bluuebunny/crossref_metadata_2025 huggingface dataset:
The resonances of a finite-length fluid cylinder and their interpretation in terms of surface waves
Authors: Gaunaurd G. C. , Tanglis E. , Überall H.
Published: October 2005

We consider a finite-length fluid cylinder surrounded by either a very tenuous or a very dense exterior fluid. This amounts to respectively considering either Dirichlet or Neumann boundary conditions on the cylinder's surface. The eigenfrequencies of such finite-length cylinders are interpreted in this paper as the resonances caused by phase matching of circumferential waves that circumnavigate the cylinder along certain helicoidal Fermat paths, and that get reflected back and forth from its top and bottom flat surfaces. We have obtained the dispersion curves of these circumferential (i.e., “creeping”) waves which are seen to correspond to a series of well-defined pitch angles of their helix, for different values of the cylinder's length-to-radius ratio. We generate and display graphs pertaining to various cylinder sizes, boundary conditions, and pitch angle of each of the resulting surface waves. [H. Überall is also at Catholic University, Washington, DC, and was additionally supported by Code 421 of ONR.]
Ultrasonic nonspecular reflectivity near longitudinal critical angle
Authors: Ngoc T. D. K. , Mayer W. G.
Published: October 2005

The intensity profile of an ultrasonic beam reflected from a liquid-solid interface is determined by a numerical integration method. This numerical approach takes into account the influence of absorption in the media and is valid for all angles of incidence. The reflected profile is calculated for a specific case: incidence near the longitudinal critical angle for a water-Plexiglas interface. The calculated results demonstrate the existence of nonspecular reflectivity near this particular critical angle and provide a quantitative description of its basic features. Theoretical results and experimental measurements are compared. [Work supported by the Office of Naval Research, U.S. Navy.]
Backscattering of short ultrasonic pulses by solid elastic cylinders at large ka
Authors: Welton P. J. , De Billy M. , Hayman A. , Quentin G.
Published: October 2005

Backscattering measurements from solid brass, aluminum, and Lucite cylinders in water have been performed at a ka of approximately 240 using short acoustic pulses. Numerous discrete echoes are received due to multiple internal reflections of the acoustic pulse at the boundary of the cylinders. Excellent agreement between the measured echo arrival times and the echo arrival times predicted by the theory of Brill and Überall [D. Brill and H. Überall, J. Acoust. Soc. Am. 50, 921–939 (1971)] is obtained for all of the cylinders. The amplitudes of the backscattered echoes from the brass and aluminum cylinders were also compared with theory and fair agreement is obtained.
The scattering of an obliquely incident plane acoustic wave from a cylindrical object
Authors: Flax Lawrence , Varadan Vasundara V. , Varadan Vijay K.
Published: October 2005

A mathematical model is developed to predict the scattering of a plane acoustic wave incident upon an elastic cylinder immersed in water at any angle relative to the cylindrical axis. Solutions to the elastic problem are constructed using scalar and vector potentials. There are three important angular regions of interest. These are at the longitudinal, shear, and Rayleigh critical angles. The scattering amplitude at these angles is derived and will be discussed.
The T-matrix approach to scattering of waves by finite elastic and viscoelastic cylinders immersed in water
Authors: Varadan Vasundara V. , Varadan Vijay K. , Flax Lawrence
Published: October 2005

In this paper, the T-matrix or null field approach is applied to make scattering and absorption calculations for finite elastic and viscoelastic cylinders in water. Various difficulties which so far have prevented the use of such a formalism for a solid-fluid interface will be discussed. The complication due to the appearance of only curl free basis functions in water which in turn makes some of the matrices involved nonsquare has been overcome by considering additional representation of the scattered and refracted fields and using a series of matrix manipulations. Numerical results displaying the scattering cross sections for a range of frequencies for various aspect ratios are presented. These results are then compared with those of a prolate spheroid of the same overall dimensions to study how the shape is critical in determining the absorption characteristics.
“Zeroes,” “ridges,” and poles, in the scattering amplitudes of elastic waves echoing from resonating fluid spheres in solids and liquids
Authors: Brill D. , Gaunaurd G. , Überall H.
Published: October 2005

We study the “resonance parts” of the scattering amplitudes of compressional or shear waves, returned when compressional or shear waves are incident on fluid spheres contained in either solids or in dissimilar fluids. The resonance parts are obtained after suitable smooth backgrounds are subtracted from each composite partial-wave amplitude. The starting point of the analysis is the three-dimensional graph of any of the modular surfaces |a−1fnPP|, |a−1fnPS|, |a−1fnSP|, and |a−1fnSS| plotted versus mode order n, and nondimensional frequency ka. We found simple expressions for the (not necessarily straight) lines of zeros that constitute the boundaries or demarcation lines of each of the “ridges” that appear so evidently in the plots. These “ridges,” which are inclined with respect to the n and ka axes, exhibit marked cleavages, and the “peaks” present in them (i.e., the resonances) are spaced in a peculiar way that is, (a) predictable from the analysis, and (b) that yields information about the material composition of the scatterer. The analytic expressions for the lines connecting the tips of the peaks along a given ridge has also been determined. Each “ridge” is shown to be associated with a “creeping wave” and it is the graphic visualization of the elastic analog of a “Regge pole.” [H. Überall is also at Catholic University, Washington, DC, and was additionally supported by Code 421 of ONR.]
The Mittag-Leffler expansion and the interpretation of poles in the scattering amplitudes of waves echoed from fluid spheres
Authors: Gaunaurd G. , Überall H.
Published: October 2005

