bluuebunny/crossref_metadata_2025 huggingface dataset:
Reduced aspect feature transcription (RAFT) as an index of speech intelligibility
Authors: Carney Arlene E.
Published: October 2005

The assessment of speech production skills of hearing-impaired speakers is difficult when utterances cannot be transcribed phonetically. Further, the direct measurement of speech intelligibility in hearing-impaired children can be complicated by linguistic ability and task requirements. Finally, results of current speech intelligibility procedures often produce descriptive data that do not provide objectives for achieving future intelligibility. A reduced aspect feature transcription (RAFT) system was developed for application to speech tokens obtained from hearing-impaired children whose vocalizations are difficult to transcribe reliably with IPA symbols. Speech tokens from 25 children with severe-to-profound hearing loss, collected in both closed- and open-set formats, were analyzed by syllabic shape, and by three consonantal and three vocalic characteristics. A profile of speech production skill was obtained for each child. These data were compared to results of more conventional closed-set speech intelligibility tests administered to each child. Results of this comparison suggest that RAFT provides an approach to the prediction of speech intelligibility and its facilitation in hearing-impaired children.
Speech changes in a postlingually deafened girl using a multichannel cochlear implant
Authors: Economou Alexandra , Chute Patricia M. , Hellman Sharon A. , Tartter Vivien C.
Published: October 2005

The speech of a postlingually deafened girl previously implanted with a single electrode implant was spectrographically analyzed from recordings taken on six separate occasions; on three occasions after her single electrode implant failed (4 days post, 5 days post, 18 days post) and on three occasions after stimulation of the Nucleus multichannel implant (1 day post, 6 months post, 9 months post). Changes in acoustic measurements of vowel formants, vowel duration, voicing, manner of articulation, and place of articulation cues are discussed. Listener judgments of target words are presented. The present findings are related to previous case studies of speech changes with a multichannel cochlear implant [Tartter et al., J. Acoust. Soc. Am. 86, 2113–2121 (1989)] and single electrode stimulation [Leder et al., J. Acoust. Soc. Am. 79, 1967–1974 (1986)].
Acoustical requirements for large multiple-use arenas
Authors: Morris Frank M. , Boner Charles R.
Published: October 2005

Multiple-use requirements for large arenas have grown over the past two decades. Activities now include such diverse events as rodeos, athletic events, tractor pulls, circuses, ice shows, road company musical performances, and large assemblies for speech reinforcement. The multiple use of these facilities places strict requirements on the acoustical design. Speech reinforcement for large assemblies is probably the most exciting, requiring controlled acoustics, low HVAC noise, and high-quality sound system performance. In order for the facility to work successfully for all activities, all aspects of the acoustical design must be carefully integrated during the design phase. Several large arenas are considered, discussing the acoustical requirements and the acoustical methods used in each. The Marriott Center, a 22 300 seat arena at Brigham Young University is highlighted as an example of a successful large arena with very demanding multiple-use requirements. The uses and corresponding acoustical requirements are examined in detail, as well as the measures taken to achieve the desired results. These methods are contrasted with less successful methods.
Using SEA to extrapolate acoustic test results
Authors: Scharton Terry D.
Published: October 2005

Three types of extrapolation have been implemented at JPL with the SEA code “Vibroacoustic payload environment prediction system (VAPEPS).” The simplest type of extrapolation incorporated in VAPEPS uses conventional scaling laws. In a second type of extrapolation, which is not explicitly incorporated in the VAPEPS code, SEA was utilized to calculate and scale acoustic absorption from a small scale experiment. The third and the most comprehensive type of extrapolation available with VAPEPS utilizes SEA equations to scale data from a baseline to a new acoustical and structural configuration. Examples from JPL's Mars Observer and TOPEX spacecraft programs are presented to illustrate these three extrapolation techniques.
Statistical analysis of an accelerometer round robin
Authors: Serbyn M. R.
Published: October 2005

Six pairs of accelerometers were circulated among 20 standards laboratories over a period of 5 years. The accelerometers were of the primary-standard type, variously made in the U.S.A., Europe, and Japan. The purpose of this international round robin was to compare uncertainty statements of the participating laboratories with the spread in calibration results. The measurand in all cases was acceleration sensitivity of the specimen. The measurements selected for the present study had been performed in the frequency range 80–160 Hz under sinusoidal excitation of 1–100 m s−2. The sensitivity values reported by the calibration laboratories were analyzed by three graphical methods: the Youden plot, the box plot, and the stem-and-leaf plot. This communication describes the requirements of the test, explains the methods of analysis, and presents several statistically significant results. Some preliminary results were reported earlier [M. R. Serbyn, Proc. IEEE I&M Tech. Conf., 120–124 (1987)].
Transducer longitudinal-vibrator equivalent circuits and related topics
Authors: Martin Gordon E.
Published: October 2005

