bluuebunny/crossref_metadata_2025 huggingface dataset:
A perceptual-anchor interpretation of categorical phenomena on a vowel continuum
Authors: Goldberg Rina , Macmillan Neil A. , Braida Louis D.
Published: October 2005

The Perceptual Anchor Model of Context Coding [Braida et al., J. Acoust. Soc. Am. 76, 722–731 (1984)], developed for auditory intensity, considers resolutions to be determined by both sensory and memory processes, and postulates that tasks differ in the memorial coding they require. The theory was tested with steady-state synthetic vowels in the range /i/-/I/-/ɛ/. Resolution was measured in four discrimination conditions (two-interval forced-choice and same-different, fixed-, and roving-level), and in complete identification conditions with and without a standard. In identification and roving-level discrimination, resolution was poorer than in fixed-level discrimination, but not uniformly so: sensitivity differences among tasks were smallest near category boundaries. The data suggest that some categorical phenomena can be understood in terms of perceptual anchors. [Work supported by NSF.]
A shift in formant frequencies is not the same as a shift in the center of gravity of a multiformant energy concentration
Authors: Klatt Dennis H.
Published: October 2005

Chistovich et al. [Frontiers of Speech Communication Research, edited by B. Lindblom and S. Ohman (Academic, New York, 1979), pp. 143–158] observed that when two formants are within about three critical bands, the auditory percept is like that of a single equivalent formant, in that a change in relative formant amplitude has about the same perceptual effect as a change in formant frequencies (shifting the center of gravity of the collective energy concentration). Klatt [Proc. ICASSP (Paris, 1982), pp. 1278–1281], on the other hand, was unable to replicate these findings. A small change in formant amplitude did not produce any measurable change in phonetic quality of a vowel. This experiment attempts to reconcile these two results by examining the various differences in stimuli and experimental design in the two studies. It is concluded that large changes in the relative levels off F1 and F2 for [ɔ] can change the perceived phonetic quality of the vowel, but the change is not the same as that induced by moving the formant frequencies because opposing changes in these two variables do not tend to cancel one another in the percept. [Work supported in part by an NIH grant.]
Acoustic analyses and perceptual data on anticipatory labial coarticulation in adults and children
Authors: Sereno Joan A. , Baum Shari R. , Marean Grant C. , Lieberman Philip
Published: October 2005

The present study investigated anticipatory labial coarticulation in the speech of adults and children. CV syllables, [s], [t], and [d] before [i] and [u], were produced by an adult male speaker and a female child speaker age 3 years 6 months. Each syllable was computer-edited to include only the noise-excited portion of fricative-vowel stimuli and only the aperiodic portion of stop-vowel stimuli. LPC spectra were computed for each excised segment. Analyses of the effect of the following vowel on the spectral peak associated with the second formant frequency and on the characteristic spectral prominence for each consonant were performed. Perceptual data were obtained by presenting the aperiodic consonantal segments to subjects who were instructed to identify in a forced choice paradigm the following vowel [i] or [u]. Both the acoustic and perceptual data show strong coarticulatory effects for adults and the absence of such coarticulations in the speech stimuli of the child. The results are discussed in terms of the articulatory and perceptual aspects of coarticulation in language learning.
Optimum central processors for spectral-shape discrimination
Authors: Braida Louis D. , Ito Yoshiko , Reed Charlotte M. , Durlach Nathaniel I.
Published: October 2005

The sensitivities of optimum central processors for discriminating spectral-shape differences in fixed- and roving-level paradigms are derived. The processors are assumed to operate on the logarithms of band levels derived from internal filters, with each log-band level corrupted by independent Gaussian noise. When the receiver is unable to use a priori knowledge of the roving-level distribution, the sensitivity of a receiver which estimates overall level is the same as that which makes decisions based on level differences between adjacent bands. When a priori Knowledge of the roving-level distribution is available, sensitivity is increased provided the roving level is narrow compared to the aggregate band-level variance. These results are extended to the case of compound external degradations in spectral shape, such as random spectral tilt and curvature, and to the case in which adjacent bands are also corrupted by correlated noise. [Work suppported by NIH.]
Toward the specification of spectral content for consonant place perception
Authors: Ellison David E. , Dubno Judy R.
Published: October 2005

Recent results from this laboratory have reemphasized the importance of the perception of broad regions of spectral energy for consonant recognition by normal-hearing and hearing-impaired listeners. In order to establish the bandwidth that is essential for recognition of specific cues, the effect of spectral content on consonant place perception was examined. High-pass and low-pass filtered consonant-vowel (CV) syllables were presented to normal-hearing individuals and to young listeners with high-frequency sensorineural hearing loss secondary to noise exposure. Stimuli included nine synthetic syllables formed by pairing three voiced plosive consonants with three vowels, and three CVs spoken by a male talker. Stimuli were presented at five speech presentation levels ranging from 24–88 dB SPL. Performance as a function of cutoff frequency for each syllable suggests substantial differences in spectral regions contributing to the perception of the three consonants. In addition, the relative importance of certain spectral regions for consonant recognition is differentially affected by the accompanying vowel. Performance by the hearing-impaired listeners demonstrates the interactive effects of speech level, audiometric configuration, and consonant spectral shape. [Work supported by grants from NINCDS.]
Comparison of model and neural responses to speech
Authors: Payton Karen L.
Published: October 2005

