bluuebunny/crossref_metadata_2025 huggingface dataset:
Air-coupled Rayleigh waves in an air-water-sediment environment
Authors: Diachok O. , Dicus R.
Published: October 2005

Resonance coupling between a horizontally propagating atmospheric wave and Rayleigh waves in the unconsolidated sediment layer occurs at frequencies for which the phase velocity of the dispersive Rayleigh wave is equal to the velocity of sound in air. Measurements of resonance coupling of atmospheric explosive signals into sediments have been reported in numerous investigations. Besides the resonance of the fundamental Rayleigh mode, for which theory was developed by Press and Ewing, higher frequency lines have also generally been reported. Resonance coupling of atmospheric signals above shallow water into sediments has also been observed. A working hypothesis to account for the observed multiple resonances and the effect of a thin water layer on recoupling resonant air-coupled Rayleigh waves was developed. The theoretical calculations, based on the FFP wave theoretical model developed by Kutschale, reveal that high-frequency lines are due to normal mode resonances and that significant coupling may occur only when the water depth is less than about one quarter-wavelength.
Auditory processing asymmetries for rapid two-element sequences
Authors: Leek Marjorie R. , Brandt John F.
Published: October 2005

Recent research has suggested that temporal complexity of an auditory stimulus is sufficient to demonstrate a right ear-left hemisphere processing superiority. This study hypothesized a greater right ear than left ear efficiency of processing a rapid dichotic auditory sequence, as reflected by reaction time to recognition of a target sequence. Stimuli were complex tones, vowels, or noises. Elements in a sequence were either 75 or 250 ms in duration, and the interval between the two sequential components was varied from 0.1 to 100 ms. Reaction times to rapid target sequences presented to the right ear were significantly shorter than left ear reaction times, regardless of the speech or nonspeech character of the stimulus. The longer duration signals resulted in greater response accuracy than did the shorter signals; there were no lateral differences in accuracy of response. These data suggest that a right ear superiority is related to the perceptual difficulty of the signal. Although both ear-hemispheres could adequately process these rapid sequences with equal accuracy, the differences in reaction time may reflect a slightly greater efficiency of processing by the right ear when temporal characteristics are similar to temporal values found in speech. [Work supported by NIH.]
Lateralization of trains of clicks having alternating center frequencies
Authors: Hafter Ervin R. , Wenzel Elizabeth M.
Published: October 2005

Listeners detected interaural differences of time (IDTs) in clicks presented through a Gaussian filter which had a center frequency of either 4 or 6 kHz. An increase in the number of such clicks in a train (n) improves performance by an amount that depends on the interclick interval (ICI). For ICIs as long as 10 ms, the threshold ΔIDT falls as n suggesting that every click in the train carries about the same amount of information. For shorter ICIs, the rate of improvement with n is reduced, a fact which suggests lowered effectiveness of clicks later in the train. In this study, we presented trains in which the clicks alternate between the two center frequencies. Alternating the frequencies should double the effective ICI in channels sensitive only to one frequency but should have no effect if judgments are made after the binaural information is combined. The results support the former notion.
FM detection by monkeys
Authors: Cole Dorothy , Stebbins William C. , Moody David B.
Published: October 2005

The information-bearing role of frequency modulation (FM) in human speech and other biological acoustic signals is well documented. Further, the sensory acuity for FM in man has been established [I. Nabelek and I. J. Hirsh, J. Acoust. Soc. Am. 45, 1510–1519 (1969); I. Pollack, J. Exp. Psych. 77, 535–541 (1968)], yet despite its confirmed role in nonhuman primate communication [e.g., S. Green, Z. Tierpsychol. 38, 304–314 (1975)] no information is available on the ability of nonhuman primates to resolve FM or other such complex “biologically relevant” signals. The experiment reported here sought to determine thresholds for FM in monkeys in and near the frequency range of their calls in an effort to better understand their perception of FM and its potential relation to their communication system. Subjects were three macaque monkeys trained by positive reinforcement behavioral procedures to discriminate FM stimuli from pure tones. The parameters of the computer-synthesized FM linear upsweeps matched critical parameters of macaque calls. Thresholds for modulation depth at four center frequencies (500, 1000, 2000, and 4000 Hz) increased as the center frequency was increased. The task was also considerably more difficult at the higher frequencies as indicated by the time required for the animals to acquire the discrimination and to perform reliably. Preliminary results suggest perceptual specialization for efficient processing of biologically significant sounds. [Supported by Research Grant BNS-77 19254 from NSF.]
The dog audiogram
Authors: Coultas Mark A. , Defran R. H. , Dixon Mitchell L. , Berry Steven S.
Published: October 2005

