bluuebunny/crossref_metadata_2025 huggingface dataset:
Stochastic vector quantization of LPC parameters
Authors: Atal B. S.
Published: October 2005

In this paper various issues related to efficient low-bit-rate coding of LPC parameters are discussed. It has been shown previously [Juang et al., IEEE Trans. Acoust. Speech Signal Process. ASSP-30, 294–304 (1982)] that vector quantization provides a significant reduction in bit rate for coding the LPC parameters. Vector quantizers have two main disadvantages: To keep the quantization distortion to a low level, a very large codebook of vectors is usually needed. It is very difficult to train such large codebooks on real speech data and it is impractical to search these codebooks for optimum codewords in real time. In this paper, a vector quantization procedure which uses a codebook of white Gaussian random numbers to encode the LPC parameters is discussed. Interparameter correlations of LPC parameters are estimated from previously quantized data and are used to create codewords with the correct distribution. The optimum codeword is selected by an exhaustive search to minimize a weighted Euclidean distance between original and quantized parameters. Use of random codewords eliminates training of the codebook and provides robust performance over different speakers and speaking environments.
Benchmarks: Are they helpful, diversionary, or irrelevant
Authors: Felsen Leopold B.
Published: October 2005

There is universal agreement that computer codes should be accurate, but less consensus as to how they should be tested. This talk summarizes the outcome of a special session on Benchmarks held at the First IMACS Symposium on Computational Acoustics, Yale University, 6–8 August 1986. Attention is then given to analytical benchmark solutions, with emphasis on idealized but exactly solvable range-dependent coordinate separable and nonseparable models. After describing what information can be extracted from such benchmarks, the question of their utility for testing codes dealing with “real world” situations remains. This discussion should set the stage for the panel discussion that follows. [Work supported by ONR.]
An exact modal solution in two dimensions
Authors: DeSanto John A.
Published: October 2005

For a one-dimensional sound-speed profile varying in depth, it is known that there is an exact integral transformation relating the solutions of the Helmholtz and parabolic equations. This relationship can be extended to two dimensions using conformal mapping techniques. In particular a class of range- and depth-dependent sound-speed profiles can be generated for which (a) the Helmholtz and parabolic solutions are related by an exact integral transform, (b) both have an exact model expansion, and (c) asymptotically the Helmholtz and parabolic modal amplitudes and phases can be explicitly compared to show their differences. Constants can be chosen to preserve one mode amplitude and one mode phase. Profile examples are presented. The only necessary computational capability is a normal mode code but here used in mapped coordinates.
The use of replica correlation to benchmark acoustical propagation models
Authors: Strozeski B. B. , Herstein P. D. , Weinberg H.
Published: October 2005

The three usual techniques employed for benchmarking acoustical propagation models involve measured acoustical data, analytical solutions, and other established acoustical propagation models. Each of these has inherent limitations. The alternative approach described here involves replica correlation to test the accuracy of acoustical propagation models. A received acoustic pressure spectrum, which is generated by the acoustical propagation model to be tested, is multiplied with the source pressure spectrum. The inverse Fourier transform of this product is a replica correlogram, which contains information of the travel time, phase and amplitude of all arrivals. Then a ray-tracing model is used to determine the travel time of the arrival. If the model to be tested is accurate, the travel times computed by replica correlation will agree with the travel time computed by ray tracing. Results will be presented for an existing acoustical propagation model under realistic ocean conditions. [Work supported by NRL.]
Benchmark problem for broadband cross-correlation models in a nonisospeed medium
Authors: Hauck W. , Bilazarian P. , Herstein P.
Published: October 2005

Some benchmark problems for broadband cross-correlation models in a nonisospeed medium are proposed. Several depth-dependent profiles are employed, which have either analytic expressions or very accurate numerical solutions for significant ray acoustic quantities. These profiles include: (1) an isovelocity layer above an isogradient layer, and (2) bilinear profiles for both bounded and unbounded media. Several multipath propagation conditions, including direct path, bottom bounce, and convergence zone, are discussed. For these benchmark problems, the spectral contents of similar eigenrays are assumed to be equal; however, the power between any two paths may vary by a scale factor. By assuming a specific source-receiver geometry and input signal spectrum, the cross-correlation function can be expressed in terms of ray travel time and amplitude differences and signal bandwidth. Thus the accurate computation of eigenray quantities can be used to evaluate broadband cross-correlation models.
Acoustical evaluation of halls for the performing arts using acoustical models
Authors: Kinzey Bertram Y. , Siebein Gary W.
Published: October 2005

