bluuebunny/crossref_metadata_2025 huggingface dataset:
Stimulus uncertainty and speaker normalization processes in the perception of nasal consonants
Authors: Haley Katerina L. , Ohde Ralph N.
Published: October 2005

Previous research has noted a reduction in perceptual identification performance when the speaker varies from stimulus to stimulus. This reduction has been interpreted in the context of a speaker normalization process that separates speaker-specific information from invariant phonemic units. Alternatively, the effect may relate to stimulus uncertainty from a general psychoacoustic perspective. The present study addressed this possibility by examining the effect of variability not only in talker identity, but also in stimulus type. The stimuli were short segments taken from nasal consonent + vowel syllables produced by one male adult, one female adult, and two children. Segments of 25- and 50-ms duration were edited from the nasal murmur and the onset of the vowel. These stimuli were then grouped according to four variability conditions and presented to listeners for place of articulation identification. The results showed that both sources of variability reduced identification performance significantly. Separate analyses for the different segment types revealed that segment variability impaired perception of all segment types approximately equally, but that the 50-ms vowel segments were selectively spared in the speaker variability condition. Implications for competing models of speaker normalization are discussed, and consideration of stimulus uncertainty effects in speech perception research recommended. [Work supported by NIH, DC00464.]
Modeling the effect of learning voices on the perception of speech
Authors: Nygaard Lynne C. , Kalish Michael
Published: October 2005

The speech signal carries information about a talker’s voice and about linguistic content along the same acoustic dimensions. Traditionally, the unraveling of talker and linguistic information has been characterized as a normalization process in which talker information is discarded in the listener’s quest for the abstract, idealized linguistic units thought to underlie speech perception. Recent studies, however, have demonstrated that the processing of voice and the processing of linguistic content are not independent. Nygaard etal. [Psychol. Sci. 5, 42–46 (1994)] have found that learning a talker’s voice facilitates subsequent phonetic analysis and suggest that familiarity with a talker’s voice involves long-term changes in the speech perceptual system. In order to explain this phenomenon, a model is proposed in which a single set of representational elements is responsible for preserving information about both talker and phonetic content. This model was instantiated as a recurrent auto-associated network trained to reproduce cochleagrams [R. F. Lyon, Proc. IEEE ICASSP ’82] of a restricted set of words, for a given set of talkers. At test, input representations included cochleagrams of novel words produced by both ‘‘familiar’’ and novel talkers. The model made fewer errors reproducing patterns from talkers encountered in training than when reproducing patterns from novel talkers. The behavior of the model was due to (1) the assumption of integrated representation, (2) significant change (perceptual learning) during training, and (3) the specifics of the neural network architecture.
The role of talker-specific information in memory for spoken sentences
Authors: Karl John R. , Pisoni David B.
Published: October 2005

Contrary to most traditional theories of speech perception, talker-specific information is not filtered out or ‘‘lost’’ during perceptual analysis, but is retained in the processing and representation of spoken language. Effects of talker-specific information have been found for words and phonemes spoken in isolation [J. W. Mullennix and D. B. Pisoni, J. Acoust. Soc. Am. 85, 365–378 (1990); Goldinger etal., J. Exp. Psychol.: Learn., Mem. Cog. 17, 152–162 (1991)]. However, the processing of spoken sentences may be quite different from isolated words due to coarticulation across words, suprasegmental information, and syntactic and semantic constraints. The present experiment investigates whether the effects of talker-specific information on the processing of sentences are similar to those found for the processing of isolated words and phonemes. Subjects first transcribed lists of sentences in either a single-talker or multiple-talker presentation format; they were given a probed recall test to assess memory for the sentences. While transcription accuracy was higher in the single-talker than the multiple-talker condition, cued recall performance for correctly transcribed sentences was not significantly different between the two presentation conditions. Implications of these findings for current theories of spoken language processing will be discussed in the context of recent episodic and multiple-trace models of human memory.
Speaker sex and formant frequencies of American [r]
Authors: Hagiwara Robert
Published: October 2005

Phonetic studies of speaker sex have primarily focused on phonation and vowel formants—very little is known about the effect of speaker sex on consonants and consonant-like sounds. Similarly, studies of American [inverted r] have not explored whether and how speaker sex affects the acoustic character of this sound. As part of a larger study of speaker sex and approximant [inverted r], 10 speakers (5 male, 5 female) of American English read three repetitions of 69 target words presented randomly in a frame. In addition, gross tongue shape used for the various allophones of [inverted r] was determined for each speaker by inserting a probe into the mouth during articulation. At least three tongue shapes can be discriminated using this method. In this presentation, the formant frequency data for the vowel tokens, including syllabic [inverted r], are examined in light of the following issues: the location of syllabic [inverted r] in a traditional vowel space (F1×F2); the quantitative effect of speaker sex on the frequency of the first three formants of syllabic [inverted r]; and whether there is any sex bias in the distribution of tongue shapes used to produce this sound, and what effect this has on its acoustic quality.
Acoustic correlates of distinctive features of Italian stops
Authors: Vannucci Armando
Published: October 2005

