bluuebunny/crossref_metadata_2025 huggingface dataset:
The vocal instrument viewed from a materials science point of view
Authors: Titze Ingo R.
Published: October 2005

The quality of musical instruments is determined by their shape and material properties. Strings, membranes, plates, bars, and tubes have predictable and dependable elastic moduli and resonant Q's and their geometry is stable. The human larynx, on the other hand, is made of materials that vary considerably with time, frequency, temperature, and biochemical composition. A stress applied along the length of the vocalis muscle by step elongation relaxes to 90% of its original value in about a second and continues to relax for several hours. Hooke's law is not obeyed, the stress-strain curves of vocal fold tissue being quite nonlinear. The damping ratio of the vocal fold tissue averages around 0.2, but may decrease under edematous conditions and increase under infectious conditions. Geometrically, the larynx sometimes displays left-right asymmetries. Given these variable properties, the larynx as a musical instrument would appear to be in the class of a plastic ukulele with rubber strings, and control of such an instrument to maintain accurate pitch and consistent quality would seem to be a formidable problem.
The effect of flow-dependence on source-tract acoustic interaction
Authors: Rothenberg M.
Published: October 2005

It is obvious that there are persons with “strong” or acoustically efficient voices as well as persons with “weak” or acoustically inefficient voices, whether in speech or in singing, and that in general, one cannot change a weak voice to a strong voice just by “talking louder” (raising the subglottal driving pressure, with concomitant readjustments in the laryngeal musculature). The research reported here is part of an effort to describe the physiological and acoustic basis for these differences in voice quality. Closed form solutions for the glottal flow waveform resulting from a triangular variation in projected glottal area, using a simplified representation of the vocal tract, and either a simple, linear flow-independent glottal source or a strict flow-dependent glottal source, show that the degree to which source-tract acoustic interaction causes a strong stimulation of the higher formants at the instant of vocal fold closure depends greatly on the degree to which the pressure-flow equations for the glottis are flow-dependent. In this paper we describe the results of an analog simulation of the glottal source and vocal tract in which the glottis can be made flow-dependent at large glottal areas, and flow-independent at small areas. Results from this simulation, presented only in capsule form previously, indicate that the aerodynamic properties of the glottis at quite small areas, up to say 10% or 15% of the maximum area attained during the vibratory cycle, can be very important in determining the excitation of the third and higher formants. These results indicate that a proper understanding of the laryngeal basis for a voice with a relatively strong higher formant component will depend on a better understanding of how the aerodynamic properties of the glottis at small areas are related to vocal fold physiology.
Heat transfer in the vocal folds in relation to phonation
Authors: Cooper Donald S. , Titze Ingo R.
Published: October 2005

Heat is continually generated in and transmitted through the vocal folds during phonation. Physiological sources are heat generated by muscle contraction, and heat brought to the folds by blood perfusion. Since the vocal folds are a viscoelastic system, a third source of heat is viscous loss in the vocal fold tissues. It has been demonstrated that vibration of the vocal folds results in a measurable increase in their temperature [Titze and Cooper, J. Acoust. Soc. Am. Suppl. 1 71, S55 (1982)], on a scale consistent with a previous theoretical estimate [Titze, Tenth Symposium, Care of the Professional Voice (1981)]. Both muscle metabolism and the viscoelastic properties of tissue are themselves functions of tissue temperature. Consequently, cooling contributes to the stabilization of both the metabolic and mechanical properties of the fold tissues. It has also been found in studies of excised larynges that the surface and internal moisture of the tissues strongly affects the oscillation of the folds. Experiments on excised larynges are described in which the vocal folds are excited by warmed humidified air. The temperature profile of the tissues is measured by an array of inserted fine wire thermocouples and the vibratory pattern of the folds is described in terms of glotto-graphic measurements. The roles of tissue moisture and heat transfer in vocal fatigue and phonation are addressed. [Work supported by NINCDS.]
Acoustical sensing by time delay spectrometry
Authors: Heyser Richard C.
Published: October 2005

