bluuebunny/crossref_metadata_2025 huggingface dataset:
Models for acoustic propagation over a seamount of the Louisville Ridge
Authors: Guthrie K. M. , Denham R. N. , Bannister R. W. , Browning D. G.
Published: October 2005

Measurements were made of the propagation loss across a seamount of the Louisville Ridge east of New Zealand in 1978. This seamount rises from a depth of some 5000 m to within 490 m of the surface, considerably above the SOFAR axis depth of 1200 m. The measured values of propagation loss recorded by two mid-water receivers for source depths of 244 and 1220 m are compared with the predictions of models of an increasing order of complexity. The simplest model assumes cylindrical spreading plus attenuation up to the seamount, followed by an extra shadowing loss given by SL = 22.2 + 10 log10 (f/230) where the frequency f is in hertz. This model, which is based on the laboratory experiments of Medwin and Spaulding [J. Acoust. Soc. Am. Suppl. 1 66, S76 (1979)], gives a good description for the 1220-m source depth. The data are also compared with the predictions of (i) a modified normal mode model which also incorporates the Medwin-Spaulding shadowing loss beyond the seamount, and (ii) range-dependent computer models.
The effect of the Mid-Atlantic Ridge on long-range sound propagation
Authors: LaPlante R. F. , Koenigs P. D. , Browning D. G.
Published: October 2005

Previous long range acoustic experiments show that the Mid-Atlantic Ridge, a major topographic feature rising to the deep sound channel axis, can have a significant effect on SOFAR propagation. [R. J. Urick, J. Acoust. Soc. Am. 35, 1413 (1963)]. In order to quantify this effect, data has been analyzed from a recent SOFAR experiment which deployed SUS charges during several transits across the Ridge. The signals were received on a hydrophone located near Bermuda, a distance of approximately 2500 km. These results are compared with data from Atlantic seamounts of similar height and ridges in other oceans. [K. M. Guthrie, J. Acoust. Soc. Am. Suppl. 1 68, S52(A) (1980)]. The enhancement or shadowing of SOFAR propagation is presented as a function of source depth and frequency for various geometries. [Work supported by NAVSEA.]
Scale model studies of scattering and diffraction at a seamount
Authors: Jordan Edgar A. , Medwin Herman
Published: October 2005

Previously, we have shown [J. Acoust. Soc. Am. Suppl. 1 66, S76 (1979) and in W. A. Kuperman, Bottom-Interacting Ocean Acoustics edited by F. B. Jensen (Plenum, New York, 1981] that a laboratory scale model of DICKENS Seamount can be used to predict the ocean transmission loss measured over such a topographical obstruction by Ebbeson et al. [J. Acoust. Soc. Am. Suppl. 1, 64, S76 (1978)]. This analog calculation technique has now been enhanced by modeling the ocean surface over the seamount. The three-dimensional seamount model has been studied, as well as a simple 14° plane wedge and a two-dimensional model of the seamount as interpreted by the parabolic equation, each covered by smooth, rough, or no “ocean surface.” The ability to physically model the ocean surface with the proper Rayleigh roughness parameter, as well as the various approximations to the seamount has permitted a detailed evaluation of the reflection, diffraction, and scattering wave paths of this complex problem. [Research supported by ONR.]
Theoretical study of the pulsed ultrasonic field radiated by a nonuniformly vibrating planar piston source
Authors: Harris Gerald R.
Published: October 2005

A mathematical method is presented for evaluating the transient field radiated by a pulsed planar piston set in an infinite rigid bafffle and having an arbitrary spatial velocity distribution. The method allows for the field to be found at a point or averaged over a finite receiving surface. The approach taken is based on an expanded convolution integral representation of the transient field using a generalized spatial impulse response function development. To illustrate the effect of a nonuniform source and finite receiver on the detected transient field, the generalized spatial impulse response is plotted for several receiver sizes and source distributions representable by analytic functions. Then corresponding plots are presented for two piston velocity waveforms: A Gaussian pulse and a Gaussian-modulated sinusoidal burst. Lastly, the relationship of this theoretical method to other mathematical descriptions of the field radiated by a planar piston is discussed. In particular, the “plane” and “edge” wave decomposition of the field of a rigid piston is generalized for the nonuniform radiator case and then related to the present approach.
Impact sound radiation from clamped circular plates in an infinite baffle
Authors: Tokunaga Mitsuaki , Akay Adrian
Published: October 2005

Acoustic radiation from an impactively excited damped circular plate in an infinite baffle was obtained analytically by employing Rayleigh's integral. The resulting integral equations were evaluated numerically to obtain the on-axis sound pressure waveforms. Theoretical results in the nearfield of the plate agree with previous experimental measurements [A. Akay, R. O. Cook, and C. W. Hamme, J. Acoust. Soc. Am. 64, S174 (1978)] in predicting the sound pressure pulse due to rapid deformation of the plate. [Work supported by a W.S.U. grant.]
Scattering of acoustic waves by a cylindrical shell immersed in water
Authors: Numrich S. K. , Dragonette L. R.
Published: October 2005