The object of this study was the determination of acoustic correlates of two distinctive features of Italian stops related to voicing and point of articulation. The analysis was carried out on 648 VCV syllables. The correlates found for voicing were the sound bar during the voiced stops occlusion and the low-frequency (LF) burst energy. Informal perceptual tests showed the relevance of only the second correlate. As to the point of articulation, the attention was focused both on formants transition from the first vowel to the following stop and on the spectral shape of the burst. For the formants transition, different groups of templates were obtained for the different vowels. The burst spectrum was then analyzed to obtain a gross representation through four centroids defining three segments with different slopes. Aposteriori classification based on either voicing (sound bar and LF burst energy) or point of articulation (gross spectral shape) yielded on the previous database to a classification score of 88% and 87%, respectively. These strategies were implemented in a system used for the recognition of Italian stops in VCV structures. An inter-linguistic study aimed at comparing Italian dental stops with British English corresponding alveolars in progress.
Acoustic characteristics of American English vowels
Authors: Hillenbrand James , Getty Laura A. , Wheeler Kimberlee , Clark Michael J.
Published: October 2005

This study was designed as a replication and extension of the classic study of vowel acoustics by Peterson and Barney (PB) [J. Acoust. Soc. Am. 24, 175–184 (1952)]. Recordings were made of 50 men, 50 women, and 50 children producing the vowels /i, i, eh, æ, hooked backward eh, inverted vee), a, open oh, u, u/ in h–V–d syllables. Formant contours for F1–F4 were measured from LPC spectra using a custom interactive editing tool. For comparison with the PB data, formant patterns were sampled at a time that was judged by visual inspection to be maximally steady. Preliminary analysis shows numerous differences between the present data and those of PB, both in terms of average formant frequencies for vowels, and the degree of overlap among adjacent vowels. As with the original study, listening tests showed that the signals were nearly always identified as the vowel intended by the talker.
VC and CV transitions and the recognition of Canadian French syllables containing /l/
Authors: Jacques Benoît , Cloutier Lise
Published: October 2005

According to recent works, the formant structure of consonant /l/ is influenced by the adjoining vowels, so that the liquid appears as a modulation of these ones in frequency and intensity. The aim of this paper was to find out to what extent the VC and CV transitions are still needed in order that a syllable containing /l/ be recognizable. To that end, nonsense /V1V/ utterances in which both V’s correspond to the same vowel were recorded by a Canadian French speaking informant and digitalized. In addition, vowels /i, e, eh, a, o, u, y/, recorded in isolation, were also digitalized. Through the splicing and editing of the acoustic signal, the first vowel of each utterance, then the second one, was replaced successively by each of the vowels previously recorded in isolation, thus giving 112 stimuli. Listening tests through a panel comprising of 16 French Canadian subjects were performed. Results showed that a syllable containing /1/ is recognized most when the replacing vowel in the utterance is /i/ or /y/. In most other cases, the syllable is not recognized and the consonant itself might be perceived as a vowel.
A phonetic analysis of voicing assimilation in Russian stops and fricatives across preposition boundaries
Authors: Burton Martha W. , Robblee Karen E. , Wislowski Ann
Published: October 2005

In Russian, voicing assimilation is usually regressive with the voicing of obstruent clusters conditioned by the final obstruent. However, there is conflicting phonetic evidence from other languages such as Polish on whether neutralization of voicing is complete [cf. W. Jassem and L. Richter, J. Phon. 17, 317–325 (1989); L. Slowiaczek and D. Dinnsen, J. Phon. 13, 325–341 (1985)]. This study investigated the effects of voicing assimilation across prepositional boundaries, an environment where voicing assimilation is believed to occur in Russian. Three native speakers of Russian produced sentences containing prepositions ending in a voiceless stop or fricative. These prepositions were followed by word tokens with initial obstruents that were voiced or voiceless. Thus there were four stop-fricative combinations [ts,dx,tz,dz] and four fricative-stop combinations [st,sd,zt,zd]. Acoustic analyses of these tokens included duration measurements and spectral analyses. Preliminary results indicate that a pattern generally consistent with voicing assimilation emerges. However, for some speakers there was variation depending on the particular combination of fricative and stop. The findings of the study will be considered in terms of phonetic and phonological theories of speech.
Multi-channel acoustical modeling of the vocal tract for /l/ production
Authors: Barsukov Vladimir M.
Published: October 2005

