bluuebunny/crossref_metadata_2025 huggingface dataset:
Spectral compression, a processing scheme for single-channel sensory aids
Authors: Hurtig Richard R.
Published: October 2005

Single-channel vibro-tactile discrimination and identification of vowels was assessed using a scheme which maintains the spectral shape of the complex speech waveform. A series of vowels and diphthongs were synthesized using the Klatt algorithm. Unlike conventional synthesis, the formant frequencies were set such that the first four formants fell under 660 Hz and the formant bandwidths were narrowed. This synthesis effectively generated 5:1 frequency compression. The synthesized segments sound speech like. Naive subjects were presented both discrimination and identification tasks. The stimuli were felt with a Audiological Engineering V1220 transducer. With no prior exposure discrimination exceeded 7%, and within a few hours of testing discrimination levels of 95% were achieved. Subjects were able to accurately identify many of the vowel segments. Furthermore examination of the confusions reveals patterns similar to those reported for auditory confusions of natural vowels. These findings appear to contradict the premise underlying the development of multichannel tactile aids and cochlear implants that the tactile senses and the impaired ear are incapable of extracting the appropriate information from a single complex speech waveform.
Judgments of intonation and contrastive stress during lipreading
Authors: Bernstein Lynne E. , Eberhardt Silvio P. , Demorest Marilyn E.
Published: October 2005

As part of work to develop vibrotactile devices to convey voice fundamental frequency to hearing-impaired lipreaders, an experiment was conducted to investigate the visibility of contrastive stress and question-versus-statement intonation contours. Four sentences (“We will weigh you,” “We owe you a yoyo,” “Chuck caught two cats,” and “Pat cooked Pete's breakfast”) with contrastive stress on one of the first three words and spoken as either statements or questions by a male and a female were presented from videodisk. Sentences were chosen to minimize indexical or affective information that might be used to judge stress or intonation. Subjects were tested in a six alternative forced-choice procedure with response alternatives labeled “question” or “statement” and stress position “1,” “2,” or “3.” Results suggest that contrastive stress and intonation can be judged visually at levels significantly above chance. Judgments of stress were significantly more accurate than judgments of intonation. Results will be discussed in terms of loglinear models to assess the relative independence of stress versus intonation in visual judgments. [Work supported by NIH.]
Effects of filter configuration on categorical perception of tactually presented speech
Authors: Eilers Rebecca E. , Oller D. Kimbrough , Miskiel Edward , Moroff Debra , Ozdamar Ozcan
Published: October 2005

The effect of filter configuration on the relationship between auditory and tactual perception of speech was investigated via a 32-channel computer controlled electrocutaneous display and normal audition. Two 11-step synthetic speech continua, /a/ to /ə/ and /sta/ to /sa/, served as stimuli for study of three filter configurations: logarithmic, linear, and average (arithmetic mean of log and linear). Four well-practiced subjects performed two tasks with each stimulus continuum and each filter configuration: (1) a standard identification procedure where all 11 steps are categorized as either endpoint 1 or 11, and (2) a pairwise discrimination task (where equal interval stimuli were discriminated across the continuum). The same tasks were presented in the auditory modality for comparison purposes. Results indicate (1) a close correspondence between tactual and auditory perception, (2) categorical perception of the consonontal continuum and more continuous perception of the vowel continuum in both modalities, and (3) an interaction between filter configuration and speech syllable type that affects the degree of similarity between auditory and tactual functions. Implications in terms of theories of speech perception will be discussed. [Work supported by NIH.]
A sentence test for minimizing learning effects
Authors: Levitt Harry , Neuman Arlene C.
Published: October 2005

Speech tests are often used for the evaluation of hearing aids. When several hearing aids are being compared, it is necessary to have lists of equivalent difficulty or lists which can be used repeatedly. Although sentences provide a much closer approximation to real-life communication than single word or syllable tests, sentence materials are seldom used for repeated testing because of the substantial learning effects involved. Typically, a sentence list is used only once with each subject. Testing with a closed response set reduces learning effects considerably and a test of this type has been developed for sentences using a true-false response format. Each list consists of balanced sets of sentences in which the meaning of each sentence has been altered by a combination of two or three simple changes; e.g., subject/object reversal, use of negation, active/passive transformation. Repeated testing with the same sentence list (order of test items randomized) showed small to negligible learning effects. The test also provided information on relative performance with different syntactic forms. [Research supported by NINCDS.]
Striking differences in the babbling of deaf and hearing infants
Authors: Oller D. K. , Eilers Rebecca E.
Published: October 2005

