bluuebunny/crossref_metadata_2025 huggingface dataset:
Accuracy of formant frequency estimation by spectrograms and by linear prediction analysis
Authors: Monsen R. B.
Published: October 2005

The accuracy of spectrographic techniques and of linear prediction analysis in measuring formant frequencies was compared. The first three-formant frequencies of ninety synthetic speech tokens were measured by three experienced spectrographic readers and by linear prediction analysis. The synthetic speech tokens were made by parallel synthesis and were chosen to represent a wide range of formant bandwidths, frequencies, and fundamental frequencies. For fundamental frequencies between 100 and 350 Hz, both methods are accurate to within approximately ±60 Hz for both first and second formants; the third formant can be measured with the same degree of accuracy by linear prediction, but only to within ±120 Hz by spectrographic means. For linear prediction analysis, accuracy does not decrease with increasing fundamental frequency, although the accuracy of both methods decreases greatly when fundamental frequency is 400 Hz or greater. These limits of measurement appear to be within the vicinity of difference limens for formant frequencies. [Supported by NINCDS Grant NS03856.]
Voiced/unvoiced decision by a clustering procedure
Authors: Espesser Robert
Published: October 2005

Previous work based on a pattern recognition/classification approach need either a-priori information or a training set of data [L. R. Rabiner, IEEE Trans. ASSP-24, 201–212 (1976)], [L. J. Siegel, IEEE Trans. ASSP-27, 83–89 (1979)]. A voiced/unvoiced classification approach which avoids these problems is presented. Energy, zero-crossing rate, LPC normalized error are measured every 10 ms over the speech segment. Feature vectors in this three-dimensional space are then classified in two groups by an iteration reallocation procedure clustering. Mahalanobis distance is used for allocation, and is recomputed at each iteration of the clustering algorithm. Initial centers and centroids of the final clusters must satisfy certain constraints. Several partitions are computed for a speech segment and the best one according to some defined criteria is retained. Mean error rate (without any smoothing algorithm) is about 3.5% for five female and five male speakers.
Lecture and laboratory demonstrations for general acoustics
Authors: Richarz W. G.
Published: October 2005

Several lecture demonstrations, as well as apparatus used in the undergraduate laboratory have been assembled. Some possess an aeroacoustics flavor; rotor-stator interference is demonstrated visually as well as audibly. A rotating point source illustrates the nature of the Doppler shift as well as the origin of propeller noise. There are also more traditional examples designed to acquaint the student with the decibel scale, resonant systems, and the hearing mechanism.
Aging, frequency selectivity, and the effective use of amplification
Authors: Hannley M. , Yee J.
Published: October 2005

To examine the hypothesis that impaired frequency selectivity accompanying sensorineural hearing impairment compromises the ability of hearing-impaired listeners to realize benefits in speech intelligibility from hearing aids, we conducted two experiments. In the first experiment psychophysical tuning curves were generated for elderly listeners whose hearing deficit was related to aging. In the second experiment the same subjects were administered the California Consonant Test (CCT) and PB word intelligibility lists under three listening conditions: (1) no amplification; (2) flat frequency response amplification; and (3) high-frequency emphasis amplification. The results of the two experiments, their interrelationships, and applicability to hearing aid usage will be discussed.
Tactile reception of vocal tract shapes: A preliminary study
Authors: Becker Robin D. , Fluster Matt , Goldstein Moise H.
Published: October 2005

Six naive subjects were trained on identification and discrimination of four different vocal tract shapes corresponding to the Russian vowels /i/, /u/, /ɑ/, and /o/ [G. Fant, Acoustic Theory of Speech Production (1960)]. The stimuli were presented to the index finger by means of a 6 × 24 vibrotactile array (Optacon). The long axis of the vibrator represented distance from the glottis, and was divided into eight sections. The area of each section was quantized to one of six possible levels. A “line” display was used so that the number of active vibrators was constant for all stimuli. Overall duration of the presentation was 375 ms, with a steady-state portion of approximately 200 ms. There were five one-half hour training sessions per week. The training sessions extended over four to six weeks. The subjects were not prescreened. Only one token per shape was used in the study, so that an upper bound on performance might be established. Three subjects achieved virtually perfect performance by the end of the training period. [Work was supported by NSF.]
Evaluation of an auditory prosthetic device for the profoundly deaf
Authors: Scilley P. L. , Frost B. J.
Published: October 2005

A vibrotactile auditory prosthetic device was shown to help the deaf: (1) identify environmental sounds, (2) improve speech production, (3) identify English words spoken “live voice,” and (4) receive information complementary to that obtained through lipreading. The device consisted of 1613 octave filters, with center frequencies ranging from 200–8000 Hz. The output of each channel was detected and after logarithmic amplification outputs were transmitted to a 16-channel linear solenoid array placed on the subject's ventromedial forearm. One artificially deafened subject learned 150 words in 55 h and was able to generalize this learning to unfamiliar speakers. The vast majority of words were identified correctly over 70% of the time. Most words that were initially difficult to discriminate were identified correctly as training time increased. A profoundly deaf 13-year-old learned to identify 50 environmental sounds in 12 h using the device. Discrimination of phonemes within lipreading mouth movement groups increased from 39% in the lipreading condition to 88% in the tactile condition. Finally, the intelligibility of the subject's speech improved 104% when vocalization were made with vibrotactile feedback.
Vibrotactile perception of suprasegmentals: A comparison of single-channel and multichannel aids
Authors: Beachler Cindy A. , Carney Arlene Earley
Published: October 2005