Pulse measurements have been made on a brass cylindrical shell immersed in water. The outer radius of the shell is 0.765 cm and its length is 0.91 cm. The ends are enclosed with hemispherical shells making the overall length 2.44 cm. The ratio of the inner to the outer radius is 0.934 providing a thickness of 0.0508 cm. Scattered returns span a range in k(l/2) from 7.7 to 160 (where l is the overall length and k is the acoustic wavenumber in water) allowing the observation of elastic effects which include the first symmetric and the first asymmetric Lamb waves. Rotating the shell at one degree increments yielded detailed beam patterns at all sampled frequencies.
T-matrix analysis of the resonances in sound scattering of an obliquely incident wave from finite elastic spheroids and cylinders
Authors: Flax Lawrence , Dragonette L. R. , Varadan Vijay K. , Varadan Vasundara V.
Published: October 2005

In this paper, the T-matrix approach is applied to the scattering of plane acoustic waves incident upon finite elastic cylinders and spheroids immersed in water at any angle relative to the bodies axis. Resonances in the range ka 10, where k is the wavenumber of the incidence sound wave and a is the length of the semi-major axis, are isolated. The three angular regions of interest here are 0°, 45°, and 90°. The scattering amplitude and resonances at these angles will be discussed.
Comparisons between our “effective modulus” predictions and those of earlier composite-material theories
Authors: Gaunaurd G. C. , Überall H.
Published: October 2005

We have developed a general dynamic theory of wave propagation in solid composite substances containing multiple fluid-filled perforations. We constructed our theory by systematically applying the so-called Ament-Toksöz model to a viscoelastic continuum with spherical fluid inclusions of various sizes. [G. C. Gaunaurd and H. Überall, J. Acoust. Sec. Am. Suppl. 1 67, S43 (1980).] Our dynamic predictions have extended the Töksrz (static) results since we kept certain key-terms in some of the resulting series expansions, and this allowed us to include the dominant effect of the giant monopole resonance. We have found an extensive body of literature predicting the “effective moduli of elastic composites,” and in this paper we compare a selection of those predictions to ours. A direct comparison is not always possible; however, in most of the cases analyzed, and this includes the more familiar and useful results, we have analytically demonstrated that they all constitute particular cases of our dynamic theory. [H. Überall is also at Catholic University, Washington DC, and was additionally supported by Code 421 of ONR.]
Ear-canal acoustic distortion products (2f1−f2) and (2f2−f1) can be suppressed or enhanced by a third tone
Authors: Kim D. O. , Zurek P. M. , Clark W. W.
Published: October 2005

It is now well established that, with two-tone stimulation at 40 to 80 dB SPL (re 20 μPa), sound pressure in the occluded ear canal of various mammals such as chinchilla and cat contains prominent intermodulation distortion products. Evidence that these distortion products are generated by a metabolically dependent mechanism within the cochlea includes the demonstrations of pronounced vulnerability of the distortion products to anoxia, to cyanide poisoning of the cochlea, and to temporary fatigue and permanent damage of the organ of Corti [Kim, Hear. Res. 2, 297–317 (1980); Zurek, Clark, and Kim, Abstr, Assoc. Res. Otolaryngol. (Jan. 1981)]. In normal intact ears of anesthetized chinchillas, we have observed that the acoustic distortion products (2f1−f2) and (2f2−f1) are generally the most prominent ones, and that their levels are comparable to each other, both ranging from −30 to −50 dB relative to the primary-tone level. We have found that either of these distortion products can be either suppressed or enhanced by applying an appropriate third tone (f3). As the level of f3 is raised, the distortion-product level sometimes is first enhanced by as much as 7 dB and then suppressed by as much as 20 dB or more. A further increase in f3 level above about 70 dB SPL, with f1 and f2 levels at 65 dB SPL, often leads to less suppression. These and other details of suppression and enhancement of the acoustic distortion products are difficult to explain with a simple single-source model of distortion-product generation, but appear to be compatible with a two-source model (Kim, 1980). [Supported by NIH grants NS00162 NS07498 and Deaf. Res. Found. grant to WU, and NIH grant NS03856 to CID.]
Representation of whispered vowels in temporal patterns of auditory-nerve fiber discharges
Authors: Voigt H. F. , Sachs M. B. , Young E. D.
Published: October 2005

We have previously shown that the temporal patterns of auditory-nerve fiber discharges provide a robust representation of the spectra of periodic steady-state vowels [Young and Sachs, J. Acoust. Soc. Am. 66, 1381–1403, (1979)]. The purpose of the study described here was to determine whether the spectra of a whispered (aperiodic) vowel could be represented by such a temporal code. A terminal analog synthesizer was excited by white noise. The first three formant frequencies of the synthesizer were set to 530, 1840, and 2480 Hz which correspond to the vowel /ε/. The resulting whispered vowel was presented in 400 ms bursts once per second. Responses to the vowel were recorded in as many as 350 auditory-nerve fibers in individual cats. Interval histograms of fiber responses were constructed from the data and discrete Fourier transforms with a frequency resolution of 64 HZ were computed for each interval histogram. For each fiber the magnitude of the Fourier transform component nearest its CF was used as a measure of the fiber's temporal response to the vowel. Plots of this temporal response versus CF across the population of fibers in individual cats showed peaks at the vowel formant frequencies. Indeed, such temporal profiles provide a strikingly accurate representation of the vowel spectrum. [Supported by NIH Grant No. NS-12112.]
Simulated auditory nerve fiber responses to speech signal
Authors: Boulogne Michel , Dolmazon Jean-Marc
Published: October 2005