Active acoustical sensing should utilize signal modalities with sufficient degrees of freedom to identify range, range rate, and those higher derivatives necessary to identify object rotation, as well as potential spectral properties which could be used for signature analysis of specific objects in a field. In addition, the specular nature of acoustic relfection from smooth objects demands signal processing which has substantial dynamic range along with good noise immunity. It is also shown that time delay spectrometry (TDS) is a modality which meets these requirements. The principles of TDS are developed as they apply to its use as a phase-coherent spread-spectrum communication technique. A constant amplitude signal with programmable phase structure is used as acoustic stimulus. System response to that stimulus consists of an ensemble of delayed replicas with complex amplitude and phase modulation. This can be interpreted as a signal whose dimensionality is determined by the degrees of freedom in the programmable phase structure. Selective spatial filtering followed by mapping to a lower-dimensional space can bring the property of interest to a usable form. This includes the conventional time domain reponses (range, rate,…) and frequency domain responses (spectrum, cepstrum,…).
Shape and position measurement using continuous wave acoustics
Authors: Buckley Shawn
Published: October 2005

The shape and position measurement of objects using continuous wave acoustics performed at Massachusetts Institute of Technology is reviewed. In the experiments, a sound source flooded the object with acoustic waves at a fixed frequency, typically between 2 and 80 kHz. Reflected waves form an interference pattern between the emitted waves and the reflected waves. The interference pattern is sampled by an array of microphones at specific locations around the object. Changes in the object's shape or position cause changes in the interference pattern as measured by the microphones. When the dimensional changes are small compared to the acoustic wavelength, the changes in the interference pattern are approximately proportional to the dimensional changes. Under these circumstances an object can be calibrated for changes in either shape or position using a matrix of sensitivities: each microphone responds to each feature change of the object in a different way. Once calibrated, mathematical techniques can deduce the amount of shape or position change using subsequent measurements of the object's interference pattern. Actual measurements show that the position of an arbitrary object can be determined to an accuracy of 0.2 mm (0.008 in.) in each of two dimensions. Shape changes of an object can be measured to better than 0.025 mm (0.001 in).
Medical and industrial applications of ultrasonic imaging
Authors: DeSilets Charles S. , Fraser John D.
Published: October 2005

Ultrasonic imaging has found widspread use in medical and industrial applications. Ultrasound in the frequency range of 1–10 MHz is used to image soft tissue in the body, a medium with many weak scatterers, acoustic impedance and velocity similar to water, and attenuation on the order of 0.8 dB/cm/MHz. Resolution is limited by depth of field and depth of penetration considerations, but typically is several times greatest than the diffraction limit. Imaging systems typically are operated in a pulse-echo mode using either mechanically focused and scanned single element transducers or electronically focused and scanned transducer arrays. Most transducers are designed with octave bandwidths to achieve short pulses for range resolution and near 100% transduction efficiency for maximum sensitivity. Industrial applications are characterized by media of widely varying propagation modes, velocities, impedances, and attenuations. Consequently, industrial systems operate at frequencies ranging from 100 kHz to 1 GHz. Most industrial systems are quite simple compared to medical ones, employing mechanically scanned single transducers to detect the presence of flaws. Imaging systems have found limited use. Ultrasonic imaging in air affords resolution and penetration similar to medical applications, but with targets similar to the specular reflectors found in industry. Transducer design is a major problem.
Model analysis of sound diffraction by the external ear
Authors: Koshigoe Shozo , Tubis Arnold
Published: October 2005

The asymmetries of the external ear structures are believed to be mainly responsible for front-back discrimination in sound localization. We have studied theoretically the dependence of the external ear filter function on specific anatomical structures. The method of boundary integral equations is used to calculate sound diffraction by the pinna flange and concha. The analysis is greatly simplified by using a Green function for the external air medium with vanishing normal derivative at the surface of the head (or at a plane boundary which simulates the effect of the head surface of frequencies ≳2 (kHz). The boundary region involved in the integral equation is thereby confined to the immediate neighborhood of the external ear. The calculated filter function is compared with experimental results for various incident sound wave directions. [This work was supported by NSF.]
Binaural horizontal plane localization: Influence of the contralateral ear
Authors: Musicant Alan D. , Butler Robert A.
Published: October 2005