The tactile percept of a speech stimulus is determined by the design of the vibrotactile aid used to deliver the stimulus. Single-channel vibrotactile aids are placed at a single site on the body; the perception of vibration frequency is limited by the resolving power of the skin. Multichannel aids perform a frequency-to-place transformation; the value of the input frequency corresponds to a particular place on the body. Two vibrotactile aids, one single- and one multichannel, were compared with regard to their ability to transmit three supresegmental aspects of speech: number of syllables, syllabic stress, and rising-falling intonation. Speech stimuli were chosen both on the basis of lexical syllabification and stress, and according to their envelopes. Subjects were pretested and subsequently trained with either the single- or multichannel device to recognize these suprasegmentals. Results indicate that these instruments transmit syllabic number and stress in a substantially different manner. These data are discussed with regard to the applicability of these devices to speech perception and production training for the hearing impaired.
A study on sound field in irregularly shaped rooms by means of an improved ray-tracing technique
Authors: Banedetto Giuliana , Spagnolo Renato
Published: October 2005

A ray-tracing technique is suggested for studying the sound field in enclosures of any shapes and plane boundaries. The sound field is represented by equal-energy rays, their point of origination and direction being preselected using a Monte Carlo method. The life history of each ray is calculated assuming geometrical reflections at bare walls but taking into account diffraction at edges and corners. Each time a ray hits an absorber its energy is diminished by a factor depending on the absorption coefficient of the material. The dependence of absorption coefficient from incidence angle is taken into account in the case of “locally reacting” materials. Also the air absorption is considered as a function of temperature and humidity, above 1000 Hz. The reflection process is continued until the energy content of the ray falls below a predetermined fraction of its initial value. The model allows to study space and time distribution of sound energy, distribution of mean free paths, probability of collision on the walls. The application to two large reverberant rooms of the Acoustical Department of I.E.N.G.F. gave results in good agreement with experimental measurements.
Discriminate acoustic cues in vowel sequence perception
Authors: Kerivan J. E. , Alfonso Peter J. , Espinoza-Varas Blas
Published: October 2005

In previous reports we have described the importance of smooth pitch continuities between adjacent first formants of four synthetic vowels /i,æ,a,u/for vowel temporal order identification [Kerivan and Alfonso, J. Acoust. Soc. Am. Suppl. 1 66, S86 (1979)]. In a followup study we asked trained listeners to discriminate vowel sequences which contained differences along the following physical parameters: (1) vowel permuted order, (2) vowel and intervowel durations ranging from 15–120 ms, and (3) pitch or loudness fundamental frequency contours, natural versus flat. Using a variable standard the task was to decide whether a “comparison” sequence was in any way different from a “standard” sequence. Preliminary results indicate that listeners can reliably discriminate (d′ = 1.0) natural from flat pitch contours of vowels in sequence at vowel durations as brief as 30 ms. They can also discriminate placement of a 15 or 30 ms intervowel duration in a given sequence at similar performance levels. Vowel permuted order effects were minimal, a finding that sharply contrasts with identification of vowels in sequence. The temporal processing capabilities of trained listeners appear sufficient to discriminate dynamic ms-level changes in pitch, loudness and duration cues of very brief vowel spectra. [Work partially supported by an NINCDS NIH grant awarded to Haskins Laboratories and the University of Connecticut Research Foundation].
Received signal characteristics from long-range transmissions of a cw tonal in the North Atlantic
Authors: Heine J. C. , Hamblen W. R. , Shepard G. W. , Smith P. W.
Published: October 2005

The statistical properties of 68-Hz signals, as received at nominal ranges of 260 and 570 nmi, were calculated and compared to properties expected of a Gaussian channel. The received signal time series corresponded to cw transmissions from radial tows of 30 nmi centered at each of the nominal ranges. The projector was towed at a depth of 400 ft, and the receiving hydrophone was located at the reciprocal depth. The experiment was performed in July of 1979 at a location east of Bermuda. Our analysis of signal envelope and intensity statistics showed that: the density functions corresponded closely to exponential; that envelope level crossings were approximately Rayleigh distributed; and that the autocovariance of interest could be approximated from the radial tow speed of the projector and a Gaussian function with spatial coherence interval given by 89λ/Hkm, where λ is the sound wavelength and Hkm is the depth excess of the channel in kilometers. [Work supported by Naval Underwater Systems Center.]
The origins of the cochlear efferent bundle of Rasmussen in primates
Authors: Strominger Norman L. , Silver Steven M. , Truscott Timothy C. , Goldstein Jerome C.
Published: October 2005