Ralph Woollett and this author began careers as Navy scientists in 1947. Advances in underwater electroacoustic transducers and their materials are described by illustrating lifetimes in parallel paths. Early activities of Woollett emphasized magnetostriction. In 1947, barium titanate ceramic ferroelectrics were introduced and began a revolution in transducer material technology. For transducer design and analysis, the esoteric theory is often interpreted in relation to equivalent circuits. Woollett used such equivalent circuits in transducer design and in the study of materials for transducer applications. The topic of longitudinal-vibrator transducers and materials is described with reference to some of Woollett's works including his dissertation.
A low-frequency high-power magnetic drive transducer
Authors: Marshall William J.
Published: October 2005

Ralph Woollett's contributions to the art and science of sonar transducer design were as a researcher, teacher, author, and reviewer. Of these roles, perhaps the most important, the one that became his legacy, was that of teacher: All of his colleagues were, in a sense, his pupils. His careful and thorough approach to transducer design problems inspired us to try to meet his high standards, and we still miss his insight, advice, encouragement, and criticism. This talk will review Ralph's influence on underwater electroacoustics, present some anecdotes about his life and work, and examine the circumstances of his death. Finally, it will show how Ralph's ideas and design philosophy have affected some of the author's present research, specifically the design of a low-frequency high-power magnetic drive transducer having low distortion.
Paul Kendig: Acoustician and teacher
Authors: Walker Eric A.
Published: October 2005

A professional account and personal observations of Paul Kendig's accomplishments and contributions to the field of acoustics.
Characterization of Terfenol-D for magnetostrictive transducers
Authors: Moffett Mark B. , Clark Arthur E. , Wun-Fogle Marilyn , Lindberg Jan F. , Teter Joseph P. , McLaughlin Elizabeth A.
Published: October 2005

Measurements were made of the piezomagnetic d33 coefficient, the free permeability, ̈33T, and the open-circuit elastic compliance coefficient, s3311, of grain-oriented Terfenol-D, Tb0.3 Dy0.7 Fe1.93, produced by a modified Bridgman technique. Prestress levels to 9500 psi (64 MPa) and magnetic bias fields up to 2200 Oe (175 kA/m) were applied with a laboratory electromagnet modified so that one pole piece served as a hydraulically actuated piston. The results indicate that d33, ̈33T, and s3311 are dependent on stress and magnetic field, so that proper mechanical prestress and magnetic bias conditions are critical to the successful use of Terfenol-D in transducers and actuators. Radiated-power limits for underwater acoustic projectors are estimated and compared with those for projectors having lead zirconate titanate (PZT-4) piezoelectric drivers. Terfenol-D based transducers can be as much as 8 dB superior to PZT-4 under low-Q, field-limited conditions (Q = mechanical quality factor). Terfenol-D is not superior to PZT under high-Q, stress-limited conditions.
Two-dimensional interactions of a vibrating string with a compliant boundary condition
Authors: Zintel Harold A.
Published: October 2005

A two-dimensional impulse response of the bridge of a guitar was measured with the strings damped. Using the measured impulse response, a finite difference method was used to predict the motion of the string and the bridge with a single string vibrating freely. Measurements were made of the bridge motion, with the string vibrating, and compared to the finite difference results. An approximate closed-form solution for the interaction of the string with the bridge was derived. The approximate solution gives considerable insight into the resulting decay rates and frequency shifts.
A method for evaluating interior sound quality of automobiles
Authors: Yamashita Tsuyoshi , Ishii Yasuo , Nakamura Mitsuo
Published: October 2005

In the past, the A-weighted sound-pressure level has been used to evaluate the noise level inside a vehicle cabin, since great importance is attached to reducing loudness. This report is an attempt to analyze sound “quality,” which is difficult to express solely in terms of loudness, using multivariate analysis performed on the results of a 20-items semantic differential method survey. The results confirm that a vehicle's image bias has a greater effect on responses than actual differences in vehicle noise, thus clearly demonstrating the importance of a blindfold test. Proceeding from this result, blindfold tests were performed using the sound recorded from actual vehicles, both ordinary passenger cars and sports cars, and principal component analysis was performed on the results. Three principal tone factors were extracted: the “beauty factor,” the “powerfulness factor,” and the “metallicness factor.” The principal tone factors for automobile interior noise are similar to the results of studies done in other fields.
Generating vehicle sounds synthetically
Authors: Champagne Anthony J. , Rogers James C. , Wales Ray
Published: October 2005

Synthetic vehicle sounds can be used for subjective listening tests. Computer models provide a great deal of flexibility while mechanical systems are not easily modified for such tests. Autoregressive (AR) parametric models were developed using real data for training. With this approach relatively few parameters are needed to model the vehicle sounds. Furthermore, arbitrarily long data sequences can be produced from these models for subjective evaluations by listeners. Interior recordings in two 4-cylinder engine cars and in two 6-cylinder engine cars were used as training data. It was found that signals with more complex spectra were modeled most successfully from the point of view of a listener. Signals with simple spectra (one dominant frequency component) were more difficult to model. Modeling difficulty manifests itself in amplitude variability with time in the sounds produced with the synthetic data. Measures to counter these effects have been met with some success. [Work supported by Ford Motor Company.]
Defect characterization of graphite/epoxy and carbon/carbon composite structures using acoustic techniques
Authors: Vaidya U. K. , Raju P. K. , Crocker Malcolm J.
Published: October 2005