In several recent reports [Musicant and Butler, J. Acoust. Soc. Am. Suppl. 1 71, S87 (1982); 72, S93 (1982)] we presented data describing the influence of pinna cues on binaural azimuthal localization. These earlier reports ascribe a critical role to the pinna for the resolution of front from rear. Monaural pinna cues due to the near ear were shown to strongly influence localization. The present experiment sought to explicate a possible role for the far ear, that is the ear contralateral to the sound source. This was accomplished by occluding the pinna cavity, leaving the meatus open, of each ear separately. Thus one ear was open while the other was partly occluded. Stimuli consisted of 4-kHz high-pass noise presented from loudspeakers located at a distance of 5 ft and placed at intervals of 15° from 360° to 180° azimuth. Results indicate a 50% reduction in the number of reversals occurring when the far ear is open compared to the number of reversals when both pinnae cavities are partly occluded. A further reduction occurs if the ipsilateral ear is open and the contralateral ear is occluded. Apparently the far ear can contribute to the resolution of front from back but not as well as the ipsilateral ear.
Localization and its effect on auditory adaptation
Authors: Wolosiansky W. , Bowers J. , Nileshwar N. , Weiler E.
Published: October 2005

The present study was designed to separate localization effects from loudness adaptation effects in order to determine their relative contribution to measured adaptation. Subjects were asked to localize a binaurally presented 400-Hz tone to the midplane by shifting the phase in the comparison ear. The experimental ear was then exposed to a monaurally presented adapting tone for seven minutes and tested for adaptation (dB attenuation). During a postadaptation localization portion of the experiment, the subjects were again asked to localize the binaurally presented tone to midline, with the restriction that the tone directed to the adapting ear remained on continuously. Once relocalization was achieved, the participants were retested for adaptation. The results revealed a significant loudness adaptation level between preadaptation scores and both the postadaptation and the postrelocalization scores obtained. However, no difference was found between the postadaptation and the postrelocalization responses recorded. Hence, it is suggested that adaptation is a loudness effect independent of the binaural interaction effects reflected by localization.
Masker bandwidth and the MLD
Authors: Zurek P. M. , Durlach N. I. , Colburn H. S. , Gabriel K. J.
Published: October 2005

Thresholds for binaurally in-phase (SO) and out-of-phase (Sπ) tones masked by diotic noise were measured as a function of noise bandwidth at 250 and 4000 Hz. Results show that the familiar dependence of the MLD for a tone in wideband noise on the frequency of the tone derives primarily from the dependence of critical bandwidth on frequency and only secondarily from a frequency dependence, per se. MLD's measured with narrowband (≈10 Hz) noise muskets are 25–30 dB at 250 Hz and about 20 dB at 4000 Hz. The difference between Sπ thresholds at 250 Hz and 4 kHz measured with narrowband maskers supports the hypothesis that the detection cue is interaural phase difference at low frequencies and interaural amplitude difference at high frequencies. In both frequency regions, “binaural sluggishness,” which has been documented by Grantham and Wightman [J. Acoust. Soc. Am. 63, 511–523 (1978)], is evident in the increase of the Sπ threshold with an increase in noise bandwidth at narrow bandwidths. [Work supported by NIH.]
Discrimination of pattern pitches derived from trains of impulses centered at high carrier frequencies
Authors: Hafter Ervin R. , Richards Virginia M.
Published: October 2005