A series of relatively new objective measures of the acoustical quality of performing arts halls such as temporal energy ratios, early decay times, and rise times has been investigated and compared to each other and the perceived quality of the halls by many researchers. Measurements of these criteria were made at multiple positions in 1:10, 1:40, and 1:100 scale models of a 1500-seat multipurpose performance hall and in equivalent positions in the prototype room. There were clearly distinguishable zones of differing acoustical response shown in reflectograms made in the prototype room and even the smallest models. The objective measurements taken in the small size models with wideband noise duplicated the measurements taken in the larger size models and the prototype room reasonably well. The measurements made on an octave-band basis in the 1:10 scale model and the prototype room at equivalent positions show acceptable correlation. Twenty thousand hertz was the midband frequency for the highest octave band in the models that yielded acceptable values without correcting for air absorption. The ease of testing and the comparative results make this a valuable tool for preliminary testing of design alternatives.
In situ auditorium measurements of quadratic residue diffusors
Authors: Graffy Kurt M. , Paoletti Dennis A.
Published: October 2005

A recently completed music hall in Moscow, Idaho has incorporated as a major portion of its renovation, quadratic residue diffusors (QRDs). The QRD surfaces were sensitively incorporated by the architect into the 1935 “collegiate gothic architecture” of the hall. In addition to subjective evaluations, objective measurements have been made to determine the field behavior of the QRDs in the vicinity of the performers' environment. Time/energy/frequency measurements and polar scattering plots have been made and compared to computer calculations and plots of the same. The hall is the 750 seat Administrative Auditorium Renovation at the University of Idaho. The Architects were Hummel, Jones, Hunsucker, Miller; with Nelson Miller as the Principal in Charge and Project Architect.
Bubble formation in tissues and agar gels during ultrasonic irradiation
Authors: Daniels Stephen , Crum Lawrence A. , ter Haar Gail R.
Published: October 2005

Ultrasound irradiation, used in either continuous or pulsed mode, at a frequency of 0.75 MHz and spatial-temporal average intensities between 60 and 1000 mW/cm2, has been shown to produce stable gas bubbles in the tissues of experimental animals [S. Daniels and G. R. ter Haar, Proc. Inst. Acoust. 8, 147–154 (1986); G. R. ter Haar, S. Daniels, and K. Morton, IEEE Trans. UFFC-33, 162–164 (1986)]. Macroscopically visible bubbles are also produced in agar gels during irradiation with ultrasound at the same frequencies and intensities used with experimental animals. The effect on the number of bubbles formed of varying ultrasonic frequency, intensity, pulse length, and duty cycle as well as ambient temperature is similar in the gels to that in animals. Many of the aspects of bubble formation in gels have been explained in a qualitative manner by a theoretical model based on growth of a cavitation nucleus by rectified diffusion. This may provide a useful theoretical basis for the explanation of bubble formation in vivo. [Work supported by MRC (UK), NSF, ONR, NIH, and CRC/MRC Joint Committee program support for the Physics Department, Institute of Cancer Research.]
In vitro single and multicell bioeffects studies
Authors: Miller Morton W.
Published: October 2005

There have been two broad categories of in vitro bioeffects studies in relation to exposure to ultrasound, postulate testing, and empirical data gathering. Both approaches have led to results, for nonthermal exposure conditions, which are generally consistent with a mechanism involving acoustic cavitation. In general, it is thought to occur in the extracellular fluid, but some evidence is available which suggests an intracellular cavitational mechanism. This postulate needs testing. A large effort has been expended to ascertain whether ultrasound induces sister chromatid exchanges since there are a small number of reported positive effects. None of the reports has been independently confirmed, and attempts at independent confirmation have been negative. [Research supported by PHS.]
Time-delay spectrometry in auditoria
Authors: McKay Ronald L.
Published: October 2005

A variety of measurements using a time-delay spectrometer in European and American concert halls and multipurpose auditoria will be presented and interpreted. Direct/reverberant energy ratios, reverberation times, lateral energy ratios, orchestra platform effects, and varying sound reflection patterns will be covered.
“Transition loss” From the practice room to the concert hall
Authors: Niemoeller Arthur F. , Singh Punita
Published: October 2005

The acoustical characteristics of music practice facilities are compared with those of some performance halls available at a university campus. Glaring quantifiable differences are observed between the practice spaces and performance spaces in terms of size, shape, reverberation, and interior construction schemes. Furthermore, the Perceived acoustical qualities of three performance spaces studied also vary greatly from each other, one being popularly referred to as “very reverberant and muddy,” another “dead,” and a third, “good.” The physical differences observed are presented, and their effect on the performance of music rehearsed in the small practice facilities and performed in the larger auditoria considered via subjective reports made by performers and listeners. These observations are further supplemented by an account of strategies employed by performers in adapting production to suit the different spaces, to compensate for the “transition loss” incurred in going from the practice room to the concert hall.
Development of vibrotactile measurement techniques for assessing mechanoreceptor performance at the fingertip
Authors: Piercy J. E. , Brammer A. J.
Published: October 2005