Acoustic analysis of the lateral consonant /l/ shows some extra, unexplained poles and zeros above the second formant. A vocal tract model with a bifurcation in the acoustic path from the glottis to the lips was analyzed to explain these acoustic characteristics. The mathematical model consists of a tube that contains an additional parallel acoustic path or a side branch with dimensions roughly consistent with the shape of the airways for /l/. A one-dimensional approximation was used to set up differential equations for sound pressure P and volume velocity U, appropriate boundary conditions were applied, and an analytical solution for the problem was found for various geometrical parameters. The analysis of this solution shows existence of the extra poles and zeros above the second formant for a reasonable set of parameters. [Research supported in part by a grant from NIDCD.]
H. Davis’s concepts of cochlear mechanics in evolution
Authors: Zwislocki Jozef J.
Published: October 2005

Two concepts are considered. One refers to the cochlear amplifier, the other, to hair cell stimulation. According to the first, a biological amplifier produces strong amplification at the falling edge of the passive wave envelope and produces a sharp amplitude peak there. When the amplifier is eliminated, only a less sharp passive peak remains at a more basal location. It has been demonstrated experimentally that, at a given cochlear location, when the amplifier is eliminated, the sound frequency of the amplitude peak is lowered by about an octave. This is equivalent to a basal shift of the maximum by over 2 mm. According to the second concept, cochlear hair cells are depolarized by deflection of their stereocilia toward the spiral ligament. The deflection is due to shear displacement between the reticular lamina and the tectorial membrane, which is supposed to take place during basilar membrane displacement toward scala vestibuli as a result of the geometry of the organ of Corti. Experiments show that this is often not true. The discrepancies can be explained on the basis of experimental evidence concerning the dynamics of the stereocilia and the tectorial membrane. [Work supported by NIDCD.]
Scattering from internally complex finite shell models
Authors: Dyer Ira
Published: October 2005

Data on acoustic scattering from finite-length internally loaded circularly cylindrical models were obtained with use of a water tank facility at the Naval Research Laboratory. Analysis of these data in the mid-frequency range (2<ka<12, where k is the acoustic wave number and a the cylinder radius) reveal three important regions of scattering phenomena: the bow/stern aspect (in a spherical coordinate system, within a polar angle of about 20°), the helical wave aspect (within about 45° to 85°), and the beam aspect (within about 85° to 90°). The models studied were closely symmetric around the polar axis and also with respect to the plane defined by the polar angle of 90°. There will be a review of the underlying physical mechanisms in these scattering regions as affected by the shell and its endcaps, by the internal deep rings (frames), and by additional internal structures mounted to the rings. [Work supported by ONR.]
Response Green’s function and scattered pressure from a fluid-loaded cylindrical shell with internal bulkheads
Authors: Cuschieri J. M. , Feit D.
Published: October 2005

The response Green’s function and the far-field scattered pressure, for a fluid-loaded cylindrical shell, for the circumferential mode n=0, with internal plate bulkheads, are determined from knowledge of the junction forces between the shell and the internal plate bulkheads. These forces are determined using a mobility (impedance) matrix approach, which matches the response of the shell and the plate bulkhead at the junction, together with an input of the shell-free response under the influence of the incident acoust pressure. The results for the Green’s function show that for low frequencies, the in-plane response of the plate bulkhead is very small and the junction behaves similar to a pinned junction. As the frequency increases in-plane resonances are set up in the plate bulkhead and the radial influence of the bulkhead is at a minimum. For the far-field scattered pressure, if the angle of incidence of the excitation acoustic wave is less than about 16 deg for a steel shell in water, the scattered pressure has significant contributions from the supersonic longitudinal waves in the shell. Outside this angle of incidence the scattered pressure is dominated by the scattering from the discontinuity. [Work sponsored by ONR.]
Response of submerged finite-length cylindrical shells with internals to an impulse load
Authors: Choi S.-H. , Igusa T. , Achenbach J. D.
Published: October 2005

A finite-length, submerged cylindrical shell with elastic endcaps containing internal substructures is excited by a short-duration load. A recently developed modal-based analysis method is used to generate the responses on the shell surface and in the near and far fields. The method was developed specifically for analyzing the acoustic effects of substructures in an efficient manner. Nearly all of the computational effort is in determining the impedance relations between the pressure and the velocity along the shell surface. This analysis requires the evaluation of a twofold integral over the shell surface for each pair of pressure and velocity shape functions [Ginsberg etal. (1986)]. Once the impedance relations are determined, the analysis of the radiation problem for a given set of internal substructures and applied loads is solved with relatively little computational effort. The efficiency of the method stems from the fact that the same set of impedance relations can be used for any configuration of internal substructures and applied loads. In addition, the method can be combined with a frequency window method when analyzing responses for a wide range of excitation frequencies. Such analysis is useful when going into the time domain using the fast Fourier transform. The study shows that substructures interact with the in-plane and flexural waves propagating in the shell, causing wave conversion and subsequent radiation into the surrounding fluid. [Work supported by ONR.]
Acoustic scattering from flexible bodies with discontinuities using analytic/numerical matching
Authors: Bliss Donald B. , Loftman Rickard C.
Published: October 2005

