bluuebunny/crossref_metadata_2025 huggingface dataset:
Mode shapes and propagation characteristics for waves propagating in nonuniformly lined ducts
Authors: Vaidya P. O.
Published: October 2005

It is well established that the sound propagation in a duct, lined in a nonuniform fashion, either in the circumferential or the axial direction, cannot be described by means of separable modes. However, under these circumstances nonseparable modes can be used. In this paper it is shown that for some specific nonuniform boundary conditions, closed form solutions can be obtained. The mode shapes of the nonseparable modes have been obtained. It has been shown that these modes can be used to convert energy from lower modes to higher modes, which are easier to attenuate.
The propagation of spinning modes through nearly choked inlets
Authors: Vaidya P. G.
Published: October 2005

It is well known that sound cannot propagate upstream against a supersonic flow. However, even at subsonic speeds, in excess of the Mach number of 0.6, considerable attenuation has been observed in practice. To explain this, an equation, for the propagation of spinning modes in ducts carrying flow with axial and radial gradients, has been derived. The equation has been used to show that when a wave passes through a convergent-divergent nozzle, the net result is an attenuation of sound. Alternative mechanisms for the sound reduction in practical flows are also discussed.
An analytical investigation of synchrophasing as a means of reduction of aircraft interior noise
Authors: Fuller C. R.
Published: October 2005

In this paper the noise control characteristics of synchrophasing (i.e., varying the relative rotational phase of individual propellers) are investigated using a simplified model of an aircraft. For the analysis considered here the aircraft fuselage is approximated by an infinite cylindrical shell and the acoustic sources due to the propellers as dipoles. The acoustic response of the interior of the shell can then be obtained by utilizing the spectral form of the shell response with forcing functions due to the dipole sources expanded into cylindrical coordinates using a special form of the Bessel addition theorem. The variation in sound pressure levels at various locations inside the cylinder is then studied for a variation in phase between the dipole sources. Correspondingly, the shell response is evaluated and decomposed into individual circumferential modes of vibration in order to give an indication of the mechanism of transmission of sound into the shell.
Methods for using a noninvasive technique for estimating glottal functions from oral measurements
Authors: Holmberg Eva , Perkell Joseph , Hillman Robert
Published: October 2005

A noninvasive technique is used to make acoustic and aerodynamic recordings in an ongoing study whose goal is the objective assessment of vocal function in normal and dysphonic speakers. Intraoral pressure, oral volume velocity (flow), and radiated sound pressure are recorded for strings of repeated productions of the syllable /pae/. A high time resolution pneumothachograph is used to record flow [M. Rothenberg, J. Acoust. Soc. Am. 53, 1632–1645 (1973)]. Transglottal air pressure, glottal air flow, and sound power for the vowel are estimated from the oral measurements, and glottal resistance and vocal efficiency are calculated. Initial results suggest that production mode (smooth versus interrupted) and rate (slow versus fast) may affect the reliability of the aerodynamic measures. An interaction between production mode and rate can result in unreliable pressures on one hand and unreliable flows on the other. Results from a separate, methodological study illustrate the importance of control over production mode and rate to obtain oral pressure and flow signals that allow for reliable estimates of glottal functions. [Work supported by The Voice Foundation.]
Active in vitro force-elongation response of canine vocalis muscle
Authors: Titze Ingo R. , Alipour Fariborz
Published: October 2005

Vocalis muscle tissue was dissected from live dogs and kept alive in Krebs-Ringer solution for several hours. The temperature of the tissue was maintained at approximately 37 °C by a circulating fluid around the sample holder. Force-elongation responses of the vocalis muscle under various levels of stimulated muscle activity were obtained through one-dimensional stretch and release. Both force and elongation were monitored electronically with a Cambridge Technology Dual Servo System (ergometer), while stimulation was applied to the muscle with fine-wire electrodes and a Grass stimulator. Families of force-elongation curves for various frequencies of stimulation and various relaxation times are given, from which average elastic constants, such as Young's modulus, can be estimated. [Work supported by NINCDS.]
The use of radiation efficiencies in the diagnosis of noise sources
Authors: Donavan Paul R.
Published: October 2005

Using the recently developed two-microphone technique of acoustic intensity measurement, radiation efficiencies of a single panel and individual panels of a complete vehicle structure have been made under controlled, laboratory conditions. The data obtained from the single panel were used to develop measurement techniques and study the sound field near the panel. Radiation efficiencies of the vehicle structure were used along with measured vibration response obtained under normal operation conditions to determine the sound power produced by each individual panel. Results describing the technique development and the application to the vehicle structure are presented in this paper.
Characteristics of the FFP to linear tone glides
Authors: Resnick S. B. , Heinz J. M. , Bookstein E. W. , Pagano R. V.
Published: October 2005

