bluuebunny/crossref_metadata_2025 huggingface dataset:
An interactive multimedia course in acoustic phonetics and speech science
Authors: Jackson Michel T. T. , Kaprow Alyce , Berkovitz Joe , Hazan Valerie , Boyce Suzanne E. , Pickett J. M.
Published: October 2005

A computer-based multimedia course in speech science is under development. The goal of the course is to provide students with a better understanding of acoustic phonetics, its practical applications, and speech research. A curriculum outline detailing interactive experiences that support the educational goals of the course will be presented. Course units presenting basic topics in acoustics (resonance, filtering) and more advanced topics in speech science (vowel production and perception) will be available to illustrate the use of the course for classroom demonstration and independent study by students. Integrated laboratory tools allow students to perform acoustic analysis. Visual, auditory, and textural reference and background material is available to the user at all times. [Work supported by NIMH.]
Dysregulation of frequency and intensity in relation to mean airflow rate. A study of 22 brain-damaged people
Authors: Pedersen M. F.
Published: October 2005

It is not only acoustic input into the brain that should be analyzed with neural network but also the resulting voice function. A possibility to get more information is to analyze the voice function in the damaged brain in a co-work between phonetician, phoniatrician, and neuropsychologists. An attempt was made by combining measurement of phonetograms with airflow and stroboscopy. In 22 clients no correlation was found between the damaged frequency and intensity ranges compared with the mean air-flow rates (r=0.15 by multivariate analysis). This is possible because frequency and dynamics are regulated in the acoustic brain and airflow is related to respiration. A discussion should be focused upon multifunctional voice analysis and neural networks in the brain, eventually based on measurements with the multifocal equipment by Key-elemetrics and brain flow measurements [M. F. Pedersen, in DieKrankheitderStimme, dieStimmederKrankheit, edited by H. Gundermann (Fischer Verlag, New York, 1991), pp. 162–171].
The influence of an inverted face on the McGurk effect
Authors: Green Kerry P.
Published: October 2005

The McGurk effect is a situation in which the perception of the speech signal is influenced by watching a talker’s face articulate a conflicting speech utterance. For example, observers typically report the syllable /da/ when the auditory syllable /ba/ is presented in synchrony with a videotape of the talker saying the syllable /ga/. It is well-known that inverted faces are much more difficult to recognize than faces presented in a normal, upright orientation. The current study investigated whether inverting the talker’s face would also influence the McGurk effect. Two groups of subjects were presented with a videotape consisting of conflicting auditory and visual syllables designed to produce the typical McGurk effect. The first group viewed the test tape on a video monitor set in its normal upright position. This group showed a typical, robust McGurk effect. The second group viewed the videotape on the monitor set in an inverted position. This group showed a significantly weaker McGurk effect. Thus inverting the face and the corresponding articulatory movements impacts on the integration of phonetic information from the auditory and visual modalities. [Work supported by NIH.]
Detection of auditory-visual and tactile-visual onset order in a speech-like context
Authors: Waldstein Robin S. , Boothroyd Arthur
Published: October 2005

The abilities of five subjects to perceive the order of auditory-visual and tactile-visual events in a speech-like context were examined. The visual event consisted of a digitized video image of an adult female’s face changing from mouth-closed to mouth-open position. The auditory/tactile event consisted of a 250-Hz tone of 500-ms duration, presented binaurally over headphones (auditory) or to the index finger of the right hand via a B&K 4810 Mini-shaker (tactile). Subjects were required to indicate which event came first: the (auditory or tactile) tone onset or the mouth-opening. Tone onset ranged from −100 to +200 ms re: mouth-opening, in 20-ms steps. Presentation of relative onsets was randomized, and modality was counterbalanced. Results revealed similar patterns of performance in auditory-visual and tactile-visual tasks. Subjects demonstrated a bias toward perceiving auditory/tactile tone onset before mouth-opening. A delay of about 100 ms was required before subjects began to perceive mouth-opening as occurring before tone onset. This delay is substantially larger than the 20-ms bimodal temporal resolving ability reported for very brief stimuli [I. J. Hirsh and C. E. Sherrick, J. Exp. Psychol. 62, 423–430 (1961)]. [Work supported by NIH Grant No. P01DC00178.]
Do 4.5-month-olds’ know their names?
Authors: Mandel Denise R. , Jusczyk Peter W. , Pisoni David
Published: October 2005

Research has demonstrated that object names are given distinct prosodic status in child-directed speech (Messer, 1981). Yet, the name most likely to attract infants is their own. Using the headturn preference procedure whether 4.5-month-olds prefer to listen to their own names was tested. Twenty-four infants were presented with four names: their own, and three others. Foils were designed to investigate whether infants would false alarm to names with similar prosodic patterns (e.g., stress): One foil matched the stress pattern of the infants’ name; the other two followed the opposite pattern. Infants demonstrated significant listening preferences for their own names—even when compared to the foil with the same stress pattern. These findings provide the first evidence that infants as young as 4.5 months recognize their names. The findings also have some potentially important implications for lexical development. Perhaps the structure of infants’ early lexicons are influenced by their first lexical entries, i.e., their names. If so, this may explain individual differences often found in early lexical development—infants may be more likely to attend to words in the language environment that share a structural relation to their names. [Work supported by NICHD-NIDCD.]
Do infants remember words from stories?
Authors: Hohne Elizabeth A. , Jusczyk Ann Marie , Redanz Nancy J.
Published: October 2005