Analytical/numerical matching (ANM) is a hybrid scheme combining a low-resolution global numerical solution with a high-resolution local analytical solution to form a composite solution. ANM is applied to scattering from a fluid-loaded cylindrical membrane with a discontinuity, e.g., a point impedance. This coupled fluid/structural problem utilizes the addition and subtraction of canceling distributed forces at the discontinuity. The problem divides into one with the point force and distributed force in opposition, and another with only a distributed force. Conditions are imposed on the problem with the distributed force opposing the point force, leading to a structural response with only local motion and minimal radiation. This local problem can be solved analytically in simplified form. The remaining problem with only a distributed force is a low-resolution global numerical problem and can be solved efficiently. The local and global problems are dynamically coupled in the composite solution. The scattering problem revealed sensitivity to whether the discontinuity was a point force or a narrowly distributed force. This sensitivity is explained, and implications for accurate modeling of scattering from structures with discontinuities are discussed. Application of the method to multiple discontinuities and general geometry is described. [Work supported by ONR.]
Two-dimensional wave-number distributions of flexural vibration in ribbed plates
Authors: Brown Richard N.
Published: October 2005

Regularly ribbed plate constructions are common in marine, aircraft, and other applications. Since vibration of these structures can be responsible for unwanted acoustic emissions, the response of ribbed plates has been a subject of many theoretical and a few experimental studies over the years. In determining radiation and near-field acoustic levels it is important to have a knowledge of the distribution of surface velocity in wave-number space. In this paper, the elegant solution of Berkman etal. [‘‘Radiation from Periodically Supported Fluid-Loaded Plates,’’ BBN Rep. 3999 (1979)] to the ribbed plate equation of motion is used to estimate the distribution in wave number of the surface velocity. In particular, the two-dimensional solution to excitation by a point force is used. The results of the study show several distinctive features: a high level, broad-(spatial) band in the bays near the excitation force; Bragg scattering of flexural energy by the periodically spaced ribs (which is accompanied by acoustic radiation due to aliasing), an alignment of flexural traveling waves to the direction normal to the ribs, and the relative inconsequence of stop/pass band behavior. Experimental data are presented showing the existence of these features.
Mid-frequency endcap reflection and radiation coefficient extraction from FEM data
Authors: Smith P. W. , LePage Kevin D. , McDaniel J. Gregory , Duckworth Gregory L. , Barile Robert J.
Published: October 2005

The response of a simple cylindrical shell terminated by rigid endcaps to various axisymmetric mechanical excitations is determined using the SARA 2-D finite element code. By assuming that the response of the shell is primarily composed of structural waves, which satisfy the fluid-loaded shell equations, the structural wave reflection matrix of the endcap is determined through an over-constrained system of equations. Results for the frequency range, 2<k0a<6, show that for this type of endcap, the reflection process may be parametrized with a smooth function in frequency that is dependent on a small number of variables. Using a similar approach, the far-field radiation patterns of the endcap due to each incident structural wave type are also determined and parametrized. This work suggests that at mid frequencies and away from trace-matched angles, many of the essential elements of the axisymmetric elastic structural response of simple shells may be modeled using a one-dimensional ray picture where all the structural wave coupling and radiation is accounted for by a single reflection and radiation matrix at each endcap. [Work supported by ONR.]
Reflection of axisymmetric waves from an arbitrary termination of a fluid-loaded semi-infinite cylindrical shell
Authors: McDaniel J. Gregory , Smith P. W. , LePage Kevin D.
Published: October 2005

This work proposes an approximate theory for the reflection of axisymmetric waves on a semi-infinite fluid-loaded shell from an arbitrary termination. The reflected and incident waves are described by wave numbers and wave shapes derived from the standard thin-shell equations for an infinite shell with fluid loading. The termination is characterized by an admittance matrix that relates stress resultants within the shell wall to axial, radial, and rotational velocities of the midsurface. The admittance matrix is determined for arbitrary terminations by finite element experiments on a fluid-loaded finite shell. An example focusing on variations in the axial admittance shows the effect of added mass at the termination. Results include the reflection and coupling between surface, longitudinal, and evanescent waves. [Work supported by ONR.]
Virtual sources, guided wave paths, and far-field radiation from an internally excited ribbed cylinder
Authors: Clark Joseph A. , Sartori Michael A.
Published: October 2005

