bluuebunny/crossref_metadata_2025 huggingface dataset:
Institute de Recherche et Coordination Acoustique/Musique—A guided tour
Authors: Hartmann W. M. , Armand J.-P.
Published: October 2005

The Institute for Research and Coordination of Acoustics and Music, directed by Pierre Boulez, pursues new ideas and techniques in music with the aid of acoustic and information science. IRCAM has personnel and facilities in place throughout the large terrain that concerns itself with the creation of musical sounds. There is research in psychoacoustics and in the acoustics of the human voice, of musical instruments and of rooms. Much of this research is of an applied nature, addressing the needs of particular compositions or performance situations. Acousticians often collaborate closely with individual musicians from the Ensemble Intercontemporain, an ensemble of professional musicians dedicated to comtemporary music, allied with the Institute. IRCAM contributes significantly to the continuing development of digital hardware and software for the analysis and synthesis of sounds. Most notable are IRACAM's high-speed digital synthesizers, which permit real-time control in the creation and modification of musical sounds. Musical acitivity at IRCAM extends from composition to performance and commercial recording. The Institute is host to composers from many countries, who employ its facilities to create electronic music. Performance and recording capabilities are greatly enhanced, by the Espace de Projection, an acoustically variable room of unparalleled flexibility. The present talk is a guided tour of IRCAM's unique laboratories and studios, with recorded examples of recent compositions.
Mutes of brass instruments—Experiments and calculations
Authors: Causse Rene , Sluchin Benny
Published: October 2005

We have performed precision measurements to determine the effects of various mutes on the input impedance, external averaged spectra, and radiation patterns of brass instruments. A straight mute introduces a parasitic impedance peak and causes frequency shifts in neighboring impedance peaks. For horns which are approximately conical (e.g., tubal) the parasitic peak lies near the lowest resonance. For horns which are approximately hyperbolic (e.g., trumpet and trombone) the parasite normally lies near the second resonance. With increasing penetration of the mute the parasite frequency decreases. In general, the parasite frequency varies as the inverse square root of the mute volume. A cup mute and a Harmon mute may introduce two parasitic peaks. These effects of a mute may be calculated by modeling both horn and mute as a series of truncated cones and computing the input impedance by an iterative procedure. Calculations to date are in reasonable agreement with experiment. The external spectrum of a muted instrument, averaged over radiation direction and playing frequency, shows up to six prominent minima. These correspond well with calculated impedance minima of the mute itself. The mute material may also significantly affect the radiated spectrum. We have, therefore, studied four geometrically identical straight mutes constructed from wood, plastic, aluminum, and cardboard.
Effects of changes in stress, voicing and place of articulation on word recognition in continuous speech
Authors: Small Larry H. , Bond Z. S.
Published: October 2005

The perceptual effects of three types of mispronunciations were investigated in a continuous speech shadowing task. Two-syllable key words were mispronounced, changing either the stress pattern, the voicing of obstruents, or the front-back dimension of vowels. Three separate prose passages, taken from a popular novel, were used in the three experimental conditions. Each passage was approximately 650 words in length and contained 20 key words. The key words in the three conditions were equated for predictability from context and for frequency of occurrence in English. Subjects were instructed to shadow all three passages. The majority of subjects' responses were exact repetitions when either stress or place was altered. When voicing was altered, the majority of subjects' responses were corrections (restorations) of the mispronounced words.
Influence of lexical status on phonetic categorization
Authors: Fox Robert Allen
Published: October 2005

Recent evidence [Ganong, J. Exp. Psych.: Hum. Perc. Perf. 6, 110–125 (1980)] suggests that the lexical status of a stimulus can shift the location of the (VOT) phoneme boundary of an initial stop, demonstrating that phonetic categorization may be directly affected by higher-level processes. In terms of this issue, two experiments were conducted to determine whether such effects (1) could be extended to a place continuum (b-d-g) or (2) eliminated by modification of the identification task. The stimuli were synthetic monosyllabic tokens whose initial stops varied in terms of a 13-step formant-transition continuum and ended either in a vowel or /b, d, g/ producing a number of word/nonword sets. In experiment I, subjects were required to identify initial stops with no imposed time constraints. Results indicated a significant effect of lexical status at the /b/-/d/ phoneme boundary, but not at the /d/-/g/ boundary. Experiment II required subjects to make their identifications as quickly as possible (RT design) and used a subset of the stimuli from experiment I (/b/-/d/ continuum). Results demonstrated that the significant lexical effect had been eliminated. These experiments are argued to show that lexical status may affect the phonetic categorization process, but purely phonetic decisions, unaffected by lexical knowledge, are possible.
Organization and response properties of neurons in the cochlear nuclei of DBA/2 mice
Authors: Willott James F. , Demuth Ronald M. , Lu Shao-Ming
Published: October 2005