To what extent do infants extract and remember information from the speech signal? Jusczyk etal. [J. Acoust. Soc. Am. 93, 2373(A) (1993)] reported infants listened significantly longer to a familiar than a novel voice suggesting that they developed a representation of that voice. The present study explores infants’ ability to remember words from stories they have heard. In this study, 7.5 to 8.25-month-old infants were exposed to recordings of stories read by five different talkers, for 10 days in a 2-week period. Two weeks later, the infants were tested in a head turn preference procedure. Stimuli were lists of words from the stories and lists of novel words, matched for overall phonemic content and general familiarity to infants. The infants listened significantly longer to the familiar words suggesting that they had formed and stored a representation of those words. What is remarkable about these results is that 8-month-old infants apparently retain information about sound patterns of frequently occurring words even when these words are not directly associated with a concrete referent in the infants view. Thus these sound patterns may serve as place holders or slots in the lexicon for meanings to be attached to subsequently. [Work supported by NICHD.]
Infants’ ability to learn and parse words
Authors: Newsome Mary R. , Jusczyk Peter W.
Published: October 2005

To what extent are infants able to detect words in the speech stream? Nine-month-olds attend to global information about words, such as the predominance of strong-weak stress patterns in English [Jusczyk etal. (1993)], but parsing requires that they use this information during fluent speech perception. At 7 1/2 months, infants have been found to identify monsyllabic words when presented by themselves or in sentences, while ignoring words structurally similar to the targets [Jusczyk and Aslin (1993)]. The headturn preference procedure was used in this experiment to test 71/2-month-olds’ ability to extract bisyllabic words with strong-weak stress patterns. Twenty-four infants were familiarized to words and then presented with passages that contained either the target words or unfamiliar words. Infants listened significantly longer to passages with the familiar targets. These results suggest that infants are able to detect bisyllabic words with strong-weak stress patterns. Because adults may access words in memory at the strong syllable [Cutler and Norris (1989)], infants may be demonstrating processing in this manner as well. Follow-up studies investigated infants’ sensitivity to words with weak-strong patterns and to embedded words in both types of bisyllables. [Work supported by NICHD.]
The role of prosody in early sentence comprehension
Authors: Shady Michele E. , Gerken Lou Ann
Published: October 2005

Research with young infants indicates that they prefer to listen to speech exhibiting exaggerated pitch contours [Fernald and Kuhl (1987)] and to utterances with pauses inserted at linguistic boundaries versus nonboundary positions. However, infant preference measures cannot tell us whether young learners actually use prosody to locate linguistic boundaries in the speech stream as some researchers have suggested [Jusczyk etal. (1992)]. To do this, the effects of prosody in the sentence comprehension of somewhat older learners were studied. Sentences were created with a DECTalk speech synthesizer and had rapid pitch changes either at a linguistic boundary (Find/the dog in the picture) or at a nonboundary (Find the/dog in the picture). Twenty-four to 26-month-olds heard either prosodically correct or incorrect sentences that told them to point to a named picture in a set of four. If children use prosody to locate linguistic boundaries during sentence comprehension, they should perform better for sentences in which pitch changes occurred at boundary positions. The results show that children performed significantly better for prosodically correct sentences (86% vs 48%). Thus it appears that by approximately 2 years of age, learners use prosody to locate linguistic units during sentence comprehension. [Work supported by NSF.]
Deriving human neural tuning curves from a mechanical model of the cochlea
Authors: Garbes P. A. , Allen J. B.
Published: October 2005

Human neural threshold tuning curves are derived using Allen’s [J. Acoust. Soc. Am. 68, 1660–1670 (1980)] resonant tectorial membrane model of the cat cochlea by appropriately scaling the parameters. Because there is no measured neural threshold data available for the human to test the derived curves, a detection criterion, defined by a relationship among the bandwidth of the frequency tuning curves, expressed as an equivalent rectangular bandwidth (ERB), the width of the excitation patterns, expressed as an equivalent rectangular spread (ERS), and the psychophysical critical ratio, is explored and verified using cat data. The detection criterion can then be used to test the derived human curves using psychophysical data, and may also provide a deeper understanding of the frequency resolving properties of the cochlea.
Effect of different boundary conditions in the finite element modeling of acoustic field problems involving infinite domains—An application to smart structures
Authors: Varadan Vasundara V. , Kim Jaehwan , Varadan Vijay K.
Published: October 2005