Auditory sensitivity of two adult Labrador retrievers (Canis familiaris) to pure-tone stimuli was analyzed. Early published reports on Canid hearing lacked the acoustical and methodological sophistication currently available, and seriously underestimated the range and sensitivity of hearing in those specimens studied. Using a hold-release response paradigm and water as a reinforcer, absolute thresholds for 11 different frequencies between 60 Hz and 45 kHz were determined with a tracking procedure. Maximum sensitivity between 0 and −2 dB (re: 0.0002 dyn/cm2) was obtained at 8 kHz for both subjects. Lower (60 Hz) and upper (45 kHz) thresholds were in close agreement for both subjects and averaged 54 dB and 40 dB, respectively. These data are in good agreement with those in a preliminary report by Heffner [H. Heffner, “Audiometry in dogs.” Paper presented at the meeting of the Acoustical Society of America, San Diego, October 1976] for dogs of different breeds within two-choice response paradigm.
The role of the gross spectral shape as perceptual cues to place of articulation in stop consonants
Authors: Blumstein Sheila E. , Isaacs Ellyn , Mertus John
Published: October 2005

This series of studies explored the extent to which the gross shape of the onset spectrum is used by the listener for the identification of place of articulation in stop consonants. Synthetic stimuli were generated with onset frequencies appropriate to the syllables [ba bi bu da di du] with the gross shape of the onset spectrum manipulated to be appropriate for either alveolar consonants (diffuse-rising) or labial consonants (diffuse-falling). Stimuli were presented for identification and discrimination. In addition, adaptation effects of stimuli containing appropriate frequency and shape and inappropriate frequency and shape were explored on a place of articulation onset continuum. Although identification performance was determined by onset frequency rather than gross shape of the spectrum, presentation of stimuli in which shape was inconsistent with frequency reduced identification performance. Further, subjects could discriminate stimuli which varied only in spectral shape. Finally, significantly less adaptation was found for a [da] onset with a labial spectrum shape than a [da] onset with an alveolar spectrum shape. These results suggest a dichotomy between the role of invariants in providing a classifactory framework for the phonetic dimensions of natural language, and in providing the primary perceptual attributes in ongoing speech processing. [Supported by an NIH Grant.]
Investigation of categorical perception for both phonetic and nonphonetic continua
Authors: Harris Laura B. , Pastore Richard E.
Published: October 2005

The phenomenon of categorical perception was examined using two synthetic speech continua and two associated nonphonetic continua. One of the two phonetic continua consisted of stimuli varying from /Bi/-/Di/ along the dimension of place of articulation while the other ranged from /Bi/-/Pi/ varying in VOT. Nonphonetic continua were synthesized using timing and frequency parameters obtained from the phonetic continua. Thus each phonetic series had a nonphonetic counterpart. Both phonetic continua were perceived in a classically categorical manner. While the nonphonetic analogs obtained comparable results in terms of labeling functions. Of interest is the variation in the obtained discrimination results for the nonphonetic stimuli. With one continuum, analogous to /Bi/-/Di/, discrimination was consistently very good across subjects, while the /Bi/-/Di/ analog continuum produced consistently poor (at chance) discrimination for two of three observers employed. These differences will be discussed with respect to the phenomenon of categorical perception. [Work supported by Grant BNS 80-03704 from NSF.]
Static versus dynamic cues to place of articulation in stop consonants
Authors: Kewley-Port Diane
Published: October 2005

Several recent studies have demonstrated that invariant acoustic information for specifying place of articulation can be found in the initial 10 to 40 ms of a stop-vowel syllable. Stevens and Blumstein [J. Acoust. Soc. Am. 64, 1358–1368 (1978)] have claimed that place can be specified by a static short-time integrated spectrum. More recently, Kewley-Port [J. Acoust. Soc. Am. Suppl. 1 68, S70 (1980)] has proposed that place can be specified by the time-varying distribution of spectral energy. To compare these hypotheses, two perceptual experiments were conducted, one using a digital parallel resonance synthesizer and the other using LPC synthesis. Two stimulus sets were modeled after natural CV's. They differed in the detailed structure of the 20- to 40-ms-long waveforms. One set was static and patterned after the shape of the 25.6-ms onset spectrum; the other set preserved the burst and dynamic spectral variation of the CV. Listeners in both experiments identified place of articulation more accurately for the dynamically changing stimuli than for the static stimuli. These results demonstrate that the time-varying dynamic information in the initial 20 to 40 ms of CV stimuli is used to reliably identify place. Static onset spectral information alone does not appear to be sufficient to characterize the properties that listeners use to identify place in stop-vowel syllables. [Supported by NINCDS grant NS-12179.]
Effect of burst amplitude on the perception of place of articulation for stops
Authors: Ohde Ralph N. , Stevens Kenneth N.
Published: October 2005

We have examined the effects of the relative amplitude of the burst on perception of the labial and alveolar place of articulation for voiceless and voiced stop consonants. The amplitude of the burst, i.e., the first 10–15 msec following consonant release, was systematically varied in 5-dB steps from −10 to +10 dB relative to a “normal” burst amplitude for two bilabial-to-alveolar synthetic speech continua—one for voiceless stops and the other for voiced stops. The distribution of spectral energy in the burst for the bilabial and alveolar stops at the ends of the continuum were consistent with the shapes observed in natural utterances of these stops, and intermediate spectrum shapes were used for intermediate stimuli on the continuum. The results showed that the relative amplitude of the burst, even for the same spectrum shape, significantly affected the perception of place of articulation for both voiceless and voiced stops, but the effect was greater for the former than the latter. The results suggest that for an alveolar consonant to be heard, the high-frequency spectral amplitude immediately following the consonant release must be equal to or greater than the spectral amplitude at the onset of the following vowel in the same frequency range, and the spectral amplitude at onset for low frequencies must be sufficiently low. [Work supported in part by NINCDS.]
Perception of /r-w/ and /s-∫/ continua by /r/ and /s/ misarticulating children
Authors: Hoffman Paul , Schuckers Gordon , Daniloff Raymond , Hasegawa Akira
Published: October 2005