This paper describes a computer simulation of vowel processing by the auditory periphery. Models of functionally separate parts of the periphery were modified and concatenated to form a composite model. The model accepts digitized temporal waveforms as inputs and calculates a population of neural rate functions. Subsequently, the model's average and synchronized rate responses are calculated. The model encompasses efforts by Guinan and Peake [MIT R-LE, QPR 84, 320–326 (1967)], Allen and Sondhi [J. Acoust. Soc. Am. 66, 123–132 (1979)], Allen [J. Acoust. Soc. Am. 68, 1660–1670 (1980)], and Smith and Brachman [Biol. Cybernet. 44, 107–120 (1982)]. Synthesized vowels were used as stimuli after an evaluation with pure tones. Results indicate that calculated neural responses, unlike simulated basilar membrane responses, are strongly synchronized only to formant peaks. The formant peaks are preserved in the population average rate data only at low stimulus levels and at onset, while a synchronized reponse represents formant peaks well at all stimulus levels tested. Results will be compared to neural population data [M. B. Sachs and E. D. Young, J. Acoust. Soc. Am. 68, 858–875 (1980)]. [Work supported by NSF.]
Loudness of complex signals presented by electrical stimulation of the auditory nerve
Authors: Kirby Virginia M. , Widin Gregory P. , Soli Sigfrid D.
Published: October 2005

An understanding of the factors affecting the loudness of complex electrical stimulation is necessary if improved speech processing schemes are to be developed for cochlear implants. This experiment used a variety of complex signal types to examine the relationship between perception of loudness and physical characteristics of electrical stimulation. Loudness was studied for a set of 19 stimuli differing in bandwidth, center frequency, peak factor, spectral shape, and tonality. Four cochlear implant subjects and two normal-hearing subjects made equal-loudness judgments for the stimuli using the method of adjustment. A 200-Hz tone at a comfortable listening level served as the reference. Equated stimuli delivered to the electrode were analyzed for amplitude and frequency characteristics. The relationship of these statistics to perceived loudness will be discussed.
Speech recognition in single- and multichannel cochlear implants
Authors: Ochs Marleen T. , White Mark S. , Merzenich Michael M. , Schubert Earl D.
Published: October 2005

Two speech processing systems, a four-channel vocoder-based model and a single-channel model, were examined in a single patient. Five isolated, computer-generated vowels were presented in a closed-set paradigm and responses were plotted on a confusion matrix. With four-channel stimulation the overall score was 64% correct. The subject never confused vowels having a low-frequency second formant (F2) with high-frequency F2 items. In the single-channel configuration, the subject did not distinguish between low F2 and high F2 items and scored 29% overall. Consonant confusion matrices were generated for seven naturally produced VCV syllables. In the four-channel configuration the overall score was 70% correct. The nasal distinction was not made and some voicing errors were observed. In the single-channel case, the subject scored 27% correct. The stop-continuant distinction was not routinely made and most errors involved multiple distinctive features. Analysis of the processed speech items explain some of the confusions observed in the four-channel mode. [Work supported by NIH Grant NS-11804.]
Auditory temporal acuity following noise exposure
Authors: Champlin Craig A. , Feth Lawrence L.
Published: October 2005

It has been previously reported that postexposure psychophysical tuning curves were generally broader than preexposure curves. Additionally, the broadened tuning curves persisted for a longer period of time than would be predicted from TTS recovery functions [L. L. Feth, E. C. Oesterle, and G. Kidd, Jr., J. Acoust. SOC. Am. Suppl. I 65, S118 (1979)]. The present investigation focused on temporary changes in psychophysical gap discrimination threshold following exposure to a moderately intense noise for a brief period of time. Octave-band noise markers were used to delineate the gap. Off-frequency spectral cues were reduced with the application of a simultaneous broadband notched noise. Gap discrimination thresholds will be reported as a function of noise marker center-frequency and postexposure recovery time. The implications of using this measure of auditory temporal acuity to evaluate the deleterious effects of noise on hearing will be discussed. [Work supported by Sigma Xi.]
Effects of noise exposure on forward masking
Authors: Feth Lawrence L. , Mott John B. , Hengstenberg Lora L.
Published: October 2005

The forward-masking paradigm is used extensively in the determination of psychophysical tuning curves (PTC). PTCs are, in turn, used as indicators of auditory frequency selectivity. Our previous work on post-noise exposure determinations of frequency selectivity using PTCs indicate that there may be temporary, frequency-dependent changes in forward masking effects just after exposure to noise. The current study was designed to determine the nature of post-noise exposure effects on the time course of forward masking as well as the forward masking function. Forward masking functions were obtained 2, 4, 8, and 16 min after listeners were exposed to an octave band of noise (1200–2400 Hz) at 100 dB SPL for 5 min. For control conditions, the 5-min exposure was reduced in level to 40 dB. Masker and probe signals were tones of 300- and 20-ms duration, respectively. Their frequency was 3000 Hz. Delta t, measured from masker offset to probe onset, varied from 10–100 ms. Results indicate that some of the variability observed in post-noise PTCs may be related to changes in forward masking effects. [Work supported by funds from the University of Kansas General Research Fund.]
Forward masking recovery functions in auditory nerve fibers after noise exposure
Authors: Shivapuja Bhagyalakshmi G. , Salvi Richard J. , Saunders Sam S. , Ahroon William A.
Published: October 2005