Graphite/epoxy (Gr/Ep) and carbon/carbon (C/C) composite structures possess properties of small thermal expansion, high heat of ablation, excellent shock resistance, high damping, high specific stiffness, and strength. Material and manufacturing anoamalies, however, cannot be avoided in these composites and a knowledge of the integrity of the structure at various stages of its performance is mandatory. The purpose of this paper is to present experimental studies on defects encountered in Gr/Ep and C/C composites. This paper reviews nondestructive evaluation techniques of composites, such as acoustic emission (AE) and acoustoultrasonics (AU). Experimental results obtained using AU and AE on tensile samples of unidirectional Gr/Ep with artificially induced defects are presented. Stress wave factor (SWF), a parameter in AU testing, was found to reduce at the location of the defects. The peak amplitude distribution of AE hits was indicative of the type of failure mechanism occurring in the Gr/Ep composites. AU studies on C/C composites, prior to carbonization and after carbonization, are also presented.
Utilization of materials with adaptive mechanical properties for active structural acoustic control
Authors: Rogers C. A.
Published: October 2005

One of the many exciting recent advances in active structural acoustic control has been the introduction of intelligent material systems. Intelligent material systems are hybrid “composite” systems of highly integrated sensor, actuator and adaptive/learning control systems within the structural element or material. One of the interesting and useful transduction techniques for structural acoustic control is active control of the mechanical properties of adaptive materials. Materials that exhibit this adaptive capability include shape memory alloys and polymers, electrorheological fluids, and ferroelectric materials. This presentation will begin with a brief introduction to the adaptive materials mentioned above and then proceed to demonstrate the utility of these unique materials. In particular, experimental and analytical results will be presented for a material system that combines the adaptability of the Young's modulus with the effect of induced strain actuation, namely, shape memory alloy hybrid composites. Results for an active control scheme recently developed and termed adaptive alternate resonance tuning will be highlighted.
A comparison of two algorithms for applying the time-temperature superposition principle
Authors: Deigan R. J. , Dlubac J. J.
Published: October 2005

The time-temperature superposition principle provides a method of extending the effective frequency range of dynamic modulus and loss factor data of viscoelastic materials. The principle states that data collected over a limited frequency range at one temperature can be superposed over data collected at some other temperature in order to extend the effective frequency range of the dynamic modulus and loss factor. Thus an apparatus of limited frequency response run at different temperatures can be used to determine the dynamic modulus and loss factor of a material over a very broad frequency range while also determining its temperature sensitivity. Consequently, algorithms that allow efficient and reproducible implementation of the principle on a computer are essential to the practical characterization of viscoelastic materials. This paper reviews the time-temperature superposition principle, then presents and compares two implementation algorithms.
Neurological factors in speech timing
Authors: Bell-Berti F. , Gelfer C. E. , Boyle M. , Chevrie-Muller C.
Published: October 2005

One hypothesis about the temporal control system of speech postulates two levels of control, a motor planning level and a motor execution level [J.-F. Bonnot, J. d'Acoust. 2, 287–296 (1989)]. This study of four ataxic dysarthric and four unimpaired speakers was designed to explore the role of cerebellar function in speech and identify some of the linguistically and physiologically determined aspects of speech timing. Preliminary results reveal a systematic but nonuniform timing disruption: a tendency for compensatory shortening effects to be preserved, even in the presence of segmental lengthening by the dysarthric speakers, and an absence of terminal lengthening effects. These results suggest that compensatory shortening is planned and sufficiently robust to survive the temporal disruption at the motor execution level, but that terminal lengthening arises from the execution of a motor sequence, rather than being part of the motor plan. [Work supported by Ministère de Recherche et Technologie, France, St. John's Univ. William Paterson College, and NIH Grants DD-00121 and RR-05596 to Haskins Labs.]
Speech intelligibility of temporally smeared speech
Authors: Hou Zezhang
Published: October 2005

In the past, the temporal resolution of the auditory system has been investigated using gap detection and temporal modulation transfer functions for nonspeech stimuli. The present study investigated temporal resolution by examining the effect of temporal smearing of the speech envelope on speech intelligibility. The envelopes of CVC nonsense syllables were calculated and convolved with a Gaussian temporal window that had different time constants. The original speech envelopes were replaced by the convolved ones which had poorer temporal resolution. Fifty non-sense syllables were processed in this way using a range of time constants. For each time constant, 50 processed CVC syllables were presented in random order to subjects. The temporal resolution of the speech envelope had a significant effect on subjects' recognition scores. The poorer the temporal resolution, the lower the recognition scores. The possible implications for the effect of temporal resolution on speech intelligibility will be discussed.
Langmuir circulation observed by sonar
Authors: Thorpe S. A.
Published: October 2005