We consider the cases of acoustic and elastic wave scattering from fluid (possibly viscous) spheres contained within either solids (i.e., coatings) or dissimilar fluids (i.e., bubbles), and study the resulting scattering matrix Sn and the poles in the associated scattering amplitude (s). The one-term Taylor series we used in the past to obtain the “one-level approximation” to Sn, which was so valuable in our earlier development of the resonance theory of viscoelastic wave scattering from cavities, can now be replaced by the exact Mittag-Leffler expansion of the quantity Fn. This quantity is proportional to the system's mechanical impedance and since all of its singularities are simple poles, it admits a meromorphic function (i.e., Mittag-Leffler) series representation. The locations of the “new” resonances and the value of their widths are found to be shifted from the values we found using our earlier approach, even in the absence of absorption in the fluid interior to the sphere. Absorption introduces further shifts and the unitarity property of Sn is lost in both instances. The new representation is not only exact, but reduces properly to the right asymptotic limits and our earlier “backgrounds” and “resonances” can be re-interpreted in the light of these new (and simpler to obtain) poles. Plots of the poles and their shifts are displayed in various cases. [H. Überall is also at Catholic University. Washington, DC., and was additionally supported by Code 421 of ONR.]
Scattering of elastic waves by an elliptical cylindrical shell
Authors: Simon M. M. , Radlinski R. P.
Published: October 2005

Much work has been accomplished in the analysis of the dynamics of an elliptical cylindrical shell. Recently, solutions have appeared for acoustic scattering from a submerged elliptical shell [Brigham, Libuha, and Radlinski, J. Acoust. Soc. Am. 61, 48–59 (1977)]. The problem of scattering of arbitrarily polarized elastic waves from an elliptical cylindrical shell is even more difficult because the basis functions for the fields in a separable coordinate system are not orthogonal for the different wave speeds. Recent advances [Pao and Varatharjulu (Varadan) J. Acoust. Soc. Am. 59, 1361–1371 (1976)], in the application of the extended boundary condition method to elastic wave propagation has led to solutions for elastic wave scattering from elliptical inclusions that are stress-free, rigid, fluid, or solid elastic. Varadan and Varadan have worked on the case of a layered elastic inclusion. This presentation deals with coupling of thin shell theory to the elastic scattering problem as described by the extended boundary condition method. The theory is ideally suited to such applications since the formulation is given in terms of normal and tangential stresses and displacements on the elliptical surface.
The Shepard demonstration revisited, again
Authors: Burns E. M.
Published: October 2005

The Shepard illusion (“auditory stairway to heaven”), in which the presentation of a cyclically repetitive sequence of complex tones composed of partials separated by octave intervals gives the illusion of continually rising pitch [Shepard, J. Acoust. Soc. Am. 36, 2346–2353 (1964)] is often cited as evidence for octave equivalence in relative pitch judgments. Evidence will be presented which demonstrates that this illusion can be produced using inharmonic complex tones (e.g., tones whose partials are separated by stretched or compressed “octaves”) and, thus, octave separation of partials is not a necessary condition for producing the illusion. [Work supported, in part, by NINCDS.]
Diotic and dichotic perception of single echoes
Authors: Koenig Arthur H.
Published: October 2005

The perception of single echoes for two binaural listening modes, diotic and dichotic was examined. Stimuli consisted of a white Gaussian noise waveform added to itself with an intervening delay. Delay values of 2, 4, 8, and 16 ms at two overall sensation levels of 30 and 50 dB SL were used. The dichotic listening mode was created by reversing the polarity of the delayed noise waveform in one ear relative to the other ear. An ABX paradigm was used to determine the absolute threshold for the presence of a single echo. Diotic listening mode thresholds were found to be significantly different from dichotic listening mode thresholds. For delay values of 2 and 4 ms, the diotic listening mode thresholds were substantially elevated relative to the dichotic listening mode thresholds. Diotic threshold data appear to be compatible with existing critical-band models. Dichotic threshold results lend support to a mechanism of binaural combination which serves to reduce spectral variation.
Handedness, sex, ear effect, and children's contralateral acoustic reflex
Authors: Johnson D. W. , Sherman R. E.
Published: October 2005

There has been no clear evaluation of handedness and sex on the contralateral acoustic reflex with aging. To investigate these effects and their interactions, 54 children aged 6 to 12 yr were selected from normal classroom settings on the basis of age, sex, handedness for writing, average academic performance, normal hearing, and normal medical history. Contralateral acoustic reflex thresholds were determined using an ascending technique with continuous white noise stimuli. When all children were grouped together, there was no age or sex effect observed; the right ear did appear to average 3.8 dB more sensitive to white noise stimuli than the left. When grouped by handedness, left-handed youngsters showed a pronounced age effect, thresholds improving 12 dB from age 6 to 12; right ears continued to be the superior ear for these left-handed children. Left-handed children were approximately 2 years later in developing contralateral acoustic reflex sensitivity equal to that of right-handed peers, but appeared to mature faster than right-handed children from ages 8 to 12 in terms of acoustic reflex threshold sensitivity.
Brain lateralization in 2-, 3-, and 4-month olds for phonetic and musical timbre discriminations under memory load
Authors: Best Catherine T. , Hoffman Harry , Glanville Bardley B.
Published: October 2005