This research was prompted by psychophysical studies showing that the time constant for forward masking can be prolonged in listeners with sensorineural hearing loss [e.g., Cudahy, E., J. Acoust. Soc. Am. Suppl. 62, S59 (1976)]. The psychophysical results suggest that neural recovery might be prolonged at some stage within the auditory pathway, perhaps at the auditory nerve. In order to explore this issue, recordings were made from auditory nerve fibers in noise-exposed chinchillas. Neural recovery functions were obtained by measuring a unit's responsiveness to a brief, low-level probe tone which was preceded in time (2–200 ms) by an adaptor tone whose level was varied. The recovery functions from units in the noise-exposed animals were generally similar to those in normal animals for adaptor tones 10–30 dB above threshold; however, some differences were noted at higher levels. These results will be compared to previous psychophysical and physiological results. [Work supported by NTH, NIOSH.]
Temporal factors may affect the binaural directionality of hearing in the mustache bat
Authors: Makous James C. , O'Neill William E.
Published: October 2005

The directional sensitivity of two Pteronotus parnellii bats to the first, second, and third harmonics of their echolocating signal was measured binaurally, under free field conditions, by recording the summated neural response at the lateral lemniscus. A speaker was mounted on a perimeter that could be rotated to form a hemisphere in front of the bat. Speaker angles were selected randomly, contralateral to the recording site, 50 cm from the bat's head. The area of greatest sensitivity to the first harmonic was 40- to 60-deg azimuth and −20 to −40 deg elevation. The response to the second harmonic was more medial ranging from 10- to 30-deg azimuth and 0 to −10 deg elevation. Most medial was the response to the third harmonic frequency that ranged from 0- to 15-deg azimuth and 0 to −10 deg elevation. The areas of greatest sensitivity (2 dB above threshold) to the first and third harmonics were more medial than areas where intensity differences at opposite ears afford the most precise localization [Z. M. Fuzessery and G. D. Pollak, Science 225, 725–728 (1984)]. This suggests that time disparities may be more important for sound localization in bats than was thought. [Research was supported by NSF grant BNS-8311627.]
Azimuthal representation within a population of interaural intensity-sensitive neurons
Authors: Fuzessery Z. M. , Wenstrup J. J. , Ross L. S. , Pollak G. D.
Published: October 2005

One-third of the central nucleus of the inferior colliculus (ICC) in the mustache bat is devoted to processing information at 60 kHz, a dominant component of the echolocation pulse. Within this 60-kHz region, E-I type neurons sensitive to interaural intensity disparities (IIDs) are grouped together. Their IID sensitivity changes in orderly fashion along the vertical axis of the ICC. Dorsal-most neurons require the highest relative inhibitory intensity to suppress activity, the most ventral require the lowest. Regardless of their IID sensitivity, all neurons had lowest excitatory thresholds for the same azimuthal sound location. IID sensitivity did, however, influence their overall responsiveness to azimuthal locations across the frontal sound field. E-I neurons with the highest inhibitory thresholds responded to sounds throughout the frontal field. As inhibitory thresholds dropped, their medial receptive field borders shifted systematically across the azimuth toward the area of lowest excitatory thresholds. The percentage of excited neurons within this population will therefore shift systematically along the vertical axis of the ICC as a function of azimuthal location. [Work supported by NIH, NSF.]
Integration of acoustical cues for auditory localization in a room
Authors: Rakerd Brad , Hartmann W. M.
Published: October 2005

We investigated room-reflection effects on auditory localization by conducting experiments in a room bounded by a single, manipulable, sound-reflecting surface. Across experimental conditions this surface alternatively served as a wall, floor, or ceiling. Previously we have reported that the azimuthal localization of slow-onset tones of low frequency (500 Hz) is extremely poor for most configurations of the room, and that the azimuthal localization of impulsive tones is adversely affected by reflections from side walls [B. Rakerd and W. M. Hartmann, J. Acoust. Soc. Am. Suppl. I 75, S88 (1984)]. In the present study we compare those perceptual data to physical measurements of the interaural-time-difference (ITD) and interaural-intensity-difference (IID) cues available to listeners in each room condition. In a room there can be very large values of IID, even at low frequencies, and we find that these significantly influence localization decisions. Results for both the slow-onset and impulsive tones suggest the hypothesis that listeners weight ITD cues according to their plausibility. Plausibility is established with reference to both 90-deg azimuth and the angle of sources as observed visuality. [Work supported by NIH and NIMH.]
Auditory depth perception of hearing impaired subjects
Authors: Gatehouse R. W.
Published: October 2005

