abnormal acoustical patterns would be observed when speech was examined over relatively longer periods of time. Speech spectra were averaged for hearing-impaired and normal adolescents using a constant frequency analysis bandwidth of 60 Hz across a 10-kHz range (integration time approximately 30 s). Comparison of the spectra reveals: (1) hearing-impaired adolescents with highly intelligible speech and normal adolescents exhibit similar spectra; (2) hearing-impaired adolescents with speech intelligibility judged to be no higher than 72% yield spectra which are sometimes different from that of the normal adolescent; (3) the most obvious of the abnormal patterns is (a) the general finding of irregularity of the spectra; (b) a reduction in acoustical power between the fundamental speech frequency and the fourth harmonic which is almost twice that seen in normal spectra; and (c) the observation that for three of the 11 least-intelligible adolescents, the third harmonic of the fundamental speech frequency is of greater amplitude than is the second harmonic.
Adaptive focusing: The likelihood ratio
Authors: Labianca F. M. , Lloyd S. P.
Published: October 2005

A prerequisite for the implementation of the adaptive focusing detection scheme [A. J. Claus and F. M. Labianca, abstract F2, this session] is a temporally stable signal field distribution across the array aperture. Stability is characterized by a low-rank signal covariance matrix. The case of absolute stability, that is, unity rank, occurs rarely in practice, but is of interest because its theoretical treatment can be carried out in closed form and lends insight to the choice of practical test statistics in less stable cases. The model is constructed under the assumption that linear filtering of the acoustic array data produces a vector time series in p-dimensional unitary space U, where p is significantly smaller than the array dimension. Under H0 (noise only) the process in U is centered isotropic Gaussian, white of unit power. Under H1 (noise plus signal) the signal has constant but unknown ray direction in U, and the amplitude process along this ray is white (complex) Gaussian of specified power. The joint likelihood ratio for L observations in U is found in closed form, suitable for numerical calculation; it is a function of the eigenvalues of the p × p sample covariance matrix. The results of Monte Carlo simulation of the model, including cumulative distributions, ROC curves and performance curves are presented with emphasis on application to cases which might occur in practice. [This work has been supported in part by the Independent Research and Development Program of the Department of Defense and in part by the Naval Electronics Systems Command, Code ELEX-320.]
Harmonic masking by two data windows
Authors: Burgess John C.
Published: October 2005

Two practices sometimes used in digital spectrum analysis are (a) using a 1/10 cosine taper at each end of a data record and (b) augmenting a short data record with zeros. Each practice is equivalent to using a data window. The spectra of both a 1/10 cosine taper data window and of a rectangular data window with 10% contiguous zeros have significant side lobe structures at amplitude ratios below about −20 dB. The use of either procedure can lead to effective masking of low-level harmonic components in the spectral representation of a data record. When there are sufficient data to provide a required record length, leakage is most effectively reduced by using a data window designed for that purpose [see, e.g., J. C. Burgess, J. Acoust. Soc. Am. Suppl 1 65, S61(A) (1979)]. If a data record must be augmented with zeros. the undesirable effects of the rectangular window can be reduced considerably by both using a low-leakage window and placing the zeros equally at each end of the data record.
Noise indices for fluctuating sound levels: A review
Authors: Bradley J. S.
Published: October 2005

A large number of noise indices have been proposed that incorporate measures of the temporal fluctuations in sound levels. Such noise indices usually relate to sound level fluctuations over periods between approximately 1 s and several minutes, but considerations can be extended to shorter periods and instrument integration times, or to longer periods and day-night differences. Unfortunately the results of field and laboratory studies have not provided strong consistent evidence to support the use of one particular index as a more successful predictor of adverse human responses to noise. It is intended to first review the various indices that have been proposed, to compare their physical similarities, and the relative difficulty of their calculation. Results from field and laboratory studies will be examined to discuss the merits of these indices as predictors of adverse human responses, and the reasons for the various successes and failures.
Effects of temporal variability of urban noise on signal detectability
Authors: Fidell S.
Published: October 2005

A summary is provided of recent research on the effects of temporal variability of background noise on the audibility of acoustic signals. Attention will be directed to two cases: detection of intermittent signals of durations that are long with respect to short term fluctuations in noise levels; and effects of circadian variability of urban noise on detection of continuous signals of low absolute level. Detailed measurements of the variance of distributions of urban noise levels at different times of day at sites of varying population density will be reviewed, as will the practical significance of such variability for prediction of signal detectability. Means of relating annoyance from exposure to low level acoustic signals to signal detectability will also be discussed.
Dislocations and shock waves in LiF
Authors: Duvall G. E.
Published: October 2005