Neurons in the inferior colliculus (IC) of DBA/2 mice (an inbred strain with genetically determined hearing loss and susceptibility to audiogenic seizures—AGS) have a high incidence of afterdischarges (ADs: a continuation of sustained discharges after termination of relatively intense sounds, indicating increased excitability) [J. F. Willott, J. Neurophysiol. 45, 35–47 (1981)]. The present study obtained recordings from the cochlear nucleus (CN) using the same preparation and found no ADs in any CN subdivisions of this strain, indicating that ADs arise at higher auditory nuclei, perhaps involving synaptic mechanisms or a particular neurotransmitter system. Thus, peripheral hearing impairment and/or other genetic factors affected neural responses differently at different levels of the auditory CNS. A second major finding of this study is that tonotopic organization and the shape of tuning curves is abnormal in DBA/2 mice when compared to C57BL/6 mice used as “controls.” In the latter strain, best frequencies (BFs) of tuning curves showed the typical mammalian tonotopic organization, with dorsoventral progression from high to low BFs. In DBA/2 mice, however, virtually all BFs were near 14–16 kHz, regardless of dorsoventral level. In addition, there was sensitization of thresholds for some portions of tuning curves relative to what is seen at a given level in the C57BL/6 strain.
Acoustic plane-wave scattering by a thin rigid plate with a two-dimensional lattice of rectangular apertures
Authors: Sezginer A. , Chang S. K.
Published: October 2005

Scattering of acoustic plane waves by a thin rigid plate with a two-dimensional lattice of rectangular apertures is solved by a numerical technique that identically satisfies the energy conservation. All fields are expressed as summations of Bloch waves using Floquet's theorem. The normal component of the velocity field in the apertures is expanded in a set of basis functions that have the square root singularity at the edges of the apertures, as dictated by the edge condition. The coefficients of the Bloch waves are expressed in terms of the coefficients of the basis functions, which are in turn solved using Galerkin's method. Reciprocity principle is satisfied to the desired accuracy by taking sufficient number of basis functions and Floquet terms. Wood's anomalies are observed for some Rayleigh critical angles.
Vowel reduction, acoustic system contrast, and vocal tract length
Authors: Koopmans-van Beinum Florina J.
Published: October 2005

This paper reports on systematics in vowel systems and their relation to the speech production mechanism. First we studied the reduction of contrasts in vowel systems in several speech conditions. In order to compare the degree of acoustic system contrast of various speakers, we introduced the parameter ASC being the dispersion or total variance of a vowel system. Vowel identification tests with excised vowels revealed that on account of the measured ASC-values predictions can be made concerning vowel identifiability [measured identifiability for (Dutch) vowels in isolation: 90%; vowels in isolated words: 84%; unstressed vowels from free conversation: 33%]. Further research showed that contrast reduction is independent of position or number of vowels in the vowel system. The reference point for calculating ASC existed in the grand mean of all measured formant frequencies per speaker. Independent of languages or speech condition these speaker centroids cluster strikingly in the formant field, suggesting a close relation with vocal tract lengths.
An electropalatographic and acoustical study on coarticulation for alveopalatals [ʎ], [ɲ]
Authors: Recasens Daniel
Published: October 2005

Electropalatographic and acoustical data on VCV coarticulation for the alveopalatals [ʎ], [ɲ] versus consonants of different place have been collected, mainly for one Catalan speaker. For alveopalatals, EPG data show almost no effect of vocalic context over time or on the point of palatal maximum constriction; consistently, corresponding acoustical measurements indicate small or no transconsonantal effects and a small range of variation for F2 frequency values at the closure period for different vocalic environments. On the other hand, palatographic and acoustical data on other consonants, e.g., alveolars, show large transconsonantal coarticulatory effects. These results allow for two different articulatory preprogramming strategies largely dependent on constraints imposed by the articulators, one appropriate to a highly invariant vocal tract configuration shaped by a tongue dorsum raising gesture towards the alveopalatal area and another one appropriate to a more variable configuration subject to coarticulation with the surrounding vocalic environment.
An inverse filtering study of Burmese creaky voice
Authors: Jaykin Hector R. , Maddieson Ian
Published: October 2005

A systematic study of the glottal characteristics of creaky voice in a language which uses it for linguistic contrast has not yet been done. In Burmese, syllables can contrast plain and creaky phonation. The characteristics of these phonation types were studied using inverse filtering [R. L. Miller, J. Acoust. Soc. Am. 31, 667–677 (1959); G. Fant, Q. Prog. Status Rep. Speech Transmission Lab. No. 1, 85–107 (1979)]. A Burmese speaker was recorded in a sound-treated booth using a high-quality condenser microphone and an FM tape recorder. The recording was analyzed through an analog multi-formant inverse filter. An Oscillomink was used to graph (1) the speech wave, (2) the output of the inverse filter (representing the differentiated glottal flow), and (3) the inverse filter output integrated to represent glottal flow. The differences between creaky and normal phonation can be described in terms of peak flow, the asymmetry between the rate of rise and fall of flow in each glottal pulse, as well as F0. [Work supported by NIH.]
Acoustic cues for vowel nasalization: A simulation study
Authors: Maeda Shinji
Published: October 2005