Although young infants show the adult pattern of dichotic ear asymmetries, it is unclear whether any early age changes exist in the pattern or strength of infant asymmetries. Knowledge about early lateralization may illuminate issues in perceptual development. In this study, 2-, 3-, and 4-month olds completed dichotic tests for ear differences in short term memory-based discriminations among synthetic syllable-initial stop consonants, and among synthesized renditions of different instruments playing one note. Discrimination results supported an REA for speech, and an LEA for musical timbre, in 3- and 4-month olds. The 2-month olds showed only the musical timbre LEA, without reliable syllable-initial stop consonant discrimination by either hemisphere under memory load. Of the individual infants, an LEA was found in 23 of those who discriminated timbre contrasts, and an REA was found in 23 of those who discriminated speech contrasts. Both portions are close to those found in adults. Implications for theories about lateralized brain development, and for infants' perception of the two classes of complex auditory stimuli, will be discussed. [Partially supported by NINCDS and NICHD.]
Binaural interaction with an aural harmonic: Cancellation and augmentation
Authors: Ayres Thomas , Clack T. D.
Published: October 2005

In the monaural tone-on-tone masking procedure, the audibility of a maskee an octave above the masker depends on masker:maskee phase. If vector summation between the maskee and an aural harmonic is assumed, the amplitude and phase of the aural harmonic can be estimated. An alternative interpretation of the phase effects is two-tone interaction between the masker and maskee. To decide between these explanations, a binaural technique has been developed for the study of octave phase effects. Using a forced-choice procedure, listeners are able to detect a change in interaural phase between a 400-Hz continuous masker presented to one ear (65–75 dB SPL) and an 800-Hz pulsed probe tone presented contralaterally (10 dB SL). When a subthreshold 800-Hz tone is added to the masker ear at a phase and level appropriate to cancel the estimated second aural harmonic, performance deteriorates significantly. Addition of this same tone at augmentation phase tends to improve performance. These findings fail to confirm the two-tone interaction interpretation, but they support the aural-harmonic explanation for monaural tone-on-tone masking results. Furthermore, these inaudible “subjective” products must be represented in the neural input to the brainstem since, like inaudible acoustic tones, they are capable of interacting binaurally with audible tones.
Release from masking for speech under pseudodichotic listeing conditions
Authors: Tolhurst G. C.
Published: October 2005

A series of studies has shown that scores of a multiple-choice speech reception test are significantly higher if the signals to one ear are processed by certain bandpass filtering or are interrupted at certain rates while the same signal to the opposite ear remains as undistorted as possible, i.e., pseudodichotic, over the condition of undistorted speech to both cars. No release from the white noise masking was found when the speech signals to one ear were time delayed variously to that presented to the opposite ear. The above results pertain whether the white noise was mixed with speech electronically or mixed acoustically. The release from masking was more pronounced at a plus 6 dB S/N than at a plus 2 dB S/N. Different groups of 30 to 35 normally hearing listeners made responses to 12 different randomizations of the test, one each for, (a) delay, interruption, or filtering signal processing (3), (b) electronic or acoustic noise mixing (2), and plus 6 dB or plus 2 dB S/N conditions (2).
On the identification of synthesized steady-state vowels in isolation and in consonantal context
Authors: Diehl Randy L. , McCusker Susan Buchwald , Chapman Laura S.
Published: October 2005

Naturally produced vowels have been shown to be much more difficult to identify correctly in isolation than in consonantal context [W. Strange, R. R. Verbrugge, D. P. Shankweiler, and T. R. Edman, J. Acoust. Soc. Am. 60, 213–224 (1976)]. In an attempt to replicate this finding under more controlled conditions, we synthesized three sets of English monophthongs. The first set consisted of 240-ms steady-state formant patterns bounded by symmetrical transitions corresponding to a b_b context; the second consisted of the 240-ms steady-state segments in isolation; and the third set was identical to the second, except that the vowels were lengthened to equal the duration of the CVC syllables of set one. Surprisingly, both the short and long isolated vowels were identified with greater accuracy than the consonant-bounded vowels. In a second experiment, we sought to make the stimulus sets more natural by (1) introducing duration differences among vowels within each set corresponding to differences observed among naturally produced vowels and (2) reducing the transition extent of the CVC stimuli from 500 to 250 Hz. Overall error rates were substantially reduced. The two sets of isolated vowels were still identified slightly more accurately than the consonant bounded vowels, but the difference was no longer significant. [Work supported by NINCDS.]
Rhythmic grouping effects on temporal order identification of vowel sequences
Authors: Alfonso Peter J. , Kerivan John E.
Published: October 2005