The spatial distribution of neurons emitting fibers of the olivocochlear bundle was determined by injecting horseradish peroxidase into the round window in a series of new and old world monkeys. Animals were perfused 24–28 h later. Sections through the pons and medulla were reacted with tetramethyl benzidine and counterstained with thionin and/or neutral red. Perikarya containing reaction product numbered over 800 in one case. The greatest concentration of labeled cells was located in the dorsal periolivary area intermediate between the dorsal margins of the lateral and medial superior olivary nuclei. Approximately 400 cells were ipsilateral to the injection, opposed to 100 contralaterally. The dorsolateral periolivary area contained over 100 labeled cells ipsilaterally, and only about one-third as many contralaterally. While 95 labeled cells occupied the region of the contralateral medial preolivary nucleus, about two-thirds as many labeled cells were found in the comparable ipsilateral nucleus. Although a few labeled neurons were present bilaterally in the lateral preolive and the lateral superior olivary nucleus, no labeled cells were found in the region of the dorsomedial or ventromedial periolivary nuclei (medial to the medial superior olive). [Work supported by the Deafness Research Foundation.]
Sound scattering from objects with sharp corners
Authors: Wall D. J. N. , Varadan V. V. , Varadan V. K. , Neubauer W. G.
Published: October 2005

The null field method with a suitable set of basis functions is employed to study acoustic wave scattering from objects with sharp corners. Numerical results will be presented for square, rectangular and intersecting circular cross sections and will be compared with other existing methods and experiments. The results indicate that there is a significant difference in the frequency dependence of the scattered field of objects with and without sharp corners.
A “cochlear antenna”: Diffraction and focusing by active, mechanically resonant outer hair cell stereocilia
Authors: Schweitzer Allan , Bialek William
Published: October 2005

Detection at (pure-tone) auditory thresholds is shown to require the lossless delivery of travelling wave power to the single receptor cell of appropriate CF. Present theories of cochlear mechanics cannot acount for such “focusing”; signal power is instead dissipated over the effective width of the travelling wave. Resolution of this paradox is possible if outer hair cell stereocilia are active elements in a “cochlear antenna”: mechanically tuned stereocilia (Schweitzer and Bialek, November 1980 ASA meeting) will scatter the travelling wave, and may thus act to diffract and focus acoustic power. Focusing “gains” of 40–50 dB are realized. Principles derived from recent theories of broadband (radio) antenna performance may be expressed in cochlear design. Critical band phenomena and psychophysical integration times may have a simple interpretation in this context. Regulation of focusing is possible if efferents effect outer hair cell mechanical activity. Threshold microstructure will arise if diffracting elements are perturbed, or deviate from ideal position. Experimental tests of the hypothesis will be proposed.
Pitch of narrow-band signals
Authors: Stover L. J. , Feth L. L. , Burns E. M.
Published: October 2005

This study was designed to investigate the pitch of complex signals contained within one critical bandwidth. Four well-trained listeners, with normal hearing, were asked to adjust the frequency of a pure tone until it matched the pitch of various multicomponent periodic signals. These complex tones were centered at 1000 Hz with bandwidths from 10–50 Hz. At each bandwidth, the number of components ranged from two to twenty. In a control condition, each subject also adjusted the frequency of the variable tone until it matched the pitch of a single tone set at 1000 Hz. After extensive practice, a total of twenty matches to each test signal was obtained for each subject. Repeated matches were distributed throughout several one-hour test sessions held on different days. Generally, the average value of the frequency of the adjusted tone did not differ significantly from the center frequency for most of the complex signals investigated. Two-component complexes appeared to be resolved at bandwidths much narrower than the accepted critical band values, however, because several listeners consistently matched the pure tone to two different frequencies. One of the four subjects actually reported multiple pitches more often than single pitches for the majority of the test signals. The results will be discussed in light of current theories of pitch encoding within the auditory system. [Supported by grants from NINCDS.]
Complex pitch perception after callosal section: Further evidence for a right hemisphere mechanism
Authors: Sidtis John J. , Gazzaniga Michael S.
Published: October 2005

It has recently been suggested that right hemisphere auditory function provides a mechanism for complex pitch perception. This possibility was examined in two patients who underwent surgical section of the corpus callosum. Both patients were right handed, had bilaterally normal hearing, and were assessed to have left hemisphere language dominance. Each patient was tested using the Complex Tone Test, which consists of 112 trials in which a dichotic pair of 550-ms square wave stimuli are followed after 1 s by a binaural probe item. Subjects responded manually, indicating whether or not the probe matched either dichotic item. Both patients revealed above average accuracy on left ear stimuli, but performance on right ear stimuli that was significantly worse than chance. This pattern of results is similar to that found for dichotically presented speech stimuli, but in the opposite direction. These data add further support to the claim that the right hemisphere provides a mechanism for complex pitch perception. [Work supported by USPHS grant number 2 R01 NS15053-02 and the Alfred P. Sloan Foundation.]
Physiological and anatomical studies relevant to considerations of sound localization in mammals
Authors: Merzenich M. M.
Published: October 2005