At the 106th ASA, meeting (San Diego, 1983) Gatehouse presented data from a new auditory depth perception paradigm [J. Acoust. Soc. Am. Suppl. 1 74, S38 (1983)]. Depth estimation was done by aligning a moveable sagittal plane “comparison” with an alternately sounding static “standard” source. Now monaural subjects of different loss types (conductive; SN) and levels (minimal to moderate) did the task. The standard (1.0 kHz) was placed 3 m from Ss, and the comparison (either 0.5 or 2.0 kHz) at initial positions of “0” (same as standard), ±91 and ±183 cm. Mean errors (average difference between “true” and average estimated standard position) and ratio (average estimated standard/“true” distance from the different initial positions) were ANOVA analyzed. The results indicate monaurals judge depth as well, and overestimate standard depth to initially close sources, while underestimating it from positions beyond “0” as normals did (1983). Again, comparison stimulus initial position is the most salient variable and frequency was not significant in estimating depth. But, frequency and initial position do interact. Normals seem to judge depth better with a high frequency comparison, while monaurals did the reverse. There were no effects of loss level or types on accuracy. The results will be compared to depth perception of bilaterally deaf subjects as well. [Work supported by MRC, Canada.]
Word-final devoicing in German and the effects of phonetic and sentential contexts
Authors: Charles-Luce Jan
Published: October 2005

The present study investigated the possible effects that place of articulation of the final stop, the phonetic environment of the target word, and sentential position might have on vowel duration, voicing into closure, and closure duration as acoustic correlates of underlying voicing. The results of the study replicate the findings that word-final devoicing is non-neutralizing in German. However, the results also show that the temporal correlates of underlying voicing are different for dental and velar stops and are different for lexical items. Moreover, for the dental stops, vowel duration, and voicing into closure as correlates of underlying voicing are not independent of phonetic or sentential contexts. The overall results suggest that the phonetic rules necessary to implement word-final stops in German must be sensitive to place of articulation, surrounding phonetic and sentential contexts, and even individual lexical items. [Supported by NIH Training Grant T32 NS-7134.]
Spectral properties of voiced stops
Authors: Amastae Jon , Houlihan Kathleen
Published: October 2005

In an attempt to provide a reliable instrumental verification of auditory categorization of voiced stops and fricatives in natural speech (Spanish), we have been led to reconsider acoustic characterstics of voiced stops. It has been claimed [M. Halle, G. W. Hughes, and J.-P. A. Radley, J. Acoust. Spoc. Am. 29, 107–116 (1957); G. Fant, Speech Sounds and Features, MIT, Cambridge, MA (1973)] that during the period of closure voiced stops contain little or no energy beyond the first spectral peak. Over 140 voiced stops from one Spanish and three English speakers were subjected to a computer-implemented pitch-synchronous FFT spectral analysis. Spectra of the midpoint pitch period and mean spectra of several pitch periods during closure in initial, post-nasal, and intervocalic stops were analyzed. Results showed that many stops had considerable energy beyond the first spectral peak, with intensity peaks occurring between 300–3500 Hz, approximately 20–30 dB down from the first peak. No claims about the influence of this energy on perception are made, but we do suggest the possibility of an acoustic voiced stop-voiced fricative continuum, characterized by location and type of energy beyond the first spectral peak.
The ineffectiveness of larynx movement
Authors: Kingston John
Published: October 2005

Vertical movement of the larynx has been held responsible for two effects in speech production: a noticeable change in intraoral air pressure (P0) as a result of contraction or expansion of the oral cavity and perturbation of the fundamental frequency (F0) of neighboring vowels as a result of changes in the vertical tension of the vocal folds. Raising the larynx is supposed to elevate both P0 and F0, while lowering the larynx is supposed to reduce both parameters. Simultaneous measurements of larynx movement and P0 during the production of voiced and voiceless stops and ejectives by three speakers of Tigrinya showed that the larynx moves much too slowly to have any significant effect on P0. Computer simulation of the stops of this language confirmed this result. Larynx movement also could not be responsible for the perturbation of F0 in vowels following stops in Tigrinya since F0 was either not elevated or even depressed after stops which are produced with larynx raising, the voiceless stops, and ejectives. F0 was only weakly positively correlated with larynx height after voiced stops—both low, uncorrelated after voiceless ones, and negatively correlated after ejectives—F0 low and the larynx high. These results Suggest that movement of the larynx during a stop is at best a passive response to other, probably oral, articulations and that the tension of the vocal folds is not directly perturbed by changes in larynx height either.
Acoustic properties of the subglottal system us determined from recordings of subglottal pressure
Authors: Boves Louis , Cranen Bert
Published: October 2005

A complete model of the speech production system should include a model of the subglottal part. For the construction of such a model measurement data are needed. The most extensive and comprehensive data available today are the input impedance measurements on five laryngectomized Japanese subjects made by Ishizaka et al. [J. Acoust. Soc. Am. 60, 190–197 (1976)]. We have made wideband recordings of the subglottal pressure variations during speech production in five normal adult Dutch males. It appears that the resonances of the subglottal system are excited by the glottal source in much the same way as the supraglottal resonances. Thus, it seems feasible to determine the frequencies and bandwidths of the subglottal resonances from the subglottal pressure signals. Using this procedure we have consistently found a frequency of the lowest resonance which is considerably lower than the one measured by Ishizaka et al. We will discuss a number of possible explanations for the different measurement results and their implications for improving the model of the subglottal system. [Work supported by the Dutch Organization for the Advancement of Pure Research ZWO.]
Brain electrical activity mapping in adductor spasmodic dysphonia
Authors: Cannito Michael P. , Finitzo Terese , Freeman Frances J. , Pool Kenneth D.
Published: October 2005

