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Proceedings of Meetings on Acoustics

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POMA - 153rd Meeting Acoustical Society of America
Conference Location: Salt Lake City, Utah Conference Date: 4 - 8 June 2007
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Proof that plane wave attenuation at low frequencies is proportional to square of frequency

Allan D. Pierce and William M. Carey

POMA Volume 1, pp. 005001 (March 2008); (7 pages)

Online Publication Date: March 24, 2008

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In regard to the attenuation of sound in marine sediments, Holmes, Carey, Dediu, and Siegmann [JASA Express Letters, 2007] report a nonlinear frequency dependence with frequency raised to a power n=1.8 (plus or minus 0.2); earlier literature gives results with non-integer values of n that are between 1 and 2. The present paper argues that the exponent should be exactly 2 in the limit of low frequencies. Plane wave propagation in a general medium allows specific modes for which wavenumber k is a given function of frequency. Attention is given to those propagating modes where the real part of k is proportional to frequency at low frequencies, so that the phase velocity approaches a finite value as the frequency goes to zero. General causality (all the past determines future) requires the exponent n to be greater than unity. A restricted type of causality, where a knowledge of only the present suffices (including a knowledge of possibly many hidden variables, corresponding to relaxation processes), with governing equations being linear partial differential equations with constant coefficients, leads to the requirement that the imaginary part of k must have a low-frequency dependence that is as the square of frequency or weaker.
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43.20.Hq Velocity and attenuation of acoustic waves
43.30.Ma Acoustics of sediments; ice covers, viscoelastic media; seismic underwater acoustics
43.35.Bf Ultrasonic velocity, dispersion, scattering, diffraction, and attenuation in liquids, liquid crystals, suspensions, and emulsions
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Wedge diffractions: Biot-Tolstoy normal coordinate solution and Medwin's lab experiments

Clarence S. Clay

POMA Volume 1, pp. 005003 (May 2008); (14 pages)

Online Publication Date: May 07, 2008

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In the 1960s, the Hudson Labs of Columbia University had coffee hours. The coffee gang included Ivan Tolstoy, Antares Parvulescu, Bob Frosch, Mel Hinich, and Peter Rona. We tested our crazy ideas, scribbled on the blackboard, and listened. Wave propagation in a messy ocean was the problem. We were well beyond ideal layered waveguides with plane interfaces. Tolstoy did normal coordinates and modes [Tolstoy and Clay, Ocean Acoustics (1966, 1986)-AO]. One summer, Hank Medwin joined us and conversations led to research on sound scatter from rough surfaces. Helmholtz-Kirchhoff (H-K) computations were accurate for sound scattered in specular directions, AO Ch. 6. Diffractions are different. The AO (1986) includes Biot-Tolstoy diffraction of impulses by rigid wedges (B-T). Interior wedge angles=[rho]/n have no diffracted waves. Clay and Medwin's Acoustical Oceanography (1977) detailed H-K methods and ignored B-T. Pushing hard, was H-K accurate for all diffraction waves? In 1978--82, Bremhorst, Jebsen, and Hank did wedge experiments and proved B-T is exact and H-K is limited. See Figs. 12.3, 2--3.3 in Medwin and Clay, 'Fundamentals of Acoustical Oceanography' (1998). Chapters 11 and 12 give details. Use normal coordinate B-T for wedges.
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43.30.Bp Normal mode propagation of sound in water
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Methodology for Physics-Based Sound Composition in Forensic Visualization

William Neale and Toby Terpstra

POMA Volume 1, pp. 015001 (November 2007); (18 pages)

Online Publication Date: November 26, 2007

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This paper describes a methodology for incorporating physically accurate sound composition in forensic visualizations. The use of sound in forensic visualization provides the viewer a more realistic and comprehensive understanding of actual accident events. Forensic visualization represents complex events such as car crashes, through animation, making it easier to understand the accident. Without sound, however, a visual representation of an accident will lack important information. For instance, sound adds a spatial dimension to animations, defining space through reflection and reverberation. Sound also provides an understanding of important details such as the duration and severity of an accident, and potential sounds heard by a witness. Sound also allows the viewer to experience events in the accident that are occluded from view. Currently, there is no methodology for compositing sound in an animation to follow the principles of sound and reflect the specifics of an accident. Acoustical principals define how sound attenuate, reflects, dampens, blends and changes in pitch and sound level. The unique circumstances of an accident define what sounds are present and the timing and sequencing of these sounds. This paper provides a methodology for creating sound the both follows acoustical principles and reflects the unique circumstances of an accident.
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43.50.Lj Transportation noise sources: air, road, rail, and marine vehicles
43.55.Ka Computer simulation of acoustics in enclosures, modeling
43.58.Ta Computers and computer programs in acoustics
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Physical models of transducer coupling in dense arrays