Recent studies of the basic organization and response properties of neurons of auditory nuclei and auditory cortical fields bear important implications for considerations of how sound localization behavior is a product of these systems. First, a series of largely parallel, functionally distinct projection subsystems have been identified. Some general conclusions as to their individual roles in auditory behavior can be drawn, given response properties of neurons and connections within. There are sheetlike subdivisions oriented orthogonally to isofrequency contours, in the central nucleus of the inferior colliculus, the ventral division of the MGB and in several auditory cortical fields. They are completely interconnected from level to level. In cortical fields and in the central nucleus, these subdivisions have been demonstrated to be response specific. Some would appear to be involved in specific aspects of sound localization, others not. Second, it now appears likely that low-frequency pitch sensation is decoded within the medial superior olive, a nucleus long implicated in sound localization. The conjoint information processing accomplishments in these two psychoacoustic dimensions and some of its functional implications will be discussed. [Supported by NIH Grant NS-10414.]
Evidence against a mediating role of cyclic AMP in the ototoxic action of loop diuretics
Authors: Thalmann I. , Paloheimo S. , Thalmann R.
Published: October 2005

We have previously reported that adenylate cyclase of the stria vascularis (SV) is strongly inhibited by ethacrynic acid (EA) and furosemide (FU) [Paloheimo and Thalmann, Arch. Oto. Rhino. Laryngol. 217, 347–359 (1977)]. In fact, concentrations of EA and FU inhibiting the enzyme in vitro closely correspond to those affecting the EP when the drugs are perfused through the perilymphatic space. To test whether the in vitro effect upon the enzyme is also present in vivo, we perfused EA perilymphatically for 15 min (10−3 M). cAMP of the SV was reduced by 27% (p < 0.05); however, ATP was also reduced, suggesting unspecific effects. When EA was applied intravenously (50 mg/kg) and the EP allowed to drop to −10 mV, no significant changes in cAMP and ATP were seen. These data cast doubt upon a mediating role of cAMP in the specific ototoxic effects of EA; they are in line with the observation that in kidney the action of loop diuretics is upon the luminal side of the tubules, whereas adenylate cyclase is present at the contraluminal side. [Supported by NIH.]
Effects of backward masking on human auditory brainstem responses
Authors: Rizzo Stephen R. , Greenberg Herbert J. , Gutnick Howard N.
Published: October 2005

The purpose of this study was to determine whether backward masking (BWM) occurs in the brainstem of the human central auditory nervous system (CANS). Separate experiments were conducted for the psychophysical and electrophysiological conditions. The psychophysical experiment established the BWM threshold shift functions between the click only (CO) and the click-masker (CM) conditions. Four subjects determined their BWM thresholds at Δt's of −1, −5, −10, −25, and −100 ms and at masker levels of 50, 65, and 80 dB SPL. For each subject, more BWM was observed at short Δt's (−10 to −1 ms) than at long Δt's (−100 to −10 ms). As the intensity of the masker increased there was an increase in the amount of BWM. This was true for Δt's less than −10 ms. For longer intervals, the effect of masker level on threshold shift was smaller. The electrophysiological experiment consisted of collecting auditory brainstem responses (ABR) to the same experimental conditions used in the psychophysical experiment. The intensity of the click was set at the psychophysical BWM threshold levels established by the 65-dB masker. The ABR conditions were designated CO, CM50, and CM80 as determined at Δt's of −1, −5, and −10 ms. The data were analyzed in terms of latency shift between CO and CM responses for waves I, III, and V. Latency comparisons of waves I, III, and V from CO and CM80 conditions at −1 ms (Δt) revealed an increase in latency. At −5 ms, the latency shift was smaller. However, at −10 ms, CO responses produced longer latencies than those latencies recorded for CM80 responses. Latency comparisons made between CO and CM50 responses showed no latency effect. These results suggest that under these experimental conditions, BWM occurs, in part, at the level of the brainstem.
Phonetic perception of sinusoidal signals: Effects of amplitude variation
Authors: Remez Robert E. , Rubin Philip E. , Carrell Thomas D.
Published: October 2005

Naive listeners, when instructed to listen for a sentence, are capable of transcribing the phonetic message of acoustic signals consisting solely of time-varying sinusoids. These unnatural-sounding signals mimic the pattern of formant center-frequency and amplitude variation over the course of polysyllabic, semantically normal utterances. To what exent does amplitude variation over time contribute to intelligibility? Our present investigation tested the hypothesis that listeners derive some information about syllable patterns from amplitude variation alone, and may therefore use semantic and other contextual constraints to deduce prosodically appropriate portions of the message in the tonal stimulus. We compared phonetic and syllabic intelligibility in four conditions of sinusoidal patterning: (1) normal amplitude and frequency variation, (2) normal frequency variation with constant amplitude, (3) frequency variation with a misleading amplitude contour, and (4) normal amplitude variation with no frequency variation. These results are discussed in the framework of phonetic perception and in terms of current theories of the perception of fluent speech. [Supported by Sigma Xi, NICHD and NIH.]
Perceiving vowels from ‘flat spectra’
Authors: Summerfield Quentin , Foster John , Gray Stuart , Haggard Mark
Published: October 2005