Alterations imposed to speech signal by the peripheral auditory system, have been studied by mean of the physical model described by J. M. Dolmazon and L. Bastet [J. Acoust. Soc. Am. 65, S14 (1979)]. This model can reproduce for any acoustical stimulus the mean discharge frequency of an auditory nerve fiber after a linear simulation of basilar membrane motion and a nonlinear simulation of mechanical to neural transduction for taking into account two-tone suppression effects or combination tone generation. We present a comparison between features extracted, from the input speech signal, by the model and by conventional analysis techniques to estimate the influence of the well-known nonlinear effects in speech perception. Special care has been taken for vowel analysis to clarify formant interaction.
Labial coarticulation in some French VCV sequences measured by electromyographic and cinematographic techniques
Authors: Gentil Michèle
Published: October 2005

The purpose of this study is to know anticipatory and carryover labial coarticulatory effects during the production of certain french vowel-sibilant-vowel sequences. These effects are defined on EMG activity correlated with lip gesture estimated from a film. EMG data are attained from orbicularis oris inferior, mentalis, depressor labii inferioris, levator labii superioris alaeque nasi of two subjects through the use of paint-on electrodes. Three groups of syllables are defined. Not very protruded syllables [∫i, ȝi, ∫e, ȝe] are characterized by an anticipatory and carryover labial coarticulation with activity of mentalis and orbicularis oris inferior corresponding to protrusion, only if preconsonantal vowel is (−lab]. As concern protruded syllables [sy, zy, sø, zø] in a [−lab]preconsonantal context, the influence [+lab] of vowel begins during the production of sibilant with mentalis activity and protrusion. In a [+lab]preconsonantal context, mentalis activity and protrusion decrease slightly during the production of sibilant. With very protruded syllables [∫y, ȝy, ∫ø, ȝø], two labial productions explain anticipatory labial coarticulation.
Precision of articulatory targets for the vowels /i/ and /a/: An examination of x-ray microbeam data
Authors: Perkell Joseph S. , Nelson Winston L.
Published: October 2005

An hypothesis on the nature of articulatory targets for the vowels /i/ and /a/ is proposed on the basis of findings on motor equivalence, vowel articulations, and acoustic considerations. The conjecture is that positioning of points on the tongue dorsum in a repetition experiment should be most accurate in the direction normal to the vocal tract mid-line, at the acoustically critical point of maximal constriction for each vowel. This hypothesis has been tested in an examination of x-ray microbeam data for two speakers. Distributions were plotted of the mid-sagittal locations of three tongue points at the time of maximal excursion toward the vowel target for numbers of examples of the vowels embedded in a variety of phonetic contexts. Visual examination suggests that these distributions are narrowest in the direction normal to the mid-line, at or near the point of maximal vocal-tract constriction for each vowel, providing initial support for the hypothesis. The paper will discuss the implications these results have with respect to mechanisms that define vowel categories and principles of motor control. Firmer conclusions about underlying mechanisms will depend on examination of additional data and statistical analysis of the distributions. [Research supported in part by NIH Grant No. NS04332].
Sound absorption in sodium sulfate (1 atm) and sodium chloride (1–307 atm) solutions from 30 to 300 kHz
Authors: Hsu C. C. , Fisher F. H.
Published: October 2005

Sound absorption from 30 to 300 kHz has been measured at 25° with a 100-liter titanium spherical resonator technique for 0.03 M Na2SO4 and 0.16 M NaCl solutions at 1 atm and for 0.58 M NaCl solutions at pressures from 1 to 307 atm. The results show that these solutions exhibit the same absorption as that for deionized water; that is, within experimental error these solutions exhibit negligible absorption. These results are in agreement with J. Acoust. Soc. Am. 26, 223 (1954), Kurtze and Tatum [Acustica 3, 33 (1953)], and the recent work of Gilligan and Atkinson [J. Phys. Chem. 84, 208 (1980)]. These results are important for understanding the relation of sound absorption to ion pairing in MgSO4 and NaCl solutions including seawater, especially as a function of pressure. [This research was supported by ONR, NSF, and ARPA.]
Vibrational-rotational energy transfer in mixtures of nitrogen and water vapor
Authors: Zuckerwar Allan J. , Griffin William A.
Published: October 2005

The following de-excitation rates have been computed according to the theoretical treatments of Shin [J. Chem. Phys. 60, 1064–1070 (1974)], and Nagel and Rogovin [J. Chem. Phys. 72, 6593–6601 (1980)] for N2−H2O mixtures: k20. de-excitation of N2 by H2O (VT); k30, near-resonant transfer (VVR); and k50, de-excitation of H2O by N2(VT). At 300°K the theoretical values are respectively 0.11, 1.76 × 105, and 3.1 × 104, as compared with the experimental values of <3 × 104, 1.25 × 1O5, and 4.6 × 104, all in (atm⋅s)−1, obtained acoustically in a resonant tube. These results demonstrate the dominance of VVR over VT transfer in the N2−H2O system, and support the conclusion of Nagel and Rogovin that the large rate k30 is “due to the vast number of VR modes H2O has available to absorb energy.”
Subjective assessment of sound transmission through party walls
Authors: Bauer Jay W. , Vian Jean-Paul
Published: October 2005