It is widely believed that deaf infants “babble” in much the same way hearing infants do, although the deaf have been said to produce less babbling than the hearing after six or seven months of age. These beliefs have been based upon sketchy and sparse data. Over the past 14 years, we have been collecting tape-recording samples of vocalizations and now have extensive recordings from 8 (severely and profoundly) deaf infants who are otherwise unimpaired and 21 hearing infants. The hearing babies all began canonical babbling (production of well-formed syllable sequences such as [bababa], [nanana], etc.) by 10 months of age while not one of the deaf babies started canonical babbling before 11 months. The onset of canonical babbling is considered significant because it represents the point at which infants manifest a capacity to produce syllables that meet all the requirements of linguistic-phonetic units. The difference in onset of babbling in the two groups of infants is reliably identified by adult listeners.
Using visual targets to model and shape /s, r/ sound production by a deaf talker
Authors: Fletcher Samuel G.
Published: October 2005

This paper will report on a training program that enabled a 17 year old, profoundly hearing-impaired girl to produce /s/ and /r/ successfully for the first time. Auditory and electropalatometric procedures were used to verify the absence of recognizable sibilant sounds in her pretreatment articulatory repertoire. The targets were an 8-mm central groove width for /s/ and a 12-mm more posteriorly located groove for the /r/. The targets were displayed on a CRT array of 96 points in a grid pattern. The subject produced the sounds in three conditions: (1) without visual feedback, (2) with points highlighted as associated sensors were contacted, and (3) with overlaid highlighting of targeted points and intensification of highlighted points when the sensors were actually contacted. When nontargeted sensors were contacted, the talker was notified by less visible overlayed asterisks. At the end of each trial, the extent of successfully matching the targeted pattern was automatically calculated and numerically displayed. The degree of match achieved in isolated sounds—and later in words and sentences loaded with /s, r/ sounds—increased steadily across the eight training sessions. Rapid learning of the articulatory patterns and emergence of auditorally and palatometrically identifiable /s/ and /r/ sounds were found.
Perceptual significance of a vocal noise measure for the evaluation of pathological voice
Authors: Kasuya Hideki , Kikuchi Yoshinobu , Hasegawa Kiyomasa
Published: October 2005

By using a comb filter, harmonic components in a sustained vowel have been separated from the vocal noise which is primarily associated with the turbulent noise produced at the glottis due to insufficient closure of the vocal folds [H. Kasuya et al., Proc. ICASSP-86, 669–671 (1986)]. An acoustic measure, normalized noise energy (NNE) is then defined on the extracted noise signal, by measuring the relative level of the noise energy to that of the original voice. The NNE has shown better detectability of pathological voice status than jitter and shimmer parameters. This paper investigates the relation between the NNE and perceived qualities of hoarseness of a pathological voice, as “hoarseness grade” and “breathiness.” From the experiments we conclude that the NNE is related to the perceptual qualities of a pathological voice much better than jitter and shimmer parameters and some other noise measures do. [Work supported by a Japanese Grant-in-Aid for Scientific Research.]
Modeling and design of transducers for electromagnetic generation of acoustics (EMAT) incorporating permeable structures
Authors: Imaino W.
Published: October 2005

As a possible means for increasing the electrical to acoustical conversion efficiency as well as enhancing the spatial resolution, we have investigated the performance characteristics of transducers for electromagnetic generation of acoustics (EMATs) that incorporate permeable magnetic structures (permeable EMAT). Since the intent of this investigation is to develop high spatial resolution EMATs for noncontact scanning applications, what we term EMAT microscopy, the basic design guidelines differ somewhat from those employed in the design of more conventional EMATs, as used in pulse-echo applications, for example. A computer program has been developed, to calculate the magnetic fields, induced currents, and generated forces, of arbitrary candidate designs, taking into strict account the stray fields due to the induced currents in the structure itself, and the anisotropic polarization of the permeable structure. The results of our calculation on even very simple structures show that an enhancement of the electrical to acoustic conversion efficiency and spatial resolution can be achieved, although at the expense of operating bandwidth.
A fiber-optic interferometric geophone
Authors: Gardner D. L. , Yarber Y. , Carome E. F. , Garrett S. L.
Published: October 2005

A fiber-optic interferometric geophone has been developed which consists of a seismic mass (520 g) supported by two rubber mandrels wound with a single layer of single mode optical fiber. The two mandrel-wound lengths of optical fiber, each 6.5 m long with reflecting ends, are interconnected via a fiber-to-fiber 3-dB coupler to form a Michelson interferometer. When the case of the sensor is displaced at frequencies above the mass-spring resonance frequency (i.e., in the mass-controlled frequency regime), the mass remains approximately at rest while the fiber around one mandrel is compressed and the other is expanded. This geometry has the advantage of not requiring a “reference leg” and providing four times the sensitivity of a single sensor by its “push-pull” operation and the fact that the light traverses each leg twice due to reflection. Sensitivities of 3500 rad/μ have been measured at frequencies above the mass-spring resonance, corresponding to an optical leverage factor of 700. [Work supported by the Naval Research Laboratory and the Office of Naval Research.]
On the noise generated in the tip region of airfoils
Authors: McInerny S. A. , Meecham W. C. , Soderman P. T.
Published: October 2005