To determine whether the first temporal derivative of spectral intensity carries information which listeners can use to perceive speech, stimuli were synthesised in which 1000 ms of the complement of a vowel (a spectral pattern with valleys replacing formant peaks, and vice versa) preceded a 25-ms amplitude transition during which the valleys were filled, creating a flat spectrum lasting 275 ms. These flat spectra were perceived as the vowels whose complements preceded them, suggesting that patterns of spectral amplitude change, dissociated from spectral peaks, can be informative of vowel identity. Subsequent experiments, however, have shown first that amplitude transitions leading into flat spectra are more perceptually potent than are transitions out of flat spectra, and secondly that the appropriate vowel is perceived both when complements directly abut flat spectra with instantaneous amplitude transitions, and also when upto 512 ms of silence intervene between complements and flat spectra in place of amplitude transitions. Thus, the effect appears to owe more to auditory contrast than to sensitivity to amplitude change, per se, but nonetheless emphasises the extent of auditory sensitivity to spectral differences and hence the importance of transient and transitional components in speech.
Jet noise spectra at low Reynolds number
Authors: Long Dean , Lent Tom van , Arndt Roger E. A.
Published: October 2005

The current interest in coherent structures in turbulent flows and their possible influence on acoustic radiation is the impetus for a detailed examination of the acoustic field surrounding a turbulent jet at low Reynolds numbers. In this study the acoustic characteristics are examined over a Reynolds number range of 16 000 to 148 000 at a constant Mach number of 0.52. This is accomplished using a series of geometrically similar nozzles ranging in size from 1.3 to 12.2 mm. The remarkable conclusion is that the spectral content changes significantly below a Reynolds number of about 1 × 105. The shift in peak frequency with increasing emission angle (the so-called reverse Doppler shift) characteristic of high Reynolds number jets is not observed. In fact, the spectra are observed to peak at a Helmholtz number, fd/ɑ0, of about 0.08, independent of emission angle. This result is discussed in light of recent findings concerning the role of initial shear layer instabilities on the subsequent development of turbulent flow. [Work supported by AFOSR.]
Experimental verification of finite element model for vibration of a narrow gap, fluid coupled, concentric flexible cylinders
Authors: Chu M. L. , Brown S. J.
Published: October 2005

The influence of a fluid environment on the dynamic characteristics of structure has been of interest for hundreds of years. Analyses have varied from classical formulations, numerical discretization, or experimentation. In this study, both experimental and numerical analysis by Finite Element (FE) are conducted in an attempt to quantify the effects of the actual or real fluid versus the idealized nonviscous fluid (as assumed in the FE) as a function of cylinder dimensions. The analytical model employed 3D linear finite element displacement technique on a plate structure and eight-node brick fluid elements. Solutions obtained are for undamped, linear elastic and small displacement response of the system. The FE method's accuracy and applicability is demonstrated by comparison of numerically computed natural frequencies and mode shapes to experimental data. Numerical solution sensitivity to parameter variations such as cylinder wall thickness, gap width and boundary conditions, and the relative significance of nonlinear and viscous effects observed in the experimental results are discussed. [Support by the Babcock and Wilcox Company and the Clinch River Breeder Reactor Project is acknowledged.]
Standardizing the acoustical factors in listening tests
Authors: Toole F. E.
Published: October 2005

Measurements notwithstanding, listening tests remain the final arbiter of sound quality available from audio system components. The acoustical properties of the listening room and the locations of loudspeakers and listeners are significant factors in the results of such listening tests. Previous attempts to reach international agreement on standardizing some of these variables have met with little success. Recently, through a working group of the IEC, progress has been made, although there remain certain parameters that will be decided more on geographic than acoustical grounds. The rationale of the new proposals will be discussed and experiments to test the procedures will be described.
A new model for a noise barrier on a rigid ground plane
Authors: Nobile Matthew A. , Hayek Sabih I.
Published: October 2005

Current models for the straight-edge noise barrier in the presence of the ground utilize the exact half-plane diffraction solution and replace the ground by source and receiver images. Although this model is generally successful, it does not account for “corner effects” (where the barrier meets the ground) which may become significant as the barrier height decreases. In this alternative model, the barrier of height h is replaced by a strip of width 2h, while the ground is replaced by a source image only. The total field at the receiver is then the sum of the diffracted field from the source and the source image, respectively. Since a strip is an elliptic cylinder of unity eccentricity, there exists an exact solution in terms of Mathieu functions. The advantage over the half-plane model is that mutual coupling between the edges of the strip (in essence, the above “corner effects”) is inherently accounted for. Results for several practical cases will be compared to existing model predictions and to recent experimental data.
Fluctuations in sound propagation: Implications for animal vocalizations
Authors: Quine Douglas B.
Published: October 2005