The FFP to rising and falling linear tone glides of 12.8-ms duration was measured over a 51.2-ms period using multichannel recording for six normal hearing adults. Averaged response waveforms based on 8192 trials were obtained to tone glides rising or falling in frequency between 312 and 625 Hz or between 468 and 781 Hz. The averaged waveforms then were subjected to various analyses including bandpass filtering (using digital filters centered at the extremes of the frequency range of the glides), spectral analyses for selected post-stimulus intervals, cross correlation (with the input stimulus), and covariance. Preliminary review of the data suggests that linear tone glides may be of particular value for estimation of response latency and that response latency is dependent on frequency range and direction of the tone glides. Results of more detailed analyses and comparison of the FFP with responses to pure tones described previously [S. Resnick, J. Heinz, E. Bookstein, and R. Pagano, J. Acoust. Soc. Am. Suppl. 1 74, S65 (1983)] will be presented.
Otosclerosis: A generalized disorder of glycosaminoglycan (CAG) metabolism?
Authors: Thalmann Isolde , Thallinger Gertraud , Thalmann Ruediger
Published: October 2005

There are numerous indications that otosclerosis represents a local manifestation of a generalized disorder of GAG and/or collagen metabolism, a contention supported by the heritable nature of the disease. Zechner and Manolidis reported a pronounced increase of total GAGs in urine of patients with active otosclerosis [Arch. Klin. Exp. Ohren Nasen Kehlkopfheilkd. 202, 634 (1972)]. We were not able to confirm their reported increase in total urinary GAGs. Therefore we searched for more subtle indicators of aberrant GAG metabolism, such as changes in ratios of individual GAGs. For this purpose it was necessary to develop a highly sensitive technique to quantitate individual GAGs; however, again no significant differences were found: dermatan sulfate (0.48 ± 0.06 and 0.32 ± 0.04), heparan sulfate (0.43 ± 0.06 and 0.40 ± 0.04), chondroitin-4-sulfate (0.60 ± 0.07 and 0.71 ± 0.08), and chondroitin-6-sulfate (1.25 ± 0.14 and 1.41 ± 0.16) in controls (N = 22) and active otosclerosis (N = 20), respectively (X̄ ± SEM μg hexuronic acid/mg creatinine). These negative data by no means rule out a possible error in GAG metabolism. More definitive conclusions should emerge from radiotracer (35SO4) studies for the detection of errors in GAG synthesis and/or degradation in skin fibroblast cultures. [Supported by Research Fund of American Otological Society and NIH Grant NS-06575.
Speech reception thresholds in noise for native and non-native listeners
Authors: Florentine Mary , Buus Søren , Scharf Bertram , Canevet Georges
Published: October 2005

The noise level at which native and non-native listeners could repeat about 50% of very simple English sentences was measured with an adaptive procedure. The 14 non-native listeners were primarily native French speaking and were 19 to 53 years old. Four native listeners were 16 to 53 years old. On each trial the listener repeated one sentence presented at 70 dB SPL via loudspeakers in an anechoic chamber. If the entire sentence was correct, the noise level was increased; otherwise it was decreased. the step size was 5 dB until the first reversal and 2 dB thereafter. The speech reception threshold, SRT, was defined as the average noise level of ten trials following the first reversal. Three SRTs were measured for each listener. All listeners could repeat eight practice sentences presented in the quiet with 100% accuracy. The average SRTs were 57 dB SPL for listeners with minimal experience in English, 62 dB SPL for listeners with moderate experience, and 68 dB SPL for listeners with extensive experience. Native listeners had an average SRT of 72 dB SPL [Work supported by the French Scientific Mission.]
An analysis of articulation index theory as applied to different speech material
Authors: Pavlovic Chaslav V. , Studebaker Gerald A.
Published: October 2005

We have reported earlier [J. Acoust. Soc. Am. Suppl. 1 73, S102–103 (1983)] the details of an articulation index (AI) scheme that was found satisfactory for the nonsense syllable material we use. We now explore the ways of extending the scheme to include speech material of different redundancy level and different phonemic composition. Using our own data, as well as that of early AI investigators, we examine the basic assumptions of the AI theory for various speech materials. These include the properties of additivity, band independency and monotonicity, as well as the importance function, and the intelligibility-articulation transfer function. The validity of the resulting AI scheme is discussed in terms of the magnitude of the error in speech intelligibility predictions for various speech materials. [Work supported by NINCDS.]
On reconciling monophthongal vowel percepts and continuously varying F patterns
Authors: Lisker Leigh
Published: October 2005

When a sequence of pictures is presented in rapid succession the illusion of continuous movement can be created. A continuously varying acoustic signal may, contrariwise, be perceived as a sequence of “still” sounds. Not only is speech perceived as discrete sounds in sequence, but speakers will oblige, especially in the case of stressed vowels, by “citing” them in the form of steady state phonations judged to match auditorily the vowels in their natural contexts. These steady state imitations are adequately characterized by just two numbers, the frequencies of the two lowest vocal-tract resonances. Acoustic analyses of a number of tokens of the English nonsense forms [bεb dεd gεg bæb dæd gæg] produced by a single talker indicate that, if each token is represented by a single pair of formant frequencies, there is a pattern of variation rather different from the cross-talker variations reported by Peterson and Barney in 1951. Moreover the variation patterns are different within syllable types, for the same vowel across contexts, for the same contexts across vowels, and for the two formants. It is, moreover, not that simple to apply the target-plus-under-shoot model to explain the patterns of variation observed. [The support of the NICHHD is gratefully acknowledged.]
Vowel recognition in the absence of formant cues: Dynamic contributions to perception
Authors: Bunnell H. Timothy
Published: October 2005