The generation of noise by turbulence in the tip region of a blunt-tipped, lifting airfoil was studied. Data were collected on surface and farfield sound pressures in the NASA Ames 2.13 × 3.05 m (7 × 10 ft), subsonic wind tunnel using an NACA 0012 wing section of aspect ratio 2.67, at an angle of attack of 16 deg. The contributions of particular source regions were determined using cross-correlation techniques on surface and farfield sound pressures. Clipping the recorded signals prior to correlation allowed the isolation of radiated sound levels up to 25 dB below the tunnel background levels within a reasonable record length. The results indicate that in the case of blunt-tipped airfoils there is a significant noise source in addition to the separated flow under the tip vortex (on the upper wing surface) predicted by other investigators. The characteristics of these two sources of noise are presented and comparison made with existing theories and prediction schemes. [Work supported by NASA Ames Research Center.]
Airfoil noise in uniform airflow
Authors: Garcia P.
Published: October 2005

An experimental investigation of the NACA 0012 airfoil noise in uniform flow has been conducted in the anechoic open flow facility CEPRA 19. The purpose is to estimate the trailing edge noise, using the theoretical models developed by Chandiramani [J. Acoust. Soc. Am. 56, 19–29 (1974)] and Howe [BBN Report No. 3679 (1977)]. These models require the knowledge of the spectral content of the turbulent-boundary-layer-induced pressure field, in the vicinity of the trailing edge. The data are obtained from longitudinal and transversal arrays of flush-mounted pressure sensors, on the airfoil. A simplified theoretical noise prediction is based on the measurement of the turbulent boundary layer pressure spectrum, the convection velocity, and the turbulence transversal integral scale. The comparison between the radiated noise measurement and the simplified prediction is reasonable in the high-frequency range only. A more general approach allows the prediction of the airfoil-radiated noise, in the whole frequency domain, and for low frequencies particularly. This general prediction formulation requires the pressure field wavenumber spectrum, induced by the turbulent boundary layer. This wavenumber spectrum is obtained from the transducer array, in contrast with Brook and Hodgson's reconstruction scheme [AIAA Paper No. 80-0977]. This approach yields a good estimate of the farfield noise. [Work supported by DRET (Direction des Recherches et Études Techniques).]
Pitch extraction of esophageal speech
Authors: Kim Heung-Kuk , Cooper Donald S.
Published: October 2005

A number of studies have been devoted to the description of the prosodic characteristics of esophageal speakers. However, pitch extraction of esophageal speech is difficult because of its low pitch, of the often quasi-periodic character of the vibration of the pharyngo-esophageal segment, and because stoma noise may be added to the signal. Commercially available hardware F0 extractors often produce artefacts in the analysis of esophageal speech. Consequently it may be asked whether the harmonic source model of laryngeal speech is inappropriate for esophageal speech, or whether it simply constitutes an extreme of this model in terms of the proportion of noise it contains. In a number of recent studies, cepstral analysis has been applied to pitch extraction of esophageal speech. This procedure handles low fundamentals well, but is computationally slow and complex. In this study, several other pitch extraction algorithms which are computationally simpler than the cepstrum will be compared to cepstral analysis in regard to their adequacy for F0 extraction with esophageal speech. Some of these, especially the harmonic product spectrum and the harmonic sum spectrum, have been shown to be superior to the cepstrum in the analysis of noise speech signals. [Work supported by the Norris Cancer Hospital, USC.]
Co-articulation in aphasic speech
Authors: Tuller Betty , Story Robin Seider
Published: October 2005

Co-articulation, the interleaving of articulatory movements for neighboring speech sounds, is ubiquitous in normal speech and its' perceptual advantages are well documented. Yet surprisingly little is known concerning the preservation or disruption of co-articulation in aphasic speech. In this study, five fluent and five nonfluent asphasics, and matched control speakers, produced two-word utterances of the form CV1(z)♯sV2C. Vowels included /i/ and /u/. Half the test sequences included a word-final /z/ (e.g., these suits), and half did not (e.g., pea soup). Multiple tokens of the eight word pairs were elicited. Analyses included only those tokens that listeners correctly identified. Here LPC spectra were computed for the fricative noise in each vowel context and spectral peaks associated with the vowel's second formant were measured at the fricative's midpoint. Control subject's spectral peaks varied with V1 and V2, as expected, and fluent aphasics showed this same pattern. In contrast, only one nonfluent speaker showed evidence of anticipatory or carryover coarticulation. For the rest, spectral peaks did not covary with vowel identity or with intervocalic duration. [Work supported by NINCDS grants to Haskins Laboratories and Cornell University Medical Center, and by a grant from the Stuttering Center, Baylor College of Medicine.]
Durational characteristics of the speech of normal elderly adults
Authors: Wasowicz Jan , Smith Bruce L. , Preston Judy
Published: October 2005