Upward-pointing high-frequency sonars have now been used for more than a decade to study the structure of the upper ocean boundary layer, its turbulence, air-sea gas flux, near-surface currents, and breaking waves. Pulsed 90- and 250-kHz upward-tilted sidescan sonars below the sea surface have revealed linear bands of scatterers aligned close to the wind direction and typically, some 10 m apart. These occur whenever there are scatterers—bubbles produced by breaking waves—to mark their presence, and appear to be clouds of the subsurface bubbles organized into linear “streets” (like “cloud streets” in the atmosphere) by the presence of Langmuir circulation [S. A. Thorpe, J. Fluid Mech. 142, 151–170 (1984)]. Features become more clearly visible in heavy rain. Experiments reveal: (a) two distinct scales of bands, the shorter being carried by the circulation of the larger and converging into the larger scale bands; (b) circulation speeds depend on wind speed; and (c) large bands migrate cross-wing. The repetition of wave-breaking in groups of waves is also observed. [Work supported by ONR and the UK NERC.]
Variation of bubble density under a breaking wave
Authors: Su Ming-Yang , Cartmill John
Published: October 2005

In this paper, some new measurements on variation of bubble densities under a plunging breaking wave in a large-scale wave tank (12 × 15 × 350 ft) located at Oregon State University Wave Research Facility will be presented. The plunging breaker has a wave period of 3 s and a maximum wave height of 5 ft occurring within an unstable wave group (packet). The bubble density is measured by a new technique called acoustical resonator, originally developed by Medwin and Breitz [J. Acoust. Soc. Am. 89, 739–743 (1989)], which cover the bubble radius from 40 to 1000 μm in our current deployment. Three acoustical resonators are mounted on a free-floating supporting frame at three depths vertically spanning the weight height. The frame is located consecutively at six different locations (10 ft apart) horizontally spanning a wave length of about 60 ft. Thus the entire series of measurements constitute a complete spatial and temporal record of bubble densities due to a breaking wave event. [The research project from which the paper is derived is supported by the Office of Naval Research Acoustical Reverberation Program.]
The study of ocean water inhomogeneities by acoustic methods
Authors: Akulichev Victor A.
Published: October 2005

This paper considers the results of experimental investigation into sound propagation through extended ocean water areas containing large-scale inhomogeneities in the form of frontal water mass zones or mesoscale inhomogeneities in the form of eddies. A comparison is made between the measured sound field and the corresponding numerical calculations. The changes in sound signal levels caused by large-scale inhomogeneities of ocean water in crossing frontal zones and eddies in the North Pacific and South Indian Oceans are shown. Distinctive characteristics of sound signal transition from the deep-water sound channel in subtropical waters to the near-surface underwater sound channel in sub-Arctic or sub-Antarctic waters (and vice versa) are discussed. The possibility of sounding different large-scale ocean water inhomogeneities by backscattering of powerful pulse signals is considered. Results of sound backscattering from frontal zones and from eddy perturbations are presented.
Improvement in the prediction of sonobuoy detection ranges for ASW aircraft using on-site acoustic measurements
Authors: Wiseman Charles
Published: October 2005

Sonobuoy detection ranges predicted at shore stations for use by ASW (antisubmarine warfare) aircraft are based on historical data and on XBT (expendable bathythermograph) data that are typically at least 6 to 12 h old. The accuracy of such predictions is questionable as shown by measurements and analysis. Prediction accuracy needs to be improved to increase the effectiveness and lower the costs of antisubmarine search and barriers using sonobuoys dropped from ASW aircraft. These predictions can be improved by measuring the on-site sound propagation loss between a specially modified air-dropped electronic SUS charge as the known sound source and the acoustic receivers in the air-dropped sonobuoys. The derived propagation loss, used in conjunction with the XBT-based predictions, can be used to more effectively select sonobuoy depths and patterns. The SUS charge can be modified to be neutrally buoyant and provide 30 ping seconds of preprogrammed transmissions over a 6 h life. The transmissions can be shaped for low probability of intercept or mimicry. Similar applications to improve sonar effectiveness for surface ships and ASW helicopters are also addressed.
Comparison between ASTM nnd FAA procedures for determining airborne sound insulation of building facades
Authors: Barnhardt Michael B.
Published: October 2005

Variations in sound level measurement procedures and the test results between American Society for Testing and Materials, “Standard Guide for Field Measurement of Airborne Sound Insulation of Building Facades” (ASTM Designation E 966), and the Federal Aviation Administration (FAA) Noise Reduction Audit used to determine eligibility for federal funds, are compared. An empirical analysis is used to compare the results of these two methods whose differences are primarily the type and location of the exterior noise source. The contribution of low-frequency sound to the noise reduction will be presented. The structures used in the analysis are homes participating in the Stapleton Noise Insulation Program (SNIP). The purpose of the SNIP program is to improve the sound insulation of homes, churches, and schools in close proximity to Stapleton International Airport. Sound measurements using both methods were conducted for a sample of homes of varying construction types before and after the construction modifications were implemented. An analysis of the sound insulation improvement as reflected by each of the testing procedures is also presented.
Reciprocity calibration of a flextensional transducer by the Delta-Z method
Authors: Janacek Theodore K. , Baker Steven R.
Published: October 2005