Near-perfect performance has been shown for identification of four synthetic vowel sequences /i, æ, a, u/ at 90–150-ms vowel durations. However, a significant permuted order effect was found for certain 30- and 60-ms vowel sequences by Kerivan, Alfonso, and Bornstein [J. Acoust. Soc. Am. Suppl. 1 65, S113(A) (1979)]. In a further experiment, we have investigated rhythmic grouping effects on the 30- and 60-ms vowel sequences which displayed the permuted order effect in the first experiment. Rhythmic grouping was created by (1) the introduction of a silent gap between two vowels in a sequence, or (2) varying the duration of a single vowel within a sequence. All possible permutations of the two rhythmic grouping conditions were created on the Haskins serial resonance synthesizer by modifying the original stimuli. The results of the experiment indicate that the permuted order effect can be significantly reduced in steady-state concatenated vowel sequences by controlling certain prosodic temporal features of the sequences. [Work supported by an NINCDS NIH grant awarded to Haskins Laboratories and the University of Connecticut Research Foundation.]
The role of formant transition duration in the perception of stress
Authors: Raphael L. J. , Dorman M. F.
Published: October 2005

The results of experiments previously reported indicated that syllable-initial formant transitions contribute by their duration to the perception of the syllable-final voicing contrast for stop consonants. The present experiment employed synthetic disyllables in an attempt to specify the contribution of the duration of syllable-initial and syllable-final formant transitions to the perception of stress. Results indicated that (1) such transitions do contribute to the durational percepts underlying stress judgments and (2) the extent of this contribution varies with the location of the transitions in the disyllable. [Work supported by NICHD.]
Differences in production and perception of VOT in Polish and English
Authors: Keating Patricia
Published: October 2005

English and Polish use different Voice Onset Time (VOT) categories to contrast voiced and voicelesstops: short lag and long lag (English) versus prevoiced and short lag (Polish). When VOT is measured for word-initial stops in minimal pairs, sentences, and conversation, the VOT distributions for voiced and voiceless stops are clearly separated in Polish, but not always in English, especially in casual speech [Lisker and Abramson, Language and Speech 10, 1–28 (1967); Moslin, Brown University dissertation (1978)]. The perception of VOT in synthetic stimuli was compared with production data for Polish and American English listeners. Both groups labeled stimuli in three continua that varied in range of VOT: −20 to + 80, −100 to +50, and −100 to +20 ms VOT. The Polish, but not the American, listeners showed a mean boundary shift (from +20 to +4 ms VOT) as a function of these ranges. Thus the Polish VOT perceptual categories are somewhat unstable and do not always match the VOT production categories, although the latter are well-separated. In contrast, the English perceptual categories are quite stable, but the production categories sometimes overlap in VOT. Distinctiveness in production may compensate for instability in perception, and vice versa.
Learning to recognize foreign speech sounds: Strategies of auditory processing
Authors: Lambert David R.
Published: October 2005

One can use two fundamentally different strategies to learn to recognize foreign speech sounds: Accept a sound as something new to be learned and form new codes which include accurate detail to represent it [Code Forming (CF) strategy], or assume the sound is a distorted version of something familiar, recognizing the sound immediately by using existing codes and ignoring inaccurate detail [Code Using (CU) strategy]. The language learning environment of the child or of a person in a foreign country encourages the CF strategy, while that of the typical classroom student encourages the CU strategy. Surprisingly, the two strategies result in about the same rate of learning. But they produce different processing capabilities, the CF strategy produces about 90 ms faster encoding; the CU strategy about 45 ms faster memorial comparison. In learning a language, one should use the CF strategy to develop fast encoding speed, while consciously focusing on other aspects of the language. (Reference: dissertation of same title, Pp. 330, 1977, PB-273 161/OGA.) [Work performed at Psychology Department, University of California at San Diego; supported in part by NIH.]
Palato-alveolar affricates in several languages
Authors: Maddieson Ian
Published: October 2005

A project to examine phonetic differences between affricates is in progress. Voiceless palato-alveolar affricates and the most similar stops and fricatives have been recorded in closely matched medial positions from 10 speakers of each of three languages speaking at two different speech rates controlled by a metronome. The languages are (Mexican) Spanish, (British) English, and Italian. Spanish does not have a palato-alveolar fricative; English distinguishes affricate, stop, and fricative; Italian distinguishes single and geminate affricates and stops and has a palato-alveolar fricative. The general hypothesis under investigation is that such differences in the number of sounds which must be distinguished have implications for the ways in which the contrasts will be phonetically realized in the three languages, for example, in the variability found between speakers and between speech rates. Preliminary measurements on durational aspects of the segments examined indicate that there are differences between the languages which can be related to the general hypothesis. [Work supported by NSF.]
On the recognition of the Spanish fricatives /s/ and /f/
Authors: Gurlekian Jorge
Published: October 2005