A number of physical and psychological changes occur as a result of normal aging. These changes often result in an increase in the time subjects require to perform various sensorimotor tasks. Although the effects of aging upon a variety of behaviors have been well documented, relatively little is known about how normal aging may affect speech motor control. The present study examined temporal characteristics of the speech of ten normal, elderly adults and ten young adults, who produced a variety of words and sentences at normal and fast speaking rates. Acoustical analyses indicated that the elderly adults' segment, syllable, and sentence durations were 20%–25% longer than those of the young adults at both speaking rates. It was also found that the durations of the older subjects' speech at the fast rate were approximately equal to those of the younger adults' speech at a normal rate. In addition to comparisons made between these two groups of subjects, comparisons were also made with durations of the speech of young children studied in previous research.
The application of present and future satellite remote sensors to oceanographic acoustics
Authors: Shuchman R. A.
Published: October 2005

An ensemble of active and passive satellite remote sensors are presently operating or will be launched in the near future that provide high resolution detailed oceanographic information on a synoptic scale. These sensors operate in the visible, infrared, and microwave region of the electromagnetic spectrum and include the NOAA 7/8 (TIROS), NIMBUS-7, LANDSAT, SPOT, and GEOS satellites presently in orbit as well as the planned ESA ERS-1, NROSS, TOPEX, RADARSAT, and JERS-1 satellite launches. The information provided by these satellites includes not only ocean surface and air/sea environmental information such as wind speed and direction, gravity wave spectral estimates, surface water height, salinity, temperature, and water vapor content, but also information about the interior of the water column (i.e., fronts, upwelling, and internal waves). Additional information about the ice-covered ocean can also be provided by these satellite data. The sea ice information includes; ice edge location, ice concentration, floe size distributions, ice type, and ice kinematics. The merging of remote sensing data with acoustical data can potentially provide new insight into understanding the interior structure of the ocean. The use of acoustical data to aid in the interpretation of remote sensing oceanographic data can in turn increase the use of the satellite information.
Satellite impact on environmental acoustics
Authors: Piacsek S. A. , Jensen F. , Van Meurs P.
Published: October 2005

The continuous surveillance of atmospheric and oceanic conditions at the sea surface by remote sensing platforms can be exploited to improve acoustic propagation prediction. This improvement is especially important in areas where surface observations are not usually taken or are difficult to take, e.g., in oceanic areas off the main shipping routes or under stormy weather patterns. It has been recently shown that both the climatology of the water mass, as well as the analyzed and/or predicted atmospheric surface fluxes can contain significant errors that are larger than those associated with the remotely sensed signals. The purpose of this paper is to illustrate quantitatively the improvement in the prediction of the acoustic environment and propagation due to remote sensing in such situations by three examples. The first two will use a 1-D mixed-layer model coupled to a range-independent acoustic model to study the impact of joint scatterometer/IR observations on propagation in surface ducts. Both a situation where mechanical stirring due to the wind or where convective stirring due to strong surface cooling is dominant are investigated. The third example will study the improvement in the description of the vertical structure and the horizontal position of an oceanic front, and the corresponding acoustic propagation patterns, due to combined altimeter/IR observations. This study will use a 2-D ocean model coupled to a range-dependent acoustic model.
Ocean sensing and modeling as a basis for acoustic prediction
Authors: Caruthers Jerald W. , Mitchell Jim L. , Bennett Theodore J. , Kerr George E. , May Paul W. , deWitt P. W.
Published: October 2005

Several ongoing projects at the Naval Ocean Research and Development Activity (NORDA) form a vertical program for the development of ocean sensing and modeling aimed at supporting acoustic predictions. These projects cover the spectrum from basic research to advanced development. This paper reviews an emerging philosophy for the integration of these several disciplines and presents an example of the application of a part of that philosophy. The example provides comparisons among acoustic propagation runs for various representations of a 600-km-long, vertical section across the Gulf Stream in the northwest Atlantic Ocean. These representations include (1) a dataset of 700-m XBT's merged with historic profiles to the ocean bottom and spaced at 20 km; (2) an optimally interpolated set of profiles spaced at 5 km; (3) a dataset developed from altimetric data spaced at 5 km; and (4) a single point profile. [Work supported by NORDA, ONT, and the Naval Oceanography Program.]
Multiple receivers in single vertical slice ocean acoustic tomography experiments
Authors: Howe Bruce M.
Published: October 2005

Will additional receivers widely spaced in the vertical on each mooring of an (x,z) tomographic experiment improve the range-dependent estimates of the sound speed and water velocity fields? Numerical simulations were performed to answer this question. For a 300-km range, additional receivers reduce the error variance of the estimated perturbation sound-speed field δc(x,z) a factor of 3 (as compared with the case with single hydrophones) to 3% of the a priori variance (0.5 m/s or ∼0.1°C rms). For a 1000-km range, range-dependent features are only marginally resolved, even with additional recovers and optimistic data error levels. Range dependence in the velocity u(x,z) is unresolved in all cases.
Ocean and satellite data sets for acoustical modeling
Authors: Mitchell Jim L. , Hallock Zachariah R. , Teague William J.
Published: October 2005