Ten children (ages 6.6–8.6) who dentalized /s/, ten children (6.4–8.2) who labialized /r/, and 10 normal children identified a 17-step /is-i∫/ stimulus continuum or a 7-step /rεd-wεd/ continuum via a picture pointing task. Normals and /s/-children identified stimuli 1–7 as /is/ at greater than chance probability and stimuli 10–17 as /i∫/ above chance as well. Stimuli 8–9, at chance levels, were the phoneme boundary for both groups. /r/-misarticulating children both identified and discriminated /r-w/ stimuli at a level significantly below that of normal children, whose identification and discrimination functions were similar to those of adults. Results indicate that older children who misarticulate /s/ do not necessarily have faulty /s/ boundaries for phonemes which are not similar to their production errors, whereas /r/-misarticulating children display depressed identification and discrimination scores as well as a widened phoneme boundary.
Human vibration exposure: Progress and problems in standardization
Authors: von Gierke Henning E.
Published: October 2005

Over the last 15 years national and international interest in human whole-body vibration resulted in several guidelines and draft standards which are at various stages of adoption. The primary document is ISO 2631 (1978), “Guide for the Evaluation of Human Exposure to Whole-Body Vibration,” with several amendments and addenda. The most important ones of the latter are incorporated into the corresponding ANSI document, ANSI S3.18-1979, “American National Standard Guide for the Evaluation of Human Exposure to Whole-Body Vibration.” The advantages and shortcomings of these documents are discussed together with the proposals under study to update and extend these guidelines based on new laboratory and field data, to specific environments such as buildings, surface transportation vehicles, and ships. Open questions and areas which need further research will be covered in this introduction to the Session on Whole-Body Vibration.
Occupational whole-body vibration, where do we go from here
Authors: Wasserman Donald , Behrens Virginia
Published: October 2005

NIOSH estimates that some 6.8 million workers are exposed to whole-body vibration in the workplace in the U.S. The majority of these workers are involved in transportation and vehicular motion (i.e., truck and bus drivers, heavy equipment and farm vehicle operation). NIOSH has conducted four epidemiology studies of bus, truck, heavy equipment workers; a series of human and animal laboratory studies; and a series of vibration field measurement studies. The results, difficulties and merits of these and other related studies will be reviewed and their interrelationships will be discussed. Suggestions for future work directions in occupational whole-body vibration will also be presented.
Whole-body vibration: A review of epidemiologicai approaches and findings
Authors: Spear Robert C.
Published: October 2005

Epidemiological studies aimed at defining the nature and extent of the effects of whole-body vibration on humans have been relatively few in number. Usually difficulties are encountered in relating effects to vibration exposure versus more general ergonomic or environmental stresses. In few of the published studies is there a quantitative description of the vibration exposure, a difficulty characteristic of most retrospective epidemiological studies. Studies conducted in Eastern Europe have tended to involve medical examination of exposed workers as contrasted with a tendency in the West to approach the problem via studies of medical records. As a result the Western studies focus on clinically recognizable problems and do not allow for the study of biochemical or physiological changes that may precede clinical disease or injury. In both the East and West there has been a trend away from the study of military groups towards workers exposed in civil occupations. A recurring problem in the studies focused on the effects of long-term exposure is the issue of selection out of exposed occupations with advancing age or the onset of disease.
Measurement of vibration related to human response
Authors: Rasmussen Gunnar
Published: October 2005

The measurement of vibrations influencing a person in many ways resembles the measurement of sound inflicting on man. The concepts of comfort, annoyance, fatigue, and hazard are all related to human reactions. It is practical therefore to adapt some of the methods developed within the acoustical field to the human vibration field. Filter techniques like block sampling FFT or continuous real time analysis should only be adapted when the significance of the different techniques are readily understood and applied. The importance of the averaging technique for the expression in single number values like peak-max. rms or equivalent energy level is especially clear when example of the nature of common vibration signals are shown. Examples of typical vibration sources measured with different transducers on different type of instrumentation will be shown.
Fluctuations of resolved acoustic multipaths at short range in the ocean
Authors: Worcester Peter F. , Williams Gordon O. , Flatté Stanley
Published: October 2005