In recent years knowledge of the basic physiology of mechanoreceptors has advanced considerably. The translation of this knowledge into psychophysical threshold measurement techniques for assessing mechanoreceptor performance at the fingertip will be described. The sensitivity of three types of mechanoreceptors, the Pacinian corpuscles, Meissner corpuscles, and Merkel disks, is obtained from threshold measurements with sinusoidal vibratory stimuli at various frequencies across the band from 2–400 Hz. Parameters affecting the coupling of the vibrating probe to the finger, namely, static force, skin indentation, and probe diameter, have a significant and different effect on the thresholds for the different receptors. The role of background vibration of physiological origin (physiological noise) on the perception thresholds will be discussed.
Detection of whole-nerve sensory action potentials generated by vibrotactile stimulation of a fingertip
Authors: Brammer A. J. , Pyykkö I. , Kolari P. , Starck J.
Published: October 2005

Current electrophysiological techniques for studying whole-nerve properties in man employ electrical stimulation of nerve pathways. They thus cannot provide information on the cutaneous nerve endings. This limitation may be overcome for the touch receptors by vibrotactile stimulation. The resulting electrical activity is recorded by wire electrodes looped around the finger, and surface electrodes located above the nerve at the palm and wrist. After signal processing to reduce physiological noise, a pulse train is recovered with peak to peak amplitude of, typically, 0.2 μV. With short duration (1.0 ms), approximately half-sine-wave pulse stimulation, and resolution imposed by the residual noise (∼0.05 μV peak-peak), the sensory action potentials consist of from one to two cycles of a near 1000-Hz sinusoidal pulse. Action potentials have been detected at, and above, 20-dB sensation level, corresponding to skin displacements of the order of 20 μm. With sinusoidal stimulation, signals believed to be action potentials have been recorded only from selected subjects. The application of this technique to the assessment of mechanoreceptor and sensory nerve function will be discussed.
The effect of a wearable 16-channel electrotactile sensory aid on receptive communication skills of profoundly deaf children
Authors: Franklin Barbara , Saunders Frank A.
Published: October 2005

Six children, 3 to 8 years of age, with profound congenital binaural sensorineural hearing losses were fitted with a wearable elecrotactile sensory aid, the Tacticon, in March 1985. Their receptive skills for both speech and environmental sounds were evaluated using a battery of selected tests. Following a 9-month training period, a comparison was made of their scores in the following conditions: (1) pre- and post-test auditory only (with hearing aids); (2) pre- and post-test auditory/visual (hearing aids and speechreading); and (3) post auditory/tactile (hearing aids and Tacticon) and auditory/visual/tactile (hearing aids, speechreading, and Tacticon). All the children were able to integrate information delivered simultaneously by the auditory, visual, and tactile senses and their scores were consistently higher when wearing the Tacticon than in the comparable condition without the tactile aid. A modified “tracking” procedure was used to determine the amount of time required to correctly identify spoken utterances. There was a substantial reduction in time in the post-test auditory/visual/tactile condition compared to the pre-test auditory/visual condition. [Work supported by NIH.]
Acoustical behavior of ringed seals in the presence of man-made noise
Authors: Cummings William C. , Holliday D. V.
Published: October 2005

A total of 24 373 underwater sounds were recorded from ringed seals (Phoca hispida) in Kotzebue Sound, AK. Of these, 81% were from 40–500-ms seal scratches used in lair and access or breathing hole maintenance (1–6 kHz, 98–102 dB re: 1 μPa at 1 m). Remaining seal sounds were vocalizations consisting mostly of rublike sounds, squeaks, and quacking barks (80 ms to 1.5 s, 0.5–9 kHz, 95–131 dB re: 1 μPa at 1 m) that peaked in occurrence at 1930 h and were more frequent during lightest (450–570 μW/cm2) hours. Vocalization was negatively correlated with windspeed and ambient temperature; scratch sounds were not correlated with temperature. Our introduction of underwater man-made noise (playbacks of on-ice Vibroseis® operations and control noises) had no statistically significant effect on sound production (three playback sessions of 14.5 h, compared to 3000 vocalizations, with control periods before, during, and after playback), but an underlying long-term increase (6 ×) existed, presumably from heightened breeding and parenting activity. Man-made low-frequency pulses of unknown origin illicited immediate vocal outbursts. [Work supported by NOAA.]
The FFT—From Fourier transform to application
Authors: Weaver H. J.
Published: October 2005

This paper will present a discussion as to how the Fourier transform and/or frequency response function generated by spectrum analyzers can be used to gain insight and an understanding of the dynamic properties of noise and/or vibrational problems. A single degree of freedom (spring-mass-damper) system will be used as the focal point of this discussion. We will present a heuristic discussion of the frequency response function of this single degree of freedom system and show how its dynamic properties can be directly related to the graphical characteristics of the frequency response function. We will also examine how the coherence function can be used as a measure of the “goodness” of the frequency response function.
Problems inherent in the utilization of the FFT
Authors: Allemang Randall J.
Published: October 2005

The effective utilization of the FFT depends upon the understanding of the problems involved in implementing the FFT. These problems result from errors associated with three aspects of the implementation: errors associated with the time truncation of the data, errors associated with the acquisition of the digital data, and errors associated with the FFT algorithm. These errors can be categorized according to the effect of the error on resultant data. With respect to estimation concepts, these errors can be categorized as random or bias errors. Typical well-known bias errors are aliasing and leakage. The physical source and severity of common random and bias errors will be presented. The effect of the resultant data can be minimized through the use of different digitization hardware, different digitization parameters, different FFT transform size, frequency-shifted FFT concepts, averaging, weighting, and signal choice. Examples of such common error reduction methods will also be presented.
Getting valid data
Authors: Atherton William J.
Published: October 2005