The present work examines the perceptual load carried by the relative intensity of the noise to the intensity of the vowel in the identification of the Argentine Spanish fricatives /s/ and /f/. The estimuli consisted of synthetic fricative-vowel syllables. The fricative portion, consisting of a fixed band noise with a central frequency of 4500 Hz and a bandwidth of 300 Hz, was varied in its relative amplitude to the vowel, to obtain a set of ten noise amplitudes in relation to the fixed vowel amplitude. Spanish listeners identified low amplitude noises as /f/ and high ones as /s/. In a second experiment, subjects were tested on the same stimuli at two different overall sound-pressure levels of the syllable: 60 and 80 dB. For the 80-dB level, subjects identified more /f/ sounds than at the 60-dB level. This result can be interpreted as a different interaction between the vocalic portion and the fricative noise. It is suggested that this kind of interaction may be due to a differential masking effect of the vowel at different amplitudes.
An INDSCAL analysis of normal and hearing-impaired listeners' consonant confusions on a nonsense syllable test
Authors: Danbauer J. L. , Doyle K. J. , Edgerton B. J.
Published: October 2005

Recently, several authors have posited perceptual feature systems to describe consonantal relationships judged by both normal-hearing and hearing-impaired listeners. While these studies have enhanced knowledge of feature usage by such listeners through confusion, similarity, and dissimilarity paradigms, few clinical applications have resulted. Lately, there has been some revived interest in the use of nonsense syllable stimuli for clinical speech discrimination testing. The purpose of this study was to evaluate feature usage by both normal and hearing-impaired listeners to the pre-vocalic consonants of a nonsense syllable test (NST). Listeners were ten normal and eight hearing-impaired adults. The NST consisted of two 25-item lists of CVCVs randomly constructed from 22 consonants and 10 vowels of English. Listeners were tested individually under phones at ascending presentation levels of 5, 15, 25, 35, 45, and 55 dB (re: their SRTs). Responses were phonetically transcribed by the experimenter using both auditory and visual cues. Confusion matrices for both listener types and lists were grouped by presentation levels and submitted to INDSCAL for evaluation in five-dimensional solutions. Results of perceptual features recovered are presented and discussed in light of those found in earlier investigations.
Intelligibility of spoken letters of the alphabet
Authors: Rosenberg A. E. , Geter C. L. , McDermott B. J. , Shipley K. L. , Wilpon J. G.
Published: October 2005

A subjective experiment was carried out to assess the effect of spelling context on the ability of listeners to identify spoken letters of the alphabet. Individual letters, spoken by a male talker and a female talker, were concatenated to form strings of up to ten letters representing the spelling of a last name (surname) and one or two initials. Three spelling contexts were observed. First, real names were selected at random from the 20 000-entry Bell Labs telephone directory. Second, strings were constructed using trigram statistics for letter sequences tabulated from the same directory. Third, letters were selected at random to form strings. In addition, three masking noise conditions were observed: no noise, low-level, and high-level broadband additive masking noise. The results show that the listeners made fewer errors identifying letters imbedded in real name or trigram strings than in random letter strings. The effect is especially pronounced in the presence of masking noise. Confusions among the spelled letters are also tabulated.
Temporal integration and the microstructure of the detection threshold curve
Authors: Cohen Marion F.
Published: October 2005

The detectability of sinusoids as a function of duration was measured for tones having durations of 10, 20, 40, 80, 160, and 320 ms and rise/fall times of 4 or 10 ms. Frequencies were selected to correspond to the peaks and valleys of each subject's detection threshold curve between 1000 and 1400 Hz [Cohen, J. Acoust. Soc. Am. Suppl. 1 65, S55(A) (1979)]. Results indicate that the threshold elevation which accompanies shorter duration is substantially larger for tones at those frequencies having a lower detection threshold level for a 350-ms tone (valleys) than it is for tones at those frequencies having a higher detection threshold level (peaks). This is explained in terms of the spread of energy which accompanies the shortening of duration. This energy spread would be expected to differentially affect detection threshold levels for peaks and for valleys. [Work supported by the University of Connecticut Research Foundation.]
Perceptual dependency of pitch and duration in categorization of pure tones
Authors: Espinoza-Varas Blas
Published: October 2005

To explore possible auditory bases of perceptual categorization, 62 naive listeners were asked to assign tones into one of four classes: “low (pitch)-short (duration),” “low-long,” “high-short,” and “high-long.” The stimuli were sets of 81 pure tones obtained by factorial combination of nine values of frequency with nine values of duration. In one condition, frequency ranged from 0.25 to 1.0 kHz in ≅ 100-Hz steps, and duration from 100 to 180 ms in 10-ms steps; in another condition the ranges were 0.536 to 1.0 kHz in 58-Hz steps and 100 to 356 ms in 32 ms steps, respectively. The tones were presented at a rate of 1/3 s and the SPL was 60 dB. A single stimulus, absolute judgement task was used and only the very initial performance was studied (first 10 rain). The 50% “low-high” pitch boundary was measured as a function of tonal duration, and the 50% “short-long” duration boundary measured as a function of tonal frequency. Listeners were able to consistently categorize the tones into the four classes from the first presentation of the set of tones. For both stimulus conditions, the pitch boundary was placed around the arithmetic mean of the frequency range (X̄ = 0.61 or 0.77 kHz) irrespective of tone duration. The duration boundary was generally placed below the arithmetic mean of the duration range X̄d for frequencies below X̄f, but above X̄d for frequencies higher than X̄f. That is, the higher the pitch the shorter the perceived duration. The results suggest that in auditory categorization with naive listeners, pitch can be judged independently of duration, but the duration judgment is not independent of pitch. [Supported by NRC Post-doctoral Fellowship to the author.]
Discrimination among two-tone complexes differing in frequency separation
Authors: Buus Søren
Published: October 2005