Brain electrical activity mapping (BEAM) was employed to study ten patients exhibiting adductor spasmodic dysphonia. BEAM is a recent neural imaging technique which utilizes digital signal processing and color graphics capabilities to generate mappings of the scalp distribution of ongoing cortical EEG activity, as well as cortical evoked response amplitudes to sensory stimulation. The technique provides data for EEG eyes open, EEG eyes closed, and auditory, visual and somatosensory evoked potentials. Patient responses were compared with normative data previously established for the BEAM technique, and significance probability mappings of patient-to-normal deviations generated. Results suggest diverse neurophysiologic abnormalities among the spasmodic dysphonic patients. Specific findings varied from patient to patient but included abnormal EEG activity and abnormal evoked responses in a significant proportion of patients tested. Regions of frequent “lesion” overlap were also present. Relationships of BEAM findings with those of other neural imaging techniques, and the possible significance of these findings for neurobiological interpretations of spasmodic dysphonia will be discussed. [Work supported by a grant from NINCDS.]
Disordered laryngeal control: Fiberoptic studies of spasmodic dysphonia
Authors: Freeman Frances J. , Cannito Michael , Finitzo Terese , Schaefer Stephen
Published: October 2005

Twenty-four patients with spasmodic dysphonia (SD) were studied using the Wolf fiberoptic endoscope (with strobe). Laryngeal videotapes were analyzed by the authors, and abnormal movement patterns identified and categorized. A composite videotape demonstrating the abnormal laryngeal movement patterns characteristic of these patients was produced, and will be presented. In patients with milder “spasms” stroboscopy was possible, and abnormal vibratory patterns are presented. Patients' abilities to consciously inhibit or suppress abnormal laryngeal movements are demonstrated. These results, when combined with the authors acoustic and BEAM studies (submitted as separate papers for this meeting), suggest that SD is a “continuum disorder,” as originally suggested by Cannito and Johnson [J. Commun. Disord. 14, 215–233 (1981)]. Dramatically differing perceptual and acoustic vocal patterns may result from different reflexive and/or conscious compensations occurring or adopted in response to a common underlying movement disorder. [Work supported by a grant from NINCDS.]
Electroacoustic means of controlling auditorium acoustics
Authors: Krokstad Asbjørn
Published: October 2005

The two methods of reverberation enhancement; assisted resonance (AR), a frequency divided system, and multiple channel reverberation (MCR), a space-divided system, are previously discussed mostly as methods of increasing reverberation time. The influence on sound intensity level, on sound distribution, and on impulse responses may be of great importance and will be discussed on the basis of accepted room acoustic criteria.
Internal tuning and external harmony of carillon bells
Authors: Houtsma A. J. M. , Tholen H. J. M. G.
Published: October 2005

Bells produce sound spectra with frequencies that are not necessarily harmonically related. In good carillon bells, however, several of the lower partials are tuned to a typical pattern given by the frequency ratios 0.5 (hum), 1.0 (prime), 1.2 (third), 1.5 (fifth), and 2.0 (octave). The fact that the third is minor might explain why most carillon music is written in a minor key, because the internal tuning of the bells agrees with the minor triads of tonic, dominant, and subdominant in such keys. It has been proposed in the past that for music in major keys it might be preferable to tune the third to a major third (1.25) or, maybe, to a neutral third (1.225) to allow music in both types of keys. Apart from the question whether or not such a tuning is physically possible, a psychophysical experiment was performed with two short harmonized melodies, one in D-minor and an equivalent transcription in D-major, played on three different computer-generated carillons. Each bell of these carillons was a pulse code-modulated recording of a real carillon bell, from which the third partial had been electronically removed and replaced by a partial of similar temporal structure and appropriate frequency (1.2, 1.225, and 1.25, respectively). Many subjects, uninformed about the sounds they heard, were asked to select the best-sounding melody in each of the 15 pairs that can be formed from the six melody versions. Rating scales produced by various groups of subjects will be discussed.
Consonance judgments of chords derived from the Pierce 3579b scale
Authors: Roberts Linda A. , Reeves Alyson , Mathews M. V. , Pierce J. R.
Published: October 2005

The Pierce 3579b scale is based on a chromatic scale having 13 equal steps in its octave (3:1 frequency ratio). In addition to the 3:5:7 and 5:7:9 chords which provide the harmonic basis of the scale, one can form other chords from notes of the chromatic scale. Listeners rated the degree of consonance of the 78 triads which can be formed from an octave range of the scale. Both musicians and untrained listeners perceived that chords were maximally dissonant when one or more of their components were within a critical bandwidth but there was some disagreement as to which chords were most consonant. We assess these results in view of two models of consonance. The same listeners made consonance judgments for a short musical composition derived from this scale, presented in different tunings (equal temperament, just intonation, or “out-of-tune”). All subjects agreed that the equal tempered version was most consonant but the ordering of the other tunings depended on musical training and on previous exposure to these nontraditional sounds.
Influence of spectral prominence on perceived vowel height
Authors: Hawkins S. , Beddor P. S.
Published: October 2005