We refer to pitch at the missing fundamental of a set of higher harmonics as “pattern pitch” in deference to differences of opinion over whether the information is extracted in the time- or frequency-domain. Stimuli were made by repeating 40-dB SPL Gaussian clicks, each pulse in the train being the product of a sinusoid and a Gaussian envelope. Carrier frequencies were 3000 Hz and higher; modulation frequencies (click rates) were either 166 or 250 Hz. For the lowest carriers tested, no audible component existed below the 12th and 9th harmonics of the fundamental, respectively. Pitches made with high harmonic numbers can be made more salient by presenting successive patterns at musical intervals. Discrimination after such training was extraordinary, being on the order of 0.5%. Evidence that this is based entirely on patterns and not on place-pitch analysis of the audible sidebands is shown by the fact that randomization of the carrier frequency between trains does not diminish performance. Of special note is the fact that difference thresholds followed Weber's Law. This indicates that postulation of a simple additive noise, such as variations in the firing times of the input neurons, is inadequate to explain the limits on pattern pitch.
Use of time separation pitch in equalizing the interpulse intervals of pulse triplets by method of adjustment
Authors: Ceruti Marion G. , Martin Douglas W. , Floyd Robert W.
Published: October 2005

Previously we reported that pulse triplets with both interpulse intervals (IPI) equal to 2.0 ms could be discriminated from pulse triplets with each IPI differing from 2.0 ms by at least 0.14 ms (M. G. Ceruti, R. W. Floyd, and D. W. Martin, J. Acoust. Soc. Am. Suppl. 1 72, S92 (1982)]. Here we report a further experiment in which we presented subjects with a triple pulse stimulus with random differences in IPI's. The Objective of this experiment was to determine the accuracy with which subjects could manipulate the timing of a variable pulse, relative to a pulse doublet with a fixed 4.0-ms interval, in order to produce a triplet containing two IPI's equal to 2.0 ms. The time delay of the doublet, relative to the variable pulse, was randomized prior to each trial. All three identical broadband pulses had durations of 1.0 ms each. Triple pulse stimuli were repeated at 9 Hz during each trial. The subjects' task was to listen to the TSP generated by each stimulus, to adjust a potentiometer controlling the timing of the variable pulse, and finally, to respond when the pulse was centered in the 4.0-ms pulse doublet. The data indicate that subjects responded correctly (forming two IPI's of exactly 2.0 ms each) on 41% of the trials, and produce intervals which both differed from 2.0 ms by 0.1 ms on 33% of the trials. We will discuss both the subjects' performance strategies for pulse centering, as well as subjects' pitch perception of the stimuli.
Binaural effects of tinnitus following monaural exposure to a pure tone
Authors: Young I. M. , Lowry L. D.
Published: October 2005

Exposure of the subject's left ear with tinnitus to a steady tone 2000 Hz, 107 dB SPL, for 10 min resulted in a permanent tinnitus in both cars with similar pitch of approximately 10 000 Hz and loudness of 50–55 dB SPL. The subject was astonished to find that he had incurred tinnitus in the nonstimulated, previously quiet ear. The left ear of this subject was exposed to a steady 125 Hz pure tone at 123 dB SPL for 35 min. In the stimulated left ear: immediately after stimulation, tinnitus was heard as 13 110 Hz. Fifteen minutes after stimulation, tinnitus pitch changed to 12 780 Hz, 20 min later, 11 100 Hz, 30 min later, 10 550 Hz, 50 min later to original pitch 10 000 Hz and stayed steady many months to date. In the nonstimulated right ear; immediately after cessation of stimulation, tinnitus was heard as a pitch 700 Hz. Thereafter, tinnitus pitch gradually increased in pitch to 1000 Hz for 1 h, 1000 Hz to 4000 Hz for 48 h and 4000 Hz to near 10 000 Hz in 6 days; the tinnitus never returned to previous pitch 10 000 Hz until 7 days after stimulation. Distinct difference in recovery pattern between two cars was compared with previous experiments of 250 Hz and 500 Hz monaural stimulation.
Accuracy of Crib-o-gram as a screening test on high risk newborns
Authors: Wright Laura B. , Rybak Leonard P.
Published: October 2005