The shock wave produced by plane impact of a projectile on a LiF crystal develops a structure in which an initial sharp increase in pressure is followed by a stress relaxation. Pressure then passes through a minimum and a second, slower rise. The initial rise travels with elastic wave speed and is called the precursor. The second rise travels more slowly and is called the plastic wave. Precursor amplitude is found to decay as it propagates, and this decay process can be related to the generation and motion of dislocations, using the equations of micromechanics developed by J. J. Gilman. When experimental decay rates are used in this way to derive dislocation parameters, it is found that the product of dislocation density and dislocation velocity is larger by two or three orders of magnitude than can be accounted for by initial measurements of dislocation density and conventional dislocation processes. There has been some success in explaining results for Mg-doped LiF through invocation of heterogeneous nucleation of dislocations around MgF2 precipitates. But recent post shock studies do not bear out this nucleation hypothesis. In undoped LiF the decay rate is too rapid to be observed, and there is no basis for a nucleation hypothesis. The problem, its anomalies, and existing evidence will be reviewed and some speculations about unconventional processes will be aired.
Influence of atmospheric pressure gradient on under-ice ambient noise
Authors: Greene Charles R. , Buck Beaumont M.
Published: October 2005

Correlations exceeding 50% have been measured between wind speed and under-ice ambient noise levels in one-third octave bands. Using barometric data, meteorologists derive geostrophic wind from the atmospheric pressure gradient. The present research involved measuring correlations between the magnitude of the atmospheric pressure gradient and under-ice noise levels in one-third octave bands to determine if noise-prediction models could be developed. Then, one could use meteorological data to generate “isonoise” contour maps for the Arctic Ocean similar to isobaric maps. Barometric and ambient noise data were available from a trio of buoys drifting in the Beaufort Sea for over a year. For one-third octave bands centered at 3.2, 10, and 32 Hz, correlations with the air pressure gradient magnitude were normally 50% or better. At 1000 Hz the correlation was nominally 25%, a result attributed to higher propagation loss at that frequency and the need for knowledge of pressure gradient on a smaller scale. Predictive models were derived for each frequency for each of the four annual sessions. [Work supported by ONR.]
Acoustical environment in the Salt Lake Mormon Tabernacle
Authors: Jones L. Dean , Seljaas Karl G. , Drommond David E.
Published: October 2005

This paper is a historical overview of the Salt Lake Mormon Tabernacle, its acoustics and uses. Emphasis will be placed on acoustical studies made over the years by qualified consultants and their subsequent recommendations. Reference will be made to a previous paper on this subject presented nearly 50 years ago. Slides will be used to illustrate original construction and later changes. Television lighting and sound reinforcement equipment are substantially the only detractors from an otherwise unspoiled atmosphere of pioneer days.
Atmospheric structure and migrating birds: Acoustic echo sounder and tracking radar investigations
Authors: Larkin Ronald P.
Published: October 2005

The migrations of birds, often taking place at night and spanning hundreds or thousands of kilometers, involve intimate contact with the lower atmosphere. Structure in the atmosphere is hypothesized to be a source of information in avian long-distance navigation and also an important source of extractable energy. Studies of the use of atmospheric structure by migrating birds employ a monostatic atmospheric echo sounder and a 3-cm radar, the latter allowing quantitative description of spatial concentrations of migrating birds and also tracing wavelike phenomena using balloon-borne radar targets. Results include: (1) The environmental impact of a pulsed acoustic sounder upon nocturnally migrating birds is minimal except for birds directly within the beam. (2) Altitudes of migrating birds are sometimes closely related to stable regions of shear appearing on the acoustic sounder records. (3) Vertical motions exceeding 1 m/s are frequent on nights when birds are migrating, providing great potential benefit to birds (many flying slower than 5 m/s horizontal speed) that detect and selectively fly in regions of rising air. [Work supported by NSF.]
Determination of excess ground attenuation for shallow angles using flyover noise
Authors: Willshire William L. , Hilton David A.
Published: October 2005