Kassiani Kotsidou and Charles Thompson

POMA Volume 1, pp. 030001 (May 2008); (13 pages)

Online Publication Date: May 19, 2008

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In this work we will examine the coupling between direct sound radiators. It will be shown that at low frequencies, the mutual impedance between a pair of transducers is analogous to that of two simple sources. Hence the magnitude of their interaction will be inversely proportional to their separation distance. The phase is proportional to the propagation time between a transducer pair. The implication of this result is explored in the design of a densely packed arrays, will be examined.
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43.38.Hz Transducer arrays, acoustic interaction effects in arrays
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Sound parameters in mosques

Wasim A. Orfali

POMA Volume 1, pp. 035001 (December 2007); (21 pages)

Online Publication Date: December 14, 2007

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Unlike auditoriums, there are no defined recommendations or rules for the acoustical parameters inside mosques. Most of the existing recommendations are developed for multipurpose halls, for opera or dramatic theaters, and for structures built for organ music. But regarding mosques the elaboration of general sound parameters requires a specific understanding of the acoustical and spiritual environment expected in such structures. Newly defined acoustical parameter values with regard to mosque volumes and types will be addressed here. New treatment rules for closed or courtyard structures are introduced. Especially so-called mosque volume dependent parameters are derived. They allow optimizing the secondary structure of a mosque by considering the primary structure determined by the architecture. Such parameters deal with optimal reverberation time or intelligibility considered for all praying modes at once. Target of the research is to get standard acoustic parameter values especially applicable for mosques.
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43.55.Br Room acoustics: theory and experiment; reverberation, normal modes, diffusion, transient and steady-state response
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Acoustics of music and voice in Jewish worship spaces

Mendel Kleiner and David L. Klepper

POMA Volume 1, pp. 035002 (April 2008); (9 pages)

Online Publication Date: April 22, 2008

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The history of Jewish worship space, the organization, and some of the customs of Jewish worship are discussed. The various strands of Jewish worship are presented as they relate to the worship space and its acoustics. The architectural and acoustic features of the various types of Jewish worship spaces and how these relate to the tradition are then presented. The difficulties and possibilities in using sound reinforcement in Jewish worship spaces are noted. Finally, the noise issues are discussed from the viewpoint of signal-to-noise ratios for speech intelligibility. The intent is to provide a background for thorough acoustical analysis.
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43.55.Fw Auditorium and enclosure design
43.55.Gx Studies of existing auditoria and enclosures
43.55.Hy Subjective effects in room acoustics, speech in rooms
43.55.Jz Sound-reinforcement systems for rooms and enclosures
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Characterizing natural soundscapes and understanding human response to human-caused noise in a Hong Kong country park

Kin-che Lam, Kwai-cheong Chau, Lawal M. Marafa, and Pak-kin Chan

POMA Volume 1, pp. 040001 (December 2007); (14 pages)

Online Publication Date: December 27, 2007

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A study was undertaken in a country park of Hong Kong to characterize the natural soundscapes and determine the affective response of visitors to natural and human-caused sounds. Located on the eastern extremity of Hong Kong, the country park is easily accessible and characterized by sandy beaches, rocky shores, rugged slopes and wooded ravines nested among silent hills and mountains. The country park is exposed to varying levels of transportation noise (motor vehicle, aircraft) and visitor-caused noise. The soundscapes of a variety of natural landscapes were characterized by sound walks and acoustic analysis of 15-minute and 24-hour sound recordings. A questionnaire survey would be undertaken in several landscape-recreational use settings with different exposure levels to transportation and human-caused noise. The findings will provide an empirical basis to plan and manage natural soundscapes, hence contributing to a growing body of research on the potential impacts of human-caused sound in country parks.
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43.66.Fe Discrimination: intensity and frequency
43.66.Lj Perceptual effects of sound
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Angular dependence of target strength for simple geometric shapes

Edward J. Tucholski

POMA Volume 1, pp. 045001 (April 2008); (7 pages)