The primary acoustic cue to vowel identity has typically been related to the center frequencies of the first two or three vowel formants. In experiments using specially degraded stimuli, results consistent with this assumption were obtained for stationary synthetic vowels, but not for vowels presented in syllabic contexts (e.g., /VwV/ and /ərVd/). For these experiments, vowel stimuli (both stationary and in context) were synthesized with high-frequency square waves substituted for the standard synthesizer voicing source (Klatt, 1980 cascade synthesizer). Spectra associated with these stimuli have peaks, due to the source harmonics, located at odd multiples of the fundamental frequency. In identification studies using the vowels [ /i/, /ɪ/, /ε/, /æ/, /a/ ], listeners tended to identify stationary vowels on the basis of the frequencies of their largest-magnitude spectral peaks. Since such peaks were invariably coincident with source harmonics, identification errors were frequent. Errors were, however, restricted almost entirely to the vowels [/ɪ/, /ε/, /æ/]. By contrast, vowels in syllabic context were reliably more resistent to identification errors, despite nearly identical acoustic structure throughout the medial portion of the vowel. Results are interpreted to suggest that listeners are well attuned to the contrast between source and vocal tract contributions to the signal. In order to separate these two contributions, however, listeners appeared to need information about changes over time in at least one function (the vocal tract function for these stimuli). [Work supported by NINCDS and the University of Maryland.]
Perceptual dimensions of dysphonic voices
Authors: Kempster Gail B. , Kistler Doris J.
Published: October 2005

The perceptual dimensions of dysphonic voices were derived through a multidimensional scaling algorithm (ALSCAL). Listeners responded to 1-s segments of the vowel /ɑ/ produced by 30 dysphonic female talkers in a triadic comparisons task. On each trial listeners were asked to select the two most similar stimuli. An acoustic analysis was performed to determine the fundamental frequency, intensity, pitch perturbation, amplitude perturbation, and harmonics-to-noise ratio of each vowel. The vowel stimuli were also rated by voice pathologists on six perceptual attributes (e.g., “breathiness”). Both the acoustic measures and the perceptual ratings were used to identify the dimensions of the perceptual space. Results are compared to a similar study by Murry, Singh, and Sargent [J. Acoust. Soc. Am. 61, 1630–1635 (1977)].
Boltzmann-Ehrenfest principle of adiabatic invariance and acoustic nonlinearity
Authors: Cantrell John H.
Published: October 2005

The Boltzmann-Ehrenfest principle of adiabatic invariance is applied to a nonlinear system consisting of a self-constrained finite amplitude acoustic wave propagating in a solid. The results predict the existence of an acoustic radiation stress having two source components. One component is associated with the stress nonlinearity of the solid and is obtained from the adiabatic variation in a parametrized natural wave velocity. The second component results from the variation in the first-order nonlinear term in the virial theorem expansion and gives rise to an acoustic radiation-induced static strain. Both components depend directly on the energy density of the propagating wave but are opposite in sign. The coefficient which couples the radiation-induced static strain to the energy density is the acoustic nonlinearity parameter which characterizes the nonlinearity of the wave equation.
Elastic waves, radiation stress, and static strains in solids: An experimental study of acoustic nonlinearity
Authors: Yost William T. , Cantrell John H.
Published: October 2005

The application of the Boltzmann-Ehrenfest principle of adiabatic invariance to a system consisting of a finite amplitude acoustic wave propagating in a nonlinear solid predicts the existence of an acoustic radiation-induced static strain. The static strain depends directly on the product of the energy density of the propagating wave and the acoustic nonlinearity parameter of the solid β. For propagating ultrasonic pulses or tonebursts theory predicts that the acoustic radiation stress generates a static displacement pulse having the shape of a right-angled triangle. The polarity and slope of the displacement pulse depend on the magnitude and sign of the nonlinearity parameter. We present measurements on single crystal silicon (positive β) and vitreous silica (negative β) which provide the first experimental confirmation of the theoretical predictions. Absolute measurements of the nonlinearity parameter determined from the static displacement pulses are in good agreement with those obtained from ultrasonic harmonic generation measurements.
The bubble pulse on deep fired/long-range underwater explosion records
Authors: Epstein David
Published: October 2005

Many years ago, the author analyzed a representative deep-fired/long-range underwater explosion record [J. Acoust. Soc. Am. 35, 800 (1963)]. The most striking feature was the so-called “double shock” formation, e.g., a strong resemblance between the shock wave and bubble pulse in both amplitude and shape. The phenomenon is attributed to the combined effects of detonation depth and waveform propagation. Recently [Proc. 11th Intern. Congress Acoust., Paris, 1983, Vol. 1, pp. 345–348] the characteristics of an explosion waveform at the source, as a function of firing depth was established. Here, weak shock theory is used to study the nonlinear distortion of the bubble pulse as it propagates. The criterion for shock wave formation depends inter alia on the strength and duration of the pulse. Pulse amplitude increases slowly, but its duration decreases rapidly, with charge depth. It is found that the shot depth plays the crucial role and that consequently the deep fired shots suffer the greatest distortion, tending towards shock wave formation at long range.
On the performance of isolated word speech recognizers using vector quantization and temporal energy contours
Authors: Rabiner L. R. , Pan K. C. , Soong F. K.
Published: October 2005