An outdoor experiment was conducted during the week of 30 October–4 November 1978 at NASA Wallops Flight Center to investigate the propagation of sound near grazing incidence. A T-38A aircraft was flown at low altitudes over the ends of two microphone arrays. An eight-microphone array was positioned along a 1850-m concrete runway. The second array consisted of 12 microphones positioned parallel to the runway over grass. Twenty-eight flights were flown at altitudes ranging from 10 to 160 m. The corresponding angle-of-incidence range for the microphone arrays used was 0.3° to 32°. The aircraft was tracked with a laser tracker and meteorological information was collected from six ground stations and a retrievable balloon instrumented for weather parameter profile measurements. The acoustic information recorded in the field was reduced by 13-octave-band techniques and time correlated with the flight and weather information. The data have been further reduced to values of excess ground attenuation as a function of frequency and look angle by two different methods. In one method, referred to as the method of Parkin and Scholes, acoustic data at a microphone position close to the flight track is chosen as a reference and is compared with those data taken at other microphone positions. A direct comparison between two microphones at an equal distance from the flight tract, but over different surfaces, was the second method used. In both methods the source emission directivity angle was the criterion used to select the portions of the acoustic signals to be compared. The paper will conclude with a comparison of the measured values of excess ground attenuation from each method.
Effects of ground cover on the propagation of sound through the atmosphere
Authors: Bolen L. N. , Bass H. E.
Published: October 2005

Measurements of sound amplitude in the vicinity of a ground plane have been made as a function of frequency of the sound source (50–2000 Hz), distance of propagation (5–300 m), and surface conditions. By treating the impedance as an adjustable parameter, the surface impedance as a function of frequency was determined from the measured amplitudes using a theoretical treatment of a spherical wave in the vicinity of a locally reacting surface. The impedance measurements covered the frequency range 50–1000 Hz. In this frequency range, the results for three distinctly different surfaces suggest that the impedance can be computed from the specific flow resistance and that grass has little effect on the surface impedance except for decreasing the flow resistance due to the root structure. The results of the values of impedance calculated from sound measurements and flow resistance measurements will be compared, and the applicability of the single parameter model of Chessell to the data will be discussed. [Work supported by U.S. Army Research Office.]
An airport community noise-impact assessment model
Authors: DeLoach Richard
Published: October 2005

A computer model has been developed to assess the noise impact of an airport on the community which it serves. Assessments are made using the Fractional Impact Method by which a single number describes the community aircraft noise environment in terms of exposed population and multiple-event noise level. The model is comprised of three elements: a conventional noise footprint model, a site-specific population distribution model, and a dose-response transfer function. The footprint model provides the noise distribution for a given aircraft operating scenario. This information is combined with a site-specific population distribution obtained from a national census data base to yield the number of residents exposed to a given level of noise. The dose-response relationship relates noise exposure levels to the percentage of individuals who would describe themselves as “highly annoyed” by those levels. This information is used to compute a single-number descriptor of the airport noise environment. In addition to providing a quantitative assessment of the noise environment in the community at large, the model generates a report which lists several demographic variables as a function of noise level which are of interest to community planners and others. These variables include population density, growth rate, average age, average home value, percent homeowners, percent renters, and others. This paper describes the structure and operation of the community response model and presents the results of initial noise impact assessment studies.
Acoustic stapedial reflex latency versus BERA wave V latency in the detection of eighth nerve lesions
Authors: Sarno C. N. , Clemis J. D.
Published: October 2005

The parameter of latency of the acoustic stapedial reflex was used to test the hypothesis that a retrocochlear lesion involving the afferent portion of the reflex arc will result in a slowed neural conduction time. Measurements of middle-ear muscle activity were made by use of an electro-acoustic impedance bridge modified to permit presentation of tonal stimuli 300 ms in duration with 10-ms rise/fall time for test frequencies of 1000 and 2000 Hz. Both contralateral and ipsilateral values were obtained for absolute reflex latency and interaural latency differences on four clinical populations which included cochlear lesions due to Meniere's disease and surgically confirmed acoustic tumor. Results reveal a dramatic prolongation of latency in the presence of retrocochlear lesions. Comparisons drawn between the acoustic reflex latency test and BERA wave V latency, obtained with tone pip stimuli, indicate that stapedial reflex latency is a more efficient method of tumor detection. [Work supported by American Hearing Research Foundation, Chicago, IL.]
Automatic acoustic-phonetic segmentation using a hidden Markov model
Authors: Edwards T. J. , Li K. P.
Published: October 2005