Online Publication Date: April 09, 2008

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Angular dependence of Target Strength for simple geometric shapes Understanding the active sonar equation is a fundamental skill for a course in underwater acoustics and sonar such as that taught at the United States Naval Academy. Students must develop an intuitive understanding of each term in both the noise limited and reverberation limited cases. In this demonstration, the angular dependence of the Target Strength term is explored using commercially available 25 and 40 kHz airborne piezoelectric transducer/receiver pairs. By rotating standard target shapes (e.g. rectangular plates, circular plates, finite cylinders, ellipsoids), reflected intensity is measured as a function of angle of rotation. The measured data is compared with that predicted by standard theoretical predictions. While the same measurements could be made in a tank using submerged transducers, the airborne transducers offer the advantage of lower cost and simplicity of apparatus. Additionally, unwanted modal interference from sound reflection off tank surfaces is reduced in the airborne measurement. By direct observation, future naval officers are able to study Target Strength so as to understand how to position their sensors to optimize their own active sonar performance and position their warship to minimize detection by enemy active sonar.
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43.30.Gv Backscattering, echoes, and reverberation in water due to combinations of boundaries
43.30.Vh Active sonar systems
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Elastic constants, Blackman diagrams, and new lanthanide-actinide insights

Hassel Ledbetter

POMA Volume 1, pp. 045002 (April 2008); (7 pages)

Online Publication Date: April 25, 2008

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Using monocrystal elastic constants and Blackman diagrams, one can infer material interconnections, physical-property trends, and knowledge about interatomic bonding. After reviewing briefly the f.c.c.-metal case, focus shifts to Ce, Pu, Th, with known monocrystal f.c.c. elastic constants, the Cij. For U and a few other lanthanide-actinide cases, one can deduce the f.c.c. Cij. From these results, for the lanthanides-actinides, there follow several conclusions: (1) elastic anisotropy varies widely; (2) Poisson ratios are low; (3) interatomic bonding varies widely; (4) against all other f.c.c. metals, all show unusual negative Cauchy pressures (three-body forces); (5) a strong covalent-bonding component occurs, perhaps related to localized (or semilocalized) f-electrons; (6) delta-plutonium behaves most oddly; (7) delta-plutonium may share some bonding features with alkali metals.
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43.35.Cg Ultrasonic velocity, dispersion, scattering, diffraction, and attenuation in solids; elastic constants
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Temporal, Intensity and Pitch Relationship on Speech Auditory Brainstem Response to Phonemes /ba/ in Normal Hearing Adults.

Idrick Akhoun, Barbara Tillmann, Annie Moulin, Stéphane Gallégo, Evelyne Veuillet, Christian Berger-Vachon, Lionel Collet, and Hung Thai-Van

POMA Volume 1, pp. 050001 (February 2008); (7 pages)

Online Publication Date: February 01, 2008

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The temporal acoustic pattern of a short speech signal is encoded very accurately in the brainstem. This compound remote response can be recorded on the scalp under the form of speech elicited Auditory Brainstem Response (Speech ABR). Speech ABR is described as the succession of a transient Onset Response (OR) and a sustained Frequency Following Response (FFR). It has been shown that the FFR is the compound phase-locking activity of brainstem cells, and that FFR mimics the periodicity of phonemes (Russo et al., 2004). In Experiment 1 reported here, we confirmed this observation (23 subjects). Experiment 2 showed that Speech ABR to /ba/ components, had different latency-intensity functions (around 15ms for FFR and 7 ms for OR), assuming that these two responses were the result of separate processing streams (11 subjects). In Experiment 3, three stimuli with steady fundamental frequencies (F0) at 133, 375 and 575 Hz vowel were used (12 subjects). Speech ABR showed a reproducible onset response (OR) around 6 ms after stimulus onset, whereas FFR seemed to vanish for high F0. This lack in synchronization gives further evidence that upper brainstem may be the main generator for Speech ABR.
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43.64.Ri Evoked responses to sounds
43.64.Sj Neural responses to speech
43.66.Hg Pitch
43.66.Nm Phase effects
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Environmental sound research as it stands today

Brian Gygi and Valeriy Shafiro

POMA Volume 1, pp. 050002 (April 2008); (18 pages)

Online Publication Date: April 09, 2008

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Environmental sound research is still in its beginning stages, although in recent years there has started to accumulate a body of research, both on the perception of environmental sounds themselves, and on their practical applications in other areas of auditory research and cognitive science. In this piecesome of those practical applications are detailed, combined with a discussion of the implications of environmental sound research for auditory perception in general, and finally some outstanding issues and possible directions for future research are outlined.
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43.66.Lj Perceptual effects of sound
43.66.Yw Instruments and methods related to hearing and its measurement
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Comparison of relative and absolute judgments of speaker size based on vowel sounds