In the present study, Crib-o-gram (COG) and auditory brainstem responses (ABR) were recorded in fifteen high risk newborns in the intensive care unit selected by the following criteria: birth weight < 2200 g, asphyxia, artificial ventilation, respiratory failure, and potential ototoxic medication (aminoglycosides). The infants tested ranged in gestational age from 27 to 40 weeks. The COG testing was performed by placing a motion-sensing transducer beneath the infant's crib mattress. All 15 infants failed the COG at least two times before having the ABR test given. The ABR testing was performed in a soundproof room using a Nicolet 1170. Twelve infants had normal ABR, one had some sensorineural loss and two infants were deaf. The rate of false positive finding is very high. Consequently, the accuracy of the COG is questionable. In spite of the high risk factors of the newborns it is difficult to implicate aminoglycosides as a single cause of hearing loss. We feel very strongly that a routine ABR evaluation should be performed on all high risk newborns. [Work supported by Deafness Research Foundation.]
Binaural interaction in the middle latency response
Authors: Hood L. J. , Berlin C. I. , Hughes L. F.
Published: October 2005

Substantial variability has been reported in the binaural interaction of middle latency potentials [Dobie and Norton, Electroenceph. Clin. Neurophysiol. 49, 303–313 (1980)]. The present investigation studies intrasubject reliability and intersubject variability of binaural interaction and lateral asymmetry in the middle latency response by employing a factorial design addressing potential earphone and electronic channel asymmetries. Summed monaural responses were subtracted from summed binaural responses to yield the binaural interaction component (BIC), while lateral asymmetries were derived by comparing right and left responses under both monaural and binaural conditions. A point-by-point analysis of variance was carried out on the middle latency responses and an exact determination was made of the probability of specific similarities. Data obtained from four subjects, each tested under 48 conditions, describe the reliability of binaural interaction and lateral asymmetry in the middle latency response, the effects of earphone and channel differences on these measurements, and consistencies within and across subjects. [Supported by NINCDS NS 11647, the Louisiana Lions Eye Foundation, and the Eye and Ear Foundation.]
Preyer reflex in neonatal jaundiced rats
Authors: Lenhardt M. L.
Published: October 2005

Recently the jaundiced rat model for humans with hearing loss secondary to neonatal hyperbilirubinemia has been questioned. This was based on the observation of normal brainstem evoked responses (BERS) in surviving jaundiced adult rats, known to have extensive billrubin neurotoxicity particularly in the prethalamic auditory tracts. Neonatal verification of the lack of hearing loss as indicated by the adult BERS would certainly strengthen the case for model rejection. The Preyer reflex (PR) was used as a behavioral indication of intact hearing in 33 neonatal rats. One third was jaundiced while the remaining were nonjaundiced litter-mate controls. The PR is a twitch of the auricle to intense sound. For rodents without cochlear hearing loss, the PR is approximately 80 dB above absolute thresholds for frequencies between 4 and 10 kHz. Mean PR's for each group were not significantly different at 4, 6, and 8 kHz. At 10 kHz, the jaundiced mean was significantly elevated. The between group variances were also significant for 15–25 kHz. Since jaundiced rats are known to have normal cochleas, the elevated PR at 10 kHz may be an indication of hearing impairment in some individuals. Model considerations will be discussed.
Risk assessment for noise induced hearing loss
Authors: Erdreich Linda S. , Erdreich John
Published: October 2005

Nationally mandated hearing conservation programs provide the protocol for the design of epidemiologically sound “natural experiments” through which we may refine the risk assessment of hearing loss from noise exposure. Although a variety of appropriate data is being collected, contemporary epidemiologic methods for analyzing them are at present not widely employed. The life table technique for dealing with people entering and leaving the program at different times and people lost to follow-up, introduced in an earlier paper [J. Erdreich and L. S. Erdreich, “Epidemiologic Strategies to Understanding NIHL,” in New Perspectives in NIHL (Raven, New York, 1980)] will be illustrated. The bias introduced by unappropriate control group will be demonstrated. Various methods for summarizing risk for dichotomous and continuous data are discussed in the context of the intended public health goal.
A comparison of significant threshold shift criteria for use in industrial hearing conservation programs
Authors: Royster Julia Doswell , Royster Larry H.
Published: October 2005