The manner in which vowel spectra are modified as the degree of the nasal coupling is varied was investigated by means of a simulation of the vocal-tract system. Connecting a side cavity, which represents the nasal sinuses, to the main nasal tract, speech synthesis by simulation could produce naturally sounding nasalized vowels [S. Maeda, “The role of the sinus cavities in the production of nasal vowels,” Proc. IEEE ICASSP82, Paris, 911–914 (1982)]. Such spectral variations were studied in detail to shed some light on acoustic cues for vowel nasalization. The advantage of the simulation approach is that the acoustic characteristics of the nasalized vowels can be calculated for arbitrary coupling magnitude, with a realistic vocal-tract model. The computed vocal-tract transfer functions were then converted to pseudo-auditory excitation patterns. A consistent effect of the coupling, for the 11 French vowels that were investigated, was a flattening of the excitation patterns, extending in the frequency range from 300 to 2500 Hz. Since those vowels with flattened spectra were actually heard as nasalized, it may be suggested that the principal cue for nasalization is spectral flattening in that wide frequency range.
On the kinematics of articulatory control us a function of stress and rate
Authors: Tuller Betty , Kelso J. A. Scott , Harris Katherine S.
Published: October 2005

In n previous paper that analyzed phase relations among various muscles as a function of speaking rate and syllable stress [Tuller, Kelso, and Harris (1982)], we found that the time of onset of consonant-related activity remained fixed relative to time of onset of activity for flanking vowels, although substantial changes occurred in peak EMG and duration of EMG in individual muscles. This finding suggests that it is the internal timing relations that are preserved invariant across suprasegmental variation. It is not known whether the kinematic structure of the movement trajectories exhibits n pattern that can be interpreted in an analogous way. To this end, we examined subject's productions of b-vowel-consonant-vowel-b utterances where the vowels were either /a/ or /æ/ and the medial consonant either /b,p,v/ or /w/. Two speaking rates and two stress patterns were varied orthogonally. Infrared L.E.D.s were attached to the lips and jaw and monitored, using a modified SELSPOT optical tracking system. Thus far, the kinematics map rather well onto the earlier EMG findings and together provide evidence for relational invariance in articulation. [Work supported by NINCDS and BRSG.]
Laryngeal adjustments in stop and fricative production
Authors: Munhall Kevin G. , Parush Avraham , Ostry David J.
Published: October 2005

A computerized pulsed ultrasound system was used to study the dynamics of laryngeal abduction during obstruent production. Subjects produced the consonants /s/ and /t/ in a /tɛCɛt/ context at two rates, with either the first or second vowel stressed. Preliminary results indicate that the time from offset of the first vowel to the maximum laryngeal opening was positively related to oral closure or approximation duration. However, the maximum opening of the gestures associated with the production of /s/ occurred closer to vowel offset than those for /t/ in comparable conditions. In addition, the interval from vowel offset to maximum opening velocity was found to vary as a function of stress and consonant. The time to maximum velocity was shorter for the gesture associated with /s/ than for /t/ and shorter for consonants following a stressed vowel than for those preceding stressed vowels. These aspects of laryngeal displacement and timing will be discussed in terms of interarticulator organization.
Focusing concentric ring electrode array transducer
Authors: Claus Richard O. , Wade Janet C. , Dockery George D. , Ocheltree Kenneth B.
Published: October 2005

We have previously described the generation of a two-dimensional Gaussian profile ultrasonic field using a piezoelectric transducer with concentric ring electrodes [R. O. Claus and P. S. Zerwekh, J. Acoust. SOC. Am. Suppl. I 71, S12 (1982)]. In this paper, two-dimensional ultrasonic field focusing achieved by a similar transducer is presented. The focusing transducer was constructed using a 7.62-cm-diam crystal quartz disk dimensioned to resonate at 500 kHz. Concentric circular electrodes 1.27 mm wide and separated by 1.27 mm spaces were deposited on one flat surface of the disk and an aluminum foil ground plane and wear plate was attached to the opposite surface using conducting epoxy. By individually varying the time delays between the 300-V 10-ns pulses applied to the electrodes, the location of the focal plane is controlled. In this plane, focus spot half-power diameters of less than two acoustic wavelengths have been obtained. Experimental measurements obtained in a water tank using electrode phasing for both linear geometrical superposition and lens-like focusing are presented and compared with theoretical results. [Work supported in part by NASA and NSF.]
Difference equation evaluation of the evolution of radially symmetric ultrasonic fields
Authors: Dockery George D. , Claus Richard O. , Zerwekh Paul S.
Published: October 2005

A simplified difference equation technique has been developed to calculate the three-dimensional evolution of radially symmetric complex ultrasonic fields. Localized changes in the magnitude of the field with respect to distance along the axis of propagation are first assumed to be small compared to those with respect to radial displacement. The complex Helmholtz equation in cylindrical coordinates then may be simplified by separating variables and approximating these variables by truncated series expansions. The resulting difference equation determines complex field values at discrete locations in a plane from corresponding adjacent locations in the preceding plane. Stability criteria which limit both the step sizes between consecutive planes and between calculated field values in one plane are discussed. The technique has been applied to the propagation of ultrasonic fields generated by two-dimensional focusing and non-focusing uniform and Gaussian profile piezoelectric transducers and theoretical and experimental data are presented. [Work supported in part by NASA and NSF.]
Point-to-point impulse response due to the presence of simple reflectors
Authors: Hazony Dov , Kocher Thomas E.
Published: October 2005