Atmospheric turbulance causes rapid fluctuations in the range of sound propagation from a constant sound source. The magnitudes of these fluctuations suggest that they could be a significant factor in the evolution of animal vocalizations. However, there are little field data on how these fluctuations vary at different times of day or in different habitats or frequency ranges. I have measured the second-to-second fluctuations of sound propagation in sites in Maine, New York, and Panama. My data implies that, for long distance vocalizations, animals should use different frequencies in forest and field habitats. Further studies, at many different times of day in both field and forest habitats, revealed that the magnitude of these fluctuations follows a daily pattern. These patterns differ in forest and field habitats. While most studies of environmental acoustics and their effects on animal communication are concerned with the range of sound propagation, the stability of sound propagation is also important. Some characteristics of long distance vocalizations may be adaptations to fluctuations in sound propagation. [Partially supported by NSF.]
Experimental and theoretical comparisons of the normal coordinate, Helmholtz-Kirchhoff, and Macdonald solutions for diffraction by a half-plane; application to a finite barrier
Authors: Jebsen Gary M. , Medwin Herman
Published: October 2005

The Biot-Tolstoy (BT) normal coordinate solution to the problem of diffraction by an infinite half-plane is compared to the usual approach based on the Helmholtz-Kirchhoff integral formulation. The two are shown to differ significantly for the simple case of coincident source and receiver (backscatter), with the advantages of the BT formulation shown by laboratory measurements. The application to shadowing by a barrier is discussed and it is found that the “image in the barrier” which is part of the Macdonald method does not have to be added to the BT solution. The time domain BT solution is used to construct the diffracted pressure field in the shadow near a barrier corner (infinite quarter-plane). The use of multiple diffractions in the time domain to predict the effect of finite barrier thickness is described. [Work supported by ONR.]
Varieties of musical cognition: A music theorist's view
Authors: Benjamin William E.
Published: October 2005

This paper develops the elements of a musical epistemology. The starting claim is that perception is inappropriate as a category of musical behavior, and that musical perception is, in fact, merely the demonstration of musico-cognitive competence. Three stages of musical behavior, which may be ordered to correspond to degrees of musical competence, are identified: one of informed listening, a second of interpretation, and a third involving the creative production of music. Musical competence is further delineated, in these stages, with respect to two levels at which musical cognition takes place, one grammatical and the other stylistic. This delineation leads to a discussion of the cognitive status of various experimental musics of the twentieth century. Finally, an attempt is made, in the light of ideas basic to the presentation, to define appropriate roles for scientific disciplines in the study of musical cognition.
A neural-counting model incorporating refractoriness and spread of excitation: Application to intensity discrimination and loudness estimation for variable-bandwidth noise stimuli
Authors: Teich Malvin Carl , Lachs Gerard
Published: October 2005

An energy-based neural-counting model, incorporating refractoriness and spread of excitation, has recently been applied to intensity discrimination and loudness estimation for pure-tone stimuli [M. C. Teich and G. Lachs, J. Acoust. Soc. Am. 66, 1738–1749 (1979); G. Lachs and M. C. Teich, J. Acoust. Soc. Am. 69, 774 (1981)]. We now examine the behavior of this model when the stimulus is variable-bandwidth noise rather than a pure tone. The theoretical predictions are in good agreement with psychophysical data for intensity discrimination [C. E. Bos and E. deBoer, J. Acoust. Soc. Am. 39, 708–715 (1966)] and loudness estimation [B. Scharf, “Loudness,” in Handbook of Perception, Vol. IV, Hearing, edited by E. C. Carterette and M. P. Friedman (Academic, New York, 1981)], pp. 187–242. The functional dependence of the theoretical intensity discrimination and loudness curves on the noise bandwidth is established by the excitation pattern along the basilar membrane. This pattern, in turn, is principally determined by the tuned-filter characteristics of the neural channels in conjunction with the spectral properties of the stimulus. We appeal neither to stimulus intensity fluctuations nor to critical bands in carrying out our analysis. [Work supported by NSF.]
Loudness adaptation induced by an intermittent tone
Authors: Botte Marie-Claire , Canévet Georges , Scharf Bertram
Published: October 2005

An intermittent tone in one ear often causes a decline in the loudness of a steady tone in the other ear, a decline that increases over time. Must the intermittent tone be in the contralateral ear in order to induce adaptation? By the method of successive magnitude estimation, we measured the loudness of a steady 1-kHz tone in the presence of an intermittent tone in the same ear or in the contralateral ear. Both tones were at 60 dB SPL. The intermittent tone was on for 200 ms and off for 200 or 800 ms. Ten listeners showed a 50%–60% reduction in loudness after 2 min when the intermittent tone was contralateral and a 20%–30% reduction when it was homolateral. Loudness remained depressed for at least 30 s after termination of the intermittent tone. Part of the homolateral reduction may have resulted from masking, but part probably resulted from the same interaction that occurs in contralaterally induced adaptation. Thus, intermittency alone may induce some loudness adaptation, but it induces significantly more when combined with interaural interactions. [Work supported by NIH.]
On the uniqueness of Doppler tracking
Authors: Shensa M. J.
Published: October 2005