The annoyance caused by music intruding into a room from a neighboring dwelling was studied under laboratory conditions. The annoyance caused by intruding music was measured for electronic simulations of different insulation curves that provided the same transmission loss when measured as an A-weighted attenuation according to French regulation. The A-weighted ratings of the transmission loss provided by the insulation curves poorly predicted the subjective assessments. Likewise, the ISO and ASTM recommended sound transmission loss rating methods also poorly predicted the annoyance reactions. The subjects showed a preference for insulation curves that had the steepest slopes (12 dB/octave), but the presence or location of coincidence dips did not systematically influence the annoyance ratings. Although the music samples were all played at the same A-weighted level, the A-weighted level of the music transmitted through the insulation curves accounted for about 14% of the variability. in the annoyance ratings and including measurements of the ambient room noise accounted for another 15% of the variability.
Methods for the calculation of axial wavenumbers in lined ducts with mean flow
Authors: Eversman Walter
Published: October 2005

A survey is made of the methods available for the calculation of axial wavenumbers in lined ducts. Rectangular, circular and annular ducts with both uniform and nonuniform flow are considered as are ducts with peripherally varying liners. A historical perspective is provided by a discussion of the classical methods for computing attenuation when no mean flow is present. When flow is present these techniques become either impractical or impossible. A number of direct eigenvalue determination schemes which have been used when flow is present are discussed. Methods described are extensions of the classical no-flow technique, perturbation methods based on the no-flow technique, direct integration methods for solution of the eigenvalue equation, an integration-iteration method based on the governing differential equation for acoustic transmission, Galerkin methods, finite difference methods, and finite element methods. Special emphasis is given to the case of uniform flow and an approach based on converting the nonlinear eigenvalue problem into a nonlinear differential equation.
Ultrasonic chemical relaxation mechanisms in protein solution
Authors: Slutsky L. J. , White R. D.
Published: October 2005

Reactions of the form −1H+ + HPO42− = −1 + H2PO4− (where −1H+ and −1 represent, respectively, the protonated and neutral forms of a given histidyl residue of a peptide or small protein) are more than usually amenable to study by acoustic techniques. The rate constants and average volume changes for this reaction have been deduced, for a few small proteins (bacitracin, myoglobin, ribonuclease, and hemoglobin), from the acoustic absorption as a function of frequency (0.24–150 MHz), pH, and concentration. The rate constants so deduced are used to estimate the spectrum of relaxation times and relaxation amplitudes associated with intermolecular and intramolecular proton exchange reactions in biological media. It is concluded that the acoustic absorption (between 1 and 10 MHz) reasonably attributable to perturbation of such equilibria is a significant fraction of the absorption observed in intact tissues. Ultrasonic absorption due to perturbation of protein-protein association equilibria is also discussed as is the possible role of “solvation” equilibria.
A review of turbo-machinery aero-acoustic phenomena in fan jet engines
Authors: Mungur Parma
Published: October 2005

Of the noise radiated from current high bypass fan-jet engines, the turbo-machinery components are still dominant especially at approach conditions. Their control and reduction at the source and/or by duct liners require detailed knowledge of the noise producing mechanisms and their coupling to the duct field. Although the basic mechanisms leading to their generation have been known for nearly two decades, deterministic evaluation of the coupling to the duct acoustic field is limited for many reasons. The coupling which controls the acoustic efficiency of the unsteady aerodynamic field is a function of many variables, some of which are independent and some are inter-dependent. Some of these variables relate to the duct, blade and vane geometries, the acoustic surface impedances, the nonuniform mean flow fields and aero-acoustic back reactions. The basic mechanisms and some relevant aero-acoustic interactions are reviewed to ascertain their influence on the acoustic efficiency and to highlight areas where further research is needed to overcome some of the limitations.
Laser interferometric measurements of basilar membrane vibrations in cats using a round window approach
Authors: Khanna S. M. , Leonard D. G. B.
Published: October 2005

In a round window approach to the basilar membrane, cochleas were opened without bleeding by use of a specially designed microcautery. The state of the cochlea was monitored using C. M. and N1 response. Microscopic gold mirrors were dropped onto the basilar membrane at selected locations without touching the membrane or removing the perilymph. Vibrations of the gold crystals on the basilar membrane were measured with an improved laser interferometer at sound-pressure levels as low as 30 dB SPL at the tympanic membrane. The observed tuning curves had high-frequency slopes up to 720 dB/oct and low frequency slopes up to 70 dB/oct. In the past, the sharpness of basilar membrane tuning curves has increased as we progressively reduced the damage to the cochlea. One of the remaining sources of damage in our experiments was the laser beam itself. The intensity of the beam has been reduced by a factor of 100 by redesign of the interferometer. Basilar membrane responses measured with reduced laser damage will be shown. [Supported by N.I.H.]
Community response to railway yard noise
Authors: Dixit A. K.
Published: October 2005