The technique of vector quantization has been widely applied in the area of speech coding and has recently been introduced into the area of speech recognition. For the conventional statistical pattern recognition word recognizer using LPC feature sets as the analysis frames, the use of vector quantization leads to a large reduction in computation for the dynamic time warping pattern matching, and a concomittant small increase in average word error rate. A second technique that has been recommended for improving the performance of isolated word recognizers is the addition of temporal energy information into the distance metric for comparing frames of speech. It has been shown that the information in the prosodic energy contour complements the segmental information of the LPC spectrum, thereby providing small but consistent improvements in performance for small word vocabularies. In this talk we present results of a series of speaker independent, isolated word recognition tests using a 10-word digits vocabulary and a 129-word airlines vocabulary. We show the effects, on recognition accuracy, of adding both vector quantization and temporal energy in various combinations, to the recognition paradigm.
Global spectrum vowel recognition and human performance
Authors: Eskanazi Maxine
Published: October 2005

We have shown [Eskenazi and Lienard, J. Acoust. Soc. Am. Suppl. 1 73, S87 (1983)] that global characterizations of the French oral and nasal vowels in a speaker-independent automatic recognition task give generally better recognition results than formant-based methods. In particular, a very rough representation in the frequency domain, characterizing the curvature of the spectrum gave good results using very little reference information for each vowel. By now, changing the analysis that the curvature characterization is based on from an FFT to an LPC has significantly improved global results. This is very close to human intelligibility of the same databases used, in terms of distance between confusion matrices. We shall compare results of human and automatic recognition in order to better evaluate machine performance. There follows a comparison between the FFT and LPC results in order to estimate the pertinence of the information furnished by each in view of vowel recognition and in the light of the problems inherent in a speaker-independent task as well as in specific vowel properties.
A modified K-means clustering algorithm for use in speaker-independent isolated word recognition
Authors: Wilpon J. G. , Rabiner L. R.
Published: October 2005

Recent studies of isolated word recognition systems have shown that a set of carefully chosen templates can be used to bring the performance of speaker-independent systems up to that of systems trained to the individual speaker. The earliest work in this area used a sophisticated set of pattern recognition algorithms in a human-interactive mode to create the set of templates (multiple patterns) for each word in the vocabulary. Not only was this procedure time consuming but it was impossible to reproduce exactly, because it was highly dependent on decisions made by the experimenter. Subsequent work led to an automatic clustering procedure which, given only a set of clustering parameters, clustered tokens with the same performance as the previously developed supervised algorithms. The one drawback of the automatic procedure was that the specification of the input parameter set was found to be somewhat dependent on the vocabulary type and size of population to be clustered. Since the user of such a statistical clustering algorithm could not be expected, in general, to know how to choose the word clustering parameters, even this automatic clustering algorithm was not appropriate for a completely general word recognition system. It is the purpose of this paper to present a new clustering algorithm based on a K-means approach which requires no user parameter specification. Experimental data show that this new algorithm performs as well or better than the previously used clustering techniques when tested as part of a speaker independent isolated word recognition system.
Investigating the voice quality dimension in Western Nilotic vowel harmony
Authors: Maddieson Ian
Published: October 2005

It has been suggested at least since 1936 (Tucker, 2nd International Congress of Phonetic Sciences, Cambridge) that the vowel harmony system in Western Nilotic languages includes a dimension of voice quality contrast. X-ray studies of Dho-Luo and Ateso have shown that there are generally differences in the superalaryngeal regions (e.g., in tongue height and/or pharyngeal volume) between vowels of the two vowel harmony sets. It has remained unclear whether these vowels are additionally distinguished by a voice quality difference between “hard” and “breathy” phonation types produced by different laryngeal settings. Techniques being developed at the UCLA Phonetics Laboratory for examining phonation types in natural languages have been applied to answering this question. These tend to confirm that there are differences in laryngeal setting, although this conclusion must remain tentative until these techniques are more fully developed and more data is available. [Work supported by NINCDS.]
Tonal scale step encoding and the recognition of octave-scrambled melodies
Authors: Dowling W. J.
Published: October 2005

Octave-scrambled melodies, having their pitches randomly distributed over several octaves, are difficult to recognize. Such melodies do not preserve pitch-interval patterns of undistorted melodies, but only their sequences of chromas—that quality of pitch shared by tones an octave apart. It was shown previously [W. J. Dowling, J. Acoust. Soc. Am. Suppl. I 64, S146 (1978)] that such melodies can be recognized if preceded by a title or a melody cue (an unscrambled version). Here melody cues preceded unfamiliar tonal or atonal, scrambled or unscrambled test melodies. Unscrambled repetitions of tonal melodies were easier to recognize than atonal ones for all subjects. Even inexperienced subjects encoded scale steps of tonal cue melodies more effectively than they encoded pitches of atonal cue melodies. Musically experienced (but not inexperienced) subjects found tonal scrambled melodies easier to recognize than atonal. Subjects apparently tested encoded cue patterns against chromas of comparison melodies. Experienced subjects used that information more effectively to evaluate the chroma patterns of octave-scrambled melodies.
Alarm signals of the great gerbil: Acoustic variation by predator context, sex, age, individual, and family group
Authors: Randall Jan A. , McCowan Brenda , Collins Kellie C. , Hooper Stacie L. , Rogovin Konstantin
Published: October 2005