The advent of microprocessors has made modern high-speed spectral analyzers possible and has given the test engineer new and powerful techniques for the analysis of structures. However, with new techniques have come new difficulties to overcome in obtaining valid data. This paper stresses the input/output nature of dynamic system measurements and builds upon this concept for the determination of valid data. First, consideration is given to various excitation techniques (swept sine, random noise, impulse) in addition to self-excitation. The distribution of energy in the frequency domain of the excitation signal offers insight as to what may be expected in the output measurement. Undesirable energy in a selected frequency range may need to be filtered out to better match the dynamic range of a signal with the input amplifier gain. Noise, which typically occurs on every signal, affects measurement accuracy. Averaging techniques are described which can sometimes help reduce the effects of noise and improve the measurements. In two-channel measurements, the use of the coherence function as a measure of the goodness of frequency response data is also introduced.
Windows in spectral analysis—what they do
Authors: Burgess John C.
Published: October 2005

“Windows” are functions used via multiplication/convolution to alter the spectral characteristics of signals represented by finite length data records. Since finite record lengths are always used for real-world spectral analysis, a window of some shape is always used in practice. The simplest window is the open window, the “hat” function by which an infinite Fourier integral becomes a finite Fourier integral. Windows of other shapes have two major functions that depend on the type of data. Windows are used with periodic data to minimize the effects of signal discontinuities at the “ends” of a data record. Windows are used with random data to improve statistical reliability of spectral estimates. Shapes intended to implement either application automatically affect the other. The assumption implicit in using the open window is that data outside the window are zero, while the assumption implicit in Fourier analysis is that the data record is periodically extended. These assumptions are often not valid.
An interactive graphic system for acquiring and analyzing proportional bandwidth acoustical data
Authors: Sneddon Matthew , Fidell Sanford
Published: October 2005

Computer-based systems for processing one-third-octave and other proportional bandwidth acoustical data are generally specific to particular applications (e.g., aircraft noise certification), narrow in range of data manipulation, inconvenient to extend to applications other than those for which they were designed, and require skilled operators. These limitations seemed tolerable when the cost of digital systems exceeded the price of human labor. Now that acoustical data analysis systems can be economically developed in high level languages, a different set of requirements for such systems is emerging. These include extensive interactive graphic analysis capability, advanced statistical treatments of data, ease of data management, user extendability to unforseen applications, generic procedures for data manipulation, simplicity of application to novel data sets, concurrent access to data sets by multiple analysts, and automated operation. An example of a modern, VAX-based acoustical data analysis system of this sort is described in detail.
Measurements of the nonlinear tuning carves of thin circular disks
Authors: Wu Junru , Rudnick Isadore
Published: October 2005

The flexural modes of a circular steel disk (diameter ≈25.7 cm, thickness ≈0.061 cm) were excited by an electromagnetic force to large amplitudes of motion, and the nonlinear tuning curves of the (p,q) modes, where p = nodal diameters and q = nodal circles, were determined. The results disagree with those of S. A. Tobias [Engineering 51 (11 July 1958) and Proc. Inst. Mech. Eng. London 171, 691 (1957)]. It is found that, as the drive level is increased, the peak frequencies of the tuning curves can shift to lower frequencies, such as (0,1), (1,1), (0,2) modes, or higher frequencies, such as (10,0), (3,1), (4,0) modes; the direction of shifting is a property of the particular modes being driven. [Work supported by ONR and DOE.]
PVDF: A wideband ultrasound transducer at ultralow temperatures
Authors: Keolian Robert , Reppy John
Published: October 2005

The propagation of ultrasound in rotating superfluid He-3 requires that the power dissipated be limited to a nanowatt or so. The usual transducers at these millikelvin temperatures are quartz crystals driven at resonance. They have low loss but work at only a few fixed frequencies. The thin piezoelectric polymer film PVDF is sensitive enough that it can be used below its resonance, from audio to at least 60 MHz. Its suitability at ultralow temperatures will be described. [Work supported by NSF.]
Relationship of the auditory brainstem response to time/intensity tradeability
Authors: Stephenson Mark , Melnick William
Published: October 2005

Dichotic clicks were presented at 70 dB nHL to a group of 12 otologically normal male subjects. The clicks to one ear were attenuated by either 6 or 12 dB. Subjects were instructed to delay the onset of the click delivered to the contralateral ear until a single image was perceived at the center of their head. These same stimuli were then employed to evoke auditory brainstem responses. When the interaural intensity difference (IID) was 6 dB, a mean interaural time difference (ITD) of 151 μs effectively recentered the image. An IID of 12 dB was similarly offset by an ITD of 594 μs. A comparison of ABR latencies for time and intensity demonstrated greater differences for wave I than for wave II or V. The difference at wave I was significant for three out of four comparisons while at wave V only one out of four comparisons was significant. Differences between ABR response latencies to time versus those to intensity were most apparent as interaural differences were increased.
Intensity discrimination: Relation of auditory-nerve activity to psychophysical performance
Authors: Delgutte Bertrand
Published: October 2005