In a previous meeting [J. Acoust. Soc. Am. Suppl. 1 64, S179(A) (1978)], we presented an evaluation of TRW's automatic segmentation program. More recently, we have sought to improve segmentation performance using a hidden Markov model (HMM) to predict the underlying phonetic segments. Utilizing a hand-transcribed data base, the HMM was initially directly calculated on the segmentation output and transcription and the new segmentation recognition result evaluated. Using an iterative procedure [J. Baker, in Speech Recognition, edited by R. Reddy (Academic, New York, 1975), pp. 521–542] the HMM was then trained using only the segmentation output and compared with the previously obtained segmentation result. Using different HMM initial conditions, the model was again trained in a test for convergence. A comparison of each of these HMM for segmentation will be provided and evaluation of the models will be discussed.
Application of post-correction techniques to connected digit recognition
Authors: Rabiner L. R. , Schmidt C. E.
Published: October 2005

A scheme is proposed for connected digit recognition in which a set of isolated word templates is used as reference patterns and an unconstrained dynamic time warping algorithm is used to literally “spot” the digits in the string. The recognizer keeps track of a set of candidate digit strings for each test string. The string with the smallest accumulated distance is used as a preliminary string estimate. To help improve the recognition accuracy, we have considered two “post-correction” techniques applied to the entire set of hypothesized digit strings. One technique creates a reference string by concatenating reference contours of the digits of the string and compares this to the test string using a constrained dynamic warp algorithm. The other technique performs a similar comparison using voiced-unvoiced-silence contours instead of the measured features. Small but consistent improvements in recognition accuracy have been obtained using these techniques for both speaker-trained and speaker-independent systems over dialed-up telephone lines.
Synthesis-based recognition of continuous speech
Authors: Paliwal K. K. , Rao P. V. S.
Published: October 2005

An acoustic phonemic recognition system for continuous speech is presented. The system utilizes both context-dependent and context-independent characteristics of the speech signal to achieve recognition. The interphonemic contextual effects contained in formant transitions are incorporated into the system by using the synthesis-based recognition approach of Thosar and Rao [IEEE Trans. Acoust. Speech Signal Proc. ASSP-24, 194–196 (1976)]. It is shown that the information contained in transition segments of the speech signal improves the performance of the system considerably. Recognition of continuous speech is accomplished here in three stages: segmentation, steady-state recognition and synthesis-based recognition. The system has been tried out on 40 test utterances, each 3–4 s in duration, spoken by a single male speaker and the following results are obtained: 5.4% missed segment error, 8.3% extra segment error, 52.3% correct recognition using only steady-state segments and 62.0% correct recognition using both steady-state and transition segments.
Are rooms with “good acoustics” really good for listeners with impaired hearing
Authors: Nabelek Anna K.
Published: October 2005

The following criteria used presently for designing room acoustics for listeners with normal hearing will be discussed in light of special requirements for listeners with hearing impairment: (1) loudness level, (2) reverberation times, (3) diffuse sound, (4) background noise, and (5) masking noise as used in open-plan offices. Needs and possible remedies for hard of hearing listeners, and for listeners with hearing impairment who use hearing aids, will be brought into attention. [Work supported by NIH.]
Ultrasonic bond evaluation in multilayered media
Authors: Havira R. M.
Published: October 2005

This paper discusses a spectroscopic and time domain method for the evaluation of bonding and the determination of thickness in multilayered media using broadband ultrasonics. Mathematical modeling of multilayered media based on Z-transform and scattering matrix techniques are presented. Experimental results using 500 KHz pulses are presented for water-steel-cement boundaries, water-steel-water boundaries and for a fluid-filled delamination between the steel and cement. The comparison between experimental and theoretical results are discussed.
Automatic music performance with computers
Authors: Ashton A. C. , Bennion R. F.
Published: October 2005

Developments of the Utah-BYU music project which have culminated in the design and implementation of a portable computer-driven music-generating system capable of interpretive playing of transcribed musical scores will be discussed, and a film depicting concurrent playing and graphing of music will be shown. The portable music system will be used to demonstrate direct interactive performance of a number of musical selections which have been notated in the Utah-BYU linear music language. Musical parameters such as pitch, duration, tempo, key, voice orchestration, and transposition can be notated for musical performance and can be dynamically modified during the automatic playing of the music. Music generation is accomplished by digital-to-analog conversion of stored digital waveforms which are programmably selectable at music generation time. Recordings of a computer-driven pipe organ will also be played and the organ-computer interface will be discussed.
Musical spectroscopy II: The sound score in composition and analysis
Authors: Cogan Robert , Potter Charles E. , Teaney Dale T.
Published: October 2005