Earlier experiments on the perception of vowel height comparing oral with nasal vowels, and one- with two-formant vowels, indicated (1) center of gravity (measured in terms of a simple weighted average of spectral components in the F1-F2 region) does not closely predict perceived vowel height and (2) F1 influences the perceived height of oral vowels more than that of nasal vowels. This experiment examined the influence of the relative prominence of formant peaks on perceived height. Two-formant vowels, /a/ and /o/, were synthesized with steady F0 and equal formant amplitudes. Each had narrow (45 Hz), medium (70–75 Hz), and wide (120–150 Hz) bandwidth versions. Continua were made from the medium-bandwidth vowels by systematically manipulating formant frequencies and amplitudes. For both /a/ and /o/, the medium-bandwidth vowels were paired with (a) the narrow-bandwidth vowel and (b) the wide-bandwidth vowel. Subjects selected the “best-match” pair for each set. Narrow-bandwidths had no effect on perceived height, i.e., subjects matched the narrow-bandwidth vowel with the medium-bandwidth vowel of the same formant frequencies. Wide bandwidths (characteristic of nasal vowels) affected perceived height: “medium-wide” matches were relatively variable and were biased away from pairs with the same formant frequencies. The direction of these biases will be discussed in terms of nasal vowel perception. [Supported by NIH grants NS-07237 and F32-NS-07196.]
Effects of contextual and noncontextual nasalization on perceived vowel height
Authors: Krakow Rena A. , Beddor Patrice S. , Goldstein Louis M. , Fowler Carol A.
Published: October 2005

Listeners' ability to separate the spectral effects of nasal coupling from those of tongue position was examined by comparing labeling responses to three continua: oral /bɛd-bæd/; contextually-nasalized /bɛ̃nd-bæ̃nd/; and noncontextually nasalized /bɛ̃d-bæ̃d/. The continua were generated by articulatory synthesis and were identical to one another in tongue position. Results showed the same percent /ɛ/ responses to the oral and contextually nasalized vowels, but significantly fewer /ɛ/ responses to the noncontextually nasalized vowels. That is, the noncontextually nasalized vowels were perceived as lower than the oral and contextually nasalized vowels. Perceptual lowering of the nasalized vowels relative to the oral vowels is consistent with upward shifts in F1 due to nasal coupling. However, the absence of a lowering effect in the contextual nasal condition needs to be explained. We propose that subjects' vowel judgments are influenced by spectral effects of nasal coupling when no conditioning environment is present. When a nasal consonant is present, these spectral effects are perceptually analyzed as due to the consonant and do not influence vowel height judgments. [Work supported by NIH grants HD-01994 and F32-NS-07196, NSF grant BNS-81-11470.]
Perceptual correlates of the tense/lax distinction in general American English
Authors: Huang C. B.
Published: October 2005

Data from perceptual tests in which subjects were asked to identify tense and lax vowels are used to suggest correlates for the tense/lax distinction in general American English. Four vowel parameters were manipulated in synthetic nonsense words of the form [dVs]: formant frequency, duration, breathiness, and first-formant bandwidth. The tense/lax pairs included [ɪ], [æɛ], [uᴜ], and [ɑʌ]. Three separate identification tests are created in which the stimuli vary only in formant frequency and one of the other three parameters. Each test was presented to five naive native speakers of general American English. Results so far indicate that shortening the vowel shifts judgments toward the lax vowel, and that this effect is greater in the low vowel pairs than in the high vowel pairs. Increased breathiness shifts judgments toward the tense vowel for high vowels. The effect of breathiness on low vowels and the effect of bandwidth of the first formant on all vowels is as yet unclear. [Supported in part by NINCDS and a NSF Fellowship.]
Reduction of formant bandwidth improves vowel identification with sensorineural impairment
Authors: Jamieson Donald G. , Ponton Curtis W. , Espinoza-Varas Blas
Published: October 2005

Accurate identification of front-back vowels depends on the ability to locate the peak of F2. Since hearing impairment reduces frequency resolution, sensorineural hearing impaired listeners often have difficulty with certain vowel distinctions. Espinoza-Varas, Jamieson, and Wahn [J. Acoust. Soc. Am. Suppl. 1 76, S80 (1984)] showed that (a) for normal listeners, equal changes in F2 frequency in critical-band units produce equal changes in the judged “goodness” of vowels on front-back vowel continua, cued by changes in F2; and (b) sensorineural impaired listeners are less sensitive to these F2 changes and less accurate in their identification of vowels. The present paper continues this work, examining whether vowel sounds can be altered to reduce masking between adjacent spectral frequencies, while preserving vowel quality. Following Assmann [J. Acoust. Soc. Am. Suppl. 1 76, S81 (1984)] we examined identification for synthesized vowels with normal versus narrow formant bandwidths. We also examined vowel identification performance for natural vowels which had been filtered to reduce formant bandwidths, while preserving the locations of the spectral peaks. Some hearing impaired listeners show significantly improved performance with these vowel sounds (for example, categorization functions for the synthesized vowel continuum /u/-/i/ become steeper). No listener showed poorer performance with the processed sounds. We conclude that (a) masking between adjacent spectral frequencies may cause hearing impaired listeners to make errors in vowel identification and (b) this masking can be reduced by processing speech signals to reduce formant bandwidth. [Work supported by grants from the AHFMR, HWCRDP, and NSERC.]
A theory toward discontinuous perception of speech
Authors: Koike Kazunari J. M.
Published: October 2005