In the modeling of structural acoustic problems involving infinite domains, finite element modeling is often used in regions involving complex geometry, material anisotropy, coupled fields, etc. These same problems often involve coupling of the structure with an infinite acoustic fluid. Several methods have been proposed involving infinite elements, Dtn boundary conditions, matching the FEM representation with analytical representations in the infinite domain, to name a few. In modeling the response of embedded sensors and actuators in a structure subject to fluid loading, we have found it convenient to match plane wave solutions in the acoustic fluid with the FEM representation. The matching can be done with and without slope constraints and the matching can also be done using the so-called Dtn (Dirichlet to Neumann) boundary condition that results from the radiation conditions in the infinite domain. A parametric study of convergence and accuracy of numerical results using each of these methods will be presented.
Calculation of the structure-borne sound power emission from machines
Authors: Moorhouse A. T. , Gibbs B. M.
Published: October 2005

The structure-borne sound power emission from vibration sources is the closest analogue to airborne sound power and has tremendous potential benefit in prediction of sound levels in buildings and machines. However, the concept has yet to find wide application because the large number of terms needed to calculate power makes practical implementation difficult. In the paper, some simplifying assumptions are investigated, aiming to reduce the number of terms while maintaining acceptable accuracy. In general, the power through one contact point between a machine and its foundation depends on the velocity contributions from other points. The phase angles of these coupling contributions are investigated by measurement of free velocities and the mobility matrix at the seven mount points of a large, resiliently mounted fan. The assumption is that any phase angle is equally likely and this is shown to be reasonable at the frequencies considered. It is shown that a simplified calculation of sound power, using just seven terms causes little loss in accuracy compared with the full 28-term formulation.
Structure-borne sound power through multiple contact points between machines and supporting structures
Authors: Fulford R. A. , Gibbs B. M.
Published: October 2005

The structure-borne sound emission from machines through multiple contact points is highly influenced by the extent of coupling between these points. When the machine is unconstrained (i.e., disconnected from the supporting structure) the coupling can be assessed by comparing the point and transfer mobilities of the machine. Once connected however, account must be made too of the force distribution amongst the contact points. While the forces themselves at the points are sensitive to the structural characteristics of the particular installation, their distribution, which is most readily described by the ratios of the contact point forces, may be less sensitive. Using combinations of real and theoretical installations, force distributions have been investigated. Studies have also been undertaken on the estimation and approximation of the force ratios and their effect on the estimate of the total active power from the machine to the supporting structure. It will be shown that this has application to the characterization of structure-borne sound sources.
A theory for vibrations of poroelastic shells
Authors: Aşkar Gülay Altay , Dökmeci M. C.
Published: October 2005

Only a few investigations concerning the analysis of poroelastic structures are directed toward solutions of specific problems [e.g., L. A. Taber, Int. J. Solids Structures 29, 3125–3143 (1992), and references therein]. This paper addresses the derivation of a linear theory for vibrations of poroelastic shells. The three-dimensional fundamental equations of poroelastic media are expressed in variational form [cf. L. Dormieux and C. Stolz, C. R. Acad. Sci. 315(II), 407–412 (1992)]. The variational fundamental equations are obtained from the principle of virtual work through Friedrich’s transformation [M. C. Dökmeci, IEEE Trans. Ultrason. Ferroelec. Freq. Control UFFC-35, 775–787 (1988) and 37, 369–385 (1990)]. The two-dimensional theory of poroelastic shells is deduced from the variational equations using Mindlin’s method of reduction for the case when the fluid–solid coupling is included through Biot’s consolidation theory and the field quantities are taken to vary linearly across the shell thickness. The shear deformable linear theory accommodates the extensional, thickness, flexural, and coupled vibrations of poroelastic shells. Specialization in geometry, material properties, and vibrations is considered, the uniqueness of solutions is examined, and also, a numerical algorithm that is based on the method of moments is described for the vibrations of poroelastic shells.
Nonlinear parametric oscillation of a beam contacting with ideal compressible liquid in a channel
Authors: Abramian A. K. , Andreyev V. L. , Indejtchev D. A.
Published: October 2005

The influence of compressible liquid on nonlinear oscillation of a channel back boundary is studied. The back boundary is a beam with a thrust on an elastic bed. The beam is excited by parametric longitudinal compressing forces. Using the Galerkin procedure the starting equation takes the form: Ẅ1+a(t)W1+εẆ1=bW31+cW1W22=0, Ẅ2+f(t)W2+γW32+gW2W21=0. The fundamental resonances of the beam are examined by using the multiple-scales averaging analysis. The presence of liquid leads to reduction of the range where stable oscillation of the system is possible. Numerical simulation of the process in the phase space has been conducted and chaotic behavior of the system has been found. Precision algorithms of Runge-Kutta (DOPRI) have been used for the numerical simulation. The numerical simulations are studied in the context of Runge-Kutta simplex methods. Qualitative analysis of process dynamics has been obtained. Lyapunov exponents and fractal dimensionality have been determined; they prove the presence of a strange attractor in the system.
Influence of timing on intelligibility of foreign-accented English
Authors: Tajima Keiichi , Port Robert , Dalby Jonathan
Published: October 2005