The fluctuations in acoustic transmission between a broadband source and an autonomous receiver moored somewhat below the sound channel axis at 23-km range have been examined. The transmitted signal was centered at 2273 Hz. A variety of measures of the observed fluctuations (pulse and cw) for three well-resolved paths computed from 72 h of data are compared with theoretical predictions based on sound-speed perturbations due to internal wave vertical displacements. Measurements and theory are found to be consistent for some statistics and inconsistent for others. The theoretical predictions depend sensitively on the mean sound-speed profile.
Vocal pitch production in a patient with expressive dysprosody: A possible right hemisphere role in speech production
Authors: Sidtis John J. , Volpe Bruce T.
Published: October 2005

Recent evidence obtained from normal listeners, from neurological patients with focal cortical lesions, and from patients who have undergone surgical section of the corpus callosum suggests that the right hemisphere auditory system has an advantage over the left in the perception of complex pitch. A possible production correlate was studied in a patient with right hemisphere tumor in whom speech was monotonic. On binaural testing, both speech and complex pitch discrimination were intact. On dichotic testing, a significant impairment was observed on pitch, but not speech discrimination. Vocal pitch control was assessed by having the patient mimic the pitch of a binaurally presented token frequency. A range of 100 to 240 Hz was tested at 20-Hz intervals. The patient's production was limited to a range of approximately 24 Hz, centered around 140 Hz. The modulation of vocal pitch in the production of intonation contour may be one way in which right hemisphere mechanisms contribute to the production of speech. [Work supported by NIH grants NS03346-19 and RR05396-20.]
Ray methods for scattering of elastic waves
Authors: Achenbach J. D. , Norris A.
Published: October 2005

Scattering of elastic waves by flat cracks is analyzed by the use of elastodynamic ray theory. The diffraction of incident rays by a crack edge, as described by the geometrical theory of diffraction (GTD) and its uniform asymptotic extension (UAT), is discussed in some detail. A theory is developed which is valued for scattering by a flat crack of arbitrary shape but with a smoothly curving edge. Specific results are presented for cracks of elliptical shape. Both interior and surface-breaking cracks are considered. For slits and penny-shaped cracks, ray-theory results are compared with exact results.
Scattering of elastic waves
Authors: Mal Ajit K.
Published: October 2005

The problem of the scattering of time harmonic plane elastic waves by an inclusion is considered. It is shown that the scattered field can be expressed either as a surface integral or a volume integral over the scatterer. The integrand contains a certain combination of the unknown displacements and stresses within or on the surface of the scatterer. Three different schemes for the determination of these unknowns are discussed. These are (1) low- and high-frequency estimates via an approximate analysis, (2) numerical determination via an integral equation formulation, and (3) numerical calculations via a finite element approach. Once these estimates are known, the scattered waves are determined from the integral representation. Results are presented for the scattering of body waves by obstacles in infinite space or of body and surface waves by obstacles embedded in a half-space.
Using zero crossing counts to provide discriminative information in isolated word recognition
Authors: Rudnicky Alexander I. , Waibel Alexander H. , Krishnan Neeraja V.
Published: October 2005

Template matching systems that use a purely spectral representation are potentially insensitive to some important phonetic dimensions of speech. For example, [PI] is often confused with both [BI] and [TI] because the necessary vocalic—aspirated—fricative discrimination cannot be reliably made on the basis of spectrum alone. The zero crossing count is known to contain sufficient information for this and for other discriminations. We evaluated the usefulness of the zero crossing count in a set of experiments that used a highly confusable subset of the alpha-digit vocabulary (3, b, c, d, e, g, p, t, v, z). In these experiments, a zero crossing count was added to a 15 coefficient spectral representation and the resulting vector was used to calculate frame distances within a dynamic warping algorithm. Testing over a corpus of 800 utterances (eight talkers), we achieved a 10% reduction in error rate. In order to obtain optimal improvement, the count had to be clipped to a restricted range, quantized to a small number of levels, and weighed appropriately relative to the spectral information. Further investigation determined that the addition of zero crossing information aided recognition by improving the distinctiveness of confusable utterances and not by improving the dynamic warping alignment of the spectral information.
Some experiments with a linguistic processor for continuous speech recognition
Authors: Levinson S. E.
Published: October 2005

The linguistic processor of a system for the recognition of fluently spoken Japanese is described. Input to the processor is a phoneme lattice [R. Nakatsu and M. Kohda, Rev. ECL 26, 1505–1520 (1978)] in which scores are given for each of 27 phonemes for each segment. Phrases composed of words from a 112-word vocabulary are recognized by an error correcting parser which tolerates both classification and segmentation errors in the phoneme lattice by means of a Substitution-Insertion-Deletion Mechanism (SID) [L. R. Bahl and F. Jelinek, IEEE Trans. Inform. Theory IT-21, 401–411 (1975)]. Some phrase errors are corrected at the entrance level by means of a Cartesian Product Sorting Algorithm. [A. V. Aho et al., Proc. 14th CISS (1980)]. The processor has been tested on a total of 80 sentences from four male speakers. The sentences comprised 496 phrases with an average of 25 phonemes per phrase. The phoneme lattices had a 70% accuracy on phonemes with roughly equal numbers of segmentation and classification errors. Under these conditions 77% phrase accuracy was observed.
Use of reciprocity in predicting the sound radiation of complex structures
Authors: Vér István L. , Mayes William H. , McGary Michael C.
Published: October 2005