In order to test the notion that saturation of auditory-nerve fibers limits psychophysical performance in intensity discrimination at high stimulus levels, intensity difference limens (DL) of single auditory-nerve fibers in anesthetized cats were measured for tones at the CF, using stimulus paradigms and detectability measures similar to those of psychophysics. The physiological DL reaches a minimum in the range of stimulus levels where discharge rate increases rapidly. In a narrow range of levels around the minimum, single-fiber DLs approach psychophysical DLs. An optimum-processor model that combines intensity information from an array of 30 000 auditory-nerve fibers with a realistic threshold distribution predicts intensity DLs that are well below psychophysical DLs over a 90-dB range of levels. This result implies that psychophysical performance is not limited by saturation in auditory-nerve fibers, but by central factors. Suboptimal processors that give more weight to intensity information from high-threshold fibers than to information from low-threshold fibers can closely predict psychophysical DLs for both tones and broadband noise over a wide range of stimulus levels. Moreover, such processing schemes, which are based on average discharge rates, provide a stable representation of the spectra of speech sounds with respect to variations in intensity. [Work supported by NIH.]
Cochlear tuning characteristics infants and adults
Authors: Bargones J. Y. , Burns E. M.
Published: October 2005

Cochlear tuning characteristics were estimated by obtaining suppression tuning curves (STCs) for spontaneous otoacoustic emissions (SOAEs) in infant and adult subjects. STCs were derived using 8 to 12 suppressor frequencies per SOAE. Infants were tested at approximately 3 weeks, 2 months, and 3 months of age. Adults were tested three times over a period of 3 months. Quantitative analyses include Q-10, Q-20, slopes of the high- and low-frequency segments of the tuning curve and tip frequency. Results indicate that cochlear tuning properties in infants approximate those found in adults; however, greater variability is observed for repeated measures of infants STCs. The results are discussed with respect to the development of frequency selectivity. [Work supported by NINCDS.]
Acoustic characteristics of emphasis
Authors: Godfrey John J. , Brodsky Joshua M.
Published: October 2005

The fundamental frequency, intensity, and duration of the stressed syllable nucleus are three of the principal cues used to convey the amount of emphasis intended on a particular word in English. In this study we examined how these three characteristics covaried in a set of 800 utterances produced by eight speakers. The sentences, which were designed and collected for another experiment [Steele, 1986], each contain one disyllabic name spoken with contrastive stress and another which is post-nuclear and deaccented. The speakers were asked, in effect, to vary the degree of emphasis on the name with contrastive stress over a wide range. Measurements of the f0, intensity, and duration of the stressed syllables in both positions suggest that individual speakers chose different “strategies” for employing these cues in combination. Pitch elevation was used most consistently over the entire range.
The nature of Korotkoff signals
Authors: West J. E. , Blank S. , Muller F. B. , Cody B. , Harshfield G. , Laragh J. H. , Pickering T. G.
Published: October 2005

Analysis of Korotkoff signals (i.e., those signals generated during standard blood pressure measurements) detected under a sphygmomanometer cuff by a foil electret sensor with a frequency range extending below 0.1 Hz reveals three distinct components, K1, K2, and K3. K1 is present above systolic pressure; K2 appears at systolic and vanishes at diastolic pressure; K3 appears between systolic and diastolic pressure and continues to be present below diastolic pressure. K1 and K3 resemble the intra-arterial pressure waveform. When K3 is calibrated according to the pulse pressure, noninvasive d(K3)/dt determinations correlated well with intra-arterial dp/dt measurements. Intra-arterial pressure recordings made with a solid-state catheter-tipped manometer distal to the cuff revealed K2 and K3 components. Comparisons of blood pressures derived from K2 with those obtained by the auscultatory (standard) method on 9 normal and 42 hypertensive subjects gave good agreement with minor systematic deviations for both systolic and diastolic values. Estimates of blood pressure using K2 were, however, closer to the intra-arterial pressure than those obtained with the auscultatory method.
Intrinsic pitch of vowels in read speech at different speech rates
Authors: Hata Kazue
Published: October 2005

Although there is abundant evidence for systematic differences in the average F0 of individual vowels (so-called “intrinsic pitch”), other things being equal, it has been claimed that these differences disappear in connected speech [N. Umeda, J. Acoust. Soc. Am. 70, 350–355 (1981)]. In the hope that it could be possible to identify the other things which, when not equal, influence intrinsic vowel pitch, how it is affected by speaking rate and emphasis (contrastive stress) was examined. Ten speakers of American English (five male and five female) read sentences containing “Leo” and “Lolly” in the target sentence-medial position with and without emphasis at three different rates. A preliminary analysis of the data reveals that, although these factors influence the intrinsic pitch differences, namely, emphasis amplified it and fast rate attenuated it, the effect was preserved on the average under all conditions.
Fundamental frequency variability in the oral reading of untrained English speakers
Authors: Solomon James R. , Soares Eric J.
Published: October 2005