Community reaction to railway yard noise is analyzed for over 500 residents living adjacent to five rail yards in Ontario. Regression models are investigated for annoyance and sleep disturbance of the exposed population as a function of the measured noise levels due to the individual sources as well as the composite of all operations in the yard. Percent of respondents highly annoyed shows a stronger correlation than does the percent annoyed at all with measured sound levels. Outdoor annoyance is correlated better than indoor annoyance with measured sound levels. Lps is judged to be a more accurate descriptor of community annoyance as compared to 24-h Leq, for yard noises.
Environmental noise impacts from coal handling at electric power plants
Authors: Teplitzky Allan M.
Published: October 2005

Since adoption of the Power Plant and Industrial Fuel Use Act of 1978, there has been increased interest in the use of coal as a boiler fuel both at proposed electric power plants and as an alternative fuel al existing oil-fired plants. Although coal has been used as boiler fuel, there is very little information available concerning noise emissions from coal handling. Therefore, a study was undertaken to provide an assessment of environmental noise impact for two types of coal delivery systems—railroad and barge. Noise estimates were developed using data obtained at other coal facilities for the following descriptors: Long-term equivalent sound level, I-h equivalent sound level, and maximum sound level, The noise estimates have been used in the preparation of environmental impact statements for the two urban sites studied. Noise from coal handling at these facilities are not expected to cause adverse environmental impacts after modest noise abatement treatments are installed and if coal is unloaded during the daytime. The study also demonstrated that coal handling noise emissions are site specific, but with the information developed, estimates of the noise impacts at other sites can be easily developed.
Absorption of ultrasound in tissues
Authors: Carstensen Edwin L.
Published: October 2005

The primary absorption of ultrasound in most soft tissues occurs at the macromolecular level. The attenuation observed when a tissue sample is interposed between a source and receiver may be affected by reflection, refraction, and phase distortion in the wave transmitted through the sample. However, when these effects are minimized, the differences between absorption and attenuation coefficients are small. Most soft tissues are characterized by small negative temperature coefficients up to physiological temperatures. At high intensities, nonlinear phenomena become important and can create losses in tissues which are mechanistically distinct from small amplitude absorption processes.
Biomolecular absorption of ultrasound
Authors: Kremkau Frederick W.
Published: October 2005

Understanding of the mechanisms of the interaction of ultrasound and biomolecules is essential to a thorough understanding of the present biophysical and medical applications of ultrasound and to the systematic and efficient accomplishment of future advances. Experimental evidence indicates that the biomolecules present in tissues play an important role in the ultrasonic propagaTion properties of tissues. Classical absorption mechanisms apparently play no significant role at the biomolecular level. Chemical and structural relaxation mechanisms have been proposed to explain the acoustic behavior observed, although generalized dispersion relationships have been reported to apply as well. Specific mechanisms of absorption for biomolecules in suspension at neutral pH have not been determined. Molecular size plays a role (in a “threshold” sense) in absorption but not in propagation speed. Molecular conformation appears to be important in some cases but not in others. Biomolecular-solvent equilibria and biomolecule-biomolecule interactions apparently are involved in the absorption processes.
Acceptability and perceived quality: a study of machinery noise components using psychophysical methods
Authors: Fleischman Rebecca N. , Lyon Richard H.
Published: October 2005

This paper presents the results of a study of listener response to sewing machine sounds. The study was designed to aid noise control engineers in the development of criteria and design strategies for the reduction of machinery noise levels and the improvement of the quality of the sound. A panel of listeners rated recorded sewing machine sounds. The stimuli were comprised of composite sewing machine sounds including varied amounts of the sounds produced by individual impacting mechanical sewing machine components. The Acceptability of the sounds and the perceived quality of the machines producing these sounds were judged by the panel trained in use of magnitude estimation, a psychophysical scaling tool. An examination of the listener response data identified problem components and shows the amounts that their sound levels would have to be changed in order to have an effect on consumer judgements of quality and acceptability.
Isolated word recognition using demisyllable templates
Authors: Rosenberg A. E. , Rabiner L. R. , Levinson S. E. , Wilpon J. G. , Shipley K. L.
Published: October 2005

An automatic speech recognition system is described for recognizing isolated words from reference templates created by concatenating demisyllables from a corpus of about 1000 demisyllables. The composition (in terms of demisyllables) of each reference word is specified in a lexicon with one or more entries for each word in the vocabulary. Experiments were carried out, using a 1109-word basic English vocabulary, to investigate the usefulness of such a representation and the effect on performance of some simple modifications in demisyllable specifications and durations of reference patterns. Performance statistics are provided.
Speaker adaptation for word-based speech recognition systems
Authors: Hunt Melvyn J.
Published: October 2005