Doppler tracking is a common procedure which can be implemented by a multitude of techniques. Also, it is well known that in the absence of a velocity change in the receiver, the solution track is not unique. This paper examines the solution set of the Doppler tracking problem, presenting several new results and placing some of the lore in a more rigorous setting. In particular, it is shown that (in two dimensions) for an isovelocity receiver the solution is determined up to a rotation and reflection in the receiver’s coordinate system. If a single velocity change is present, then there are exactly two solutions. Generalizations to three dimensions are also provided.
The role of onsets in perception of stop place of articulation: Effects of spectral and temporal discontinuity
Authors: Chang Sun , Blumstein Sheila E.
Published: October 2005

This study explored the role of onsets on the perception of place of articulation by investigating the effects of later-occurring transitions on the perceptual information residing in the onsets. In particular, the perceptual effects of spectral discontinuities introduced after the burst and early transition of stimulus onset were explored. Identification responses for place of articulation as well as judgment responses for quality and number of syllables were obtained for synthetic CV syllables in which two types of discontinuity were introduced by (1) inserting a silent interval between the stimulus onset (burst and following 3 glottal pulses) and remaining transition and steady-state information, and (2) replacing portions of the transitions and steady-state following the onset with a silent interval. Silent intervals ranged between 8.1 and 56.7 ms. All the stimuli were consistently identified, regardless of the duration of the silent interval or the type of discontinuity introduced. Subjects perceived a discontinuity when the silent interval was greater than 16 ms. These results support the view that the perceptual analysis of stop consonants may be defined in terms of a temporally-defined window encompassing the burst and early transition information and further confirms the importance of such onsets as determinants of perception of place of articulation.
Spectral estimation of space–time signals with a DIMUS array
Authors: Tuteur Franz B. , Presley Joe A.
Published: October 2005

The DIMUS (digital multibeam steering) technique is a method for processing the output signals of the elements of a receiving array to permit the simultaneous generation of a large number of beams. This paper deals with the estimation of the spectral density of the signal received by a DIMUS array processor. It is shown that there is substantial frequency distortion introduced into the spectral estimate by the finite size of the array. Also the hard clipping which is part of the DIMUS techniques introduces a nonlinear distortion manifested by a filling in of spectral valleys. Techniques for correcting both of these effects are proposed.
Effect of engine noise on aircraft wing laminar boundary-layer stability
Authors: Mangiarotty R. A.
Published: October 2005

High-intensity acoustical disturbances can cause transition of controlled laminar flow. An investigation was made to determine whether main propulsion engines installed on an aircraft wing would cause excessive transition of laminar to turbulent flow. A method was developed for analyzing the influence of noise on the stability of a controlled laminar boundary layer, based upon the Tollmien–Schlichting traveling wave solution of the Orr–Sommerfeld equation and some wind tunnel experimental data. It is concluded that wing-mounted, high-bypass-ratio engines with sufficient acoustic treatment for controlling turbomachinery noise would not cause excessive loss of wing laminar flow. Additional analytical and experimental work is needed, however, to improve the accuracy of engine nearfield noise prediction, and the need to improve the proposed models to account for the acoustic transfer function for predicting transition.
Transient field of a baffled planar piston having an arbitrary vibration amplitude distribution
Authors: Harris Gerald R.
Published: October 2005

A theoretical model is presented for evaluating the transient velocity potential and pressure fields radiated by a pulsed planar piston set in an infinite rigid baffle and having an arbitrary spatial velocity distribution. The method is based on the development of a generalized spatial impulse response function which describes the velocity potential, either at a point or averaged over a finite receiving surface, resulting from the velocity impulse excitation of a uniformly or nonuniformly vibrating piston source. For the specific case of a circular source and receiver this function is plotted using several source distributions and receiver sizes. Then corresponding plots are presented for two piston velocity waveforms: a Gaussian pulse and a Gaussian-modulated sinusoidal burst. These plots are compared and the effects of a nonuniformly vibrating source and finite receiver are discussed. Lastly, a previous solution by Schoch, in which the field of a rigid piston is separated into geometrical and boundary diffraction waves, is extended to account for a nonuniform source, and the relationship of this more general result to the present approach is illustrated.
Configurations with finite numbers of scatterers—A self-consistent T-matrix approach
Authors: Varadan V. V. , Varadan V. K.
Published: October 2005

A self-consistent scheme is developed to analyze the scattering of waves by a configuration containing a finite number of scatterers. The T matrix obtained using the null field equations is used to characterize the response of a single scatterer to arbitrary excitation. Translation theorems for the spherical basis functions are used not only to express the T matrix of individual scatterers with respect to a common coordinate system, but also to take care of multiple scattering between the scatterers. The formulation given is equally applicable for the scattering of acoustic, electromagnetic, or elastic waves. The scatterers may have different shapes and be of different types; e.g., sound soft, sound hard, or permeable in the acoustic case. Numerical results are presented for the case of two elastic cavities in a solid.
Speeds and differential equations of large deformation waves: Hyperelastodynamics and hypoelastodynamics
Authors: Ziv M.
Published: October 2005