Quasisynoptic ocean data sets consisting of thermal sections of data collected from deep (800-m) Airborne Expendable Bathythermographs (AXBTs) and sea surface topography measured by overflights of the U.S. Navy GEOSAT altimetric satellite are presented and analyzed. These data, collected as part of the NW Atlantic Regional Energetics Experiment (REX) during August 1985, cover a significant portion of the Gulf Stream front from approximately 57°W to 68°W including three warm meanders and the intervening two cold meanders. Additionally, two warm core rings and one Sargasso cold core ring are included in the region mapped during the six-day period of the AXBT survey. Using climatological regression between the dynamic thickness (0/3000 dbar) and isotherm depth, these in situ thermal data are compared with sea surface topography as measured by the GEOSAT altimeter. These data sets form the basis of the range-dependent acoustical model runs discussed in detail in a jointly submitted invited paper NN3 in this session.
Estimating sea surface spectra with acoustic tomography
Authors: Miller James H. , Chiu Ching-Sang , Lynch James F.
Published: October 2005

A technique for estimating space- and time-varying sea surface spectra using acoustic tomography is described. The technique uses acoustic (mode and/or ray) phase or travel time perturbations as data for the inversions. The inverse problems for spatially homogeneous and spatially nonhomogeneous frequency-directional wave spectra are discussed. Resolution and accuracy of the technique are addressed. Results of inversions of synthetic data are presented as well as an application of this technique to data taken during the MIZEX '84 preliminary tomography experiment. Directions of future research are indicated.
Sound-speed profile inversion in the ocean
Authors: Boden Linda , DeSanto John
Published: October 2005

For sound-speed profiles which vary only in depth, a method has been developed whereby the scattered field data in frequency (or k-space) can be related to the sound-speed profile correction (from an assumed profile guess input) as a quasi-Fourier transform pair. The inversion is straight-forward using this Fourier relationship. The method uses a Fourier-Bessel representation of the acoustic field, a Born approximation on the depth dependent part of the Green's function, a WKB representation for the wave functions and asymptotics and linearizations to derive the transform pair. In spite of all the approximations, good results are obtained for profile recovery using synthetically generated data.
Application of discrete linearized inversion to the sofar inverse problem
Authors: Kaczkowski Peter , DeSanto John A.
Published: October 2005

Inversion for the one-dimensional sound-speed profile in the sofar waveguide is performed using damped least squares (Marquardt-Levenberg algorithm). The study uses the split-step parabolic equation method to solve for the synthetic acoustic pressure field in the ocean. Data for the inversion are also provided by the same model, and the robustness of this technique is investigated using different samples of the sound field: horizontal and vertical arrays of varying length and, single point data of varying bandwidth. The parameter resolution matrix and the singular value decomposition of the matrix of partial derivatives lend insight into the inversion and provide quantitative measures of the relative merit of different experimental configurations, and this will be discussed.
Residential noise insulation for mild climates
Authors: DuPree Russell B.
Published: October 2005

Since 1974 the California Building Standards Law has required that new multifamily housing, hotels, and motels be designed to prevent the intrusion of exterior noise above a community noise equivalent level of 45 dB. At about the same time, the State also adopted energy insulation standards which require low air infiltration rates for new dwellings. While these requirements seem to be complementary from the standpoint of noise insulation, the relatively mild climate of costal communities often obviates the need for air conditioning or even mechanical ventilation. This paper discusses some of the design, cost, and enforcement conflicts between adequate ventilation and noise insulation for areas with mild climates.
Sound absorption and transmission by periodically supported double panel structures
Authors: Bolton J. S. , Baines N. C.
Published: October 2005

Double panel structures are frequently used in modern lightweight constructions, e.g., as factory roofing. Measurements indicate that these structures may provide the majority of low-frequency absorption in the spaces they enclose. Conventional infinite double panel models significantly underestimate the absorption provided by these structures. As a result the authors have instead modeled these surfaces as two parallel infinite arrays of simply supported rectangular panels separated by a finite depth airspace, thus introducing component panel dimension as a model parameter. When the incident wave field is plane, the panel motions and the reflected, interpanel and transmitted acoustic fields may be expanded in functions periodic in the panel dimensions and their component strengths determined by application of sets of boundary conditions. The fraction of the incident energy that is either dissipated by each panel layer or transmitted may then be calculated. Absorption coefficients calculated in this way are consistent with those measured for factory roof structures and indicate that panel damping may control low-frequency sound absorption.
Residue pitch and beats as heard in a musical context
Authors: Pierce John R.
Published: October 2005