The Delta-Z method is a procedure by which the transmitting or receiving sensitivity of a reversible underwater transducer may be obtained from measurements of its input electrical impedance in water and in air, provided its free-field radiation impedance and diffraction constant in water are known. This method has previously been successfully applied to a hollow piezoelectric spherical shell transducer [R. Bedard and S. R. Baker, J. Acoust. Soc. Am. Suppl. 1 83, S19 (1988)] and to a tonpilz transducer [Patton et al., J. Acoust. Soc. Am. Suppl. 1 84, S28 (1988)]. The successful application of the Delta-Z method to a flextensional transducer is reported in this paper. The results were found to agree generally within about 1 dB with those of a standard comparison calibration. These results demonstrate that it is possible to obtain a good estimate of the transmitting response of a low-frequency piezoelectric sonar transducer from impedance measurements made in a small tank, i.e., without the need of a deep-water test facility. [Work sponsored by NAVSEA, NRL-USRD, and NPS.]
Numerical modeling of the interaction between class IV flextensional transducers
Authors: Debus J. C. , Lavie A. , Hamonic B. , Decarpigny J. N.
Published: October 2005

The design of low-frequency arrays using closely packed flextensional transducers implies careful analysis of the interaction effects, which are assumed to be larger than in conventional arrays. These effects can be set into two different groups. In the first case, acoustic mutual interaction and scattering strongly modify for each elementary transducer the radiation loading and thus, the radiated power, but the modeling of this effect can be performed by assuming, for each transducer, a fixed velocity distribution [L. L. Foldy, J. Acoust. Soc. Am. 21, 595–603 (1949)]. Then, the acoustic near field and far field radiated by the array can be computed with the help of an integral equation method using, for example, equivalent circuits to relate for each transducer the velocity degree of freedom to the radiation load [D. Lalisse and D. Boucher, J. Acoust. Soc. Am. Suppl. 1 84, S5 (1988)]. In the second group, fluid-structure interaction can be strong enough to modify the velocity distribution on elementary transducers. Then, a whole numerical approach has to be used, which provides the transducer velocity fields as well as the pressure field simultaneously, in a self-consistent way. In this case, a finite element model or a mixed finite element/integral equation model has to be used. This communication will provide the results obtained in both cases, using the EQI integral equation code and the ATILA finite element code to describe the interaction between close class IV flextensional projectors. [Work supported by D.R.E.T, Paris.]
The music of speech to infants: Affective and linguistic functions
Authors: Fernald Anne
Published: October 2005

The prosodic contours of mothers' speech to infants are typically exaggerated in pitch range and slower in tempo, compared to the prosody of adult-adult speech. Cross-language acoustic analyses reveal that mothers use similar pitch contours in similar communicative contexts with preverbal infants. The universality of these melodies in mothers' speech suggests that exaggerated intonation may serve important functions in the early development of communication and language. Three studies will be presented that investigate both affective and linguistic functions of intonation in speech to infants. The first study demonstrates that 4-month-old infants show greater differential emotional responsiveness to vocal expressions than to facial expressions. The second study shows that 5-month-old American infants respond with appropriate affect to positive and negative vocalizations in mothers' speech in several unfamiliar languages as well as in English. The third study investigates the role of exaggerated intonation in facilitating lexical acquisition in 12- to 18-month-old infants.
Acoustic modal features associated with mesoscale eddy
Authors: Shang E. C. , Wang Y. Y.
Published: October 2005

Acoustic modal features associated with oceanic mesoscale eddy are the basic measurements for remote sensing and inferring mesoscale eddy by using modal ocean acoustic tomography (MOAT) [Shang, J. Acoust. Soc. Am. 85, 1531–1537 (1989)]. In this talk, modal travel time perturbation caused by mesoscale eddy has been calculated by three different methods and comparison has been made. Since the linear inverse is one of the conventional inverse schemes, the nonlinearity of modal travel time perturbation has been investigated for different eddy parameters as well as different frequencies. In order to determine the validity of using the adiabatic mode theory to MOAT, some interesting results of mode coupling caused by mesoscale eddy will also be presented in this talk. [Work supported by NOAA and ONR.]
Sound propagation in capillary-tube-type porous media with much smaller pores in the capillary walls
Authors: Arnott W. Pat , Sabatier James M. , Raspet Richard
Published: October 2005