In Visible Speech [R. Potter et al., Van Nostrand, New York (1947)] musical applications of a suitably adapted sonogram were foreseen, and Charles Seeger [Musical Quarterly 44, 184–195 (1958)] gave both practical examples of and the theoretical apology for descriptive music writing. In Sonic Design [Cogan and P. Escot, Prentice Hall. New Jersey (1976)] extended music-spectrographic methods are developed for both analytical and procedural purposes. Our spectrometer (see preceding abstract) generates a simple sound score on a grey-scale storage monitor. The display is, in effect, proportional notation of the spectral components over a 5-octave range against a 5- to 50-s horizontal span. The spectral density function. presented at the (z axis) luminance signal, is weighted to give approximately uniform brightness for a sine tone, top to bottom. Klavier or register staff lines are overlaid, and an audiographic equalizer permits modest refinements. Normally read in real time while listening to the music, the sound score can be photographed frame by frame. Examples from diverse musics will be presented.
Sampling of temporal fluctuations in community noise levels
Authors: Sutherland Louis C.
Published: October 2005

A theoretical basis exists for defining the statistical behavior of fluctuations in community noise levels providing the latter can be described in rather ideal terms. This paper briefly reviews some aspects of this theoretical framework and compares the statistical behavior of several sets of actual community noise measurements to the trends expected according to theory. Deviations from the theoretical trends are illustrated which are attributed to the nonideal (i.e., non-Gaussian) behavior of real community noise environments. The results help to establish guidelines for temporal sampling schemes for various types of community noise environments to achieve a desired degree of accuracy. However, additional data are called for to more accurately define the temporal and frequency character of a wider variety of types of noise environments. Suggestions are outlined as to what type of data are required and how they may be obtained. [Work was supported, in part, by EPA, Office of Noise Abatement and Control.]
Pulmonary ventilation by high-frequency oscillations
Authors: Fredberg J. J.
Published: October 2005

Bohn et al. [Fed. Proc. Fed. Am. Soc. Exp. 38 (3), 951 (1979)] reported that paralyzed beagle dogs maintained normal gas exchange for six hours or more when small oscillatory flows were maintained at the airway opening (15 cc tidal volume @ 15 Hz). These tidal volumes were 25% of pulmonary dead space and, thereby, were too small to permit convective gas exchanges with pulmonary airspaces. To test the hypothesis that effective gas exchange can be achieved by enhanced axial diffusion promoted by high-frequency oscillatory flows, I have modelled that process and computed the time constant for concentration equilibration in the lung as a function of flow amplitude and frequency. Knowing the distribution of oscillatory flows within the bronchial tree [Fredberg and Moore, J. Acoust. Soc. Am. 63, 954–961 (1978)], the enhanced diffusion due to oscillatory flows [Chatwin, J. Fluid Mech 71, 513–527 (1975)] may be integrated along the bronchial tree. The results indicate that gas concentration gradients within the lung can be substantially abolished within 100 to 10−2 s. This suggests that diffusion enhanced by small-amplitude oscillatory flows (tidal volume ≪ dead space) can support effective gas exchange in the lung in the absence of convective transport (breathing). [Work supported by the Physicians' Service Incorporated Foundation, Ontario.]
Temperature variation of the acoustic properties of laboratory sediments
Authors: Shirley Donald J. , Bell David W.
Published: October 2005

The compressional wave speed and attenuation and the shear wave speed and attenuation of unconsolidated artificial laboratory sediments have been measured as a function of temperature. No overburden or pore pressure in excess of that found at a few centimeters depth was applied. The compressional wave speed of the sediment was found to vary approximately as would water with a slight increase in the slope of the curve of the sediment over that of water. Shear wave speed appears to be independent of temperature within the accuracy of the measurement. Attenuation of both types of acoustic waves also appears to be independent of temperature. [Work supported by the Office of Naval Research.]
Nearfield of ultrasonic transducer-lens systems: Theory with Gaussian-Laguerre formulation
Authors: Cavanagh Eduardo , Cook Bill D.
Published: October 2005