Recently there has been considerable activity in the area of time-dependent impulse response of acoustic radiators [P. R. Stephanishen, J. Acoust. Soc. Am. 49, 1629–1638 (1971)]. A logical extension of these ideas is to the problem of acoustic radiators acting as reflectors. The impulse response for a system consisting of a simple source, a reflector, and a receiver was determined for several reflector geometries. Each reflector was analyzed with a source (P1) and a receiver (P2) for several important cases. The specific case, when P1 = P2, i.e., transmit-receive, provides a very important special case. The principle tool used was Rayleigh's integral. [Work supported by NEI ♯5R01EY03251-02 and USAF ♯F33615-81-C-0103.]
Geometric reconstruction of flaws by one-dimensional inverse Born approximation
Authors: Hsu D. K. , Rose James H. , Thompson R. B. , Thompson D. O.
Published: October 2005

We report a three-dimensional reconstruction of the size, shape, and orientation of volumetric flaws (inclusions and voids) based on the results of one-dimensional Born inversions of the scattering amplitudes for observation directions confined to a finite angular aperture. The reconstruction is realized by performing nonlinear least squares iteration of the Born inversion results in terms of an equivalent ellipsoid. We have successfully reconstructed spherical and nonspherical inclusions in the bulk of plastic samples and an oblate spheroidal void in a titanium disk. In addition we have applied the ellipsoidal reconstruction method to a spheroidlike inclusion very near the surface of a sample and obtained good results. The method was found to remain quite successful even with experimental data confined to a rather limited aperture. Effects on the one-dimensional inverse Born algorithm due to characteristic resonances of the inclusions and flaw-surface interactions will be discussed. [Work sponsored by Engineering Program, Office of Basic Energy Sciences, USDOE and by Center for Advanced NDE, operated by Ames Laboratory, USDOE, for AFWAL and DARPA under contract No. W-7405-ENG-82 with Iowa State University.]
Observation of the acoustic glory: Scattering from an elastic sphere in near backward directions
Authors: Marston Philip L. , Hanson Timothy J. B. , Williams Kevin L.
Published: October 2005

We have measured the scattering for small angles γ (relative to the backward axis) from a fused silica sphere of radius a≈52 mm. Tone bursts in water corresponding to ka≈450 were incident on the sphere; their short duration permitted glory and axial returns to be separated in time. The γ for the probe hydrophone was scanned to test a model [P. L. Marston and L. Flax, J. Acoust. Soc. Am. Suppl. I 68, S81 (1980)] of diffractive effects on backward axial focusing. Observations tend to support the model as adapted to fused silica: (1) from the arrival time, the strongest echo is evidently due to the 4-chord shear glory ray; (2) its amplitude is ∝J0(kb sin γ) where b is the calculated glory circle radius; (3) its amplitude at γ = 0, though slightly smaller than predicted, exceeds that of the first axial reflection; and (4) the times, amplitudes, and γ dependences of other echoes are correlated to predictions. The first null of the strongest echo occurs at γ≃1°. Consequently, we demonstrate for the first time the diffraction limited backward focusing of echoes from a sphere. [Work supported by ONR. Marston is an Alfred P. Slosh Research Fellow.]
Some numerical techniques and their use in the extension of the T-matrix approach to scattering
Authors: Flax L. , Hackman R. , Werby M. F.
Published: October 2005

The T-matrix methodology of Waterman has been used to describe acoustic, electromagnetic, and elastic scattering. Some of the limitations on this method from a calculational point of view have been due to difficulties in treating large matrices which arise in association with the need for large sets of basic states required for the description of surfaces which deviate from classical symmetries as well as for high-frequency calculations. We present a number of useful numerical techniques for large, ill-conditioned matrices which improve the range of applicability of the T-matrix theory.
Implications of a population study of hearing thresholds and noise exposure
Authors: Gatehouse S. , Davis A. C. , Haggard M. P.
Published: October 2005

The Institute of Hearing Research is currently undertaking a 4-yr 3-phase national study of hearing in the UK. The multicenter team is applying a comprehensive clinical and audiological evaluation to a stratified sample of approximately 2400 individuals drawn from a questionnaire sample of 36 000. This permits linkage of data on impairment, pathology, and disability to population prevalence. The data furnish many results; two are reported here. Data from equivalent noise exposure levels of ⩽80 dB(A), 81–90 dB(A) and > 90 dB(A) show significant effects of noise exposure at 2000 Hz and above for the highest exposure band, but not for the midexposure band. This implies that the concept of socioacousis, where prolonged exposure to relatively low levels of noise causes a hearing deficit, may not be valid. There is an interaction with age and a consistent dip in the thresholds at 6000 Hz. The hearing levels of young otologically screened subjects deviate systematically from the ISO standard for audiometer calibration and again exhibit a discernible dip at 6000 Hz. These data throw some doubt on the ISO standard, particularly at 6000 Hz.
Impact on telephone operator word recognition performance of headphone type and background noise level
Authors: Johnson David W. , Sherman Robert E.
Published: October 2005