Complex structures such as the fuselage of an aircraft or the body of a car are usually subject to airborne as well as to force excitation. To formulate noise control strategies, it is necessary to know what portion of the interior sound field is due to airborne and what portion to force excitation. A special reciprocity method described in this paper, can be beneficially employed to achieve this desired separation. The paper reports on the theory, the experimental methodology and on a successful application of the reciprocity method to predict the force-induced sound field in a complex full-scale structure.
The state of the art of assessment of noise-induced annoyance
Authors: Fidell S.
Published: October 2005

Relating noise-induced annoyance to acoustic quantities has proved to be a frustrating undertaking. In several decades of pursuit of formal means for quantifying adverse attitudes of individuals and groups toward noise exposure, the successes have been relatively narrow in scope, and are the exception rather than the rule. One is as hard pressed to predict in precise terms how acceptable a new noise source will be to a community as to characterize the absolute acceptability to individuals of degraded speech quality. Many are inclined to attribute the meager success in predicting annoyance from acoustic quantities to problems of measurement—either physical or social. The viewpoint presented in this paper is that the problems are more fundamentally those of theory and analysis, and that substantial progress in this field is unlikely to result from further applications of old approaches and methods.
Vertical noise distribution studies at the Marine Physical Laboratory
Authors: Anderson V. C.
Published: October 2005

A review of the experimental studies by the Marine Physical Laboratory in vertical directionality of ambient noise. Two regimes of deep ocean ambient noise—wind-generated surface noise and distant shipping noise are discussed. In both of these cases the nonstationarity of noise as observed through the directional beams of a hydrophone array is of interest. Wind-generated noise statistics in the form of envelope spectra have been derived from data with a high-gain 720-element array operating over the band of 800 to 3200 Hz. Lower frequency data has been obtained with a linear array suspended from the stable research platform FLIP.
Vertical directionality of low frequency ambient noise in the South Fiji Basin
Authors: Browning D. G. , Yen N. , Bannister R. W. , Denham R. N. , Guthrie K. M.
Published: October 2005

The vertical directionality of ambient noise has been measured at two sites in the South Fiji Basin for the frequency range 10–200 Hz. The results are compared with the depth dependence of omni-directional data taken previously at the same location. [R. W. Bannister, J. Acoust. Soc. Am. Suppl. 1 60, S20 (1976)]. For frequencies above 100 Hz the measured noise is uniformly distributed throughout the water column and is principally due to local wind generated noise. Below 100 Hz there is an additional broad peak in level centered at the deep sound channel axis. This peak is apparently due to long range noise sources received via SOFAR propagation paths. An analysis of the standard deviation could not determine conclusively whether these distant noise sources were storms or ships.
Effect of propagation distance on rotary wing aircraft sound duration
Authors: Raspet Richard
Published: October 2005

Military aircraft noise contouring programs employ an empirical factor describing the change in duration of a flyby with distance. In the past the SEL or EPNL was calculated from the maximum A-weighted level by the use of a duration correction given by 10 times the logarithm of the distance ratio, applicable to spherical divergence without absorption. Recent measurements have indicated that a better factor for a variety of military aircraft is six times the logarithm of the distance ratio (J. D. Speakman, “Effect of Propagation Distance on Aircraft Flyover Sound Duration,” AFAMRLTR-81-28, May 1981). This paper describes the results of an experimental and theoretical study of the duration factors for rotary wing aircraft. The theoretical study investigates the effect of surface conditions, coherence, and atmospheric absorption on the duration correction.
Noise emissions from new electric options: Coal conversion and on-site generation
Authors: Teplitzky Allan M.
Published: October 2005

Two alternatives being considered for reducing the use of imported petroleum are the reconversion of oil-fired electric power plants, to burn coal or the construction of small on-site generators which would make use of the waste heat from diesel generators to improve fuel efficiency. In urban areas there may be insufficient distance between the noise sources and residents to act as an acoustical buffer zone to attenuate noise to the local permissible limit. Calculations made during the preparation of environmental impact statements will determine noise abatement requirements either for achieving compliance with local noise limits or for minimizing community annoyance. Several studies were undertaken to provide a noise emission data base for the sound sources associated with both alternatives and to develop procedures for evaluating the effects of environmental noise changes. Noise emissions from two types of coal delivery and handling systems are reviewed, since these are expected to be the main sources of noise resulting from coal reconversion of a central power station. Noise emissions from on-site cogenerators, which will most likely be diesel engine-generators, will be discussed briefly since it was the subject of a prior paper [A. M. Teplitzky and L. N. Miller, J. Acoust. Soc. Am. Suppl. 1 67, S87(1980)]. The studies have shown that noise emissions from either alternative are compatible with the urban environment when adequate noise abatement devices are installed.
The worth of noise control
Authors: Schomer Paul D.
Published: October 2005