Within the regions of validity of the Fresnel approximations, a Gaussian-Laguerre formulation permits rapid calculation of fields of transducer-lens systems. Separation of lens from the transducer is found to change significantly the structure of field. When the lens is at a focal length from the transducer, the field is found to be symmetric with respect to the focal plane. The asymmetry when the lens is not at this distance depends on the location of the lens and the ratio of the focal length to the length of the nearfield.
The role of potassium and sodium in cochlear transduction: A study with amiloride and tetraethylammonium
Authors: Salt A. N. , Konishi T.
Published: October 2005

The effects of amiloride and tetraethylammonium (TEA) on cochlear microphonics (CM), action potentials (AP), and endocochlear potential (EP) were studied in guinea pigs. It has been reported that amiloride selectively reduces sodium permeability in a variety of ion transporting epithelia. Perilymphatic perfusion (10−3 M) or intravenous administration (20 mg/kg) of amiloride suppressed AP, but did not significantly alter CM or EP. Application of amiloride to the endolymph by iontophoretic or perfusion techniques also produced no greater changes of CM and EP than were observed during control procedures. TEA has been shown to suppress the potassium permeability increase in excitable cell membranes. Perilymphatic perfusion of TEA (10-2 M) did not suppress CM or EP, but AP was reduced. Iontophoretic application of TEA to the endolymph markedly suppressed CM, while EP increased in value. The effects of TEA applied to the endolymph were similar to those effects previously reported to occur during noise exposure (J. Acoust. Soc. Am. Suppl. 1 64, S132(A) (1978)]. This result adds support to the hypothesis that noise induced CM suppression is a consequence of a potassium permeability decrease of the endolymph/perilymph barrier. The contribution of sodium ion movements to cochlear transduction appears less certain in the light of the insensitivity of CM and EP to amiloride.
Stimulus-induced release of endogenous amino acids from the Xenopus laevis lateral-line organ
Authors: Bledsoe S. C. , Bobbin R. P. , Thalmann R. , Thalmann I.
Published: October 2005

Previously, we described a method for studying stimulus-induced release of substances from the Xenopus lateral line [Bledsoe et al., J. Acoust. Soc. Am. Suppl. 1 65, S11(A) (1979)]. To date, 13 experiments have been completed in which the release of endogenous amino acids was studied by comparing the effects of pulsatile water motion on the efflux of glutamate and aspartate from isolated skins with and without lateral-line stitches. For a given experiment paired stitch and nonstitch skins were subjected to two. 30-min periods of stimulation and two, 30-min periods of no stimulation in a rotated order-of-occurrence. In an overall comparison of mean amino acid levels for the first and second periods of the stimulated versus nonstimulated conditions, stimulation applied to the outer skin surface caused a significant increase in glutamate and aspartate efflux from stitch (p < 0.01) and nonstitch (p < 0.01) skins. The stimulated efflux of glutamate from stitch skins was significantly greater than the stimulated efflux from nonstitch skins (p < 0.01). For aspartate efflux the between skin comparison was less clear cut with stimulation causing a significantly greater efflux from stitch skins than from nonstitch skins (p < 0.01), only when comparing the mean aspartate levels for the first periods of the stimulated versus nonstimulated conditions. Although the source and mechanisms underlying the greater stimulated efflux from stitch skins remain to be determined, the results demonstrate differences between stitch and nonstitch skins under stimulus conditions which should induce release of the afferent transmitter substance(s). [Work supported by NIH and The Kresge Foundation.]
Modulation of cochlear nerve fiber activity by low frequencies
Authors: Ingvarsson K. , Dallos P.
Published: October 2005

A 100-Hz tone of relatively high intensity (40–80 dB SPL) has a modulating effect on the activity of auditory fibers when the cochlea is stimulated with this tone and a tone at the characteristic frequency (CF). This effect can be noted even when the low-frequency tone itself does not stimulate the fiber. The phase of the 100-Hz tone at which enhancement of activity driven by the CF-tone is seen to occur corresponds to the phase where the 100-Hz tone alone elicits activity. In fibers of CF greater than 2 kHz, the velocity component of the 100-Hz tone is not appreciable, compared to the CF velocity component. Thus the effect described lends support to the theory that the static position of the basilar membrane has a biasing effect on the inner hair cell excitation. [Supported by grants from the NINCDS.]
Psychoacoustic model of categorical perception for speech and nonspeech continua
Authors: Espinoza-Varas Blas
Published: October 2005