The just noticeable increase in bandwidth of a two-tone complex was measured as a function of bandwidth at three center frequencies: 500, 2000, and 4000 Hz. The bandwidths of the stimuli ranged from one-fourth to four times the critical bandwidth, the overall intensity was 60 dB SPL and the duration of each two-tone complex was 600 ms with 25 ms rise-fall time and 600 ms interstimulus interval. Using a same-different paradigm, discrimination threshold was determined with a transformed up-down procedure. The just noticeable increase in bandwidth is small at narrow bandwidths, but increases dramatically once the bandwidth exceeds some limit. At 500 and 2000 Hz, the limit corresponds to the critical bandwidth, whereas at 4000 Hz, the limit corresponds to approximately half the critical bandwidth. As the bandwidth is increased beyond two to three times the critical bandwidth, a second change in the function occurs, and the just detectable increase in bandwidth remains constant or decreases slightly. These results suggest that the interaction between two tones within a critical band can give rise to a new, discriminable cue, i.e., envelope frequency. [Work supported by NIH Grant No. 2R01NS07270-07A1 and HEW Grant No. RR07143.]
Effects of temporary threshold shift on combination-tone generation and two-tone suppression
Authors: Smoorenburg G. F.
Published: October 2005

In 1972 (G. F. Smoorenburg, J. Acoust. Soc. Am. 52, 615–632) I reported that the combination tone 2f1−f2 (CT) is not generated in the ear if f2(f2 > f1) is inaudible because of a permanent threshold shift (PTS) whereas the same stimulus does generate the CT in normal ears. The PTS was local such that no PTS was present in 2f1−f2. Recently, a similar experiment was performed with a local temporary threshold shift (TTS). TTS was induced by a 2000 Hz, 110 dB SL, 5-min stimulus. During the measurements TTS dropped from 30 to 10 dB in the f1,f2 region, there was no TTS at 2f1−f2 (=1800 Hz, f2/f1 = 1.15) . For L1, L2 ⩽ 40 dB SL (re normal threshold) a marked decrease of CT level was found after inducement of TTS. Up to 40 dB SL suppression effects are small and TTS effects were not yet found (suppressor at f1, suppressee at 2f1−f2). For stimulus levels above 40 dB SL there was little or no effect on both CT-generation and two-tone suppression. The results show that the nonlinearity generating the CT is affected by reversible. presumably sensory-neural, changes and that it is not simply an aspect of basilar membrane mechanics.
The effects of high-frequency masking bands on midfrequency frequency discrimination
Authors: Stanton M. E. , Nelson D. A.
Published: October 2005

To evaluate the contribution of high-frequency hearing during frequency discrimination at lower frequencies, an adaptive 4-IFC pure-tone frequency discrimination task was performed by two highly practiced normal-hearing listeners at signal levels from 10 to 80 dB SPL, with and without high-frequency band-pass masking noises. The spectra of the high-frequency masking noises ranged from 1.8 to 2.1 kHz, from 2.8 to 3.1 kHz, and from 4 to 8 kHz. The DLF-intensity functions, describing DLFs as a function of sensation level, that were obtained in the presence of the high-frequency masking noises were essentially the same as the DLF-intensity functions obtained without masking noises. DLF-intensity functions obtained from one of the two listeners were in close agreement with the results reported by Wier et al. [J. Acoust. Soc. Am. 61, 178–184 (1977)]. The functions from the other listener were similar in form, but exhibited consistently larger DLFs at all sensation levels. No practice effects were found throughout the investigation. [This research supported by NIH research grant NS12125.]
Psychometric functions in pure-tone masking
Authors: Widin Gregory P. , Viemeister Neal F. , Wakefield Gregory H.
Published: October 2005

Psychometric functions were obtained for detection of a 20-ms, 1-kHz sinusoid, in the presence of forward or simultaneous pure-tone maskers. The psychometric functions are considerably steeper in simultaneous than forward masking. For example, the range of the psychometric function for on-frequency masking between the 60% and 90% correct points is 3–4 dB for simultaneous masking and about 10 dB for forward masking. The slope of the functions appears to vary little as masker frequency is changed, for constant probe frequency, in either simultaneous or forward masking. Thus, comparisons of selectivity in simultaneous and forward masking will not depend on performance level. The steep slope in the simultaneous-masking condition is consistent with earlier observations. [L. A. Jeffress, J. Acoust. Soc. Am. 58, 399–403 (1975); D. M. Green and J. Nachmias. J. Acoust. Soc. Am. Suppl. 1 65, S59(A) (1979)], and may reflect relatively high uncertainty regarding signal onset and duration for short signals. [Research supported by Sigma Xi, NINCDS, NICHD, NSF, and the Graduate School of the University of Minnesota.]
Frequency selectivity. A comparison of methods
Authors: Wier Craig C. , Norton Susan J.
Published: October 2005