Frequently in cost/benefit analysis the question is posed: “What is the benefit to the receiver of reduced noise emissions?” or, alternatively, “What are the societal costs associated with noise pollution?” Clearly the study of this question is of necessity interdisciplinary in nature and includes both physical and psychoacoustical dimensions as well as economic and legal dimensions. As a member of an interdisciplinary team which has performed several cost/benefit analyses, this author will give an acousticians perception of the nature of the problem, the nature of the data from various sources and what these data taken together indicate. The general indication is that the worth of noise reduction is a function of the environmental noise level. Using day/night average sound level (DNL) as a measure, the worth of noise control becomes very large at high noise levels and goes to zero at low noise levels. The data indicate that the worth (in terms of property value) becomes 100% in the range DNL 75 to 85 and that the proper course of action is to buy the affected properties and remove the occupants from this environment. At low noise levels the data indicate that the worth of noise control goes to zero. This low level apparently lies somewhere in the range of DNL 45 to 60. In between these extremes, the worth of the noise control progressively and smoothly increases from the zero to the 100% figure. One of the major problems with the data is that the worth of noise control to an individual is usually expressed only indirectly in terms of reduce property values rather than directly in terms such as “x dollars per person per day.”
Comparison of the partial-wave series and a model for ultrasonic scattering from fluid spheres near lhe critical angle
Authors: Marston Philip L. , Kingsbury Dwight L.
Published: October 2005

Consider the scattering of plane waves from an inviscid sphere of sound speed ci and density ρl imbedded in a fluid with a sound speed c0 < ci and a density ρ0 ≈ ρl. Naive application of ray acoustics predicts that the derivative of the modulus of the form function f has an unphysical divergence as the scattering angle φ approaches a critical scattering angle φc, and furthermore with φ ⩽ φc, the surface reflectivity is unimodular with a phase advancement. A divergence-free model has been developed which is analogous to that for light scattering by bubbles [P. L. Marston and D. L. Kingsbury, J. Opt. Soc. Am. 71, 192–196 (1981); 71, 917 (1981)]. The model uses rays to construct virtual waves at the scatterer; the waves diffract to the farfield. To test the model, a modified Mie algorithm summed the acoustic series for f with ka as large as 10 000 (a = sphere radius, k = 2φ/λ, λ = wavelength). When φ < φc, interference and diffraction cause a coarse structure in the scattering with a quasiperiod ≲ (π/a)1/2 radians; the main features of this structure in the exact result are described by the model provided ka ≳ 25. [Work supported by ONR. P. Marston is an Alfred P. Sloan Research Fellow.]
Further observations on the effects of broadband noise on the BER
Authors: Burkard Bob , Hecox Kurt
Published: October 2005

At a previous meeting of the Society [Burkard et al., J. Acoust. Soc. Am. Suppl. 1 69, S85 (1981)] we described the effect of broadband noise on the BER as a function of click intensity, rate, and noise level. At that time the possibility of nonadditivity of the effect of stimulus rate and noise on wave V latency was raised, leading to a more detailed analysis of the effects of noise on the time course of rate effects. An adaptation paradigm was used in which the latency of the wave V response to the first click in the train was compared to subsequent responses. Less adaptation was observed at noise levels which influenced wave V behavior. This nonadditivity suggests that the effects of broadband noise and stimulus repetition rate may be mediated by overlapping mechanisms. This supposition is supported by the differences in the time course of adaptation seen in noise versus no-noise conditions. The effects of broadband noise on responses evoked by tone-burst stimuli will also be described. [Work supported by NIH.]
Frequency-specific effects of stimulus rise-fall time on the human BAEP
Authors: Deegan Don , Hecox Kurt
Published: October 2005

High-pass masking was used to determine the effect of varying rise-fall time (0, 1, 2, and 5 ms) on the frequency specificity of the brainstem auditory evoked potential (BAEP) to 50 dB nHL noise bursts. The latencies and amplitudes of frequency-specific waveforms were obtained by subtractive masking [Don and Eggermont, J. Acoust, Soc. Am. 63, 1084–1092 (1978)]. Results showed increasing latency and decreasing amplitude of wave V with decreasing frequency band. Increasing rise-fall time within a frequency band prolonged latencies and decreased amplitudes. There was a convergence of latency values between rise-fall times as frequency band decreased consistent with a place mechanism. However, divergent latency differences between rise-fall times but within frequency bands suggests that additional mechanisms may be operative. Amplitude effects were complex but there was a suggestion that increasing rise-fall time results in an apical shift in the generation of the BAEP. Traveling-wave velocities calculated using previously published techniques and the latencies described herein are in good agreement with prior estimates in the human. [Work supported by NIH.]
Asymmetries in the binaural interaction of the auditory brainstem response
Authors: Berlin C. , Allen P. , Parrish K.
Published: October 2005