The great gerbil, Rhombomys opinus, is a highly social rodent that usually lives in family groups consisting of related females, their offspring, and an adult male. The gerbils emit alarm vocalizations in the presence of diverse predators with different hunting tactics. Alarm calls were recorded in response to three predators, a monitor lizard, hunting dog, and human, to determine whether the most common call type, the rhythmic call, is functionally referential with regard to type of predator. Results show variation in the alarm calls of both adults and subadults with the type of predator. Discriminant function analysis classified an average of 70% of calls to predator type. Call variation, however, was not limited to the predator context, because signal structure also differed by sex, age, individual callers, and family groups. These variations illustrate the flexibility of the rhythmic alarm call of the great gerbil and how it might have multiple functions and communicate in multiple contexts. Three alarm calls, variation in the rhythmic call, and vibrational signals generated from foot-drumming provide the gerbils with a varied and multi-channel acoustic repertoire.
Monaural and interaural temporal modulation transfer functions measured with 5-kHz carriers
Authors: Stellmack Mark A. , Viemeister Neal F. , Byrne Andrew J.
Published: October 2005

Temporal modulation transfer functions (TMTFs) were measured for detection of monaural sinusoidal amplitude modulation and dynamically varying interaural level differences for a single set of listeners. For the interaural TMTFs, thresholds are the modulation depths at which listeners can just discriminate interaural envelope-phase differences of 0 and 180°. A 5-kHz pure tone and narrowband noises, 30- and 300-Hz wide centered at 5 kHz, were used as carriers. In the interaural conditions, the noise carriers were either diotic or interaurally uncorrelated. The interaural TMTFs with tonal and diotic noise carriers exhibited a low-pass characteristic but the cutoff frequencies changed nonmonotonically with increasing bandwidth. The interaural TMTFs for the tonal carrier began rolling off approximately a half-octave lower than the tonal monaural TMTF (∼80Hz vs ∼120Hz). Monaural TMTFs obtained with noise carriers showed effects attributable to masking of the signal modulation by intrinsic fluctuations of the carrier. In the interaural task with dichotic noise carriers, similar masking due to the interaural carrier fluctuations was observed. Although the mechanisms responsible for differences between the monaural and interaural TMTFs are unknown, the lower binaural TMTF cutoff frequency suggests that binaural processing exhibits greater temporal limitation than monaural processing.
Temporary threshold shift in bottlenose dolphins (Tursiops truncatus) exposed to mid-frequency tones
Authors: Finneran James J. , Carder Donald A. , Schlundt Carolyn E. , Ridgway Sam H.
Published: October 2005

A behavioral response paradigm was used to measure hearing thresholds in bottlenose dolphins before and after exposure to 3 kHz tones with sound exposure levels (SELs) from 100 to 203 dB re 1μPa2s. Experiments were conducted in a relatively quiet pool with ambient noise levels below 55 dB re 1μPa2∕Hz at frequencies above 1 kHz. Experiments 1 and 2 featured 1-s exposures with hearing tested at 4.5 and 3 kHz, respectively. Experiment 3 featured 2-, 4-, and 8-s exposures with hearing tested at 4.5 kHz. For experiment 2, there were no significant differences between control and exposure sessions. For experiments 1 and 3, exposures with SEL=197dB re 1μPa2s and SEL⩾195dB re 1μPa2s, respectively, resulted in significantly higher TTS4 than control sessions. For experiment 3 at SEL=195dB re 1μPa2s, the mean TTS4 was 2.8 dB. These data are consistent with prior studies of TTS in dolphins exposed to pure tones and octave band noise and suggest that a SEL of 195 dB re 1μPa2s is a reasonable threshold for the onset of TTS in dolphins and white whales exposed to midfrequency tones.
Vibrato of saxophones
Authors: Gilbert J. , Simon L. , Terroir J.
Published: October 2005

Several alto saxophone players’ vibratos have been recorded. The signals are analyzed using time-frequency methods in order to estimate the frequency modulation (vibrato rate) and the amplitude modulation (vibrato extent) of each vibrato sample. Some parameters are derived from the results in order to separate the two ways of vibrato playing: vibrato “à la machoire” and vibrato “sur l’air.” Moreover, time domain simulations of single-reed instrument vibratos are created. The model is controlled by two parameters: the mouth overpressure and a parameter characterizing the reed-mouthpiece system. Preliminary comments and comparisons between the simulated vibratos and recorded vibratos results are made.
Consonant confusions for temporally smeared envelope of syllables in noise
Authors: Yoon Yang-soo , Gooler David , Allen Jont
Published: October 2005