Twenty switchboard operators with clinically normal hearing were tested for ability to recognize W-22 words presented to control for order and sequence effects in six approximately matched 25-word lists. Tape lists were dubbed from an earlier generation of taped lists where signal-to-(cafeteria)-noise ratios were 0 to + 15 dB. Lists were presented with operators wearing their own headsets (e.g., Plantronics Star Set) and the newly introduced Danavox Stetomike (which allowed either monaural or binaural listening). Testing performed in a standard double-wall construction sound booth allowed testing each headset configuration (i.e., their own monaural headset, the Stetomike monaural headset, and the Stetomike binaural headset) in quiet and in background noise approximating an actual listening environment faced by operators (a tape of actual operator room noise presented at + 55 dBA). There was great individual difference in the subjects' ability to correctly recognize words with older subjects performing significantly poorer than younger and the background noise greatly impairing performance overall. There was no statistically significant difference in performance which could be attributed to headphone configuration in either quiet or noisy background conditions.
A psychophysical evaluation of the dependence of hearing protector attenuation on noise level
Authors: Humes Larry E. , Ahlstrom Jayne B.
Published: October 2005

The attenuation characteristics of ten commercially available hearing protectors (five muffs and five plugs) were examined for one-third octave-bands of noise centered at 1000, 2000, 3150, 4000, and 6300 Hz in ten normal-hearing young adults utilizing four psychophysical procedures. One of these procedures, the real-ear attenuation at threshold procedure described in the American standard for the evaluation of hearing protectors, is designed for use at one-third octave band noise levels below approximately 50 dB SPL. Three new real-ear psychophysical procedures were also developed and evaluated. These procedures were: (1) a reaction-time paradigm; (2) a loudness magnitude-estimation procedure; and (3) a masked bone-conduction threshold technique. Each procedure was designed to evaluate protectors at one-third octave band noise levels ranging from approximately 50 to 90 dB SPL. Mean data indicated that: (1) attenuation was linear over the range investigated, although some exceptions to this generalization were apparent; (2) attenuation estimates derived with the reaction-time and magnitude-estimation paradigms were typically lower than those obtained with the other two methods; and (3) all attenuation estimates, regardless of procedure, were lower than manufacturer's specifications for the majority of the protectors. Implications for existing standards are discussed.
Music perception us detection of pitch-time constraints
Authors: Balzano Gerald J.
Published: October 2005

Music is viewed as constrained pitch-time structure. Perceiving music is taken fundamentally to be a process of detecting constraints in pitch-time information. These contraints emerge as invariants-under-transformation relative to certain mathematical groups. Groups for pitch and time structures are typically specified by an order relation and an equivalence relation. For pitch, the order relation is realized by pitch points that can be generated by a unit pitch interval (“semitone”), the equivalence relation by the octave. For time, the order relation is realized by time points that can be generated by a unit time interval, and the equivalence relation is created by the “measure” or “barline.” By rendering pitch points separated by octaves as closely related, and similarly for time points at corresponding places in different measures, music reduces the number of its essentially different transformations drastically over pitch-time structures not so constrained, such as intonation contours in speech. In a number of experiments, listeners' ability to detect musical constraints is tested with “pseudomelody” stimuli—pitch-time structures consisting of approximately 80 note-events—exhibiting different kinds and degrees of constraint, and findings are reported. The present view of music perception as detection of existing structure is contrasted with current views of perception as construction or invention of structure, and a plea for a realist perspective in music research is expressed.
Acoustic streaming induced by the “vortex whistle” is the cause of the Ranque-Hilsch effect
Authors: Kurosaka M. , Goodman J. R. , Chu J. Q.
Published: October 2005

In 1933, Ranque discovered a striking phenomenon: When pressurized air is injected tangentially into a pipe and imparted a swirling motion, its total temperature separates into a colder one at the centerline and a warmer one at the periphery. The separation takes place spontaneously, without the aid of any external mechanical work. The effect became popularized after the Second World War by the work of Hilsch; the so-called Ranque-Hilsch tube or the vortex tube is now commercially available. Even for inlet air at only a few atmospheric pressure and at room temperature, the total temperature at the tube center can easily become freezingly cold; the total temperature at the periphery exceeds its upstream value correspondingly. Although there exists a general consensus that some unsteadiness is needed to account for this phenomenon, the crucial issue as to the precise form of unsteadiness or its explicit mechanism has never been resolved. Now, it is a known fact that a pure tone of high intensity or vortex whistle often emanates from the vortex flow, the Ranque-Hilsch tube included; its frequency increases proportionally to the swirl. We submit here that acoustic streaming induced by the vortex whistle is the mechanism of the Ranque-Hilsch effect. We demonstrate this, based on our recently published work [Kurosaka et al., J. Fluid Mech. (in print)] and on additional results obtained subsequently. [Work supported by the Air Force Office of Scientific Research.]
Spherical acoustic resonators for thermophysical property and standards measurements
Authors: Moldover Michael R. , Mehl James B.
Published: October 2005