An experimental analysis of structural dynamics and acoustic radiation associated with a large scale (7.5 m long, 1.5 m diam) immersed hull structure is presented. Pressure data were collected with an automated scanning frame and an array of hydrophones at 0.3-m intervals over a measurement surface conformal to and 0.3 m distant from the body. Visualizations of the pressure field in the measurement plane were analyzed to verify data quality and to characterize dominant phenomena (hull resonances, low-order mode shapes, virtual source locations, and scattering discontinuities). The data were then backprojected to the hull using near-field acoustical holography algorithms to obtain (normalized) pressure, velocity, and intensity distributions on the hull. Finally, algorithms based on the Helmholtz integral were employed to determine far-field radiation patterns. [Work sponsored by NAVSEA.]
Analytical solutions for axisymmetric radiation and scattering from a spherical shell with internal circular plates
Authors: Subramaniam Murugan , Bennighof Jeffrey K.
Published: October 2005

Analytical solutions for problems of radiation and scattering from a spherical thin shell containing one or more circular thin plates are presented. The geometry of both the structure and the loading is axisymmetric. These solutions can be used to evaluate computational methods for radiation and scattering from finite three-dimensional structures having internal complexity. In this case the internal complexity is associated with the internal plates, which are represented in terms of their axisymmetric modes of vibration. The motion of the spherical shell is represented in terms of spherical harmonics. The analytical solutions are verified with numerical results obtained using an adaptive multi-level substructuring approach, which obtains an optimally reduced finite element model of the structure, which is coupled with a boundary element model of the acoustic fluid. [Work supported by ONR.]
Scattering from a multi-layered cylindrical shell containing a bulkhead
Authors: Ricks David C. , Schmidt Henrik
Published: October 2005

A multi-layered cylindrical shell is modeled with the direct global matrix approach (DGM). The DGM approach allows the shell to have multiple viscoelastic layers, which are modeled with the full 3-D equations of elastodynamics. The DGM formulation is numerically stable for the wave types of interest (membrane compression, membrane shear, and flexural waves). The shell also contains a thin elastic bulkhead, which is modeled with the Mindlin thin plate theory. This coupled system is excited by obliquely incident plane waves in a fluid medium that surrounds the shell. The scattering caused by the bulkhead is computed. The effects of viscoelastic layers are investigated. [Work supported by ONR.]
Sound radiation by cylindrical shells with discontinuities
Authors: Ekimov A. E. , Lebedev A. V.
Published: October 2005

Sound radiation by an arbitrary structure affected by discontinuities is analyzed. A discontinuity strongly influences the structure’s radiation, a small inhomogeneity not being a sign of slight variations of the acoustical field. Its effect depends on the Q factor of the structure and its kind. The attention is concentrated on the analysis of peculiarities caused by the type and distribution of the discontinuities. It is shown that the greater alternation of the radiation is affected by a single, local discontinuity, while any distribution of the latter leads to a decrease of this alternation. From the obtained expressions one can easily see that thin shells are of special interest for the investigation of their radiation properties alternations under discontinuities. This report is concerned with qualitative analysis for an arbitrary structure and concrete results for the shell, whose acoustic characteristics depend on discontinuities most strongly. Because of that, most of the report is concerned with the discussion of experimental study results. The measurements were made on an initially homogeneous cylindrical shell under local mass loadings. While a vibration exciter is additional discontinuity, the reciprocity method was used for accurate measurements. The results obtained are in good agreement with the simple analysis conclusions.
Articulatory phonology and speech recognition: A case study involving use of dynamically defined speech primitives
Authors: Deng L. , Sameti H.
Published: October 2005

Recent efforts will be reported in the design and implementation of a speech recognizer that has been motivated by a modern form of phonology arguing for use of multi-dimensional articulatory structures [Browman and Goldstein, Phonetica 49 (1992)]. The earlier work [Deng and Sun, J. Acoust. Soc. Am. (to be published)] has recently been extended such that the primitive speech units, constructed via constrained overlap among five-dimensional articulatory features/gestures (lips, tongue blade, tongue dorsum, velum, and larynx), have changed from their previous ‘‘static’’ representation to the current ‘‘dynamic’’ one. The statistical model underlying the speech recognizer is a version of the nonstationary-state HMM [Deng, Signal Process. 27 (1992)], where a bulk of the Markov states are characterized by time-varying Gaussian-mean functions (implemented as mixtures of polynomial functions of sojourn time within the Markov state). These nonstationary Markov states are constructed only for the feature constellations arising from assimilation of one or more primary articulatory features (i.e., lips, tongue blade, tongue dorsum). The physical reality is that manipulations of the articulatory structure indexed by any primary articulatory feature(s) during speech production necessarily generate the acoustic signal that is transitional in nature. In addition to the above physical motivations, algorithmic issues relating to implementation of the speech recognizer will also be addressed. Evaluation of the recognizer for the task of phonetic classification (TIMIT) containing all classes of English sounds is currently in progress.
Sonority constraints on perceptual errors
Authors: DePaolis Rory A. , Christman Sarah S.
Published: October 2005