The reduced intelligibility of foreign-accented speech is usually attributed to errors in the positioning of the articulators. But how much would correction of their timing improve intelligibility? One way to estimate this effect is to manipulate the acoustic timing of foreign accented speech. Short English phrases spoken by a native Chinese talker were manually edited so as to align the duration of acoustic segments with tokens of the same phrases spoken by a native English talker. Editing methods included: (i) insertion and deletion of pitch periods, frication noise, and silence, and (ii) amplitude reduction for approximation of nasal segments. A group of native American listeners identified each phrase in a two-alternative forced-choice task: the correct phrase (e.g., ‘‘equalsize’’) versus a distractor phrase suggested by listening to the Chinese production (‘‘you’reconcise’’). Performance was only slightly above chance for the unmodified tokens, but reached 80% correct for the modified versions. Performance on the native-accented tokens was nearly 100%. Addition of white noise had little effect on performance. These results suggest that improvement in the articulatory timing of non-native speakers might substantially improve intelligibility. [Research supported by subcontract from Communications Disorders Technology, Inc. and NIDCD.]
Temporal envelope and fine structure cues for speech intelligibility
Authors: Drullman Rob
Published: October 2005

A number of listening experiments were run to investigate the relative contribution of temporal envelope modulations and fine structure to speech intelligibility. Firstly, the amplitude envelopes of 24 1/4-oct bands (100–6400 Hz) were processed in several ways (e.g., fast compression) to assess the importance of modulation peaks and troughs. Results show that reduction of modulations by the addition of noise is more detrimental to sentence intelligibility than the same degree of reduction achieved by direct manipulation of the envelope; in some cases the difference in speech-reception threshold (SRT) is almost 10 dB. Here, Leq−3 dB defines a perceptual cross-over level for which removing modulations either x dB below or above yields the same intelligibility score, whereas Leq−15 dB defines the median envelope level (acoustic cross-over level). Secondly, the fine structure of each 1/4-oct band was altered by manipulating the distribution of speech and noise over the sentences. Results indicate that noiseless peaks do not increase intelligibility; removing the speech fine structure in the troughs, however, yields a 2-dB increase of the SRT. In general, no one-to-one relation between the modulation-transfer function (MTF) and the intelligibility scores could be established. [Work supported by NWO.]
Hard-of-hearing listeners’ perception of consonants preceded or followed by stressed vowels
Authors: Revoile Sally , Dillon Harvey
Published: October 2005

Knowledge is limited of the effects of syllable stress on consonant acoustic cues. Differences in consonant acoustic cues according to syllable stress may affect perceptibility by hard-of-hearing listeners. In this presentation, the perceptibility of consonants for hard-of-hearing listeners was examined depending on the stress patterns of the syllables in which the consonants resided. Each of 22 English consonants were spoken in /iCi/, /aCa/ and /open ohcopen oh/ with stress on the initial vowel or the final vowel. The VCV’s were extracted from a spoken sentence frame for the consonant identification tests. Seven listeners with moderate-to-severe hearing loss identified the consonant in each of the VCV’s, which were presented at listeners’ most comfortable levels. The listeners’ perception was better for the consonants preceding the stressed vowels (56% mean) than when following the stressed vowels (38% mean). This disparity occurred across the vowels and consonant manner classes. However, the magnitude of the perceptual advantage for the consonants preceding stressed vowels differed noticeably among manner classes and vowel contexts. These perceptual differences were not explained by acoustic characteristics of consonant segment duration or intensity. [Work supported by NIDCD, NAL, and Gallaudet University.]
Predicting hearing-impaired listeners’ use of acoustic cues for consonant recognition
Authors: Kozma-Spytek Linda , Nelson Peggy B. , Revoile Sally G. , Holden-Pitt Lisa
Published: October 2005

Reduced consonant recognition and large inter-listener variability among individuals with sensorineural hearing loss are neither well characterized nor understood. Previous attempts to account for consonant recognition using threshold and suprathreshold measures have produced equivocal results. Classifications of listeners according to performance patterns for acoustic cue use are lacking. The present study classifies hearing-impaired listeners according to their use of information in successive vowel and consonant segments for identification of consonants. Seventy hearing-impaired (moderate to profound) and 19 normal-hearing listeners identified /n/, /l/, and /d/ in spoken VCV’s extracted from connected speech. The VCV’s were presented unmodified and with consonant and vowel-transition segment deletions. Percent information transmitted scores for each consonant and stimulus condition were submitted to a hierarchical cluster analysis to classify all listeners into homogeneous groups based on the extent to which given consonant and vowel segments contributed to /n/, /l/, /d/, identification. A discriminant analysis was used to examine thresholds, suprathreshold measures, and listener history as variables predictive of group membership. Variables that contributed to differentiation among performance groups will be reported. [Work supported by NIDCD and Gallaudet University.]
Objective predicates of word intelligibility
Authors: James Chris J.
Published: October 2005