The purpose of this study was to better understand the contribution of speech temporal envelope cues to consonant recognition in noise (−8, 0, 8, 16, 24, and quiet dB SNR). Four tasks were performed for hearing-impaired listeners: Speech-in-Noise test for the measure of sentence repeat ability in noise, gap and intensity detection for the measure of ability to detect changes in sound over time, and consonant identification for confusion matrices. For consonant identification, the temporal envelope of 16 consonants with a vowel /a/ (CV) was extracted from each of 26 critical bands. Each processed CV was temporally smeared by low-pass filtering (4, 8, and 16 Hz). The results show that the mean Pc increases gradually as SNR increases SNR < 16 dB for all conditions, but decreases at SNR > 16 dB for no-smearing and 8-Hz smearing conditions. Consonant confusions result from certain sets of consonants, but the degree of confusion is a function of SNR. The results also show that measures of Speech-in-Noise and gap detection are more related to pure-tone threshold, while intensity detection is less related to pure-tone threshold. However, the effect of interstimulus interval is consistent regardless of degree and configuration of hearing loss.
Ultrasonic method for flow field measurement in wind tunnel tests
Authors: Engler Rolf H. , Schmidt Dieter W. , Wagner Wolfgang J. , Weitemeier Bernd
Published: October 2005

An ultrasonic measuring system has been developed which is useful for fast and nondisturbing exploration of the flow field around models in wind tunnels, especially—according to its integrating method of operation—suitable for the measurement of vortices. It is based on the measurement of the flow-induced running time difference of short ultrasonic pulses, propagating along one or two measuring sound beams, requiring no critical adjustment and no special calibration. From the computer-aided evaluation of the measured data all essential parameters of the vortices under test (position in the flow, core diameter, maximum circumferential velocity, and circulation) can be determined accurately. The method has been successfully employed to steady and to unsteady vortices. In comparison to the conventional method of point by point measurement using directional pressure probes, the measuring times needed are, in general, reduced by about one order of magnitude. This property, besides leading to a corresponding reduction in costs, makes it especially valuable as a quasi real-time method for investigations concerning the influence of even small modifications of the model on the resulting flow field.
Finite rank acoustic scattering problems
Authors: Möhring W.
Published: October 2005

By comparing several known exact solutions of acoustic scattering problems, it is observed that the scattered fields show some joint features. The directivities which are functions of the direction of incidence and of the observation direction can be expressed in terms of one or two functions of one variable. By a type of acoustic momentum equation this is shown to be related to the occurrence of edges in the scattering region. The number of functions of one variable, which we call the rank of the scattering problem, is related to the number and type of edges.
Vibrational relaxation in liquid carbon disulfide
Authors: Takagi K.
Published: October 2005

Ultrasonic velocity and absorption were measured in liquid carbon disulfide at 10°, 20°, and 30 °C over a frequency range from 3 MHz to 5 GHz. Three experimental techniques were used: pulse-echo overlap at 3 MHz, HRB (high-resolution Bragg reflection) from 50 MHz to 1.5 GHz, and Brillouin scattering in the hypersonic region. The obtained spectra of the velocity dispersion and absorption suggested two relaxation processes, one at 100 MHz and the other at ∠6 MHz. A hypothesis of vibrational double relaxation was proposed, in which the lower two fundamental modes, ν1 and ν2 have a common V–T relaxation time at 2.2 ns while the highest ν3 relaxes independently at 30 ns.
Sound transmission loss of gypsum wallboard partitions. Report ♯1. Unfilled steel stud partitions
Authors: Green David W. , Sherry Cameron W.
Published: October 2005

Using the data bank of the acoustics laboratory of Domtar Research, statistical equations based on surface density are derived for predicting the sound transmission loss and sound transmission class of double leaf wall partitions. The partitions are composed of gypsum wallboard attached to light gauge steel studs with screws. The equations, which accurately predict the STL and STC, are in good agreement with results obtained at other laboratories but not with theoretical predictions reported in the literature. Using the equations to investigate the effect of variations in wall constructions on acoustic performance, it was found that the primary factors that affect sound transmission loss are (1) surface density, (2) stud size, (3) method of attaching the panels to the studs, and (4) the method of laminating the sheets in multilayer construction. No improvement in STC was noted for partitions having balanced construction.
Computation of rigid body scattering by prolate spheroids using the T-matrix approach
Authors: Varadan V. K. , Varadan V. V. , Dragonette Louis R. , Flax Lawrence
Published: October 2005

The T-matrix formulation is utilized to obtain calculations of the response of a rigid prolate spheroid to a plane incident acoustic wave, at an arbitrary angle of incidence. Computations are made as a function of frequency in both monostatic and bistatic geometrics. The major features of the monostatic and bistatic response curves obtained agree with predictions based on the interference of specular and diffracted contributions, thus demonstrating the legitimacy of the method.
Adaptive ultrasonic array imaging system through an inhomogeneous layer
Authors: Hirama Makoto , Ikeda Osamu , Sato Takuso
Published: October 2005