Speeds and numerically integrable differential equations of waves, known as the wave characteristics formulation, are derived for large amplitude dynamic deformation in hyperelastic and hypoelastic solids. Dynamic hyperelasticity is formulated in Eulerian and Lagrangian descriptions for an arbitrary strain energy function. Dynamic hypoelasticity is formulated in Eulerian description for the case of elastic-rate independent perfectly plastic material flow applicable also to soils. The method for obtaining the wave characteristics formulation is based on Hadamard’s surface discontinuity relations made to be compatible with the geometric description of hyperbolic partial differential equations. In addition to the resultant wave equations and wave speeds for nonlinear motions, exact infinitesimal ideal elastodynamics is also formulated. An immediate application of this study is in the numerical integration of boundary-value problems involving wave propagation.
Effects of multidimensional stress on radially polarized piezoelectric ceramic tubes
Authors: Tims Allan C.
Published: October 2005

This report is concerned with the effects of multidimensional compressive stress on commerical ceramic materials produced under MIL–STD–1376 (SHIPS), types I, II, and III. The effects of high stress on the acoustic sensitivity M0 and on the dielectric constant k33T of radially-polarized, gas-backed, capped ceramic tubes of various diameter-to-wall thickness ratios and material types are given.
The lyriform organ of the orb-weaving spider A
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s: Vibration sensitivity is altered by bending the leg
Authors: Finck Alfred
Published: October 2005

The patella of the spider A. sericatus contains a lyriform organ which responds to vibrations applied to the tip of the leg. Single unit activity indicates that this sense organ has an elevated threshold when the leg is bent toward the cepalothorax. The leg appears to function like a mechanical attenuator in which its position determines the efficiency of stimulating the lyriform organ. This system would allow spiders to exert control over the vibrational input by merely varying the position of their legs.
Reply to the book review by James F. Curtis of S
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r [J. Acoust. Soc. Am. 68, 1908 (1980)]
Authors: Borden Gloria J.
Published: October 2005

It is felt that the reviewer of the book [G. J. Borden and K. S. Harris, Speech Science Primer (Williams & Wilkins, Baltimore, 1980)], has to a certain extent misunderstood the nature of the program for which the book was developed. This is clarified in the present note.
Comments on ’’Correlation of the phase and amplitude fluctuations between direct and ground-reflected sound’’ [J. Acoust. Soc. Am. 68, 297–302 (1980)]
Authors: Clifford S. F. , Wandzura S. M.
Published: October 2005

Some variations have been encountered in the article by G. A. Daigle.
Elastic wave invariants for acoustic emission
Authors: Pardee W. J.
Published: October 2005

It is shown that there are four conserved properties of an elastic wave in an infinite isotropic plate: the energy, the two components of wave momentum parallel to the surface, and wave angular momentum normal to the surface. All four invariants are volume integrals of quadratic functions of the spatial (Eulerian) coordinates. The canonical energy-momentum density tensor and the orbital, spin, and total angular momentum density tensors are constructed and sufficient conditions for their conservation are demonstrated. A procedure for measuring the wave momentum of a surface wave is proposed. It is argued that these invariants are likely to be particularly useful characterizations of acoustic emission, e.g., from a growing crack. Experimental tests are proposed, and possible applications to practical monitoring problems described.
Transient streaming potential measurements on fluid-saturated porous structures: An experimental verification of Biot’s slow wave in the quasi-static limit
Authors: Chandler Richard
Published: October 2005

The time behavior of the streaming potential is identical to that of differential fluid pressure when local laminar flow is maintained and electromagnetic relaxation is not important. The time evolution of the streaming potential waveform resulting from the application of a pressure pulse to one face of a cylindrical water-saturated porous structure is found to depend on the elastic properties of the fluid and rock frame and on the porosity and permeability of the core. The analysis of this quasi-static flow based on Biot’s soil consolidation work [Biot, J. Appl. Phys. 12, 155 (1941)] and advanced by J.R. Rice and M.P. Cleary [Rev. Geophys. Space Phys. 14, 227 (1976)] is completely equivalent to that obtained from Biot’s slow wave model [M.A. Biot, J. Acoust. Soc. Am. 28, 168 (1956)] in the limit of zero frequency. Both analyses result in a homogeneous diffusion equation in pore pressure (and streaming potential) where the diffusivity is expressed in terms of the bulk moduli of the fluid and solid constituents, bulk and shear moduli of the solid frame, fluid viscosity, porosity, and permeability. The predicted streaming potential transient response is in excellent agreement with experimental observations, permitting, for example, the extraction of sample permeability. Models assuming an incompressible frame are shown to be grossly inadequate in describing the temporal features of quasi-static flow.