There have been many attempts in the past to systematically attribute the physical properties of speech to subjective characteristics. The aim of this study was to look in more detail at how objective properties interact to contribute to the shape of performance-intensity functions for individual words. The interaction of such features as speech level, familiarity, and spectral consistency were found to be complex but enlightening. In this study the largest effect is due to familiarity, however this is shown not to be as important under some conditions and for subsets of words with particular characteristics. Although the results shown by no means explain the whole story of speech perception, they do provide some insight into the play of factors for the fairly simple case of monosyllabic words. [This work was supported by the National Physical Laboratory, Teddington, UK.]
The intelligibility of sentences in which multiple segments are replaced by noise bursts
Authors: Goldman Susan L. , Braida Louis D.
Published: October 2005

The performance of aids for the deaf based on automatic speech recognition (ASR) is limited by errors made by the recognizer. To estimate the effects of these errors on the reception of automatically generated cued speech, acoustic speech signals were degraded to correspond to the errors made by a current ASR system. Phonemes in sentences were replaced by bursts of broadband noise according to the ASR phoneme error pattern. Five hundred and eighty sentences were generated with total segment replacement rates of 10%, 20%, 30%, and 40%. Measured phoneme error rates for auditory reception of the processed sentences (without speechreading) were substantially lower (by a factor of 4 for replacement rates of 10% to 20% and a factor of 2 for replacement rates of 30% to 40%) than the segment replacement rate. Findings are discussed as they apply to both the feasibility of using an ASR as a front end for an assistive device and phoneme restoration. [Research supported by NIH.]
Training speech perception in deaf children: Generalizing from word to sentence context
Authors: Hnath-Chisolm Theresa
Published: October 2005

Although the training of auditory speech perception skills has long been considered an important component in the treatment of childhood deafness, little research has focused on training issues. Thus the overall goal of this work is to examine the process of speech perception training as it relates to speech production training and language. As a first step, eight profoundly deaf children (5 to 7 years old) were trained to discriminate words, presented in isolation, which were differentiated by vowels. Perception of the words in isolation was compared to perception in syntactically correct sentences. Data were obtained over three time periods: (1) traditional speech/language treatment (TST); (2) TST plus experimental training (TST+EXP); and, (3) control. During the control period no therapy was provided. Results indicated improvement in the perception of the words in isolation during both the TST and TST+EXP periods, with greater improvement during the TST+EXP period. There was no generalization, however, to the sentence level. No changes in performance occurred during the control period. The lack of generalization from words to sentences highlights the importance of providing practice at different levels of linguistic complexity. [Work supported by NIH Grant No. 5KO8DC00049.]
Distinctive feature-based scoring of errant responses to rhyme test words
Authors: Goshorn Edward L. , Byers Vincent W.
Published: October 2005

A distinctive feature-based system [W. A. Wicklegren, J. Acoust. Soc. Am. 39, 388–398 (1966)] for scoring errant responses to rhyme test words was developed. Words were presented in noise (0, 4, 8, and 12 dB signal-to-noise ratio) at four intensities (20, 40, 60, and 80 dB HL) to five normal hearing subjects. Errant responses were assigned values from 1 to 7, and categorized as mild, moderate, or severe, according to number of features missed. A basic computer program analyzed responses and yielded a total feature error score (TFES), the number of mild, moderate, and severe errors, and a transformed percentage correct score in rationalized arcsine units (rau) for each 50-item list. The TFES and rau data yielded parallel functions for signal-to-noise ratio and intensity. The correlation coefficient for TFES and rau was −0.965. An ANOVA for rau yielded three significant two-way interactions, the TFES only one. As conditions became difficult and percentage correct diminished, listeners tended to make more mild errors rather than severe. Results have implications for development of word recognition tests.
Kirchhoff scattering for fourth-order structural wave systems
Authors: Martinez R.
Published: October 2005

Real structures always contain discontinuities that act as scattering agents for the smooth-geometry elastic wave systems that they otherwise support. A typical such structural-wave diffractor of continuing interest is a partial arc frame on a thin cylindrical shell. This paper aims to turn that mathematically unseparable problem into a canonical one by developing a Kirchhoff scattering theory for the shell’s fourth-degree wave systems: both for the plate-like flexural motion and for the in-plane ‘‘membrane’’ fields, which are each governed by the operator (∇2+k2p) (∇2+k2s) at high frequencies. The suggested quasidecoupling of the radial motion from the other two (which remain coupled) is the result of an intermediate perturbation expansion of the shell equations in terms of two parameters. The structurally diffracted field of the radial motion, delivered analytically by the new structural Kirchhoff scattering theory, becomes an extended source of sound that is now likewise available analytically. The predictions to be presented of the target strength of an internal partial frame in a cylindrical shell generalize those made by Rumerman for a full end frame [J. Acoust. Soc. Am. 93, 55–65 (1993)].
High-frequency scattering from a spherical shell: Thickness quasiresonance
Authors: Sammelmann Gary Steven , Kargl Steven , Todoroff Douglas G.
Published: October 2005