This study explored phonological constraints upon word misperceptions elicited from normal listeners by degrading the speech signal with noise and various high- and low-pass filters. Pre-vocalic sound sequences of error words were compared to American English targets. Syllable onset substitutions were evaluated with respect to the sonority sequencing principle (SSP), which holds that the least sonorous sounds of languages (those produced with a relatively constricted vocal tract) possess little perceptual prominence and are preferred in onset position to more sonorous sounds of languages (those produced with a more open vocal tract). Results suggest that errors pattern in accordance with predictions from sonority theory and suggest that several different phonological mechanisms may account collectively for findings. The primary mechanisms include partial signal analysis and/or activation of a default lexical search mechanism which accesses words possessing the least-marked of possible pre-vocalic segmental sequences (e.g., obstruent-vowel strings). Confusion matrices indicate that misperceptions are remarkably resistant to filter type.
Coarticulation modeling by linear filters in a pseudo-articulatory domain
Authors: Bakis Raimo
Published: October 2005

A speech synthesizer for use in analysis-by-synthesis speech recognition is described. Coarticulation is modeled by applying linear FIR filters to target gestures in a pseudo-articulatory domain. This domain is treated as a hidden, unobservable layer between the phonetic input to the synthesizer and the acoustic spectrum output. That output is obtained from the hidden-layer signal by means of a memoryless nonlinear transformation that is implemented by a neural net with elliptic basis functions. The entire model, including phonetic targets, FIR filter shapes, and neural-net parameters, is trained by a pre-conditioned conjugate gradient method, using the mean-squared error between synthetic and actual spectra as the objective function. The gradient is calculated by a back-propagation algorithm. It is found that after training, the FIR filter shapes typically resemble noncausal two-pole lowpass characteristics, with one pole in the right and the other in the left half-plane, representing right-to-left (anticipatory) and left-to-right coarticulation, respectively. Performance of the synthesizer on isolated-word speech, continuous read speech, and spontaneous speech will be described, and results from recognition experiments on speaker-dependent and speaker-independent tasks will be reported.
Experimental determination of the stiffness of a saxophone reed by means of the evaluation of the reactive power
Authors: Gibiat Vincent , Boutillon Xavier
Published: October 2005

A simple model for a saxophone or a clarinet reed—one pure spring with stiffness k—is acceptable for frequencies beneath the resonance frequency of the reed. When the instrument sustains a harmonic tone, Eq. (1) of the previous paper holds and the right-hand side quantities can be experimentally determined in order to evaluate k or k/S2. Experiments were driven on a saxophone so as not to encounter large uncertainties due to the weakness of even harmonics and corresponding minima of the input impedance of a cylindrical pipe. The reed stiffness is derived from separate measurements of the input impedance (TMTC method) and of the internal pressure spectrum when the saxophone is played by a musician or blown by an artificial system. Combined with an evaluation of the reed area, results on reed stiffness under playing conditions are in good agreement with compliance values measured on isolated reeds by other authors. The reactive power balance between the reed and the pipe also sheds a new light on the playing frequency changes that are observed when the saxophone is played softly or loudly without any mouth correction. A link with the anharmonicity of the pipe resonances will be shown.
Manufacturing processes and their relationship to musical qualities of flutes
Authors: Wasser Steven A.
Published: October 2005

Manufacturers of musical instruments are under constant pressure to both improve productivity and enhance the performance qualities of their products. However, the higher the perceived musical quality of an instrument, the more difficult it becomes to implement technological changes. For example, apparent improvements in materials and/or the manufacturing process may have subtle effects which could adversely affect particular performance qualities which characterize the manufacturer’s instrument. It is known that some imperfections in materials and manufacturing processes may actually enhance the artist’s musical abilities. Therefore, it becomes the responsibility of the manufacturer to establish a dialogue between the subjective artistic requirements of the musician and the relatively objective manufacturing factors such as material properties, dimensions, and processes. The issues of how a manufacturer of a distinctive, traditional handcrafted flute (with a loyal following among professional flutists) approaches the design and manufacture of a new flute to meet the needs of a wider range of players will be discussed. Particular emphasis is placed on the steps taken to maintain the family relationship between the musical qualities of the new flute and those of the traditional one and, at the same time, to ensure sufficient differences in performance capabilities in order to maintain a clear distinction between the two instruments.
Differential formulation: A powerful tool for woodwind instrument numerical simulations
Authors: Grand Noel , Barjau Ana , Gibiat Vincent
Published: October 2005

A woodwind instrument is well described by a linear resonator introducing a delay and a nonlinear excitator without delay. Thus one can model the woodwind instrument with two simple equations (one in the Fourier domain, the other one in the time domain) calling out the acoustical pressure, flow, and admittance of the resonator. Under some conditions, these two equations can be rewritten as a single nonlinear differential equation with delay, the degree of which depends on the resonator’s geometry. As an example, a cone can be described by a second-order differential equation which transforms into a first-order one for a cylinder. This differential formulation has some advantages: The minimal phase space dimension transitions to chaos are clearly displayed; moreover, resulting numerical algorithms are much quicker and more stable than those obtained by integral or Fourier transform methods; the control parameter is directly related to the resonator losses (which is easy to control). And last, it’s a powerful tool to observe the characteristics of the small oscillations (by increasing a control parameter), which is essential to provide support for the theoretical model.
The development of the data base for ISO-1999, an evaluation of its strengths and weaknesses
Authors: Johnson Daniel L.
Published: October 2005