Six criteria for significant threshold shift (STS) were applied to the audiometric data for white males in better and poorer hearing conservation programs over seven annual monitoring tests. Higher percentages of workers in the poorer programs were tagged as showing STS by five criteria. Three of the criteria produced equivalent percentages of tags. However, the validity of tags varied. Advantages and disadvantages of each criterion are compared in terms of relative protection of employees' hearing and magnitude of annual follow-up needed for the identified workers.
Environmental sound exposure in children
Authors: Siervogel R. M. , Roche Alex F. , Chumlea Win. Cameron , Johnson D. L.
Published: October 2005

Measurements of sound exposure (n = 151) were recorded in children aged 6 to 18 years with Metrosonics dB 301 Metrologgers. For each child, a log equivalent sound level (Leq) and corresponding sound source were recorded for 480 separate 3-min intervals during a 24-h period. Data for each individual were summarized into 20 activity (sound source) categories, and an Leq (8) and Leq (t) computed for each, where t is the total time spent engaged in a specific activity. Analysis of variance reveals highly significant differences in Leqs among activities, and Duncan's multiple range test suggests four groupings. Lawnmowers/combustion engines, live music, school bus, and school assembly/recess are major sound sources for children; each sound source has an Leq(t) > 80 dB in boys and girls and average exposure duration of 0.5 to 2.1 h per day for those exposed. There is a significant sex difference in total sound exposure; Leq(24) = 77.8 ± 6.1 and 75.2 ± 5.3 in boys and girls, respectively. Boys appear to place themselves in a noisier environment than girls, since girls have a lower mean Leq than boys for virtually every activity. [Work supported by EPA and USAF.]
Effects of Jet noise on mortality rates
Authors: Meecham W. C. , Shaw N. A.
Published: October 2005

The test area is in the 90 dBA contour, for 1970–1980, and contains about 100 000 people, under the landing patterns at Los Angeles International Airport. A control area has approximately the same number of people, contiguous to the test area with racial distribution and income the same within a few percent. We can control age distribution by mortality in an age group and compare stress-related nonstress-related deaths. Deaths from respiratory disease, cancer, and mental disorders showed no significant increase in the high noise area. Cardiovascular deaths are increased by 18% in the high noise area for the 75 + age group (97% confidence level); violent deaths by 61% same age group (96% level); suicides alone by over 100% in the 45–54 age group (99% level). This gives 193 extra deaths.
Evidence for a resonant mechanism in auditory hair cell stereocilia
Authors: Dear Steven P. , Saunders James C.
Published: October 2005

A mathematical analysis of stereocilia height and cochlear tonotopic organization along the length of the receptor epithelium in six species provided the basis for a resonant model of hair cell stereocilia. The analysis demonstrated an inverse power function between the distribution of frequency (f) and stereocilia height (h). The average empirical relation was: f∝h−2.67. These results are consistent with a resonant “clamped bar” model which has the relation: f∝h−2.00. The model provides conceptual insight into the mechanical properties of stereocilia by showing that Young's Modulus remains constant for all stereocilia in a given cochlea. The mechanical properties of stereocilia can be understood further in terms of their macromolecular structure and the bending of crossbridge molecules. The uniform bending of every crossbridge molecule, coupled with the constant number of crossbridges per unit volume within the stereocilia, leads to a constant value for Young's Modulus. Finally, the model raises the intriguing possibility that nature may have evolved two frequency selective mechanisms in the cochlea. [Work supported in part by The Deafness Research Foundation and NINCDS.]
Neurophysiologic assessment of endolymphatic hydrops
Authors: Morizono Tetsuo , Sikora Michael A.
Published: October 2005