A characteristic common to the speech of virtually all individuals with dysarthria (a motor speech disorder) is “monopitch” or “monotone”; yet many such patients possess variations in fundamental frequency (F0) that are perceptually apparent and instrumentally demonstrable. In an attempt to establish reference data for the degree of F0 variability in the oral reading of normal English speakers, 76 randomly selected, naive native speakers of American English were asked to read aloud a standard paragraph used to assess contextual speech in both normal and deviant speakers (the “Grandfather” passage) as part of a study correlating perceptual and acoustic measures of expressiveness in speaking. Selected sentences of the tape-recorded paragraphs were visually inspected on a real-time F0 analyzer (the Visi-pitch), with measurements made (wherever possible) at regularly occurring intervals in the sentence. Mean F0's for each sentence were then calculated as well as standard deviations, which reveal the degree of departure from a theoretical monotone (s.d. = 0). These data along with details of instructions to subjects and acoustical analysis techniques used will be presented.
Nuclear accent F0 peak location: Effects of rate, vowel, and number of following syllables
Authors: Steele Shirley A.
Published: October 2005

Reported here are results from an investigation of the alignment of speech segments with the fundamental frequency (F0) contour at the end of an intonational phrase. Findings suggest that the F0 peak on the main sentence stress (nuclear stress) occurs at some proportion of the length of the vowel, instead of at a fixed distance into the vowel. The vowel may be shortened by a faster speaking rate, an intrinsically shorter vowel, and added post-nuclear syllables. The F0 peak delay, however, is shortened by faster speaking rate and intrinsically shorter vowels, but lengthened or unaffected by added syllables. Thus vowel length and post-nuclear syllables interact to determine the location of the F0 peak.
Measuring the contribution of formant frequency targets, bandwidths, and transitional timing to the perception of a vowel idiolect
Authors: Wright James T. , Malsheen Bathsheba J. , Yue Melanie
Published: October 2005

One goal in speech synthesis-by-rule is to replicate the idiolectal properties of human speakers in order to produce more natural and distinctive synthetic voices. The spectral properties of vowel idiolects can be expected to vary in formant frequencies, timing of transitions, bandwidths, and source spectra. These characteristics can be combined into a model that specifies vowels in terms of formant targets for the nuclei and offglides of the vowels, the percent of the duration at the midpoint of transitions, and the duration of transition [J. Allen, From Text to Speech: The MITalk System (1986)]. These parameters were measured in stressed monosyllables for diphthongs and [Vr] sequences in a frame sentence. Data from an AX discrimination test will be presented which indicate the relative contribution of each model parameter to simulating the natural vowels.
Characterization of range-dependent shallow water waveguides
Authors: Frisk George V. , Diemer Ferdinand J. , Dahl Peter H.
Published: October 2005

A technique for characterizing range-dependent shallow water waveguides is described. The method consists of determining the beamformed output of a horizontal array over short apertures for signals due to a cw point source. By modeling the acoustic field locally as a sum of damped normal modes and using Prony's method to perform the beamforming, the local modal structure of the waveguide can be resolved. As a result, the modal composition of the waveguide as a function of range can be determined and interpreted in terms of range-dependent mode theories (e.g., adiabatic mode theory). In addition to identifying important propagation characteristics such as mode cutoff, the method can be used to determine range-dependent acoustic properties of the bottom. Examples of the application of the technique to the case of propagation in a wedge-shaped ocean are presented. [Work supported by ONR.]
Attenuation of the modes of propagation in an homogeneous floating ice plate
Authors: Stein Peter J.
Published: October 2005

The characteristic equation for plane-wave propagation in a homogeneous floating ice plate was solved numerically to determine the phase speeds and attenuations of the first- and second-order modes. While discussion of the phase speeds of the first-order modes constitutes a review, the discussion of the second-order modes, along with the attenuation characteristics of the modes when ice absorption is introduced, gives new insight into which modes might be observed in Arctic pack ice. Only the flexural and longitudinal waves, which exist below a frequency-ice thickness product of 300 Hz-m, propagate with losses less than 0.1 dB/m in ice less than 3 m thick. This is important to the study of noise from nearby ice events. Results of using a nearby explosive charge to measure the ice longitudinal wave speed and attenuation are given. The ice loss in the 40-Hz region was found to be approximately a factor of two higher than expected from current empirical absorption values. This may be important to understanding losses from ice interaction in long range propagation. [Work supported by ONR.]
Limitations of sound propagation in the ocean: The curtain effect
Authors: Browing D. G. , Hanrahan J. J. , Christian R. J. , Mellen R. H.
Published: October 2005