This work is aimed at enhancing the speaker-independent performance of word-based speech recognition systems by rapidly and automatically deducing general characteristics of the current speaker and using them to derive speaker-normalizing transforms. DP matching is used to align and compare corresponding frames of the incoming speech and reference vocabulary. A single transform is then computed for all voiced speech and another for all unvoiced speech. The transform consist of a linear filtering component and, optionally, a constrained frequency shift. Experiments have been carried out with twenty male and female, native and non-native English speakers each producing 150 digits. Adaptation on all 150 digits reduces recognition errors by a factor of three (4.5% to 1.5%). With adaptation on just three randomly selected digits, the reduction factor is two. Frequency shifting is useful only when the amount of adaptation material is large and the reference speech is not exclusively from the same sex as the current speaker. Best performance is obtained using a transform without frequency shifting and with all input and reference speech from the same sex. [Work supported by DCIEM, Department of National Defence, Canada.]
Acoustic-reflex effects on middle-ear performance
Authors: Rabinowitz W. M.
Published: October 2005

The influence of middle-ear-muscle contractions on the transmission characteristics of the middle ear will be reviewed based on data from the human, cat, guinea pig, and rabbit. Attention will be focused on (a) the size and frequency dependence of the changes in middle-ear transmission and input immittance associated with different levels of muscle contraction, (b) the dependence of these changes on the level of sounds used as acoustic-reflex elicitors, and (c) the effects of a constant level of muscle contraction on the linearity of the middle ear system. An attempt will be made to account for the experimental data by quasistatic changes in the linear incremental values of middle-ear models. Concerning (c), we shall examine the hypothesis (derived from certain psychophysical experiments) that muscle contractions have little or no effect on the transmission of low-intensity stimuli. [Work supported by NIH.]
Observation of Q of 1 million in a water-filled 100-liter titanium spherical resonator at 25 kHz
Authors: Hsu C. C. , Fisher F. H.
Published: October 2005

Leonard (Tech Report No. 1, Department of Physics, UCLA, June 1950) reported a Q of 760 000 at 56 kHz for degassed distilled water in a 50-liter glass spherical resonator suspended in a vacuum by piano wires. Using essentially the same technique we observed a very strong mode at 25.37 kHz with a decay rate of 0.67 dB/s. This mode corresponds to a Q of slightly greater than 106 and was exactly semilogarithmic over the entire potentiometer range of 50 dB. Two polar end caps for filling and pressurizing the sphere and an equatorial weld bead were the only departures from spherical symmetry. Otherwise the sphere, a ballast tank from the research submarine ALVIN, is concentric and true to within 0.00254 cm. Degassing time to achieve these results is about 100 h. The structure of the high Q mode is unknown. For cylindrical resonators azimuthal modes yielded the highest Q. The assumption for the spherical resonator is that radial modes yield the highest Q. [This research was supported by ONR, NSF and ARPA.]
Sound absorption in seawater at pressures up to 307 atmospheres
Authors: Hsu C. C. , Fisher F. H.
Published: October 2005

Using a 100-liter titanium spherical resonator sound absorption from 45 to 350 kHz has been measured in Lyman and Fleming seawater at 25° and at pressures of 1, 71, 188, and 307 atm. Assuming a single MgSO4 relaxation process, the data were analyzed for the values of the maximum absorption per wavelength, (aλ)max, and of the relaxation frequency fr At 1 atm (aλ)max = (61.65 ± 0.34) × 10−6, in good agreement with that measured by Wilson and Leonard [J. Acoust. Soc. Am. 26, 223 (1954)] and by Simmons (Ph.D. thesis, University of California, San Diego, 1975). The relaxation frequency of 133 kHz is lower than those reported by Wilson and Leonard and by Simmons. At elevated pressures the relaxation frequency remained the same contrary to the increase observed by Bezdek [J. Acoust. Soc. Am. 53, 782 (1973)] in field measurements. Absorption decreased linearly with pressure according to the equation a(p) = a(l)(1− 9.1 × 10−4P), where P is in arm. This decrease is 25% smaller than Bezdek found but nearly the same as Fisher [J. Acoust. Soc. Am. 38, 805 (1965)] measured in 0.5 M MgSO4 solutions. [This research was supported by ONR, NSF and ARPA.]
Acoustical design of the Dalhousie Athletics Complex
Authors: Terroux Peter
Published: October 2005

The necessity of introducing a major scale athletics complex within a residential neighborhood, which had already shown considerable opposition to the project, resulted in the selection of an inflated stainless steel-membrane roof structure to minimize the visual impact of the 150 000-sq-ft complex. The steel membrane roof structure, because of its minimal thickness and load-carrying capacity, presented challenging acoustical problems in sound isolation, to minimize the impact of activity noise within the field house on the surrounding neighborhood, and to control the interior noise from rainfall on the exposed metal roof surface. A suspended acoustical ceiling system was developed to control external noise radiated, attenuate rain noise, and simultaneously control reverberation within the field house and control potential echoes from the shallow-domed ceiling. This ceiling system was designed to permit partial deflation of the membrane, and subsequent recovery, without damage, and within the severe weight restrictions. A sound-reinforcement system, consisting of concentric rings of separately amplified high-frequency horns and low-frequency loudspeakers was used, with electronic signal delay to control echoes and enhance directional realism.
The effect of surface coatings upon brass-instrument tone quality
Authors: Pyle Robert W.
Published: October 2005