An adaptive ultrasonic array imaging technique aiming at reconstruction of the diffraction-limited images of general objects even through an inhomogeneous layer is proposed. The special feature of the system is the estimation of the complex amplitude distribution of the inhomogeneity by measuring the degree of focusing, that is, by measuring the degree of correlation between the transmitted signals and the signals reflected from the object under observation. The construction of a proper measure function, an iterative procedure for the estimation of the inhomogeneity, and the imaging method that uses the estimated inhomogeneity are discussed in detail. The effectiveness of the method is verified both by numerical analyses and experiments.
Generalized Kirchhoff approach to the ocean surface-scatter communication channel. Part I. Transfer function of the ocean surface
Authors: Ziomek Lawrence J.
Published: October 2005

The underwater acoustic propagation path between transmit and receive planar arrays via the surface of the ocean is treated as a linear, time-varying, random WSSUS communication channel. The random, time-varying, transfer function of the ocean’s surface is derived for a bistatic geometry using a generalized Kirchhoff approach. The result for the bistatic configuration can then be easily reduced to either the specular or backscatter geometries. The generalized Kirchhoff approach uses a Fresnel corrected Kirchhoff integral, no small slope approximation, and the Rayleigh hypothesis that the scattered acoustic pressure field can be represented as a superposition of plane waves traveling in many different directions. The transfer function obtained in this paper is shown to contain additional terms when compared with those expressions for scattered acoustic pressure previously derived by the classical Kirchhoff approach, especially for the specular and backscatter geometries.
Comparative frequency selectivity in fishes: Simultaneously and forward-masked psychophysical tuning curves
Authors: Coombs Sheryl , Popper Arthur N.
Published: October 2005

Behavioral methods were used to determine psychophysical tuning curves for three teleostean fish species (Notopterus chitala, Adioryx xantherythrus, and Osteoglossum bicirrhosum) for 300- and 500-Hz signals. Simultaneous masking techniques revealed that 300-Hz curves were similar for all species, with peak masking occurring when the frequency of the masker equaled 300 Hz. In contrast, there were considerable interspecific differences in simultaneously masked 500-Hz curves. The 500-Hz curve for Adioryx was a broadly tuned, V-shaped function with peak masking occurring in the frequency region of the signal, whereas the curve for Notopterus was a sharply tuned, multipeaked function with peak masking occurring for both 500- and 300-Hz maskers. Comparisons of tuning curves obtained with both forward and simultaneous masking techniques for Notopterus revealed little or no difference between 300-Hz curves, but substantial differences between the 500-Hz curves. These results suggest that there are interspecific and frequency-dependent differences in the frequency selective processes of fish auditory systems.
Acoustic propagation in finite length elastic cylinders. Part I: Axisymmetric excitation
Authors: El-Raheb Michael
Published: October 2005

The acoustic propagation in a perfect finite length thin elastic cylinder is studied from an exact solution to the coupled elasto-acoustic equations of motion. Eigenfunction expansions are obtained for Koiter’s consistent shell equations and the Helmholtz equation governing the acoustic field. The acoustic pressure is expressed as the sum of modal acoustic pressures each factored by a normalized influence coefficient related to the corresponding generalized coordinate in the elastic cylinder eigenfunction. A set of nonlinear homogeneous algebraic equations in the generalized coordinates are obtained when satisfying the coupled equations and the compatibility condition at the fluid–cylinder interface. The method when applied to a clamped cylinder filled with water and excited by a plane wave demonstrates the existence of narrow nonresonant peaks in maximum cylinder displacement and a frequency range where the average response rises considerably.
Velocity and attenuation of sound in arterial tissues
Authors: Rooney J. A. , Gammell P. M. , Hestenes J. D. , Chin H. P. , Blankenhorn D. H.
Published: October 2005

The velocity and attenuation of sound has been determined for freshly excised human and canine arterial tissues using a time delay spectrometer (TDS) technique. Frequency was swept from 0 to 10 MHz with data being taken in the range from 2 to 10 MHz. The velocity was determined using a comparison of the time delay for the received signal between a water path and a sample tissue of measured thickness. The velocity of sound was measured for various pathologies and related to biochemical assays of tissue. It was found to increase with increasing ultrasound attenuation of the tissue. The velocity was shown to increase with increased collagen, C, expressed as a percentage of wet weight of the tissue, [V = 17.8*C+1561 m/s at 37 °C, r = 0.77] but was not strongly dependent on tissue cholesterol or low levels of calcium. For highly calcified lesions, the velocity of sound was found to be approximately 2000 m/s at 37 °C.
Optimizing copper spheres for precision calibration of hydroacoustic equipment
Authors: Foote Kenneth G.
Published: October 2005

An operational definition of backscattering cross section is developed for the wideband reception of finite echoes. This is supported by relative measurements on a set of copper spheres by each of four echo sounders operating at frequencies from 38 to 120 kHz. Experiential and theoretical arguments are advanced for the superiority of commercial, electrical–grade copper in the application. An optimization problem for determining the sphere size is then formulated, and solved for the case of calibration of a 38 kHz echo sounder by a sphere of the described material. The solution: that the copper sphere diameter be 60.00 mm, is tested through a variety of measurements. These demonstrate an accuracy of 0.1 dB. The further exercise of theory indicates the feasibility of precision calibration of diverse hydroacoustic equipment by copper spheres over most of the kilohertz frequency range.
Measurement of vortices in the wake of saw teeth
Authors: Price Kirk B. , Mote C. D.
Published: October 2005