Thomas C. Walters, Phil A. Gomersall, Richard E. Turner, and Roy D. Patterson

POMA Volume 1, pp. 050003 (August 2008); (9 pages) | Cited 3 times

Online Publication Date: August 22, 2008

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Judgments of speaker size are largely determined by two acoustic variables: glottal pulse rate (GPR) and resonance scale (i.e., vocal tract length (VTL)). Both variables change with age (or height), but the rate is governed by different factors. The interaction of the variables was previously measured using absolute judgments of speaker size [D.R.R Smith and R.D. Patterson, J. Acoust. Soc. Am. 118, 3177-3186 (2005)]. The resulting size surface (over the GPR-VTL plane) bends down outside the normal range. In this paper, a method is developed for deriving the surface using size-discrimination data. In a two-alternative forced-choice experiment, listeners compared sequences of vowels scaled in GPR and VTL to represent speakers with slightly different sizes; they were required to choose the interval with the smaller speaker. Comparisons about a point in the plane reveal the gradient vector, and the vectors across the GPR-VTL plane can be integrated to estimate the size surface. The results indicate that the size surface would be essentially planar if determined by size discrimination. This indicates that relative size judgments are different from absolute size judgments, probably because some source knowledge is required for the absolute judgments.
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43.66.Lj Perceptual effects of sound
43.71.An Models and theories of speech perception
43.71.Bp Perception of voice and talker characteristics
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Ensemble-based Bayesian detection and tracking

Brian R. La Cour

POMA Volume 1, pp. 055001 (February 2008); (15 pages)

Online Publication Date: February 13, 2008

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This paper introduces a novel approach to Bayesian tracking in which the posterior distribution is represented by a random sample or ensemble of possible target states. Such a representation may be viewed as a special case of the traditional particle filter approach wherein all particles maintain strictly uniform weights. Measurement updates are performed using a Markov Chain Monte Carlo technique which has been adapted to use multiple chains and a variable pseudo temperature akin to that used in simulated annealing. The general formalism is illustrated in an example of sonar-based target tracking for antisubmarine warfare. For this example, specific motion models and likelihood functions are developed for both target and clutter hypotheses. The technique is examined in the context of results from a recent multistatic seatrial using an echo repeater target and compared against those of a traditional particle filter.
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43.30.Vh Active sonar systems
43.60.Bf Acoustic signal detection and classification, applications to control systems
43.60.Jn Source localization and parameter estimation
43.60.Uv Model-based signal processing
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Temporal characterization of auditory-visual coupling in speech

Adriano V. Barbosa, Hani C. Yehia, and Eric Vatikiotis-Bateson

POMA Volume 1, pp. 060001 (April 2008); (14 pages)

Online Publication Date: April 24, 2008

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This work examines the coupling between the acoustic and visual com- ponents of speech as it evolves through time. Previous work has shown a consistent correspondence between face motion and spectral acous- tics, and between fundamental frequency (F0) and rigid body motion of the head [Yehia et al. (2002), JPHON, 30, 555-568]. Although these correspondences have been estimated both for sentences and for running speech, the analyses have not taken into account the tempo- ral structure of speech. As a result, the role of temporal organization in multimodal speech cannot be assessed. The current study is a first effort to correct this deficit. We have developed an algorithm, based on recursive correlation, that computes the correlation between measurement domains (e.g., head motion and F0) as a time-varying function. Using this method, regions of high or low correlation, or of rapid transition (e.g., from high to low), can be associated with visual and auditory events. This analysis of the time-varying cou- pling of multimodal events has implications for speech planning and synchronization between speaker and listener.
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43.70.Jt Instrumentation and methodology for speech production research
43.72.Ar Speech analysis and analysis techniques; parametric representation of speech
43.72.Lc Time and frequency alignment procedures for speech
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On the perception of Korean and English sibilants in second language acquisition

Sang Yee Cheon

POMA Volume 1, pp. 060002 (May 2008); (15 pages)

Online Publication Date: May 23, 2008

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This paper presents the findings of two perception experiments that examine both the identification of Korean contrast (/s-s*/) by American English learners of Korean (Experiment 1) and the identification of English contrast (/s-š/) by Korean ESL learners (Experiment 2). Two prominent L2 models that are primarily based on the perception of L2 segments are the Speech Learning Model (SLM) and the Perceptual Assimilation Model (PAM). From a PAM perspective, the result of Experiment 1 did not support the prediction of the Category Goodness (Korean /s-s*/) contrast, which expected a better identification performance than chance accuracy. The result of Experiment 2 supported the prediction of the Two Category (English /s-š/) contrast, which expected an excellent identification performance. From a SLM perspective, on the other hand, it was predicted that American English advanced learners of Korean perceived the Korean /s/ accurately. But their overall mean identification scores were slightly above the chance level. Korean advanced learners of English perceived the English contrast accurately, as expected. In sum, the results of each experiment were partially compatible with the predictions of the two models.
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43.71.Es Vowel and consonant perception; perception of words, sentences, and fluent speech
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A motor differentiation model for liquid substitutions in children's speech