Published residue pitch measurements give the pitch of the missing fundamental for tones consisting of three, and even two, successive harmonics over a wide range of harmonic numbers and frequencies. Presentations closer to a musical context give other results. Scales spanning an octave played with two and three sinusoidal components of constant frequency difference sound like steadily ascending scales. The last tone (frequency ratio 3:2 or 4:3:2) sounds higher in pitch than the first (frequency ratio 2:1 or 3:2:1) when played immediately after it. Other examples contrast the first 6 equal-amplitude harmonic partials with tones consisting of the upper 2, 3, 4, and 5 harmonics. These latter tones do not match the pitch of the 6-partial tone when the literature says they should. Tunes and scales were played with tones with two sinusoidal components spaced by the pitch frequency. The tune or scale is heard only at high levels, and “in the ear,” not coming from the speakers. Can there be pitch without place? Reported residue pitches do not correspond to pitches heard in a musical context.
Pedagogy of tenor high voice mechanisms
Authors: Large John W.
Published: October 2005

The Italian pedagogical model was utilized in a study of tenor registration, focusing primarily on high voice mechanisms. Charts were developed to contrast the Italian model with the German model and to relate variable transition tones to five tenor classifications, five vowels, and three levels of intensity. Vocalizes designed to establish the Italian model were then taught to ten tenors, ranging from beginner to professional, with varying degrees of success. The model and its variables, the vocalizes, and the results, suggest that one transition and its resultant register are determined primarily by resonance adjustment and another transition and its resultant register by laryngeal adjustment. Examples of appropriate repertoire for each tenor classification and for each student subject are given.
Acoustical problem in the bassoon
Authors: Backus John
Published: October 2005

The bassoon is an orchestral instrument of considerable antiquity, which has evolved into its present form through centuries of tinkering. Unfortunately, it still has a number of deficiencies. Some notes are considerably out of tune. The played scale is not uniform; certain notes have a different quality from their neighbors. As an amateur bassoonist for some years, the author is well acquainted with these deficiencies, and hopes to correct them, using the acoustical knowledge and apparatus now available. To that end equipment has been set up to measure the resonance frequencies of the instrument, compare them with the playing frequencies, and ultimately to see what alterations in tone-hole size and location might bring about better intonation. The first measurements, on two instruments, show that the resonance frequencies are about 1/4 semitone below the playing frequencies for about the first octave, after which the resonance frequencies rather suddenly rise so as to be as much as a semitone above the playing frequencies. The reason for this behavior needs to be determined. The bassoon reed is a very important part of the instrument, and is the subject of much folklore. Some preliminary measurements on reeds indicate that much of this folklore may have no basis in fact.
Applications of acoustic propagation to remote sensing of inhomogeneities in the atmosphere and oceans
Authors: Brown Edmund H.
Published: October 2005

The inverse problem in the propagation of sound through inhomogeneous fluids, that is, determining quantitative parameters characterizing the inhomogeneity fields from the changes in acoustic waves propagating through them, forms the basis for acoustic remote sensing. After a brief review of the development of remote sensing methods, recent advances—and problems—will be discussed, including measurement of velocity fields, and profiles of temperatures versus altitudes or depths. The possibilities of obtaining phase information and much larger scattering cross sections from fields of Rayleigh scatterers when their spatial correlations do not vanish (a topic under way in studies of radar sensing of clouds) may present opportunities for improved acoustic remote sensing.
Noise reduction by damped sandwich beams
Authors: Xi Dechang , Chen Qinghua
Published: October 2005

Many papers have been published in recent years on the acousto-elasticity of damped sandwich structures. Interaction between sound fields and structural vibration is important in aerospace engineering, underwater acoustics, naval engineering, and architectural acoustics. Many authors have explored the ability of sandwich structures to increase noise reduction across a structure. Transmission loss may be improved by increasing the coincidence frequency through use of a thicker core in the sandwich. This paper describes sound-transmission-loss characteristics and corresponding structural response of a damped sandwich beam. Resonant vibration may be controlled by selection of design parameters. The concept of sound energy is used to derive a closed-form expression for transmission loss. Experimental investigations show the effects of core loss factor, sound-incidence angle, and physical and geometric parameters. Sandwich beams are shown to have better sound-transmission-loss characteristics than comparable homogenous beams.
A method for distinguishing between the attenuation due to scattering and the attenuation due to absorption for waves propagating in a dissipative, randomly inhomogeneous medium
Authors: Wenzel Alan R.
Published: October 2005

Waves propagating in real media such as the atmosphere, ocean, earth, seafloor sediments, etc., are subject to attenuation due to both intrinsic absorption and scattering by medium inhomogeneities. Measurements of attenuation in such media yield the combined effect of these two mechanisms but do not yield directly the individual effect of each of them acting in isolation. In order to obtain information on these individual attenuation mechanisms from measurements of the total attenuation, it is necessary to use analytical techniques based on the theory of wave propagation in the medium. The purpose of the present investigation is to derive such a technique for the case of scalar waves propagating in a one-dimensional, weakly dissipative, randomly inhomogeneous medium. The approach makes use of analytical expressions derived previously for the mean intensity and mean squared intensity of the field. With the aid of measurements of these two quantities, both the absorption coefficient and the scattering coefficient (of attenuation) of the medium can be obtained. [Research supported by NORDA.]
On the singularity index and the unfolding of the diffraction catastrophes
Authors: Brown Michael G.
Published: October 2005