Sound propagation in gas-filled, capillary-tube-type porous media was investigated. The capillary tubes were taken to be nominally straight with very small pores in the walls of the capillary tubes. The central assumptions (which are frequency dependent) are that the wall pore diameters are much less than the viscous penetration depth, and that the acoustic pressure in the main pore is only a function of the longitudinal direction. As a consequence of these assumptions, the excess temperature of the gas in the wall pores can be taken as negligible. Walls were taken to be rigid. Propagation constants and the characteristic impedance of such a media were computed. Application to ceramic samples having square capillary pores and porous walls is developed as a possible explanation for the anomalous tortuosity factor previously inferred for this material [Roh et al., J. Acoust. Soc. Am. Suppl. 1 87, S139 (1990)]. Comparison is made to the theory for sound propagation in ducts having finite impedance walls.
Measured and theoretical Biot attenuation and velocities for ultrasonic P and S waves in sintered glass beads
Authors: Nihei Kurt T. , Cook Neville G. W. , Myer Larry R.
Published: October 2005

While many studies have shown Biot velocity predictions to be consistent with observations in sintered beads [e.g., J. G. Berryman, Appl. Phys. Lett. 37, 382–384 (1980)], fewer studies have investigated attenuation. In contrast to Winkler and Murphy [K. W. Winkler and W. F. Murphy, III, J. Acoust. Soc. Am. 76, 820–825 (1984)], significant attenuation in water-saturated sintered glass beads was observed. Both the P and S-wave attenuation were accurately predicted by Biot theory when the frame moduli were estimated using Digby's theoretical expressions for a random packing of bonded spheres [P. J. Digby, J. Appl. Mech. 48, 803–808 (1981)] and a structural parameter, α = 1.25, appropriate for a coarse grain material was selected. Berryman's theoretical prediction for spherical particles, α = 1.85, predicts too little (P- and S-wave) attenuation. Velocities are much less sensitive to the value of α. [Work supported by Dept. of Energy.]
A poroviscoelastic Biot model for acoustics of marine sediments
Authors: Turgut Altan
Published: October 2005

A poroviscoelastic Biot model is developed for acoustic wave propagation in porous media. A constant-Q viscoelastic model is incorporated with the poroelastic Biot model to treat the inelastic behavior of the skeletal frame. Kramers-Krönig integrals for index of refraction are evaluated numerically to establish causality requirements between phase velocity and attenuation. It is shown that the poroviscoelastic Biot model satisfies the causality principle. Noncausality of previous Biot models with a slightly inelastic frame assumption is also demonstrated using the same integral relations. In addition, applicability of this model to marine sediments is verified experimentally. Direct measurements and model predictions of porosity and permeability of the sediments are compared. Consistency between predicted and directly measured porosity and permeability indicates that acoustic remote sensing of porosity and permeability of marine sediments is possible.
The continuum between comodulation masking release (CMR) and profile analysis (PA): Modulation depth
Authors: Fantini Deborah A. , Moore Brian C. J. , Schooneveldt Gregory P.
Published: October 2005

The existence of a continuum between CMR and PA was investigated by varying the modulation depth of five sinusoidal components. In the unmodulated condition (PA), a 2.0-kHz tone was presented either along (reference), or with four flanking tones presented to the same or opposite ear. In the modulated conditions (CMR), each tone was sinusoidally amplitude modulated (SAM) from 20% to 100%. The signal was an increment to the 2.0-kHz tone. The conditions were run with or without a random level variation of +10 dB about a median value of 50 dB per SAM tone. Randomizing level impaired performance in the reference condition at low modulation depths, and a masking release occurred with both monaural and dichotic presentation of the flanking SAM tones. At high modulation depths (60%–100%), randomizing level did not impair performance, probably because the signal produced a change in modulation depth that could be used as a cue. In this case, there was no masking release.
Measurement and specification of the envelope correlation between two narrow bands of noise
Authors: Bernstein Leslie R.
Published: October 2005

Measurements show that when two independent, narrow-band, Gaussian noises are “mixed” according to the “two-generator” case [Licklider and Dzendolet, Science 107, 121–124 (1948)], the correlation between the envelopes of the two resulting narrow-band noises is approximately equal to the square of the correlation between the waveforms. This relation holds somewhat less well for waveform correlations produced by decorrelating two perfectly correlated noises by the addition of a sinusoid that is phase reversed (NoSπ). For the NoSπ case, raising the waveform correlation to the power 2.3 results in a good approximation to the envelope correlation for small signal-to-noise ratios. A method is detailed whereby any desired envelope correlation may be achieved with reasonable accuracy between two noises of the same or different center frequency. This method may prove particularly useful in studies of listeners' monaural and binaural sensitivities to differences in the envelope fluctuation of bands of noise. [Work supported by NIH and AFOSR.]
Uncertainty in signals and maskers: A signal detection theoretic analysis
Authors: Feinman Gall R. , Wakefield Gregory H.
Published: October 2005