Theoretical calculations have shown that the high-frequency scattering from a thin spherical shell is dominated by a single peak that occurs near the opening of the first symmetric Lamb wave. This peak is associated with a region of strong negative group velocity surrounding the opening of the first symmetric Lamb wave. Experimental verification of the existence of the thickness quasiresonance on a 2% stainless steel shell is given. In addition an analysis of the thickness quasiresonance in the complex-ka plane is presented for shells of different material parameters. It is shown that the thickness quasiresonance bifurcates as a function of Poisson’s ratio in such a manner that the region of negative group velocity remains close to the opening of the first symmetric Lamb wave. [Work supported by ONR.]
Review of some contributions on resonance scattering emphasizing their applications to acoustics, elastodynamics, and electromagnetism
Authors: Gaunaurd Guillermo
Published: October 2005

Some of my early (1977–80) contributions on resonance scattering as they applied to the three disciplines in the title will be reviewed. Of main interest was the splitting of the partial waves that make up the sonar cross sections (SCS) of any object into the two interacting portions denoted ‘‘backgrounds’’ and ‘‘resonances.’’ This early work was first presented by H. Überall, and by myself, in two separate lectures, in a 1977 IUTAM Congress on Elastic Wave Propagation in Chicago. This identical work was later published in two JASA articles [J. Acoust. Soc. Am. 63, 723–731, 1699–1712 (1978)]. This process of so splitting the SCS, and an analogous one in radar were patented by myself in 1980 on behalf of the Navy, and received much publicity in the secular press. By 1981 there were dozens of articles out on the subject [summarized in: L. Flax, G. Gaunaurd, and H. Überall, PhysicalAcoustics (Academic, New York, 1981), Vol. 15, Chap. 3] and by the end of the decade there were hundreds (see an overview in: G. Gaunaurd, Appl. Mech. Rev. 42, 143 (1989)]. Today, although substantially modified from its primitive form, the approach still attracts the interest of researchers, and yet, it has not triggered any Naval Program, and possible reasons for this outcome are conjectured. [Work supported by the NSWC/DD’s IR Program and the ONR.]
Development and application of the spheroidal coordinate-based T matrix to elastic wave scattering
Authors: Hackman Roger H. , Lim Raymond
Published: October 2005

A spheroidal coordinate-based T-matrix formalism is developed for the description of elastic wave scattering from a collection of obstacles embedded in a homogeneous, unbounded medium. The development of the spheroidal formalism for the scattering from a single obstacle is based on the earlier work of Hackman [J. Acoust. Soc. Am. 75, 35–45 (1984)]; a discussion of the extension of this approach to a many-inclusion system is a generalization of Lim and Hackman [J. Acoust. Soc. Am. 91, 613–638 (1992)]. Calculations are presented for the elastic wave scattering from (single) prolate spheroidal and finite cylindrical objects and from both finite and infinite collections of spherical obstacles. The single inclusion calculations presented have bearing on a study of anechoic mechanisms in composite materials presented earlier [Lim and Hackman, J. Acoust. Soc. Am. 87, 1076–1103 (1990)].
Modal analysis of hammered dulcimers
Authors: Canfield Gregory H. , Rossing Thomas D.
Published: October 2005

Vibrational modes of four different hammered dulcimers were studied by means of holographic interferometry and experimental modal testing with impact excitation. Vibrational modes in the four dulcimers, by four different builders and having substantially different designs, showed some similarities but a number of differences as well. Unlike other string instruments (e.g., violin, guitar), the soundboard and back plate vibrated quite independently of each other. Nodal lines tended to occur along the bridges, in most vibrational modes. Mode frequencies are compared to those calculated for rectangular and trapezoidal plates.
Vibrations of a yangqin soundboard
Authors: Tsai Jianming
Published: October 2005

The yangqin is a Chinese hammered dulcimer with a trapezoidal soundboard. The soundboard studied by the author, which is crowned to a height of 4 cm in the center, is supported by seven unequally spaced transverse ribs. Vibrational modes of the soundboard in the frequency range 100–700 Hz have been studied by impact modal analysis as well as by scanning with an accelerometer as the soundboard is driven by a small shaker. Modal shapes indicate that the transverse stiffness is substantially greater than the longitudinal stiffness in the braced soundboard. Nodal lines tend to follow the stiff transverse ribs. The impedance at most points on the bass bridge shows a maximum around 100 Hz and then falls off at roughly 6 dB/oct. The impedance on the treble bridges, on the other hand, reaches a broad maximum around 2 kHz and falls off quite slowly with frequency, at least up to 5 kHz. Experimental values of mode frequencies fit well to the analytical ones obtained by considering the trapezoidal ratio and the curvature effect. The soundboard boundary conditions are somewhat complicated by the frame. They appear to be close to simply supported edges at the lower frequencies and close to clamped edges at the high frequencies.
Musical demonstration of the hammered dulcimer and Southern folk music styles
Authors: Peterson David R. , Peterson Donna , Peterson Christopher
Published: October 2005

The sounds of several hammered dulcimers will be demonstrated, both by themselves and in ensemble with fiddle, guitar, lap dulcimer, percussion, and voice. The difference in tone produced by varying the hammer hardness and playing position will be demonstrated. Several experimental instruments will show the effect of internal bracing and other design criteria. The musical foundation will be rooted in Southern highlands reels, jigs, and songs, as well as ragtime and other dance music. [Following the session, the Peterson family will lead a folk dance and teach the basics of dances from the Southern highlands.]
The effects of two types of level variation on the size of the binaural masking level difference
Authors: Richards Virginia M. , Henning G. Bruce
Published: October 2005