An experiment by Guberina (1963) was replicated for perceptual and acoustical analyses. The vowel /i/ spoken by a female voice and recorded on a tape was presented via a loudspeaker to normal hearing listeners through the following conditions: (1) no filter; (2) the band with cutoff frequencies of 200–400 Hz at most confortable level (MCL); (3) the band with cutoff frequencies of 2400–4800 Hz at MCL; and (4) two bands just below threshold of intelligibility simultaneously. The results were summarized as follows: (1) the vowel /i/ was perceived in no filter condition; (2) the vowel /u/ was perceived through the 200–400 Hz. Only the first formant was observed; (3) the vowel /i/ was perceived through the 2400–4800 Hz. Only the second and third formants were observed; and (4) when the two discrete bands were combined, the vowel /i/ was perceived. Only the first formant was observable. It was speculated that the suprathreshold low frequency speech energy enhanced the perception of the sub-threshold high frequency speech energy and as a result the vowel /i/ was perceived. A theory toward discontinuous perception of speech will be discussed especially as it is applied to the rehabilitation of hearing-impaired listeners.
Music and meaning
Authors: Cohen Annabel J. , Trehub Sandra E. , Guerriero Lena , Marshall Sandra K.
Published: October 2005

College students and preschool children rated dichotomous tone sequences varying in intensity and range on the bipolar adjective scale of sadness/happiness. Both groups assigned the modal response of happy to the high/fast stimulus and the modal response of sad to the low/slow stimulus. In another study, differences in the meaning of two contrasting selections by Prokofieff were indicated by ratings of college students on 12 bipolar adjective scales. The selections, when used as soundtracks for a short animation, led to different bipolar adjective ratings of elements in the film. In a final study, original contrasting soundtracks differing in meaning, as indicated by student ratings, also led to a significant difference in the meaning assigned to the film. Overall these results imply that musical relations give rise to meaning in systematic ways and that such meaning may be acquired as early as the preschool age. Since music can influence the interpretation of nonmusical events, it is suggested that musical meaning is presented in a general semantic system where disjunctive entities at various levels of abstraction from different modalities may conjoin to form new concepts.
Pressure wave reflections in a barred organ windchest
Authors: Finch T. L. , Nolle A. W.
Published: October 2005

The effects of windchest design on the pressure rise and hence on the starting transient of organ pipe speech have been investigated by Caddy and Pollard [Acustica 7, 277 (1957)] and by Lottermoser [Z. Angew. Phys. 20, 424 (1966)]. Their results were described by equivalent circuits with lumped constants. We show measurements of windchest pressure, pipe sound output, and wind velocity into the pipe foot as functions of time, using a 1.5-m-long note channel of a barred windchest with a hand-operated pallet valve. The results indicate that a long channel must be considered as an acoustic transmission line. For a rapid opening of the pallet, the pressure signal advancing along the channel consists of (a) a negative pulse due to the pallet displacement, followed by (b) a rising pressure step of height ps, the supply pressure. When the pulse is reflected from the rigid far end of the channel, a pressure pedestal of height approaching 2ps, and duration 2(length)/c is observed there. At other positions, the initial pressure rise is followed by a delayed further rise due to the returning reflection. [TLF is visiting Scholar, The University of Texas at Austin, 1984–1995.]
Piano strings and low-mass hammers
Authors: Hall Donald E.
Published: October 2005

Consider a string of length L and mass M struck at a distance b from one end by a hammer of mass m. In the limit where m<M, the hammer rebounds from the string just after the arrival of the first reflected wave at t = 2b/c. It regains 1/e2 = 13.5% of its original energy. The envelope of the string spectrum is given not by sin2 nb/L but by (1 + 1/e)2 sin2 nb/L−(4/e) sin4 nb/L, and the strongest harmonics are those with sin2 nb/L = 0.64 rather than 1.0. In a better approximation, the two impulses delivered to the string are not instantaneous but have durations of order mL/2Mc, so that the spectrum drops off rapidly above f = Mc/mL. The range of parameters b/L and m/M for which a complete solution may be calculated with a single reflection will be discussed.
Computer strings for musical performance
Authors: Pinkston Russell F.
Published: October 2005

Most computer models of acoustic instruments have been designed for exact timbral approximation, rather than applicability to real performance situations. However, the subtle nuances that good players instinctively provide in the dommains of pitch, timbre, rhythm, and dynamics are absolutely essential to “musical” performances. A recording of portions of an original string trio will be played, as performed by an IBM 370 series computer, using a set of rules for “espressivo” playing and a synthesis algorithm designed for precise control of multiple performance variables.
Further investigations on sound absorption in water fog
Authors: Wei Rong Jue , Tian Yuren , Lu Qiujiang
Published: October 2005