We are studying the feasibility of using the resonances of a low density gas enclosed by a thick spherical shell for measuring various thermophysical properties, including the thermodynamic temperature, and the universal gas constant R. The radially symmetric resonances have high Q's (2000–10 000). Thus very simple instrumentation can be used to measure the speed of sound in a gas with an accuracy of 0.02%. We have used more elaborate instrumentation to measure resonance frequencies, fx, and resonance halfwidths, gx, with a precision on the order of 10−7 fx. The ratios of fx for various resonances, extrapolated to zero pressure, are within ± 3 × 10−6 of the ratios predicted by our theoretical model. For the same resonances, the measured values of gx exceed the theoretical values by less than 5 × 10−6 fx. These results suggest that an acoustic measurement of the thermodynamic temperature or the gas constant could be accurate to 0.001%. The simple geometry of this oscillating system makes it easy to incorporate many phenomena in a theoretical model. We have included the following boundary effects: (1) the thermal boundary layer; (2) shell elasticity; (3) transducer coupling holes and a fill hole; (4) adsorption and desorption; (5) geometric imperfections, and (6) the viscous boundary layer (for non radially symmetric modes).
Interaction of ultrasonic waves with cracks
Authors: Adler Laszlo
Published: October 2005

An overview is presented on recent studies of ultrasonic waves interacting with artificial and real cracks. Various experimental methods will be described to obtain quantitative information concerning both geometrical [such as size, orientation] parameters as well as physical and surface parameters [such as stress intensity, surface roughness, distribution function, closure] of cracks. Various analytical approaches to support experimental results and carry out inversions will also be emphasized. [Work supported by DARPA/AF through Ames Laboratory.]
Application of x-ray diffraction to monitor fatigue deformation in high strength alloys
Authors: Pangborn Robert N.
Published: October 2005

A number of x-ray diffraction techniques have been applied to measure the fatigue deformation introduced during axial and flexural loading in high strength aluminum and nickel base alloys. X-ray double-crystal diffractometry and x-ray line-broadening analyses were conducted to evaluate the localized and average microplasticity, respectively, generated prior to crack initiation. The modifications in diffraction peak profiles recorded using these techniques were interpreted in terms of changes in lattice distortion and dislocation density and correlated to the surface topographic features developed during fatigue cycling. These methods were also utilized to examine the fatigue deformations accrued in the subsurface and bulk of the samples. Both stepwise removal of surface layers and nondestructive evaluation using x rays of different penetration capability were employed to obtain the depth profiles. X-ray stress measurements were made to disclose the modifications in residual stress occurring during fatigue, their relationship to the dislocation distribution, and their role in crack nucleation. The combination of x-ray methods provided information useful both to identification of the failure mechanism and to monitoring cumulative deformation preceding ultimate failure, even under spectrum amplitude testing conditions.
Perceptual scale for voice onset time (VOT) in synthetic /bae/ /pae/ syllables
Authors: Espinoza-Varas B.
Published: October 2005

The scale used by the perceptual system to represent variations in VOT appears to be different from the physical VOT scale. The perceptual scale, ranging from voiced to voiceless, has zero point at the phonetic boundary (the zero voiced-voiceless point). The degree of voicedness (voicelessness) increases with the distance between the VOT value and the boundary. Further, the perceptual effect of a difference in VOT near the boundary is greater than at points remote from the boundary. A rescaling of the VOT continuum that is more consistent with the properties of the perceptual scale is given by the function Dxi = k |xi − xb |β,0 < β < 1, where xi is a VOT stimulus value, xB the boundary VOT, k a constant, and Dxi the perceptual magnitude of xi along the voiced (voiceless) scale. The perceptual distance, Δ D, between two stimuli xi,xi + 1, is given by the difference between Dxi and Dxi + 1; that is, Δ D = k ‖xi + 1 − xB|β − |xi − xB|β|. The power transformation at the perceptual level is suggested by the following: (1) the relation between cumulative disciminability and cumulative distance from the boundary, in log-log coordinates, is well described by straight lines with positive slopes smaller than one. This is observed in /bae/ /pae/ discrimination data obtained in the present and in previous studies [Elman, J. Acoust. Soc. Am. 65, 190–207 (1979)]; (2) for a constant msec difference between xi and xi + 1 the function Δ D reaches a maximum when the pair straddles the boundary, and decreases monotonically as the distance between the stimuli and the boundary increases; (3) changes in discriminability associated with changes in the size of the VOT steps Of the /bae/ /pae/ correlate strongly with changes in Δ D.
Laterality differences in speaker and consonant identification in dichotic listening
Authors: Tartter V. C.
Published: October 2005