Observers were required to detect 500-, 110-, or 20-ms bursts of 250-, 500-, or 5000-Hz tones presented in simultaneously gated narrow (30-Hz) noise bands using standard two-interval forced-choice tracking procedures. The noise was in phase at the observers’ ears; the signal was in phase in one set of experiments and π radians out of phase in another. Three different ‘‘roving-level’’ conditions were used: (1) fixedlevel the noise-power density, N0, was fixed (50 dB SPL), (2) inter-intervalrove a random gain factor was chosen for every observation interval from a set uniformly distributed in decibels (40-dB range; 0.1-dB steps) to produce N0 centered on 50 dB SPL. The gain factor affected signal and noise in both ears equally and thus left the signal-to-noise ratio, interaural phase differences and amplitude ratios unaffected, (3) interauralrove the random gain varied from ear-to-ear in every observation interval. Reducing duration reduced BMLD’s in all conditions; roving levels reduced BMLD’s by small amounts except at 20 ms where interaural rove removes them. [This research was supported by The National Institutes of Health.] a)On leave from the Dept. of Exp. Psychol., Oxford.
A real-time model of binaural sound source localization resolving spatial ambiguities
Authors: Peissig J. , Albani S. , Kollmeier B.
Published: October 2005

The human binaural hearing provides a precise internal image of external sound source locations. Although the determination of the azimuthal position of a sound source is primarily based on the evaluation of interaural time and intensity differences, the psychoacoustic processing of these cues to form an ‘‘auditory spatial image’’ is yet unclear. Especially for all angles of incidence on the ‘‘cone of confusion,’’ interaural differences are equal and therefore provide an ambiguous representation of the source location. However, neurophysiological studies with barn owls show that by integration of directional information across frequency bands an unambiguous internal representation of sound source locations can be obtained. These findings form a model of binaural localization which was adapted to the system characteristics and psychoacoustic parameters of human hearing. The model was implemented in real-time on a multiprocessor setup. First results with the localization of sounds under anechoic and normal room conditions indicate that incidence directions from ahead, above and from the back can be distinguished. A possible use of a preprocessing stage in a directional hearing aid is discussed.
FM detection and F0 discrimination of complex tones
Authors: Plack Christopher J. , Carlyon Robert P.
Published: October 2005

Earlier experiments have shown that listeners are very poor at detecting frequency modulation (FM) imposed on the fundamental frequency (F0) of complex tones consisting only of unresolved harmonics. In the first experiment, the detection of 5 Hz FM was measured for a complex tone with a 62.5 Hz F0 and harmonics bandpass filtered between 1375 and 1875 Hz. These results were compared to performance on a task in which listeners were required to detect an F0 difference between two 50-ms bursts of the complex separated by 50 ms. It was shown that performance on the two tasks (measured in terms of maximum F0 deviation at threshold) was similar. A subsequent experiment showed that, in a two interval discrimination task, there was a dramatic deterioration in F0 discrimination for complexes composed of unresolved harmonics as the interstimulus interval was reduced from 500 to 100 ms. It seems, therefore, that poor performance on the FM detection task was due to difficulties in comparing F0s over short time intervals, rather than a difficulty in processing FM per se. The possibility that the auditory system uses a long temporal window when determining the pitch of these complexes will be discussed.
Perceptual variance along tone and speech continua
Authors: Schouten M. E. H. , van Hessen A. J.
Published: October 2005

One of the assumptions underlying the calculation of almost every d′ in the literature is that the distribution of sensations resulting from repeated presentation of a stimulus is normal and is equal to the distributions produced by the other stimuli in an experiment. This could be a reasonable approximation for pure tones, but it is doubtful whether it applies to more complex stimuli such as speech. A series of magnitude-estimation experiments was carried out, in which subjects were asked to indicate the position of each stimulus on a line on a monitor screen, which ran either from ‘‘soft’’ to ‘‘loud’’ or from /p/ to /t/. The stimuli were practically identical to those used by [L. D. Braida and N. I. Durlach, J. Acoust. Soc. Am. 51, 483–502 (1972), and by M. E. H. Schouten and A. J. van Hessen, J. Acoust. Soc. Am. 92, 1841–1855 (1992)]. Training was done by means of identification of the same stimuli on a similar line, but now subdivided into segments. Each stimulus was presented for magnitude estimation 400 times before and 400 times after training; as a result, the shape and size of each distribution could be traced out.
The application of frequency and time domain kurtosis to the assessment of hazardous noise exposures
Authors: Lei Sheau-Fang , Ahroon William A. , Hamernik Roger P.
Published: October 2005