Forward-masking and pulsation thresholds were measured using both method-of-adjustment and two-alternative, forced-choice psychophysical procedures. The forced-choice pulsation-threshold procedure was similar to that described by DuMond and Stern [J. Acoust. Soc. Am. Suppl 1 65, S58(A), (1979)]. Signals and maskers were digitized sinusoids. Two sets of stimulus conditions were tested: 250-ms masker and 20-ms probe, and 125-ms masker and 125-ms probe. These conditions approximate those often reported for forward-masked and pulsation thresholds, respectively. Data were plotted as psychophysical tuning curves for evaluation. Differences in frequency selectivity measured across stimulus conditions and psychophysical procedures are the result of a combination of factors, including stimulus-ensemble characteristics and decision criteria. These stimulus and procedure variables must be taken into account when comparing estimates from different laboratories. [Research supported by PHS Grant No. RR-07096 awarded to the University of Washington.]
Discrimination of time-varying signals
Authors: Collins M. J. , Stromberg H.
Published: October 2005

In general, modelling of the auditory system on the basis of long-term spectral characteristics of signals has proved adequate for prediction of monaural performance. There is evidence, however, that for time-varying signals, such as short duration tonal glides, detectability of signals with identical long-term spectra may differ due to other characteristics, e.g., direction and rate of frequency changes [Collins and Cullen, J. Acoust. Soc. Am. 63, 469–473 (1978)]. In the present study, difference limens were determined for signals with similar long-term spectra which were different in the time-frequency domain. The stimuli were signals composed of 30 ms tonal glides preceded or followed by 200 ms fixed frequency segments. Measurements were made about reference glide segments with 0-, 17-, or 34-Hz/ms linear rate of frequency change. Experienced, normal-hearing listeners served as subjects, and an adaptive procedure was used. Smaller difference limens were obtained when glide segments followed rather than preceded the fixed frequency segment. This finding cannot be easily explained by peripheral events alone. Rising glides tended to be more discriminable than falling glides when comparing signals with glide segments of equal rate and temporal position relative to the fixed frequency segment. The latter observation can be accounted for on the basis of phase differences between rising and falling, spectrally similar signals, and a model will be presented. [Work supported by NINCDS, Grant No. IF32 NS 06053.]
Temporal order biasin an AXB paradigm
Authors: Collins M. J.
Published: October 2005

Temporal order of presentation of stimuli in discrimination tasks has long been recognized as a possible source of error. The present study examined temporal-order errors in an AXB paradigm. Stimuli were signals composed of 30-ms-glide segments preceded or followed by a 200-ms fixed-frequency segment. Data were collected using a transformed up-down procedure both with and without interclaving of independent runs. Listeners had experience with psychoacoustic listening and were trained in the present task. Subjects were asked to determine whether the second signal (X) was more like the first or more like the second. Approximately equal numbers of all possible orders (AAB, BAA, ABB and BBA) occurred for each difference limen estimate for each subject. Averaging across stimulus condition, no significant differences were found due to order. However, a significant interaction was found between order and direction of frequency change of the glide segment. That is, when frequency increased during the glide segment, performance was best when the first two stimuli were the same (AAB and BBA); when frequency decreased during the glide segment, the percent correct was higher when the last two stimuli were the same (ABB and BAA). This was true independent of temporal position of the glide segment relative to the fixed frequency portion, rate of frequency change, and interleaving versus noninterleaving. [Work supported by NINCDS, Grant No. 1F32 NS 06053.]
The critical band and two-tone suppression
Authors: Soderquist D. R. , Wilkes M. R.
Published: October 2005

A forward masking paradigm [T. Houtgast, J. Acoust. Soc. Am. 51, 1885–1894 (1972)] was used to examine two-tone suppression as a function of four signal frequencies (500. 1000, 2000, and 4000 Hz). Data revealed (a) a measure of the critical band at each of the signal frequencies, (b) an effective region of suppression beyond the CB of the signal, and (c) the effects of suppression increased (in dB) and expanded (broader frequency range) as a function of the increase in signal frequency. In general, a suppressor tone will effectively increase signal detectability when the suppressor lies beyond the CB of the signal; a reduction of signal detectability occurs when the suppressor is within the CB.
Random response of identical, one-dimensional coupled subsystems
Authors: Smith P. W.
Published: October 2005

A precise statistical analysis has been carried out for the steady-state response of a general one-dimensional wave-bearing system formed of two identical subsystems coupled together at an end. The statistics correspond approximately to averaging in frequency. Cross correlation between the wave fields incident on the coupling from the two subsystems (neglected in most statistical analyses) strongly affects the magnitude of the coupling power and, for dissipative couplings, the dissipative power. Asymmetry of the wave field in each subsystem (also usually neglected) can have a significant additional effect even when the dissipative loss factor is small. These results from a scattering analysis are compared with prior results [T. D. Scharton and R. H. Lyon, J. Acoust. Soc. Am. 43, 1332–1343 (1968)] from a modal analysis of a particular system.
A statistical energy analysis of the vibration of piping structures
Authors: DeJong Richard G.
Published: October 2005