An experiment was conducted to see if lacquer and silver plating have any measurable effect on the tone quality of brass instruments. A French horn fitted with a detachable bell was tested with two bells. One bell was initially lacquered, the other silver-plated. The tests were repeated on the same bells after the lacquering and plating were chemically removed. Lacquer was found to decrease the acoustic output of the horn, more so at high frequencies than low; silver plating had no detectable effect. Anecdotal evidence from players qualitatively confirms the experiment and suggests that the effect of lacquering an instrument, though small, is not musically insignificant.
Perceptual discrimination of just and equal tempered tunings
Authors: Mathews M. V. , Sims Gregory
Published: October 2005

Just and equal tempered intonations have been discussed for centuries. However, few perceptual comparisons have been made because it is difficult to repeat a musical performance exactly after changing the tuning. Pairs of short examples were synthesized on a computer in just and tempered intonation. Except for tuning, the two members of a pair were identical. Subjects listened to a pair and judged which tuning was played first. Results were complex. Highly trained musicians discriminated with high accuracy. Everyone else performed at close to chance levels. Harmonic (simultaneous notes) judgments were more accurate than melodic (sequential notes) judgments. Listeners typically based harmonic comparisons upon the strength of beats and used pitch memory for melodic judgments. Some intervals (3rds) were easy to discriminate, though others (5ths) were almost impossible.
Study of the relations between instrumentist and instrument in computer music
Authors: Cadoz C. , Luciani A.
Published: October 2005

Man-machine communication is a very decisive point in digital synthesis of sounds used as a musical creation tool. We are concerned here with the instrumental gesture aspect of this problem where gesture is regarded as the most basic form of the relationship. Two complementary axes of study are necessary: (1) Analysis of gesture in instrument-instrumentist relationship. An all important class of gestures is based on the energetical exchange between the instrumentist and his instrument. In such as case, the instrumentist receives information (by touch and dynamical perceptions) which determines his behavior and his listening. So we have built a special device for sound control, with mechanical feed-back, taking into account the fact that the gesture is simultaneously a transmitter and a receiver channel. (2) The carrying out of sound synthesis by means of concrete source simulation. The simulation system relies on a first analysis of the instrument as a combination of an exciter structure connected to a vibrating structure. The latter are then decomposed into elementary mechanical components. Algorithmic models for mechanical components then allow a representation by the computer programs that we have elaborated of the main types of phenomena encountered in traditional instruments.
Analysis of the potential association between noise-induced hearing loss and cardiovascular evaluation in aircrew members
Authors: von Gierke H. E. , Kent S. J.
Published: October 2005

In recent years, many studies focused on noise exposure and its potential relationship to different measures of cardiovascular function. Several investigations reported significant correlations between hearing loss and certain cardiovascular parameters while others reported no relationships at all. Most evaluations have been retrospective in nature and as a consequence may include data which lack completeness or reliability, especially in the definition of noise exposure. Ascribing chronic medical consequences to noise exposure poses serious implications for individuals who are exposed to noise in work and leisure time environments. The present study explored the correlation between cardiovascular evaluation and noise-induced hearing loss in medical records of 2250 aircrew members referred to the Air Force School of Aerospace Medicine for clinical evaluations. Aircraft flying hours, as well as permanent hearing threshold shift were used as indices of noise exposure. No significant associations were found between hearing impairment and various cardiovascular parameters or pathologies. How our results can be extrapolated to different populations will be addressed. How our findings should be viewed in terms of other contradictory findings and in terms of future exploration will be presented.
Schultz's noise annoyance synthesis—Theory and interpretation
Authors: Krammer Frank G.
Published: October 2005

A simple explanation is argued to derive both an improved theoretical basis for Schultz's curve [T. J. Schultz, J. Acoust. Soc. Am. 64, 377–405 (1978)] and a mathematical model for fitting both the curve of clustering surveys and the curves of nonclustering and new surveys. In addition, deriving Schultz's population response curve of percent highly annoyed from a simplified theoretical model of individual degree of annoyance provides insight into likely reasons for deviations from the synthesized curve. The degree of the frequently observed shift of nonclustering survey curves left of the synthesized curve, for example, is directly proportional to the noise-source-dependent intercept and inversely proportional to the slope of the degree of annoyance as a function of noise level. Assuming this slope as constant for theoretical reasons and ignoring differences in annoyance scales, the relative “steepness” of non-clustering survey curves is related directly to the variability of individual annoyance responses.
Acoustic radiation from a four-bar mechanism due to impact in sleeve bearings
Authors: Bengisu M. Turgay , Burr Paul , Akay Adnan
Published: October 2005

This study investigates the acoustic radiation from a four-bar mechanism with flexible links due to impact in sleeve bearings. Impact occurs in sleeve bearings due to clearances and sudden changes in the direction of forces induced by the unbalanced mechanism. A finite element method is used to determine the accelerations of the nodal points of the finite element mesh, vibratory characteristics of the links, and the resulting sound radiation. A four-bar mechanism with simple beamlike links is designed for experimental analysis allowing for two-dimensional analysis of the links. This finite element analysis can be used for more complex link configurations and will be the basis used to diagnose and determine wear in bearings. [Work supported by NSF.]
Variation in community reaction to train noise and vibration
Authors: Dixit A. K. , Simmie P. M.
Published: October 2005