Five computer synthesized broadband noises, each having the same average spectrum and the same unweighted Leq of 100 dB SPL but very different temporal structures were used to produce hearing loss in chinchillas. Despite the same exposure energies and spectra, each noise exposure produced a different magnitude and frequency distribution of hearing loss and sensory cell loss. The results indicate that the statistical properties of a signal are important in the determination of hearing loss. When the audiometric and histological results are compared to a metric based upon kurtosis measured in the time and the frequency domain for each exposure, there is a strong indication that these matrices are good predictors of the magnitude and frequency distribution of the acoustic trauma. [Research sponsored by NIOSH Grant 2R010H02317.]
The effects of primed and interrupted noise exposure paradigms on hearing loss
Authors: Roberto Michele , Ahroon William A. , Hamernik Roger P. , Davis Robert I. , Case Christopher J.
Published: October 2005

Exposure to low-level noise (priming) produces a protective effect on the auditory system evidenced by a reduced permanent threshold shift (PTS) from a subsequent high-level exposure. Similarly, regularly interrupting a high-level noise exposure causes the threshold shift following daily repeated exposures to the noise to be reduced with a concomitant lowering of PTS. These effects, collectively referred to as ‘‘toughening,’’ can exceed 35 dB. If the toughening mechanism elicited during both types of exposure paradigms has a common origin, then combining the paradigms should yield predictable results. Results from nine exposure paradigms with five to six chinchillas in each paradigm are reported. Impacts of 113 or 119 dB peak SPL and pink noise of 72 or 78 dB SPL presented over five or 20 days in an interrupted or noninterrupted paradigm were used. Results suggest that priming can affect the PTS but has little or no effect on the toughening produced during interrupted exposures or the asymptotic threshold shift (ATS) produced by an uninterrupted exposure. Similarly, the toughening produced during an interrupted exposure affects PTS but not ATS from an uninterrupted exposure. These results suggest independent mechanisms for the two toughening phenomena. [Research sponsored by NIOSH.]
Prediction of inner ear properties by the dynamics of the cochlear amplifiers
Authors: Furst Miriam , Cohen Azaria
Published: October 2005

The role of the outer hair cells as cochlear amplifiers has been recently shown experimentally and theoretically. The nonlinear transmission line model was chosen as a framework to test the role of the cochlear amplifiers to different cochlear properties. It was found that there are phenomena such as rate suppression, or threshold microstructure in the vicinity of spontaneous otoacoustic emission, that can be predicted by such a model only if it is assumed that the local cochlear amplification is dynamically changing as a function of the stimulus. The dynamics of the cochlear amplifiers was achieved in the model by assuming that each outer hair cell amplification gain depends on the electrical potential across its membrane. It is most probable that the cochlear microphonics, which represent the potential changes in the scala media, are indication to the electromechanical feedback loop. The electrical potential in the model is derived by assuming that it produces an external mechanical force that is applied to the outer hair cells that in return act as a damped-spring mass. The model was simulated in the time domain, and its prediction to various cochlear phenomena will be discussed.
Norms for a headphone simulation of the Hearing in Noise Test: Comparison of physical and simulated spatial separation of sound sources
Authors: Nilsson Michael J. , Soli Sigfrid D.
Published: October 2005

Norms for a headphone-based procedure for administering the Hearing in Noise Test has been developed [Nilsson etal., J. Acoust. Soc. Am. 95, 1085–1099 (1994)]. Sentence speech reception thresholds (SSRTs) were measured adaptively in the presence of spectrally matched noise for 23 young, normal hearing male and female adults using two presentation systems: a sound field presentation and a headphone simulation of the sound field. Speech was presented at 0° azimuth in all conditions, and noise (when present) was presented at either 0°, 90°, or 270° azimuth at 65 dB(A). The headphone simulation used head-related transfer functions (HRTFs) measured off a KEMAR mannequin to introduce the appropriate interaural cues. Correction factors between the current headphone and sound field measurements were calculated to correct previous sound field norms. SSRTs were based upon 3 repeated measurements in each condition, and differences between the sound field and headphone data varied between approximately 0.5 and 2.5 db, depending upon the condition. SSRTs in quiet are elevated in the headphone system, most likely because of a higher noise floor caused by the instrumentation. SSRTs in noise are all lower in the headphone system, attributable to the elimination of room and speaker effects. Improvements in SSRTs with spatial separation of the signal and masker were 6.38 dB in the sound field and 6.65 dB under headphones. [Work supported by Hoover Foundation.]
Detection and recognition of narrow-band sound effects
Authors: Myers Laurie L. , Letowski Tomasz , Abouchacra Kim S. , Haas Ellen C. , Kalb Joel
Published: October 2005

Pure-tone audiometry is not always appropriate with young children and with difficult to test populations. In such cases, various other audiological tests that are based on broadband sound effect detection and recognition tasks are used. However, results of those tests do not provide frequency specific information about the client’s hearing. The purpose of the present study was to determine whether selected sound effects that are spectrally limited to 1 octave bandwidth could be used as a basis for frequency-specific environmental audiometry. Twenty adults with normal hearing sensitivity participated in the study. Their task was to detect and recognize various bandlimited musical and environmental sounds presented in quiet and noise. The results of the study indicate that environmental audiometry based on filtered sound effects is a promising alternative to pure-tone audiometry. Further studies with children and the development of normalized thresholds using frequency-specific sound effects are needed.