Two dichotic listening experiments were conducted using the syllables [ba], [da], [pa], and [ta] each spoken by two male and two female speakers. Twenty right-handed subjects participated in each experiment. Each experiment consisted of two parts with order counterbalanced across subjects: in one, subjects identified the two consonants; in the other, after a brief training session to familiarize them with the speakers, they identified the two speakers. The experiments differed in whether the nontarget dimension varied. In experiment 1 if subjects were identifying speaker, the same consonant was presented to both ears on a given trial, whereas in experiment 2 both speaker and consonant varied. Both experiments resulted in significant right-ear advantages for consonant identification, typical feature-sharing advantages and blend errors for consonants, significantly fewer errors in speaker identification than consonant identification, and greater confusion between same-sexed voices than different-sex voices. Experiment 1 showed no significant ear advantage for speaker identification while experiment 2 revealed a marginal right-ear advantage. The difference is attributed to greater involvement of the left hemisphere incurred by the extra phonetic variation.
Perceived manner and the intervocalic place cues of /s/
Authors: McCasland George P.
Published: October 2005

A set of 12 pairs of CVCV /sɪsi,sɪsɑ/ tokens spoken by one male were subjected to PCM editing to remove the friction noise of the intervocalic /s/. In a perceptual identification test subjects judged the consonants represented by the intervocalic silent intervals as one of /p,t,s,f,θ/. In a second test subjects were forced to choose only fricatives /f,θ/. For the /sɪsi/ series of tokens with the /−i/ final vowel, when the manner judgment was a stop, it was predominately /p/ indicating a labial place cue. When the manner judgment was a fricative, it was predominately /θ/ indicating a dental-alveolar cue. Perceived place depended on perceived manner. For the /sɪsɑ/ series, a manner-place effect was not apparent; nearly all judgments were /t/ or /θ/. Clearly, any association between place and manner judgments may be specific to the vocalic context. This investigation extends the work previously reported by the writer [J. Acoust. Soc. Am. Suppl. 1 71, S105, 1982] and the work of Cardin, Levitt, Jusczyk and Walley [Percept. & Psychophys. 29, 26–36 (1981)]. [Haskins Laboratories provided valuable assistance in preparing speech samples on NICHD Contract No. NIH-71-2420.]
Signaling of syntactic structure in whispered speech
Authors: Lehiste Ilse
Published: October 2005

Several recent studies have shown that the internal structuring of a sentence can be signaled by manipulation of the time domain [for a review, cf. R. Scott, J. Acoust. Soc. Am. 71, 996–1007 (1982)]. Other studies have associated the signaling of syntactic boundaries with specific pitch movements, such as a fall-rise in the intonation contour [cf. W. E. Cooper and J. M. Sorensen, J. Acoust. Soc. Am. 62, 683–692 (1977)]. An experiment was designed to explore whether there is any difference in the perception of syntactically ambiguous sentences produced in two modes: with normal phonation and in whisper. Two Speakers of American English recorded phonated and whispered versions of a list of 20 sentences containing instances of four syntactically ambiguous sentences. Twenty-five listeners identified the meanings intended by the speakers. The correct scores, averaged for the two speakers, were 97.1% for phonated speech and 97.6% for whispered speech. Analysis of the sentences showed that while whispered sentences were somewhat longer than phonated sentences, the speakers had made no special effort to compensate for the absence of F0 cues by exaggerating durational cues.
Accuracy and criterion in the perception of speech by young and old listeners
Authors: Yanz Jerry L. , Anderson Shirley M.
Published: October 2005

Several authors have used signal detection theory (SDT) to demonstrate that older listeners use stricter criteria than younger listeners in detecting tones in noise [e.g., J. N. Rees and J. Botwinick, J. Gerontol. 26, 133–136 (1971); M. Potash and B. Jones, J. Gerontol. 32, 436–440 (1977)]. Our aim was to determine if such criterial differences also exist in the perception of speech. The identification of monosyllables (CID W-22 lists) presented in a broadband noise background (S/N = 0 or 5 dB) was evaluated in young and old listeners. Immediately after identification of a test item, listeners rated the accuracy of their own identification on a six-point scale [see I. Pollack and L. R. Decker, J. Acoust. Soc. Am. 30, 286–292 (1958)]. Performance accuracy and decision criteria were separated according to a SDT analysis. Data showed no difference in criterion between young and old groups and a difference in accuracy only for the more favorable signal-to-noise ratio. Two performance measures will be discussed—percent correct, the conventional measure in speech audiometry, and P(A), the nonparametric measure of performance accuracy in SDT—with regard to the quantification of perceptual accuracy and communication effectiveness.
Absolute judgments of speech rate as a function of vocal frequency and intensity
Authors: Feldstein Stanley , Bond Ronald N. , Simpson Sallie , Brady Elizabeth
Published: October 2005

Previous studies have found that vocal frequency and intensity both influence the perception of speech rate when a standard, or “anchoring,” stimulus preceded each experimental stimulus. The two studies reported here replicated the previous studies but omitted the anchoring stimulus. In one study, 30 judges rated nine “content-masked” speech stimuli generated from a 20-second female speech sample by factorially combining three levels each of manipulated frequency and intensity. In the other study, 29 judges rated 18 content-standard stimuli generated from two 20-s speech samples, one from a woman and one from a man. The actual rate of each stimulus was 150 wpm. With the masked stimuli, frequency and intensity separately influenced the perception of speech rate. With content-standard stimuli, frequency and intensity jointly affected speech-rate perception. Moreover, the joint influence was affected by the gender of the speaker; stimuli from the male speaker were judged to be faster. The studies suggest that an anchoring stimulus is not needed to demonstrate the influence of frequency and intensity on speech-rate perception.
Near and farfield transfer-function technique for reverberation room response studies
Authors: Chu W. T.
Published: October 2005