Residents' response to train noise and vibration is analyzed for two communities similarly exposed to train traffic but widely different in character. One community has newer, larger, detached homes, while the other is an older community of smaller homes. A hypothesis was tested that statistically reactions of people from two areas would be significantly different. An application of the multi-discriminant analysis technique confirms the hypothesis. As an independent test, the reactions of respondents in a third community of new semi-detached homes also exposed to the same train traffic was analyzed. Sixty-six percent of responses fell in the same category as the responses from the first community, suggesting habituation and socio-economic parameters are vital in developing land-use policy for new residential communities. This work forms the continuation of Train Noise Program of Ontario Ministry of the Environment under which railway yard noise has been previously investigated.
Automated system for measuring noise levels of large power transformers
Authors: Schulz M. W. , Dilick M. D.
Published: October 2005

Large power transformers have been noise tested in accordance with industry standards for more than forty years. Huge anechoic rooms used for factory testing can no longer accommodate the larger units and many tests have been made on weekends on the factory floor. To overcome the delays and inconvenience of such testing and to provide for the projected increasing need for more noise data, a computerized noise test system was installed in the General Electric factory at Pittsfield, MA. This paper describes the system and its operation. Up to 96 microphones are deployed around a transformer and scanned under computer control. The acoustic signals are analyzed by hard-wired FFT processors and the results stored for later, further processing. With the microphones set up during normal factory operations the data can be acquired in a short time, such as a lunch break, during which the factory can be quieted if necessary. There is no need to wait until a weekend. Printed reports containing tables and graphs of the overall sound levels and various spectra can be generated by the computer at any convenient time after the data is acquired and stored. The permanently stored data are available for further engineering analyses and studies.
Rural community noise caused by 345/138 kV substation transformer
Authors: Campanella Angelo J.
Published: October 2005

Residents 360 m (1200 ft) from a large (6 × 8 × 4.5 m high) 345/138 kV transformer installed in a new power substation in a rural setting complained of its noise emission, especially at night. Octave band and 24-h A-weighted noise measurements were made. The 120-Hz sound level was found to be 90 to 105 dB at the transformer surface. Transformer noise emission did not vary significantly with transformer loading or time of day. The distant (360 m) noise level was from 40 to 47 dBA (N-30 to N-45), depending on intervening terrain and time of day. In calm summer air, the annoying sound was found to be in the 125-Hz band at the residence beyond a vegitated rise and 250 to 500 Hz for a residence with line-of-sight contact over a shallow depression. The line-of-sight resident's complaint that the noise was greatest at night was corroborated by the 24-h measurement. That noise level was found to be typically 38 dBA from 11 a.m. to 7 p.m., and 45 dBA from 9 p.m. to 6 a.m. It is postulated that the depression accumulated cool air at night, thus refracting the sound onto that site. Recommendations for a noise barrier wall was made to the power company operator.
Active acoustic attenuation of electric transformer noise
Authors: Angevine O. L.
Published: October 2005

This paper presents further efforts to attenuate the hum of large transformers by active means [Angevine et al., J. Acoust. Soc. Am. Suppl. 1 67, S86 (1980)]. Theoretical and experimental investigations of the relation between attenuation and the number of secondary cancellation sources and variation with frequency of the hum harmonic are reported, together with some criteria for control circuits.
What should a model of speech perception be like?
Authors: Studdert Michael
Published: October 2005

From the facts of child language acquisition as well as from the capacity of a normal speaker to shadow, rapidly and precisely, the utterances of another, it is argued that elemental units of speech perception and of speech motor control are isomorphic. Two types of perceptual models are then distinguished on the basis of their treatment of acoustic-phonetic features. The first takes the features to be substantive components and proposes a process of perceptual construction; the second regards the percept (whether syllable or phoneme) as an unanalyzed given and treats the features as its descriptive attributes. The first attempts to be fully explicit about process, and regards machine implementation as a reasonable test of a model's validity; the second is concerned with biological validity, but not with explicit process. Only models of the second type, it is argued, conform to the constraint of perceptual-motor isomorphism. [Preparation of this paper supported by NICHD.]
Is speech perception a cognitive process?
Authors: Repp Bruno H.
Published: October 2005

In modeling speech perception, we tend to draw on concepts and operations employed in linguistic analysis and/or in information processing technology. However, it is quite possible that perception works neither like a linguist nor like a computer. An alternative view is to consider perception as a systemic brain function that serves the cognitive system by supplying information about the environment. In this view, perception and cognition are distinct, complementary systems with different principles of operation. In the case of speech input, the information transmitted by the perceptual system relates primarily to the behavior of a talker's vocal tract. There is no need to postulate a hierarchy of discrete perceptual mechanisms for the “bottom-up” processing of this information. Rather, the information accrues continuously and is interpreted by the cognitive system at a level appropriate to the situation. [Preparation of this paper supported by NICHD]