The caustics of high-frequency wave propagation may be classified using catastrophe theory. The wave field in the vicinity of any caustic is described by the corresponding diffraction catastrophe. The singularity index β is a measure of the rate at which such a wave field diverges as ω → ∞ at the point where all control parameters and toodull are set equal to zero. It is shown that away from this point β also describes a balance between two different measures of the unfolding of the wave field in each control direction, β = σn ρn. The indices σn and ρn describe, respectively, the rate at which individual ray arrivals separate in time and decay as a function of control parameter. Thus the behavior of the wave field in the vicinity of any caustic is governed to a large extent by a single number, the singularity index.
Bubble swarm acoustics
Authors: Commander Kerry W. , Moritz Elan
Published: October 2005

A study of the sensitivity of sound attenuation in bubbly liquids to variations of bubble distribution functions and void fractions was conducted using several theoretical models [A. L. Anderson and L. D. Hampton, J. Acoust. Soc. Am. 67, 1865–1889 (1980); A. Prosperetti, Ultrasonics 22, 115–124 (1984); R. Caflisch, M. J. Miksis, G. C. Papanicolaou, and L. Ting, J. Fluid Mech. 153, 259–273 (1985)]. The distributions studied include uniform, Gaussian, naturally occurring, and others. The frequencies covered ranged from dc to 500 kHz. Differences in predicted attenuations between the theories are discussed as well as limitations of theories vis-à-vis empirical data. [Work supported by ONT.]
Discrimination of five-component tonal complexes differing in crest factor
Authors: Preece John P. , Wilson Richard H. , Arcos John T.
Published: October 2005

Hartman et al. [J. Acoust. Soc. Am. 79, 1915–1925 (1986)] presented data on discrimination of tonal complexes differing only in number of spectral components within a fixed bandwidth. The Hartmann et al. data suggested that discrimination could be based upon perception of temporal fluctuations in the intensity levels of the sounds, or upon the detail of the spectral structure of the complexes. The present experiment assessed discrimination of tonal complexes that differed in only the phase relationships among five fixed frequency components. The phase relationships established a range of crest factors (peak/rms amplitude) for the complexes. When presented at equal loudness, the tonal complexes were easily discriminable by a musically trained subject, and were discriminable by all subjects with training. The data from the current study support a model of discrimination based only upon the temporal fluctuations in the complex envelopes. Discrimination between tonal complexes can be made for complexes differing either in rate or depth of such fluctuations, as long as the fluctuations are within the limits of temporal integration of the car.
Temporal specificity
Authors: Leis-Rossio Beverly , Small Arnold M.
Published: October 2005

The listener's response process is modeled as a temporal window through which the incoming stimulus waveform is viewed with the window positioned so as to maximize signal-to-noise ratio. To test this model, listeners were asked to detect a 0.5-ms pulse in a noise background during a 1500-ms observation interval. In a yes/no task, a primary (fixed temporal position) signal was presented on 40%, a probe (variable temporal position) on 10%, and noise alone on 50% of the trials. Listeners' performance, which was measured as hit rate, was maximal at those positions near the primary, independent of primary position. In companion experiments not utilizing the probe signal method, it was determined that signals positioned at any point within the observation interval were equally detectable if presented in isolation. However, if a signal could occur with equal probability at any position (temporal uncertainty), then performance worsened. This decrease can be accounted for by a temporal window which changes from a narrow configuration yielding a large signal-to-noise ratio in the first instance to a broadened state producing a reduced signal-to-noise ratio in the second case.
Effect of frequency region on pitch discrimination
Authors: Richards Virginia M. , Hafter Ervin R.
Published: October 2005

The ability to discriminate between pairs of signals having different “missing” fundamental frequencies was measured. The listeners' task was to distinguish a “standard” four-component complex from one composed of the same four harmonics, but a slightly different fundamental frequency. The complexes occupied one of three frequency regions. They were composed of the 3rd through 6th (low), 12th through 15th (moderate), and the 16th through 19th (high) harmonics of fundamental frequency. Several fundamentals were used, the median value being 250 Hz. Thresholds were determined as a function of the duration of the signal. Durations ranged from 20 to 190 ms. For both high and moderate frequency regions, discriminability improved steadily with the duration of the signal. For the low-frequency region, thresholds decreased rapidly as the duration was increased from 20 to 32 ms. However, for these signals, increasing the signal duration beyond 32 ms led to little additional improvement in performance. [Work supported by NIH and UC Chancellor's Patent Fund.]
Matching the pitch of a mistuned harmonic in an otherwise periodic complex tone
Authors: Hartmann W. M. , McAdams Stephen , Smith Bennett K.
Published: October 2005