Studies on experimental uncertainty indicate that a large degree of signal uncertainty produces only a slight degradation in detection performance. In contrast, recent experiments have shown that masker uncertainty has a more significant effect on performance. In addition, a nonmonotonic relationship between performance and masker uncertainty is observed, which is not demonstrated for signal uncertainty. Explanations for the small effect of signal uncertainty on performance have proposed an additional source of uncertainty, intrinsic to the human observer, that dominates under these experimental conditions. It has been difficult to reconcile the differences seen between signal and masker uncertainty, however, since the implications of masker uncertainty on performance are not well understood theoretically. Through mathematical formulations and simulations, the present study investigates the effect of uncertainty on the performance of an ideal receiver. It is proposed that the apparent anomalous effects of masker uncertainty are predicted by signal detection theory for a receiver that is characterized by uncertainty concerning the stimulus set. [Work supported by grants from the AFOSR (AFOSR-87-0193) and the NIH (NINDCD NS21440).]
Effects of the pattern of spectral spacing on the perceptual fusion of harmonics
Authors: Roberts Brian , Bregman Albert S.
Published: October 2005

Harmonic relations are important in the perceptual fusion of frequency components, but other factors can influence how much any given harmonic is integrated into a complex tone. This study considers whether the pattern of harmonic spacing can act as such a factor. A complex tone consisting only of odd-numbered harmonics has a regular harmonic spacing of twice the fundamental frequency. The addition of a single even-numbered harmonic will locally disrupt this regular pattern. If harmonic relations alone limit the perceptual integration of the added harmonic, it should be as well integrated into the complex as its odd-numbered neighbors. Subjects were required to “hear out” one of the components of the complex and either rate its perceived clarity (experiment 1) or judge its pitch in relation to a pure tone 6% higher or lower in frequency (experiment 2). For a fundamental of 100 or 200 Hz, but not 400 Hz, the even harmonic generally could be heard out more easily than its odd neighbors. It is proposed that the poorer integration of the even harmonic at low fundamentals results from a cross-channel comparison of the amplitude-modulation rates in the output of the auditory filterbank. [Work supported by NSERC, Canada.]
Discrimination of arrhythmic tonal sequences: Effect of temporal transformations
Authors: Sorkin R. D. , Widman D. A.
Published: October 2005

A correlation model was proposed [R. D. Sorkin, J. Acoust. Soc. Am. 87, 1695–1701 (1990)] for describing how listeners discriminate between arrhythmic, tonal sequences. Subjects heard two, successively played (approximately 0.6 s) sequences of eight tones, and reported whether the sequences had the same or different patterns of tone inter-onset times. In general, subjects behaved as though they decoded and stored a list of inter-onset times from each sequence and then computed the correlation between the two lists. In the present experiment, the first sequence was presented to the subject's left ear (all tones at 1000 Hz) and the second to the right ear (tones at 2300 Hz). In different conditions: (a) The sequences were expanded in time by a uniform factor k, where 0.6 < k < 1.4; and (b) the starting times of the two sequences were offset from 1 ms to 2.5 s. Discrimination performance was worst when the sequences over-lapped by 50%. When the sequences were nearly simultaneous (offset by 10 ms or less}, performance was very good and appeared to be based on a binaural comparison of the sequence envelopes. When the two sequences were separated in time, performance was consistent with the correlation model but decreased with the amount of time expansion or compression, |k −|. [Work supported by AFOSR.]
Temporal relations in profile comparisons
Authors: Green David M. , Dai Huanping
Published: October 2005

In these experiments, the standard alone consists of 21 equal-amplitude components spaced at equal log-frequency intervals between 200 to 5000 Hz, presented for 500 ms. The listener's task is to discriminate whether the 1000-Hz (signal) component is at the same level as the 20 other components or slightly higher in level. Absolute level of the signal component is not a reliable cue because the overall level of the tones is chosen randomly on each presentation. The results show that the listener is very sensitive to the relative difference in the temporal onset of signal and standard. The threshold for an increment is smallest when the onsets are the same, but increases 15–20 dB if the signal component begins 50 ms before the onset of the standard. The results imply that the internal representation of intensity level is not a static quantity but a process having considerable dynamics. Unless the starting times in relevant channels are nearly the same, the channels are not coherent, and any cross-channel comparison of relative level suffers. Some additional experiments with amplitude variation of the standard support this view. [Work supported by AFOSR.]
Acoustic holographic reconstruction of arbitrarily shaped sources
Authors: Maynard J. D.
Published: October 2005

Acoustic holography has been shown to be a powerful tool for the study of sound radiation. In the most manageable form of holography, reconstruction of the surface of the source can be obtained only if the shape of the source is a level surface of a separable coordinate system. Arbitrarily shaped sources can be reconstructed using finite element numerical techniques, but problems with singular, nonunique, and unstable solutions become formidable. In this talk, several techniques for circumventing these problems, such as singular value decomposition, will be reviewed. [Work supported by ONR.]
The effect of amplitude modulation on the intelligibility of sentences in noise
Authors: Carrell Thomas D.
Published: October 2005