Some of the data that are used in the current ISO standard on noise-induced hearing loss are over 30-yr old. In addition, the ability to measure noise exposure has improved significantly. This factor, as well as other assumptions, will be discussed with an attempt to indicate how they affect the accuracy of the predictive model. A review of some recent studies will be used to illustrate that the predictions of ISO-1999 do not seem out of line. Because of the impact of hearing conservation programs, more definitive future studies are not likely to be available. The current version of ISO-1999 appears to be a reasonable model and should retain its validity for the future. [Work supported by U.S. Army Medical Research & Development Command, under Contract DAMD17-88-C-8141.]
Effect of the population selected to represent the ‘‘age effect’’ component of hearing loss when predicting hearing thresholds for a population using ISO 1999:1990(E)
Authors: Royster Larry H. , Royster Julia Doswell
Published: October 2005

In attempting to predict the effectiveness of hearing conservation programs either by studying the changes in the affected populations’ hearing thresholds over time or by utilizing the ISO-1999 model, it is critical that the control population adequately represent all of the age-related factors contributing to total hearing loss except on-the-job noise exposure. This paper will briefly review the characteristics of several available ‘‘age effect’’ populations including data base B in ISO 1999 and the four NINEP populations. The review will include a comparison, when appropriate, of the hearing characteristics for the ‘‘age effect’’ populations presented.
Hazard from impulse noise: Problems and prospects
Authors: Price G. Richard
Published: October 2005

Research findings continue to challenge the adequacy of existing impulse noise standards while consensus on a better formulation remains elusive. It is generally accepted that frequency weighting (reducing contribution of low frequencies) would be appropriate for impulse noise standards. However, data now present standards with twin problems which are opposite in character. On the one hand, the ear can be destroyed by intense exposures containing little energy (less than 10 J/m2) [Hamernik etal., J. Acoust. Soc. Am. 81, 1118–1129 (1987); Price and Wansack, J. Acoust. Soc. Am. 86, 2185–2191 (1989)]. Conversely, the ear can also tolerate immense amounts of energy at high intensities (≳100 kJ/m2) [Johnson and Paterson, Proc. 1992 Hearing Conserv. Conf. 103–106 (1992)]. A mathematical model of hearing hazard being developed [Price and Kalb, J. Acoust. Soc. Am. 90, 219–227 (1991)] promises to handle this complexity by incorporating a nonlinear stapes as well as middle ear muscle contractions into a hazard assessment, which is based on calculated basilar membrane displacements. Among other things, the model suggests that occasional exposure to intense impulses may be responsible for much of both occupational and nonoccupational noise-induced hearing loss.
Effects of intense noise on fetal sheep hearing mechanism
Authors: Pierson Linda L. , Gerhardt Kenneth J. , Griffiths Scott K. , Abrams Robert M.
Published: October 2005

The auditory brain-stem response was recorded from in utero fetal sheep from 111 to 136 days gestational age. Fetuses were prepared for chronic recordings. The auditory brain-stem response was evoked by clicks and tone bursts of 500, 1000, and 2000 Hz. Pregnant ewes were exposed to an intense broadband noise of 120 decibels sound-pressure level for 16 h while carrying fetuses at gestational ages of either 113 days (early noise-exposed group) or 130 days (late noise-exposed group). A third group of animals was nonexposed. Auditory brain-stem response threshold and latency increases were identified immediately after the noise exposure for the late noise-exposed group. Although there was no immediate effect on the auditory brain-stem response for the early noise-exposed group, when auditory brain-stem responses were elicited from these animals at later gestational ages, higher thresholds were identified in the noise-exposed group than in the nonexposed animals. Cochlear reconstructions and cytocochleograms completed from serial celloidin sections obtained from both noise-exposed and nonexposed fetuses had a similar appearance. Results showed that exogenous sounds can penetrate the uterus and that these sounds result in alterations of the fetal auditory brain-stem response. Light microscopy showed no sensory cell differences between the noise-exposed and the nonexposed animals. [Work supported by U.S. Army.]
Experimental investigations of an acoustic soliton
Authors: Denardo Bruce , Kolaini Ali
Published: October 2005