Twenty normal listeners generated auditory brainstem responses to simultaneous condensation 100 μs transients of 70 dB HLN to the left ear, right ear, and finally under binaural conditions. ABR was recorded simultaneously through two matched preamplifiers with vertex as a G1 electrode, the respective ear lobes as G2 for each preamplifier, and the nasion as a ground. Because of the recording montage and because, during binaural stimulation both right and left preamplifiers were active, it was possible to study asymmetries in the following five relationships: (1)[BinR − BinL], (2) [BinR + BinL] −ε[RI + RC) or (LI + LC), (3) [BinR + BinL] −ε[RI + LC) or (LI + RC)], (4) [BinR + BinL]/2 −ε[LI + LC) or ε(LI + LC) or ε(RI + RC)], (5) [BinR + BinL]/2 −ε[(LI + RC) or ε(RI + LC)], in which R = biological data from right amplifier, L = biological data from left preamplifier, I = ipsilateral stimulation, C = contralateral stimulation and Bin = binaural stimulation. Data support, Decker and Howe [J. Acoust. Soc. Am. 69, 1084 (1981)] in that either the left or right ear usually dominates the binaural interaction, but also show that recording montage and binaural stimulation conditions lead to other forms of recordable asymmetries. [Work supported by NINCDS 11647.]
Phasor admittance measurements of the middle ear
Authors: Lutman Mark E.
Published: October 2005

Conventional techniques for the measurement of the acoustic admittance of the middle ear are heavily dependent upon the mobility of the most flaccid parts of the tympanic membrane and relatively insensitive to abnormalities of the ossicular chain. This paper describes a method which has been developed to characterize the vibratory properties of the tympanic membrane and the ossicular chain separately. The technique is based on the analysis of trajectories traced by the middle-ear admittance phasor as either the external ear canal pressure, or the stapedius muscle tension, is modified. Consequently, the tympanic membrane and ossicular chain are each characterised by means of a natural frequency and damping ratio. Normative data are presented from 68 ears screened for middle-ear disease. The results indicate that the two measures are each relatively consistent between subjects, yet the two measures within subjects are independent of one another. Thus they provide tractable measures of middle-ear status.
Effects of linear frequency modulated ramps on stapedius muscle reflex (SMR) in children
Authors: Lenhardt M. L.
Published: October 2005

Thirty 6-year-old children with normal hearing, speech discrimination, and SMRs to tones and noise were given FM stimulation. A 2000-Hz tone was presented at 15 dB + SMR threshold until SMR decayed. The frequency was either modulated upward (to 40000 Hz) or downward (to 1000 Hz) in 100 ms for a series of intensity steps until a full contralateral SM contraction was recorded. Decay of the tonal SMR preceded FM testing at each step. The reciprocal to the 2000-Hz rising ramp was also employed and presented re the 4000-Hz tonal SMR. Ramps were filtered to equate intensity. All FM ramps induced a reactivation of the SMR. When equated at the percent of full contraction the 2000-Hz rising ramp had a larger dynamic range than either the falling or reciprocal conditions. The SMR waveform morphology varied with sound intensity. At high levels the SMR onset and offset was fast and the amplitude high, but as the sound intensity decreased onset and offset times increased and amplitudes reduced resulting in a broadening of the waveform.
Perstimulatory adaptation of acoustic reflex in normally hearing subjects
Authors: Thompson David J. , Hawkins H. Stephen
Published: October 2005

This was an investigation of acoustic-reflex adaptation in ten adults in each age decade between 20 and 79 years. Reflex-activating stimuli, presented by earphone to the ear contralateral to the acoustic-immittance probe, were four tones (0.5, 1.0, 2.0, and 4.0 kHz) and two filtered noises. Sound pressure levels were +5, +10, +15, and +20 dB re: acoustic-reflex threshold. Stimulus duration was 60 s. Reflex responses were measured with both components of aural acoustic admittance. Custom software was written for automated digitization, storage, quantification, and plotting of the responses. Statistical analyses of conductance and susceptance data included static acoustic admittance, acoustic-reflex threshold. maximum amplitude of reflex, rate of adaptation, and shift of baseline during reflex activation. Adaptation rate was highest for the 4.0- and 2.0-kHz activators and varied with stimulus level. Comparison of multiple regressions revealed age-related trends in measures of adaptation. [Work supported by VA-RER&D.]
An attenuating layer with acoustic impedance close to that of water
Authors: Burton Thomas E.
Published: October 2005

It is well known that resonant voids in rubber absorb sound while lending a springlike complex part to the acoustic impedance [M. C. Junger, J. Acoust. Soc. Am. 69, 1573–1576 (1981)]. A modest extension of a mixture theory [W. S. Ament, J. Acoust. Soc. Am. 25, 638–641 (1953)] shows that heavy resonant balls in rubber also absorb sound, while lending a masslike complex part to the impedance. The two effects can be combined to yield a lossy equivalent medium with an impedance which is close to that of water over a wide frequency range.
Resonance reflection of acoustic waves from a submerged, perforated and bilaminar rubber coating model
Authors: Jackins P. D. , Gaunaurd G. C.
Published: October 2005