Bryan Gick, Penelope Bacsfalvi, Barbara May Bernhardt, Sunyoung Oh, Slade Stolar, and Ian Wilson

POMA Volume 1, pp. 060003 (June 2008); (9 pages)

Online Publication Date: June 05, 2008

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Studies of lip-jaw coordination in children have shown a lack of motor differentiation between anatomically coupled articulators in young children's speech [Green & al. 2000, JSLHR 43: 239-255]. A model is described in which children contending with their developing motor systems generally strive to reduce the degrees of freedom of complex anatomical structures (e.g., the tongue). The claim is pursued that segmental substitutions (e.g., /w/ replacing /r/ or /l/) are the result of specific compensation strategies which aim to simplify the complexity of the articulatory task. The proposal that gestural simplification may dictate substitution strategies for liquid consonants has been suggested previously [Studdert-Kennedy & Goldstein 2003, Language Evolution, Oxford U. Pr. 235-254]. It is proposed here that gestural simplification may be achieved via one of two basic mechanisms: gestural omission and stiffening (and hence merger), and that these two mechanisms account for all of the commonly attested substitutions for English /r/ and /l/. Supporting data are presented from ultrasound studies of: postvocalic /r/ production of an 11-month-old female speaker of English, liquid production of a group of 3-5-year-old speakers of English, and liquid production and substitutions in the speech of adolescent speakers of English with speech and hearing disorders.
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43.70.Bk Models and theories of speech production
43.70.Dn Disordered speech
43.71.Gv Measures of speech perception (intelligibility and quality)
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Voice F0 responses elicited by perturbations in pitch of auditory feedback in persons who stutter and controls

Jay J. Bauer, Carol Hubbard Seery, Rachelle LaBonte, and Lauren Ruhnke

POMA Volume 1, pp. 060004 (June 2008); (13 pages)

Online Publication Date: June 26, 2008

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This study aimed to increase our understanding of the underlying mechanisms of vocal control in frequency-altered conditions of auditory feedback for people who do and who do not stutter by assessing the vocal responses to perturbations in pitch of auditory feedback. Past research has shown that the speech of people who stutter improves during frequency-altered feedback, but the mechanisms responsible for this fluency remain unclear. Typically, brief modulations in pitch of voice auditory feedback lead to short-latency corrective voice F0 responses during sustained phonations in non-stuttering individuals. However, data are lacking regarding audio-vocal control mechanisms in individuals that stutter. Brief upward (+) and downward (-) perturbations in pitch (50 or 600 cents in magnitude) lasting 200 ms in duration were introduced intermittently into vocalizing subject's auditory feedback. Four mild to moderate developmental stutterers and four gender-matched non-stutterers were tested using the "pitch-shift paradigm." Analysis of vocal reflex parameters elicited by 50 cent perturbations in pitch indicated that voice F0 responses during sustained vowels were more variable, slower in latency, and more likely to decrease in F0 in individuals that stutter compared to gender-matched controls. However, responses were more similar for 600 cent stimuli.
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43.70.Dn Disordered speech
43.70.Fq Acoustical correlates of phonetic segments and suprasegmental properties: stress, timing, and intonation
43.72.Ar Speech analysis and analysis techniques; parametric representation of speech
43.70.Jt Instrumentation and methodology for speech production research
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Control of aircraft interior noise using heterogeneous (HG) blankets

Kamal Idrisi, Marty Johnson, and James Carneal

POMA Volume 1, pp. 065001 (May 2008); (20 pages) | Cited 1 time

Online Publication Date: May 30, 2008

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This study is concerned with the passive control of vibration and sound radiation of interior cabin noise in aircraft at low frequencies (<500 Hz) using heterogeneous (HG) blankets. HG blankets consist of poro-elastic media with small embedded masses, which act similar to a distributed mass-spring-damper system. HG blankets have shown significant potential to reduce low-frequency radiated sound from structures, where traditional poroelastic materials have little effect. A mathematical model of a double panel system with an acoustic cavity and HG blanket was developed using mobility and impedance matrix methods. Theoretical predictions are validated with experimental measurements. Results indicate that proper tuning of the HG blankets can achieve in broadband reductions in sound transmission through the double panel system with less than 10% added mass. Future work includes expanding the model and experiment to multiple panel systems.
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43.40.At Experimental and theoretical studies of vibrating systems
43.40.Dx Vibrations of membranes and plates
43.40.Tm Vibration isolators, attenuators, and dampers
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