Following a previous review [J. Acoust. Soc. Am. 70, 1213–1219 (1981)], this paper presents some interesting findings on the sound absorption of fog composed of water droplets down to submicron size and on the influence of fog kinetics. Theory [J. Sound Vib. 43, 467 (1975)] has claimed an attenuation increase due to mass transfer to be several orders of magnitude larger than that for micron-sized particles. This is accompanied by a corresponding frequency shift towards higher frequencies that obeys theory. The relaxation times thus introduced are not justified numerically for liquid water droplets; a correction factor is also proposed from the viewpoint of modern fog kinetics. The result predicts a counter effect or a drastic decrease in the absorption abnormality due to submicron droplets, but the effect is less the larger the droplets. This may lead to a theoretical generalization of the problem applicable to droplets of all sizes. Reverberation chamber experiments with laser monitoring show qualitative agreement with the existing theories but deviation from Knudsen's classical data. The complicated nature of the problem is summarized.
Instrumentation for the detection of atmospheric infrasound in the frequency range 0.25 to 20 Hz
Authors: Bedard A. J. , Simms S. , Ramzy C. , Gregg D.
Published: October 2005

We describe techniques for the study of infrasound from 0.25 to 20 Hz. These include a wind noise reducing device covering a diameter of 20 ft with a microphone at the center. We have applied methods of test calibration in this frequency range consisting of portable devices, a pistonphone, pressure step function generator, and Helmholtz resonator. A spectrum analyzer/facsimile recorder combination allows us to produce continuous sonograph type displays for any microphone. A six-microphone test array located around a 300-m meteorological tower permits studies of the infrasonic pressure levels in a well-defined atmospheric boundary layer. Data are normally recorded digitally with the meteorological parameters permitting flexible options for cross-correlation analyses. We will describe in more detail each of the detection elements outlined above.
Infrasonic observation of the Coalinga and Bishop earthquakes
Authors: Mutschlecner J. P. , Whitaker R. W. , Bunker S. S. , Painter C. A.
Published: October 2005

Low-frequency acoustic observations of the Coalinga (2 May 1983) and the Bishop, California (23 November 1984) earthquakes were made with infrasonic arrays in St. George, Utah, and Los Alamos, New Mexico. Each array consists of four microphones operating in the 0.1- to 10-Hz band. Array data analysis by a correlation beam-forming algorithm provides direction, trace velocity, and spectrum of the signal. We believe the Coalinga detection to be the most distant detection in the short period infrasound region. The signal durations were approximately 20 min for Coalinga and 13 min for Bishop. Both sets of power spectra vary during the signal train and exhibit power concentrated in the 0.2- to 0.6-Hz band. The travel time of the principal signal, for each detection, suggests direct acoustic transmission from the epicenter. However, in the Coalinga detection, and possibly the Bishop detection, other signal features are consistent with possible secondary sources such as seismic surface waves interacting with major geographic features.
The measurement and statistical analysis of atmospheric turbulence
Authors: Johnson Mark A. , Raspet Richard
Published: October 2005

Measurements of atmospheric turbulence under various weather conditions were taken at heights ranging from 1 to 33 m. The strength and scale of wind and temperature fluctuations were determined. The results are examined to see what simplifications can be made that will yield a statistical model that can be utilized in applications involving acoustic wave propagation. This work is an extension of Daigle et al. [J. Acoust. Soc. Am. 64, 622–630 (1978)] to higher altitudes.
Amino acids and proteins of tectorial membrane (TM)
Authors: Thalmann Isolde , Comegys Thomas H. , Thalmann Ruediger
Published: October 2005

The primary function of the TM is apparently mechanical; nevertheless, certain alterations in its chemical environment exert profound effects upon the shape of the TM, most likely through conformational changes in its fibrous proteins. Thus, elucidation of the chemical nature of the TM is of considerable functional importance. Using two-dimensional polyacrylamide gel electrophoresis, we have found that the three prominent, high molecular weight proteins (135–155 kDalton) demonstrated by a one-dimensional technique in the mouse TM [K.P. Steel, Acta Otolaryngol. 89, 27–32 (1980)], are also present in the guinea pig TM. We further found that these three proteins are highly alkaline (pI 8.4–8.6). The free amino acid profile of the TM is remarkably similar to that of endolymph, which supports the concept that the TM is chemically “transparent.” Our data on the amino acid composition of the proteins of the TM, as reflected by analysis of hydrolysates, are in part at variance with earlier studies [S. Iurato, Z. Zellforsch. 52, 105–128 (1960)]; most notably, we found glycine to be significantly higher and hydroxyproline to be present. The potential functional significance of these findings will be discussed. [Work supported by NIH and NSF.]
Analysis of the stationarity of models of auditory-nerve fiber discharge patterns
Authors: Johnson Don H. , Kumar Anand
Published: October 2005

The spontaneous activity and the responses to single, high-frequency tones of single auditory-nerve fibers are often described as a stationary point processes. Using a doubly stochastic Poisson process model as the analysis framework, it is shown that the instantaneous rate of discharge varies more than is consistent with a stationary model. Variability indices (which equal unity for a stationary Poisson process model) were found to be no smaller than 1.5 and at least as large as 6.9 for the data analyzed. Assuming this variability to be due to the presence of a noise process modulating the instantaneous rate, the spectra of the noise processes were measured. These spectra were low pass, having upper frequencies no greater than about 0.1 Hz. Some spectra may contain spectral lines, indicating the presence of nearly periodic components. The presumed noise process, whether containing periodic components or not, could not be readily related to ambient acoustic noise. [Work supported by NINCDS.]