The current qualification procedure for discrete frequency measurements in reverberation rooms is difficult and time-consuming. The possibility of using the transfer function between a near-field microphone close to the speaker and another microphone in the reverberant field with narrow-band random noise excitation has been explored. Preliminary results indicate that this technique can be a very attractive alternative. It is fast and does not require any near-field measurement of the speaker in an anechoic room.
Transverse Doppler acoustic current meters
Authors: Clarke Thomas L.
Published: October 2005

Limitations of existing profiling acoustic current meters are examined. The characteristics of both single pulse processing and pulse to pulse coherent processing force severe compromises in performance. A new transducer geometry is proposed that, in conjunction with coherent processing, relaxes these constraints. The velocity component perpendicular to the beam is measured by utilizing the differential or transverse Doppler shift between the signals received by two spatially separated transducers. Examples are given of the application of this technique to a variety of flow regimes, and experiments designed to prove the feasibility of this technique are outlined.
Deduction of bottom reflection phase change using normal modes
Authors: Yang T. C.
Published: October 2005

For discrete normal modes in shallow water, the mode characteristic equation is known to depend on the phase change of bottom reflection. Precise measurement of mode time-frequency dispersion has enabled us to deduce the phase change using just the shot data. We discuss the method and present the phase-change data for grazing angles between 9° to 10.4°. This proves to be a useful technique since direct experimental measurement of phase change is extremely difficult. Past work which investigated the bottom properties have concentrated on the reflectivity coefficients. We find that the phase-change information can also shed light on the acoustic properties of the bottom. It is hoped that this technique for measuring the phase change will be utilized to gain further understanding of the ocean bottoms.
Heterodyne interferometry and holography for vibration measurements
Authors: Dändliker René
Published: October 2005

Two frequency or heterodyne interferometry transforms the optical interference phase into the phase of an electronically detectable beat-frequency signal. This allows to use powerful signal processing for increased sensitivity far below the optical wavelength λ and high temporal resolution, especially for vibration analysis. The principle and the properties of this heterodyne technique will be illustrated by presenting laser interferometry for displacement and velocity measurements. With an extended version [R. Dändliker and J.-F. Willemin, Opt. Lett. 6, 165–167 (1981)] amplitude and phase of in-plane and out-of-plane microvibrations (amplitudes 1 nm, spatial resolution 30 μm) at frequencies from 5 kHz to 5 MHz can be analyzed in real time. Experimental results for piezoelectric ultrasound transducers will be presented. Two-reference-beam holographic interferometry allows to use the heterodyne technique for accurate fringe evaluation and interpolation (λ/1000), since the two object fields are stored and accessible independently by the corresponding reference beam [R. Dändliker, Progress in Optics (North-Holland, Amsterdam, 1980), Vol. 17, pp. 1–84.]. For vibration analysis, however, the object has to be recorded holographically by two or more coherent light pulses, synchronized to the object movement, using pulsed lasers or stroboscopic light modulation. Experimental results of deformation measurements by heterodyne holographic interferometry will be presented. The strength and weakness of this technique applied to vibration analysis will be discussed in particular.
A reliability model for predicting electric flashover failures of transducer ceramics
Authors: Browder Lynn P.
Published: October 2005

The electrical breakdown of sonar transducers has been a matter of great concern in recent years. Transducer replacement is generally very expensive, so high reliability is required of each unit in order to reduce life-cycle cost and to improve sonar system readiness. Since it is advantageous to be able to mathematically predict the life time of a transducer in its design stage, a reliability model has been developed by considering electric flashover failures at the ceramic/gas interface. The applied voltage that causes flashover may now be calculated as a function of time-to-break-down in a transducer. Based on the voltage endurance test results on ceramic samples, the effects of physical parameters such as creepage distance and frequency, and environmental conditions including temperature, gas pressure, air contamination, and water vapor were determined. A random factor was also included to approximate the random variation of flashover voltage levels due to the combined effect of all the other factors. In addition to presenting the model itself, potential application to transducer reliability estimation will also be discussed.
Development of a hydraulically powered underwater acoustic projector for use in the range of 1 to 10 Hz
Authors: Hugus George D.
Published: October 2005

Development of a hydraulically powered acoustic projector with a minimum source level of 160 dB re:1 μPa at 1 m over the 1 to 10 Hz range will be presented. This projector will be used at the Underwater Sound Reference Detachment for low-frequency underwater acoustic testing. Design parameters and their relation to the unique capabilities of hydraulic power for this low-frequency application will be discussed. Construction details, and acoustic as well as mechanical performance will also be presented. [Work supported by Naval Sea Systems Command, Code 63R.]