Measurements of the wake velocity behind a single tooth on a rigid rotating disk indicated a flow structure characteristic of periodic vortex shedding. The flow structure persisted as the tooth number increased, though the strength of the vorticity was reduced.
’’Practically perfect pitch’’: Some comments
Authors: Hall Donald E.
Published: October 2005

A plea is made against use of the popular but unscientific term ’’perfect pitch,’’ and for greater care to exclude use of relative pitch ability in experiments intended to test absolute pitch ability.
Practically perfect performance
Authors: Lockhead Gregory R.
Published: October 2005

People who can identify piano notes with essentially no errors are often said to have absolute, or perfect, or relative pitch. But it is not pitch that these people identify so well; it is musical notes.
Experimental investigation of the bulk reaction boundary condition
Authors: Bliss Donald B. , Burke Shawn E.
Published: October 2005

A local boundary condition to account for the effect of bulk reaction on the performance of sound absorbing layers was proposed by D. Bliss [J. Acoust. Soc. Am. 71, 533–545 (1982)]. The new boundary condition differs from the usual impedance boundary condition by the inclusion of an additional term involving the Laplacian of pressure taken along the surface multiplied by a complex bulk reaction coefficient, B(ω). The present work shows that B(ω) can be determined experimentally in a relatively straightforward manner. The experimental apparatus and the measurement procedure bear some similarity to the use of an impedance tube. The experimental results demonstrate that bulk reaction effects are important for Owens–Corning PF-705 Fiberglas board. For example, the calculated random incidence sound absorption coefficient for this material increased by an average of 39% over the range of measurement frequencies when bulk reaction was taken into account.
Experimental study on acoustical birefringence in stressed and slightly anisotropic materials
Authors: Imanishi Etsujiro , Sasabe Mitsuo , Iwashimizu Yukio
Published: October 2005

The acoustoelastic effect in rolled metals is examined experimentally by the ultrasonic method. The first experiment is concerned with the birefringence due only to the texture-induced anisotropy. In the second experiment, the uni-axial tensile stress is applied to five specimens which are differently inclined from the common rolling direction, and the birefringence due to both the slight orthotropy and stress is examined. Though the experimental results are a little complicated, they are well explained by those theoretical acoustoelastic relations which one of the authors previously proposed for slightly orthotropic materials. This means that, in general, the polarization directions are fairly rotated by the stress, which is explicitly reaffirmed by the third experiment. It is the main conclusion of the present paper that the acoustoelastic relations referred to above are essential for rolled metals. In previous experimental works, slight anisotropies of polycrystalline metals were hardly taken into account, and hence the stress-induced rotation of the polarization directions could not be treated quantitatively.
Impedance of an orifice under a turbulent boundary layer with pressure gradient
Authors: Goldman A. , Chung C. H.
Published: October 2005

The acoustic impedance of an orifice under a turbulent boundary layer with a pressure gradient was measured. A single orifice was tested in a wind tunnel with freestream velocity varied from 10 to 30 m/s with an imposed pressure gradient which varied from mildly separating to strongly accelerating. The impedance of the orifice as a function of frequency was correlated with variations in the boundary layer parameters. The impedance was insensitive to changes in the outer layer variables, i.e., the boundary layer thickness and pressure gradient. Using inner layer variables, a nondimensional resistance R/ρu* and end correction δe/δeo could be correlated with ωd/u*. It was found that the nondimensional impedance asymptotically approaches a constant value when ωd/u* is greater than 40.
Measurements of atmospheric attenuation at ultrasonic frequencies and the significance for echolocation by bats
Authors: Lawrence Beatrice D. , Simmons James A.
Published: October 2005

The absorption of sound propagating through the atmosphere under laboratory conditions of 25 °C and 50% relative humidity was measured at frequencies from 30 to 200 kHz. The attenuating effect on the passage of ultrasonic sounds through air ranged from 0.7 dB/m at 30 kHz to 8 dB/m at 200 kHz. These measurements confirm theoretical expectations and earlier observations that atmospheric attenuation is progressively more severe at higher frequencies and that the atmosphere acts as a low-pass filter for conducting sounds in the frequency range used for echolocation by bats. Different species of bats use different portions of this range of frequencies, and bats emitting sonar signals predominantly above 100 kHz encounter especially severe attenuation of over 3 dB/m. With the greatly restricted operating distances for echolocation at such high frequencies, bats using these higher frequencies must be under compelling ecological pressures of a higher priority than long-range detection of targets.
Lift/drag ratios and sonic boom intensities of a circular wing
Authors: Padmanaban K. , Bose T. K.
Published: October 2005

The order of attainable lift/drag ratios of a wing of circular planform with biconvex profile has been estimated based on the linearized supersonic flow theory. For this wing, the ground over pressures due to volume and lift have been computed for different flight Mach numbers, thickness to chord ratios, flight altitudes, and wing loadings. It is noted that the booms due to volume and lift are of comparable magnitude even for high flight altitudes.