An objective method to assess endolymphatic hydrops in the experimental animal model of Meniere's disease is reported. A particular phase of very low-frequency sound (biasing sound) results in displacement of the basilar membrane. With increased pressure of the endolymphatic space, however, the effect of low-frequency sound to the basilar membrane becomes less, hence, causes less changes in the probe-tone elicited auditory responses. The endolymphatic hydrops was created in the guinea pig by obliteration of the endolymphatic sac with bone wax. Subsequent histologic verification confirmed the hydrops. Both amplitude and latency of whole nerve action potential (AP) from the round window for probe tone (4 and 8 kHz) showed significant difference in modulation for a biasing tone of 50 Hz and 90 dB SPL (P < 0.01). As far as we are aware, no other method to assess endolymphatic hydrops has been available for both animal and human. We believe that this method has a potential clinical use for objective assessment of the Meniere's disease.
Cochlear effects of locally applied inhibitors
Authors: Rybak Leonard P.
Published: October 2005

The round window has been used as a route for introducing ototoxic substances into the inner car in order to bypass barriers between the systemic circulation and the inner car. We have used this method to locally administer sodium, potassium-ATPase inhibitors and chloride transport inhibitors to the inner ear of the chinchilla. Drugs dissolved in Ringer solution were applied on the round window membrane. Endocochlear potential (EP) was recorded from the basal turn using the round window approach. The EP was not altered following application of Ringer solution as a control. Following application of ouabain (10 mM), the EP steadily declined. After vanadate (10 mM), the EP initially increased, and subsequently declined. Sanguinarine did not alter the EP. The loop diuretics furosemide and piretanide caused a marked decline in the EP after local application. However, the stilbene derivative DIDS did not alter the EP after topical application. These findings raise questions about whether the loop diuretics have any effect on chloride transport in the cochlea and makes it appear unlikely that active chloride transport contributes to the normal EP. [Work supported by NIH and Deafness Research Foundation.]
Onset responses in single auditory-nerve fibers
Authors: Smith Robert L.
Published: October 2005

The maximum response at the onset of a CF tone burst was obtained as a function of sound intensity level and prior adaptation. A stimulus rise time of 1 ms was used to maximize the onset response as well as to produce a simultaneously recorded whole-nerve action potential (AP). As intensity increased, the onset response increased and in some units reached a maximum value of 1 spike per stimulus presentation within a 1-ms interval. The absolute refractory period of the fiber prevented a further increase in the number of spikes. Nevertheless, further increases in intensity affected the onset response by reducing the latency to the onset spike and the variability in its time of occurrence. Consequently, the maximum response in spikes per second continued to increase when it was measured using a sufficiently small time interval, e.g., 55 μs. Prior adaptation reduced the magnitude and increased the latency and variability of the onset response. These effects could account for some of the concurrent changes in the AP.
Responses from units in the AVCN of the cat before and after inducement of a noise lesion
Authors: Smoorenburg G. F. , van Heusden E.
Published: October 2005

Responses of single units in the Anteroventral part of the Cochlear Nucleus (AVCN) were studied together with compound 8th-nerve action potentials (AP). Halfway through the experiment the cats were exposed for half an hour to pink noise at 105 dB SPL producing an average threshold shift 30 dB (maximum 50 dB) in the 2–6 kHz region. After the noise exposure spontaneous activity and phase locking of the response of the units to the stimulus waveform were not significantly different from the pre-exposure findings. Response latency tended to increase. Therefore, the decrease of latency found for APs must be due to a shift to higher frequencies of the population of units contributing to the AP. The sharply tuned tip segments of tuning curves shift to higher levels whereas the low-frequency tails remain at about the same level. Q10 decreases by at most 50%, which was also found for AP tuning curves. Response spectra for clicks and noise (reverse correlation function) did not show a significant decrease of frequency selectivity. Units with CF < 3 kHz may show a shift of the CF to a lower frequency by 10%–20%. After inducement of the noise trauma the sharply tuned tip segment of a tuning curve may not be found and CF may be assigned to a local minimum in the low-frequency tail of the curve.
A comparison of several electrophysiological measures of 500-Hz bearing thresholds in normal-hearing and hearing-impaired subjects
Authors: Chambers Ron D. , Brown D. Douglas
Published: October 2005