Although initially very high, the rate of spreading loss decreases rapidly with range, while the rate of attenuation remains constant for a given frequency. At increasing ranges the two loss curves cross, with attenuation becoming the dominate mechanism. This results in a “curtain effect” due to rapidly increasing propagation loss. Examples are given of convergence zones obtainable as a function of frequency for various oceans and of the transition between near range and distant ambient noise. [Work supported by NUSC.]
Some thoughts on impact isolation evaluation
Authors: Daly Edward A. , Standlee Kerrie G.
Published: October 2005

As the Portland condominium market was developing in the 70s each of the authors encountered problems using standard impact isolation test data as a design aid. There was no correspondence between subjective response received and that predicted. In response, each independently developed and used a simplified field test for evaluating modifications of ceiling/floor systems. The authors became aware of the other's work. They jointly ran a series of tests using both of the field tests methods. The findings of their joint study indicate (1) subjective response is closely related to the amount of low-frequency sound generated by impacts, (2) the impact mass used and the construction of the floor/ceiling system directly affect the level of sound generated below 250 Hz and (3) most normal floor isolation treatments are effective only in the frequency bands above 250 Hz. These findings support the following conclusions: (1) the standard test should be a field test to account for floor system construction effects, (2) the test should include frequencies below 100 Hz, and (3) the impact mass should sufficiently generate low-frequency sound.
Biological effects of vibration on the hand and arm: Historical perspective and current research
Authors: Taylor William
Published: October 2005

Raynaud's phenomenon of occupational origin, or the vibration syndrome of hand and arm, was first recognized in North America by Dr. Alice Hamilton in the limestone quarries of Bedford, Indiana around 1890 to 1900. It is a tribute to the American pioneers in this area that the Acoustical Society of America now formally recognizes Biological Response to Vibration as a technical area. The objective of this paper is to highlight gaps of information regarding mechanisms of vascular, neurological, and musculo-skeletal damage caused by vibration. Also addressed is evidence that high noise level may act synergistically to the development of vibration syndrome of the hand and arm. Areas of research currently active in psychophysical and neurophysiological investigations to increase our understanding of tactile and spatial discrimination are discussed. Although the importance of sensory loss or “fine touch” is understood there is neither a proven objective scientific test with which the syndrome can be diagnosed nor is there a scale of damage assessment. Determining the exact role of the central nervous system in assessing damage from vibration is difficult in view of nonspecific symptoms reported from Eastern Europe and from Japan. To complicate matters still further, there is the possibility that repeated, rapid mechanical movements of the hand and arm associated with handling heavy tools produce Carpal Tunnel Syndrome but that the injury is not directly attributed to vibration. Therefore, it follows that there could exist an element of Carpal Tunnel Syndrome in many vibration syndrome cases. Clearly, there is an area within the framework of the Acoustical Society of America for worldwide cooperative efforts to solve many fundamental problems concerned with the effect of vibration on a hand or arm.
Demonstration experiments to show fundamentals of FFT analyzers
Authors: Brittain Frank H. , Pryshepa John
Published: October 2005

A series of demonstration experiments will be performed to supplement the special session on FFT analyzers for noise and vibration from a user's perspective. These experiments will present some fundamentals of FFT analyzers, primarily single-channel analyzers. Fourier representation of a periodic signal will be used to illustrate the time and frequency domains. The interrelationship between frequency range, number of lines, and resolution will be shown. The concepts of sampling, folding, leakage, and windows will also be illustrated. Some noise and vibration data will be used to indicate the types of information that can be obtained using FFT analyzers. The experiments will be used to demonstrate fundamentals common to all analyzers and not any specific hardware.
Sound amplitude fluctuations in the presence of atmospheric turbulence
Authors: Bass Henry E. , McBride Walt , Noble John
Published: October 2005

The fluctuations in received sound pressure levels at a microphone array 1 m above the ground and 5–100 m from a source 1–30 m off the ground have been recorded simultaneously with fluctuations in wind speed and temperature. The recordings were then played back through a multichannel analyzer which gives the number of acoustic cycles with peak amplitudes within 1024 amplitude intervals. Normalizing by the number of counts gives the probability of observing a given amplitude. These measurements were made at octave-band preferred frequencies between 63 Hz and 8 kHz. At frequencies of 500 Hz and below, the probability distribution appears Gaussian. At higher frequencies, the distribution is better represented by a log normal distribution. In each case, the shape of the curve was dependent upon turbulence parameters (scale and magnitude). [Work supported by the Army Research Office.]
Experimental study of acoustic radiation from a boundary layer transition region
Authors: Perraud J. C. , Julienne A.
Published: October 2005