It has been predicted that an acoustic breather soliton can exist in a rigid-wall waveguide filled with a liquid [Aranha etal., J. Fluid Mech. 121, 465–485 (1982)]. This is a propagating nonlinear wave whose particle motion is primarily perpendicular to the waveguide, and whose amplitude is exponentially self-localized along the waveguide. The wave is mathematically described to lowest order by a nonlinear Schrödinger equation. If a transverse mode of the waveguide is driven at one end at a frequency below cutoff and with a sufficiently large amplitude, it is also predicted that the solitons will be spontaneously ejected at a periodic rate. Current attempts to observe the acoustic soliton in a long tube filled with water will be described. The existence of the solitons and ejection process in other physical systems will also be described.
Elastic wave propagation in randomly disordered layered media
Authors: Esquivel-Sirvent R. , Noguez Cecilia
Published: October 2005

The elastic properties of randomly disordered multilayered systems that are periodic on average are studied. Specifically, a layered structure is considered that is made up of two different materials with elastic waves propagating perpendicular to the interfaces. The localization length for frequencies of the propagating waves around the band gaps in the dispersion relation of the average periodic system are computed. Two types of disorder are considered. In one case the specific acoustic impedance of each slab in the structure is kept constant while randomly varying the thicknesses of the slabs. In the second case the period of the structure is kept constant while randomly varying the specific acoustic impedance of the layers. The effects of dissipation on the localization length are also studied.
Nonlinear tube waves
Authors: Johnson D. L. , Kostek S. , Norris A. N.
Published: October 2005

The nonlinear characteristics of an acoustic tube wave propagating along the axis of a fluid-filled circular borehole in an elastic solid which is locally isotropic but whose properties may vary radially are considered. The analysis is carried out in the quasistatic limit. All terms are considered through quadratic in the amplitude of the wave and the amplitude of 2nd-harmonic generation is expressed as well as the pressure dependence of the tube wave speed, dVT/dp, in terms of the fluid and formation of nonlinear parameters. The results show that if there is no radial variation of the shear modulus of the solid then both the amplitude of 2nd-harmonic generation and dVT/dp are independent of the third-order elastic constants of the solid and nearly equal to those of the fluid alone. If there is a radial variation of the shear modulus then our numerical calculations indicate that both the amplitude of 2nd-harmonic generation and dVT/dp can be completely dominated by the nonlinear parameters of the solid. A perturbation theory is derived that is valid for the case in which the shear modulus is nearly constant, which demonstrates that the nonlinear response is scaled by the value of the third-order parameters of the solid, leveraged by the degree and depth of alteration of the shear modulus.
Interaction of flexural modes of a borehole and a cylinder
Authors: Hsu Chaur-Jian , Sinha Bikash K.
Published: October 2005

A low-frequency dipole source excites flexural waves in cylindrical structures. Flexural waves in rods and pipes assume vanishingly small phase velocities at low frequencies. On the other hand, the flexural waves of a borehole surrounded by an infinite formation asymptotically approach formation shear wave velocity at low frequencies. These two individual lowest-order flexural modes interact with each other in a composite structure where a rod or pipe is concentrically placed in a borehole surrounded by an infinite formation with liquid in the annulus. This interaction results in two coupled modes of the composite structure. Depending on how strong this interaction is, these two coupled modes may resemble or drastically differ from the two individual modes of the rod (or pipe) as well as the borehole. The interaction is stronger at frequencies where the two individual modes are closer in phase velocity. Results of experimental and theoretical studies will be reviewed and compared.
Nonlinear processes in thermoacoustic engines
Authors: Prosperetti A. , Watanabe M.
Published: October 2005

In the first part of the paper it is shown how, on the basis of a different form of the energy equation, a more compact derivation of the Rott theory of thermoacoustic effects [N. Rott, Z. Angew. Math. Phys. 20, 230–243 (1969)] can be given. In the second part, a weakly nonlinear theory is built starting from the same formulation and the steady-state amplitude of the oscillations setting in above the stability threshold is calculated. [Work supported by the Physical Acoustics Program of ONR.]
Self-focusing of sound beams in cubic nonlinear media
Authors: Rudenko O. V.
Published: October 2005

In usual dispersive quadratic nonlinear media, self-focusing (SF) does not exist. In recent years, thermal SF of quasimonochromatic waves in highly viscous liquids like glycerin, and thermal SF of sawtoothlike waves in inviscid fluids, were observed experimentally. However, both phenomena are very inert (characteristic stabilization time at least of order 10 s). A general question in nonlinear wave theory is whether inertialess SF in cubic nonlinear media without dispersion can exist (e.g., for shear waves). An acoustic beam in a cubic medium can be described by a modified KZK-type equation. It is common practice to seek a solution (following the approach in nonlinear optics) in the form of a harmonic wave with slowly varying amplitude A. A nonlinear Schrödinger equation can be obtained for A which describes the increase in A due to plane front instability. However, A decreases due to nonlinear absorption. To investigate the real behavior of the wave, a more appropriate analytical approach, together with computer methods, were used. It was shown that SF has remarkable features. One can observe a marked decrease of the beamwidth. The increase in A, however, cannot be considerable. [This work was partially supported by NATO.]