Previous work has demonstrated that amplitude-modulated time-varying sinusoidal (AMTVS) replicas of natural sentences were more intelligible than simple time-varying sinusoidal (TVS) sentences [T. D. Carrell, J. Acoust. Soc. Am. Suppl. 1 84, S158 (1988)]. More recent work indicated that this improvement was very likely based on the grouping effects of comodulation masking release [T. D. Carrell, J. Acoust. Soc. Am. Suppl. 1 86, S102 (1989)]. It was further proposed that amplitude modulation, which is often found in natural signals such as voiced speech, comodulates the components of a sound from a single source and may be used to help separate an auditory figure from its background in natural listening environments. The present experiment tested this claim directly. Eight TVS sentences and eight AMTVS sentences were presented in a background of multispeaker babble at a signal to noise ratio of + 6 dB. Listeners perceived only 36.9% of the phonemes in the unmodulated TVS sentences correctly, whereas they perceived 72.3% of the phonemes in the AMTVS sentences correctly. These results suggest that the amplitude comodulation of the components of a speech sound allow them to be grouped together and segregated from simultaneous sounds from other sources. This grouping and segregation is claimed to account for the improved intelligibility that was found.
Modulated noise reference unit (MNRU) tests using DRT, DAM, and spelling alphabet test materials
Authors: Schmidt-Nielsen A. , Sueda Retha A. , Tremain Thomas E. , Voiers William D.
Published: October 2005

The modulated noise reference unit (MNRU) has been widely used for reference conditions in evaluating voice coders for telephone applications. Opinion scores using the mean opinion score (MOS) are referenced to equivalent modulated signal-to-noise level. The DoD Digital Voice Processor Consortium has conducted extensive tests of voice processors using the Diagnostic Rhyme Test (DRT) to evaluate intelligibility and the Diagnostic Acceptability Measure (DAM) to evaluate acceptability. Spoken materials for the DRT, the DAM, and the ICAO spelling alphabet words and digits were degraded by speech-modulated noise at levels from + 30 to − 15 dB. The resulting tapes were evaluated by trained listeners. Even small amounts of noise degraded acceptability, DRT intelligibility degraded more slowly, and the spelling alphabet was moderately intelligible even at the worst speech to noise levels. Relations among the different types of tests will be discussed.
A nonspeech replication of the McGurk effect using pluck and bow stimuli
Authors: Saidaña Helena M. , Rosenblum Lawrence D.
Published: October 2005

A replication of the McGurk effect was conducted using nonspeech stimuli. The McGurk effect is a well-known phenomenon in speech perception that demonstrates how visual information for articulation can change an auditory speech percept [H. McGurk and J. McDonald, Nature 264, 746–748 (1976)]. The McGurk effect is often used to support the notion that a specialized speech module exists in the nervous system, which processes all information related to speech regardless of modality. In the current study subjects were presented with both consistent and discrepant audio-visual tokens of plucks and bows on a cello. Audio stimuli consisted of a continuum of tokens that ranged from plucks to bows. The tokens were dubbed synchronously on to a video image of a musician either plucking or bowing a cello. It was observed that subjects' auditory judgments could be affected by the visual stimuli suggesting that the McGurk effect might not be special to speech. These results will be discussed in terms of auditory, fuzzy logical model, motor, and ecological theories of speech perception.
Listener discrimination of women's voices in two age categories
Authors: Morris Richard J. , Murry Thomas , Brown W. S.
Published: October 2005

The purpose of this study was to determine the acoustic and perceptual features a group of listeners would use to separate a set of women's voices into clusters. The speakers for the study were ten women who were 20–30 years old and ten women who were 75–90 years old. Each woman produced a 3-s sustained /ɑ/ at comfortable frequency and intensity levels. Each vowel was paired with all the others in both the first and second position. Thus there were 400 vowel pairs, plus 10% duplication for determining listener reliability for a total of 440 vowel pairs on the experimental tape. The listeners were 30 undergraduate students who rated the vowel pairs on a five-point scale from 1, representing the greatest dissimilarity, to 5, representing identical vowels. These ratings were then analyzed using a discriminant analysis paradigm. The results will be discussed in relation to the clustering of the voices by age group as well as acoustic and perceptual features of the voices.
Modeling the perception of a complex VC stimulus continuum
Authors: Nearey Terrance M.
Published: October 2005

Some recent approaches to the perceptual modeling of phonetic categorization can be approximated by linear logistic regression. Important questions [Nearey, J. Phon. (in press)] concerning the perceptual relevance of segments versus “larger” units [e.g., diphones, syllables, cf. D. Massaro and M. Cohen, Percept. Psychophys. 34, 338–348 (1983)] can be assessed directly using logistic regression. An analysis is presented of the categorization of VC syllables synthesized in a multidimensional stimulus continuum (varying vowel duration, voice-bar duration, F1 frequency and F1–F2 separation). The perceptual space spans ten syllables of Western Canadian English (viz., all combinations of the five back vowels /u, ᴜ, o, ʌ, ɒ/ plus final /t,d/). Logistic regression is used to explore the relative independence of phoneme choices in a complex stimulus-response situation, addressing the extent to which the choice of a particular VC pair can be “additively” decomposed to the independent choice of a vowel and consonant [D. Whalen, Percept. Psychophys. 46, 284–292]. [Work supported by SSHRC.]