Wall pressure fluctuations were measured on a rigid axisymmetric body in the CEPRA 19 low-noise, anechoic wind tunnel, using flush-mounted microphones placed from the laminar region to the fully turbulent boundary layer. Microphones placed in the laminar flow region are used to detect noise radiated from the transition region, which occurs naturally, without separation, under a slightly positive pressure gradient. Cross-spectral analyses show upstream acoustic propagation in a very wide frequency band, 4–30 kHz, detected in the laminar region. A method of conditional analysis is then used to establish the sequence of events from the onset of near-harmonic instability wave packets to the generation, about 10 ms later, of turbulent spots leading to the acoustic emission. This intermittent acoustic radiation is detected in the nearfield for wind velocities ranging from 20–70 ms. Farfield detection was not achieved probably because of instrument limitations and propagation effects. [Work supported by DRET, Direction des Recherches et Etudes Techniques.]
Scattering of light by a coated bubble in water near the critical and Brewster scattering angles
Authors: Marston Phillip L. , Billette Stuart C.
Published: October 2005

Microbubbles in the ocean may be coated by a thin film of surfactant since such substances can be abundant in natural waters. Such films may affect the optical and acoustical properties of bubbles. We investigated theoretical light scattering patterns for a spherical gas bubble (of radius a) coated by a film of uniform thickness h and refractive index nf surrounded by water of refractive index n ω = 4/3. The patterns were computed from the partial-wave series of Aden and Kerker for ka ranging from 100–2500, where 2π/k is the optical wavelength in water. The corresponding range of a is 7.5–189/μm; h ranged from 0–3/μm and nf was typically real and equal to 1.5. Noncoated bubbles exhibit coarse irradiance oscillations as the scattering angle θ decreases below a critical value for total reflection (θc = 82.8°); a broad minimum in the polarized irradiance is expected near the Brewster scattering angle θB = 106.3° [P. L. Marston et al., Appl. Sci. Res. 38, 373–383 (1982)]. Coatings shift the coarse oscillations towards larger θ when nf > nω in agreement with predictions of ray optics. If the irradiance near 82.8° is used to size bubbles, the effects of this shift are negligible for anticipated coating parameters. The minimum near θB, however, is predicted to be significantly lifted by coatings. [Work supported by NORDA and by ONR.]
Numerical models used in transducer design
Authors: Montgomery Robert E. , Ruggiero Clementina M. , Henriquez Theodore A.
Published: October 2005

Numerical methods currently used to design transducers will be reviewed. The applicability, advantages, and disadvantages of each method will be discussed. Two methods, finite elements and a method for computing acoustic radiation, will be discussed in detail. These two methods will be illustrated by application to a piezoelectric Helmholtz resonator. Computed performance values such as transmitting voltage response, electrical admittance, and normal modes of vibration will be presented and compared to measured values. The presentation will conclude with an overview of needs and future plans.
The effects of a broadband masker on frequency DLs for short tones
Authors: Freyman Richard L. , Balakrishnan Uma
Published: October 2005

In an earlier study [R. L. Freyman and D. A. Nelson, J. Acoust. Soc. Am. Suppl. 1 75, S6 (1984)], it was observed that normal subjects' frequency DLs for very short tones often do not improve monotonically as the level of the standard and variable tones is increased. In some subjects (at least at 1 kHz), performance deteriorated as the test-tone level was increased from approximately 30—80 dB SPL, then improved again at still higher levels. The current experiment investigated the effects of broadband noise on the size of frequency DLs for short tones presented at moderately high levels. Frequency DLs for 5-ms, 1-kHz tones were first obtained in quiet as a function of stimulus intensity. DLs were then obtained with the signal level fixed at the SPL at which the largest DL in quiet was observed—this time in the presence of varying levels of white noise that partially masked the tones. The results indicated that changing the signal-to-noise ratio for fixed SPL tones produced similar changes in the frequency DL to those observed when the presentation level was varied in quiet. That is, in subjects with poorer DLs at moderately high levels in quiet, discrimination performance at those same levels improved when white noise was introduced. The size of the DL in noise was found to be comparable to that obtained in quiet when equated for SL. [Work supported by BRSG.]
Invariant acoustic cues in stop constants: A cross language study using the Wigner distribution
Authors: Garudadri H. , Gilbert J. H. V. , Benguerel A. P. , Beddoes M. P.
Published: October 2005

The Wigner distribution (WD) is a powerful tool in analyzing the speech signals [Garudadri et al., J. Acoust. Soc. Am. Suppl. 1 79, S94 (1986)]. The WD is being used to investigate acoustic invariance in stop consonants. In a pilot study of CV syllables, bilabials showed an energy concentration in the low-frequency region during the burst, followed by the formant pattern of the vowel. Alveolars had a diffuse spectrum prior to the vowel region; they were also characterized by an absence of low-frequency energy during the burst of the voiceless tokens. Velars displayed a distinctly compact spectrum centered near the frequency of the second formant of the vowel. The diffuse nature of the bilabials and alveolars, reported by Lahiri et al. [J. Acoust. Soc. Am. 76, 391–404 (1984)] and by the authors referenced therein, can be attributed to the temporal averaging of the burst spectrum and the diffuse vowel spectrum. This smear does not occur in velars because their burst is quite long. The WD allows one to study the burst and vowel spectra independently of each other without introducing any substantial time averaging. A formal study of the invariant acoustic properties of stop consonants from English, French, and Telugu is underway. The results of the study will be presented. [Work supported in part by NSERC, Canada.]