The model assumes: (1) that categorization of a stimulus continuum xl,xi+1…,xn is made according to whether the stimuli fall above or below a decision “boundary,” xB, i < B < n; that discrimination between any two stimulus values, xp, xr, of the continuum is based on the physical parameter φ, where φ = |xp − xr|/|xr − xB|; xp, is the member of the stimulus pair that is proximal to the boundary, and xr the one that is remote from it. That is, discrimination is based on the distance between the pair of stimuli, proportional to the distance between the boundary and the remote stimulus of the pair. For both speech and nonspeech continua it is found that, given a distance |xp − xr|, the parameter φ reaches a sharp maximum for stimuli near the boundary, xB, and decreases monotonically as the distance between the remote stimulus of the pair and the boundary increases. The model was used to predict discrimination data for VOT [Wood, J. Acoust. Soc. Am. 60, 1381–1389 (1976); Elman, J. Acoust. Soc. Am. 65, 190–207 (1979)], onset of F2 transition and duration of stop closure [Elman, ibid.), and noise-buzz sequences [Miller et al., J. Acoust. Soc. Am. 60, 410–417 (1976)]. For most of these data, discriminability appeared to be an increasing function of φ. A corollary of the model is that enhanced discriminability around the boundary is a consequence of the listener adopting such boundary, rather than vice versa. [Supported by NRC Postdoctoral Fellowship to the author.]
Determination of temporal discriminations by an adjustment procedure
Authors: Clack T. D. , Benson P. J.
Published: October 2005

Identification of initial stop consonants along the voicing continuum exhibits sharp category boundaries as demonstrated with experimental manipulations of the voice onset times of natural and synthetic speech. The existence of discrimination thresholds for temporal onset differences has been suggested as a simple explanation of this phenomenon. Evidence of such a threshold for simple nonspeech sounds has been obtained using the ABX method, but with considerable inconsistencies among listeners [D. Pisoni, J. Acoust. Soc. Am. 61, 1352–1361 (1977); P. J. Benson and T. D. Clack, J. Acoust. Soc. Am. Suppl. 1 65, 58(A) (1979)]. This variability might be primarily methodological in origin and consequently a different psychophysical procedure has been developed. Discrimination thresholds were determined by an adjustment procedure similar to Bekesy audiometry. The results for the same subjects and listening conditions are evaluated relative to our previous ABX results.
Effect of talker sex on sentence discrimination scores
Authors: Gerber S. E. , Yrchik D. A.
Published: October 2005

The effects of talkers' sex on sentence discrimination scores of normal hearing listeners were examined. Two talkers each recorded ten synthetic sentences and a competing story. From this, four talker-masker combinations were prepared: male talker, male masker; male talker, female masker; female talker, female masker; female talker, male masker. Each combination was presented with the talker and masker in the same ear and in one ear only. Three different message-to-competition ratios (+ 10, 0, −10 dB) were used to present the four talker-masker combinations to 16 listeners. At each level, the talkers' sentence stimuli remained fixed at 60 dB SPL while the competing story was varied from 50 to 70 dB. Statistical analyses of the results indicated that significant differences in discrimination were produced by the message-to-competition ratios, the talker-masker combinations, and the interaction between them. Implications of these differences are discussed in the context of these results.
Direct Measurement of Wall Reflections in an Anechoic Chamber
Authors: Weinreich Gabriel , Arnold Eric B.
Published: October 2005

The system developed for measuring the radiation fields of a violin [G. Weinreich and E. B. Arnold, J. Acoust. Soc. Am. Suppl. 1 65, S72(A) (1979)] allows a direct measurement of the angular distribution of amplitude and phase of the wave reflected from the wall of an enclosure. By means of a special boom system, two microphones sweep out two concentric spheres surrounding the source of sound. The data are recorded in computer-readable form and then analyzed. By expanding in spherical harmonics and corresponding Hankel functions, the outgoing (transmitted) and incoming (reflected) components are separately determined. Data will be shown for the anechoic chamber of the University of Michigan Phonetics Laboratory [G. W. Peterson, G. A. Hellwarth, and H. K. Dunn, J. Audio Eng. Soc. 15, 67–72 (1967)]. [Work supported by NSF.]