Each of the perforated rubber layers constituting the multilayered composites used to absorb underwater sound waves can be (ideally) modeled as a fluid layer having density ρi and sound speed Ci. The volume concentration of the gas-filled perforations controls the (effective) values of ρi and Ci in each of the layers. We consider a plane two-layer coating having a (possibly different) fluid on each side, and we study its reflection coefficient R(f, θ) as a function of frequency f and incidence angle θ, as plane sound waves are reflected by it. Resonances are evident in R(f, θ) both as functions of f and θ, and we display many of these in three-dimensional graphs that are as informative as esthetically pleasing to view. We then show how these resonances in R can be analyzed in the light of the resonance scattering theory (RST) in order to generate simple (and approximate) but quite accurate reflection predictions, which we then use to extract information about the material composition of the bilaminar composite. The method determines which of the reflection features is caused by which of the two interacting layers.
Piezomagnetic and elastic properties of metallic glass alloys 2605CO and 2605SC
Authors: Meeks Steven W.
Published: October 2005

Piezomagnetic and elastic properties of two new commercially available metallic glass alloys are reported. These alloys, Metglas 2605CO and 2605SC (Allied Corp.), are of composition Fe67CO18B14S1 and Fe81B13.5Si3.5C2, respectively. After these alloys are heat annealed in the presence of a transverse magnetic field they exhibit an enormous magnetomechanical coupling coefficient of the order of 0.90. Also reported are the very high values of d33 which are more than 40 times larger than that of nickel. The value of the hydrophone figure of merit, g33 ⋅ d33 is three times larger for metallic glass than for PZT-4. Data are presented on the large changes in the elastic moduli of these alloys as a function of magnetic bias field. The otimum annealing process, the implication for practical sensor use, and potential hydrophone designs are also discussed.
New technique for dynamic moduli and loss factor measurements
Authors: Madigosky Walter M. , Lee Gilbert
Published: October 2005

A new resonance technique capable of providing rapid and accurate dynamic modulus and loss factor measurements on a wide range of materials (soft and rigid) over a wide range of frequency and temperature has been developed. Miniature accelerometers are placed on the ends of a small strip of material and one end is driven by a noise source. The output from the two accelerometers is analyzed by a fast Fourier transform (FFT) spectrum analyzer. At certain frequencies, the amplitude of the acceleration ratio goes through peaks due to resonances. At these resonances, or more properly when the phase difference is 90 degrees, the equations of motion are easily solved. The amplitude and phase of the acceleration ratio are measured continuously over a frequency range of five decades (0.2 to 25000 Hz) and the computerized data analyzed to provide a family of Young's modulus and loss factor curves. The data is presented in two ways: (a) a frequency plot showing the relaxational nature of the material, and (b) a temperature plot showing the glass to rubbery transition and a measure of the glass transition temperature. A number of materials varying from a foam rubber to a metal matrix composite (modulus 105 to 1011 dyn/ cm2 and loss factors 0.01 to 10) have been characterized using the apparatus.
Space Shuttle Main Engine Pogo testing and results
Authors: Jewell R. , Jones J. , Fenwick J.
Published: October 2005

To effectively assess the Pogo stability of the Space Shuttle vehicle, it was necessary to characterize the structural propellant, and propulsion dynamics subsystems. Extensive analyses and comprehensive testing programs were established early in the project as an implementation of management philosophy of Pogo prevention for Space Shuttle. This paper will discuss the role of the Space Shuttle Main Engine (SSME) in the Pogo prevention plans, compare the results obtained from engine ground testing with analysis and present measured data from STS-1 flight.
Glottal flow calculations
Authors: Ananthapadmanabha T. V. , Fant Gunnar
Published: October 2005

The time variable and nonlinear transform relating glottal flow and vowel waveform to input parameters of glottal area function and lung pressure have been studied. Effects of sub- and supra-glottal impedance, time variable glottal impedance, and period to period superposition are discussed. The validity of simplified linear transforms is discussed and perceptual constraints are considered. This work is a followup of earlier studies [G. Fant, STL-QPSR 3–4 (1979), 2–3 (1980), and 1 (1981); M. Rothenberg, Proc. Conf. Vocal Fold Physiol., Kurume (1980)] and continues with attempts of dynamic parameterization of glottal source data. A two-stage derivation of the glottal source, its main pulse form and its excitation function is performed. [The work has been supported by grants from the Bank of Sweden Tercentenary Foundation and the Swedish Board for Technical Development.]
Cross-linguistic differences in fundamental frequency perturbation induced by voiceless unaspirated stops
Authors: Caisse Michelle
Published: October 2005

That fundamental frequency (F0) is lower following voiced stops that voiced ones is assumed to be an automatic consequence of the articulatory gesture which yields the voicing distinction in stops. In this study it is shown that this F0-perturbatory effect differs cross-linguistically within the VOT category voiceless unaspirated. F0 was measured after initial voiceless unaspirated stops ([bů, dů, gů]) in naturally produced English tokens, and similar data was collected from other languages. The results show that F0 is low after these stops compared to F0 following [p, t, k] or [ph, th, kh]. This result implies that the glottal gesture differs for [bů, dů, gů] and [p, t, k], even though both are voiceless and unaspirated. This implication was tested by reducing intra-oral air pressure during the production of stops. The results support the claim that the mechanism of production differs for the two types of voiceless unaspirated stops.