Listeners adjusted the frequency of a sine tone to match the pitch of a single mistuned harmonic in a complex tone consisting of 16 harmonics. Fundamental frequencies were 200, 400, or 800 Hz, and mistunings ranged from 0.5% to 8.0%. The successful matches, those close to the actual mistuned harmonic, show highly consistent and unexpected pitch shift effects; the pitch shifts can be twice as large as the frequency shifts, for both positive and negative frequency shifts. The percentage of matches which are successful provides an estimate of a listener's ability to segregate the mistuned component from the complex tone. Best performance occurs for mistuned harmonics in the region of spectral dominance. The highest frequency which can be segregated is a decreasing function of the fundamental frequency. The latter result suggests that the segregation operation depends upon both place and time coding in the auditory system. [Work supported by the NIH, the NSF, and the CHRS—France.]
Resonant transfer in longitudinal vibration testing
Authors: Jimeno-Fernandez Isabel , Überall H. , Madigosky W. M. , Fiorito R.
Published: October 2005

Materials characterization can be carried out experimentally by measuring the complex modulus of linear viscoelastic materials from the displacement ratio of a bar, excited at one end, while the other end (which may carry an end mass) is allowed to move freely. This method, devised by Norris and Young, was recently developed [W. M. Madigosky and G. F. Lee, J. Acoust. Soc. Am. 73, 1374 (1983)] to cover a frequency range of 25–20 000 Hz. Standing waves cause resonances in the transfer function, and the positions and widths of these determine the real and imaginary parts of the modulus. The individual resonances are exhibited through a meromorphic representation of the transfer function; the corresponding facilitation in measuring resonance widths then leads to the possibility of experimentally determining the loss function of the material with improved accuracy.
Reverberant acceleration fields on a plate with both boundary and surface damping
Authors: Wallace C. E.
Published: October 2005

Expressions for the direct and reverberant flexural vibration energy densities are derived for a thin plate excited by a random force applied at a point. The plate has both a surface and a boundary damping treatment. An expression for the vibration power introduced by the random force is presented and the maximum damping which will allow for an accurate measurement of the reverberant acceleration field is computed. [Work supported by Garrett Fluid Systems.]
Postvocalic consonantal voicing and constancy of syllable duration
Authors: Gopal H. S. , Syrdal A. K.
Published: October 2005

In American English, a vowel preceding a voiced consonant has frequently been shown to be of longer duration than one preceding a voiceless consonant. However, Port [J. Acoust. Soc. Am. 69, 262–274 (1981)] reported no effect of postvocalic consonant voicing on the total duration of the VC unit. Port attributed this finding to an inverse relationship between vowel and consonant durations. Our study replicates and extends this work to the entire CVC syllabic unit across changes in speaking rate. Syllable and segmental durations were measured for /pVC/ target syllables. The target syllables used eight vowels and voiced or voiceless cognates of the final consonant, which was either stop or fricative. Syllables were produced in sentence contexts at three speaking rates by four female and four male native American English speakers. [Work supported in part by NIH.]
Artificial choral speech: Using digital signal processing algorithms in speech research
Authors: Neuburg Edward P.
Published: October 2005

Much psychoacoustic speech research is done with nonspeech, such as synthetic speech or linear predictive coded (LPC) speech; such stimuli are repeatable and controllable, but not natural. Nondestructive alteration of natural speech to impose known, controllable parameters is becoming practical, using digital processing algorithms. A combination of such algorithm, was used to synchronize the speech of several talkers, each of whom had independently recorded the same sentence; the result is choral speech. To align the speech of talker A to the timing of talker B: (a) Calculate a log LPC spectrum each centisecond for each sentence; (b) correlate each of A's spectra with each of B's spectra; (c) find a dynamic time warp “best path” through the matrix of correlations; (d) estimate pitch for talker A every centisecond; (e) speed and slow A's speech according to the time warp found in (c), using a pitch-dependent algorithm to maintain naturalness. Algorithms used will be described and/or referenced. Sentences recorded before and after warping will be played to demonstrate their naturalness, and choral speech will be played to demonstrate the effectiveness of the synchronization.
Temporal organization of articulatory movement—A multidimensional complex spring model for running speech
Authors: Fujimura O.
Published: October 2005

A general descriptive framework of speech timing is proposed using a hierarchical linear (elastic) representation of speech units, with a loose linkage between different dimensions (articulators). Inherent temporal properties of phonetic units are represented by their spring constants, and prosodic properties of utterance units are represented by additional springs associated with relevant substructures. For describing a process of speech utterance, an open-ended structure can be defined by terminal forces in place of position specifications, continuously building up the utterance structure as the speaker produces (or preprograms) the speech signal. Some examples of data from microbeam data will be discussed from this point of view, using “iceberg” patterns as timing marks [O. Fujimura, “A Linear Model of Speech Timing,” in Ilse Lehiste Festschrift, edited by L. Shockey and R. Channon (Foris Publications, to be published)].