The vibration characteristics of piping structures were investigated using statistical energy analysis. Previous analytical expressions for the modal density and impedance of cylindrical shells [M. Heckl, J. Acoust. Soc. Am. 34, 1553-1557 (1962)] were expanded to obtain more accurate results in the frequency range below the ring frequency. The case of a pipe connected to a plate was considered, and an expression for the coupling loss factor between the two structures was developed for a wide frequency range extending from well below to well above the ring frequency of the pipe. Laboratory measurements were made on three pipe-plate structures having different geometric ratios. The results indicate the importance of the various order cylinder modes in the vibration characteristics of piping structures. [Work supported in part by DTNSRDC/Annapolis and EPA-ONAC.]
Equivalent circuit for radial vibrations of thick walled hollow cylinders
Authors: Wilder W. D.
Published: October 2005

The exact closed form distributed equivalent circuit and four-pole parameters are derived for radial vibrators of thick walled hollow cylinders. The formulation applies to cylinders which are either very short (free) or very long (clamped) in the axial direction, and to lostless or viscoelastic materials.
Dynamic response of fluid coupled coaxial cylinders to seismic excitation
Authors: Chu M. L.
Published: October 2005

This study deals with the overall dynamic behavior of concentric flexible cylinders coupled with fluid in the annular region, subjected to both sinusoidal and seismic excitations. Three different combinations of acrylic cylinders are used, i.e., one outside cylinder and three inside cylinders with different inside diameters. The cylinders have the same thickness and length, which when paired with the outer cylinder provide three annular gap sizes. To determine the sinusoidal response of the system the outside cylinder is point-excited and the natural frequencies and corresponding mode shapes are determined. For the seismic tests, the three coaxial setups are mounted on a rigid steel support frame. The support frame is suspended from the ceiling by flexible rods and excited by a hydraulic shaker with a simulated seismic input. Two distinct responses are observed, i.e., either in-phase or out-of-phase breathing modes between the inner and outer cylinders. The out-of-phase modes approach some limiting value as the gap size decreases, while the in-phase modes increase in frequency as the gap becomes smaller. Comparison between the inner and outer cylinder displacement responses from the seismic loadings shows the ratios of the averaged peak responses varies as a function of the gap between the inner and outer cylinder. Similar trends were observed on the spectral densities of the responses. It also appears that the gap size has a strong influence in the frequency response of the system.
Demisyllabic speech synthesis
Authors: Browman Catherine P.
Published: October 2005

In the November 1979 ASA Meeting, a general purpose set of programs for speech synthesis, called Lingua, was described. Lingua has been used to synthesize speech from demisyllables. In this paper the details of the rule synthesis from demisyllables are described, with particular emphasis on the duration rules. A model is used to adjust the duration of various portions of the demisyllables differentially. The resulting synthesis will be demonstrated.
Multi-language speech synthesis—A search for synthesis universals
Authors: Hertz Sue
Published: October 2005

In the past few months, Cornell's interactive speech synthesis system has been used to develop synthesis rules for a variety of languages (German, Spanish, and Indonesian). In each case, intelligible speech was produced after only a few weeks of work. This rapid development can be attributed to two factors. The first is the flexibility of the synthesis system itself, which allows users to easily test competing synthesis strategies. The second is the overlap between our English synthesis rules, which existed when the multi-language work began, and the rules in the other languages. This overlap suggests that some of these rules may be appropriate for many or even all languages. The use of the Cornell Speech Research System to develop rules for more languages should shed light on the following questions: (1) To what extent do the synthesis rule sets for different languages overlap? (2) How can this overlap be explained ? (3) What implications will these observations have for phonological theory? Will they help explain certain sound changes and other sound processes?
A new approach to connected digit recognition
Authors: Myers Cory S. , Rabiner Lawrence R.
Published: October 2005

A new approach to connected digit recognition is described. The recognition system is based on a novel dynamic time warping (DTW) algorithm which efficiently builds candidate strings from successive reference patterns of isolated words. The system operates over dialed-up telephone lines and can be used as either a speaker trained or as a speaker independent recognizer. The DTW algorithm is described and the effects on performance of several key parameters of the recognition system are discussed. An important aspect of this connected digit recognizer is the effect of the training procedure on the performance of the system. It will be shown that when isolated word reference templates are used, it is important to perform appropriate normalization of the length of the reference templates to achieve good performance scores. In formal evaluation tests, average digit accuracy of about 99% with average string accuracy of about 96% was obtained with 480 variable length strings (from six talkers) for both speaker trained and speaker independent templates.
Two processor continuous speech recognition system
Authors: Brown Peter F. , Spohrer James C. , Baker James K.
Published: October 2005

A research-oriented continuous speech recognition system based on separating the grammar level from the word level processing in order to exploit a two processor architecture has been developed by the Continuous Speech Recognition Group at Dialog Systems, Inc. A high speed array processor performs acoustic pattern matching and word level dynamic programming, while a general purpose mini-computer performs sentence level dynamic programming, overhead, and I/0 functions. Software components that allow graph generation, sentence level syntax generation, model training, and model evaluation will also be discussed in the framework of this parallel processor system.