The four neuroelectric potentials most commonly used for the measurement of low-frequency hearing are the conventional and 40/sec middle latency response (MLR), the slow negative potential (SN10), and the frequency following response (FFR). The potentials obtained for 500-Hz tonebursts were evaluated for agreement between electrophysiological and behavioral thresholds in normal-hearing and hearing-impaired adult subjects. The degree of hearing loss in the hearing impaired ranged from mild to moderate in the region below 2 kHz. In a subgroup of both the normal and hearing-impaired subjects, the EEB record was monitored to determine the effect of subject state on the font evokee potentials. Of these four electrophysiological techniques, the MLR was most effective for predicting behavioral thresholds, particularly when sleep state was controlled. However, none of these responses was completely satisfactory in predicting 500-Hz bearing sensitivity. [Work supported by NIH.]
The total-energy and equal-energy principles in the chinchilla
Authors: Ward W. Dixon , Fabry David A.
Published: October 2005

The total-energy principle postulates that the damage caused by noise is some function of the total A-weighted sound energy that has entered the ear, regardless of temporal pattern. This principle has been proved incorrect in an earlier experiment that showed damage to be reduced by breaking up a 15-day continuous exposure into 45 8-h exposures separated by at least 16 h. [W. D. Ward, C. W. Turner, and D. A. Fabry, J. Acoust. Soc. Am. Suppl. 1 72, S52 (1982)]. However, the less grandiose and more practical equal-energy principle merely posits that repeated daily work-week exposures of equal A-weighted sound energy will lead to equal amounts of damage to an auditory mechanism that is initially normal. In this theory, only the pattern of noise during the work day is thought to be irrelevant. This hypothesis was tested by exposing chinchillas for 9 weeks to 700–2800-Hz noise at 102 dB SPL for 48 min per day on Monday through Friday, and operating the effects with those displayed by animals given daily exposures to the 700–2800-Hz noise at 92 dB for 480 min per day in the earlier experiment. Differences in temporary and permanent behavioral threshold shifts and in hair-cell destruction will be presented, and implications of these results for exposure standards will be discussed. [Work supported by NIH grant NS 12125.]
Scanning electron microscopic study of impulse noise—Induced mechanical damage in the cochlea
Authors: Hamernik R. P. , Turrentine G. , Salvi R. , Henderson D. , Roberto M.
Published: October 2005

Binaural chinchillas were exposed at normal incidence to 160 dB peak SPL impulse noise at the rate of 2 impulses per min for 50 min. Animals were sacrificed at post-exposure times varying from t = 0 through 30 days. The cochleas were prepared for SEM observation using a standard protocol. Immediately following exposure, a large (6-mm) area of the organ of Corti was separated from its attachments to the basilar membrane along a fracture line that follows the outer pillar cells. The separated portion of the organ of Corti is left floating in the scala media with both ends attached to viable portions of the remaining sensory epithelia. Surprisingly, in the denuded areas of the basilar membrane, the inner hair cell surface structure remains comparatively normal during the early post-exposure times while outer hair cells in the region bordering the main lesion show considerable changes in cilia structure and in the appearance of the reticular lamina-cuticular plate complex. Scar formation and the absorption/phagocytosis of the free-floating portions of the organ of Corti will be described, as well as the differing susceptibilities of inner and outer hair cell cilia to morphological changes. [Work supported by U.S. Army Med R and D Command, DAMD 17-80-C-0133.]
The transmission of signals by auditory-nerve fiber discharge patterns Don H. Johnson
Authors: wami Ananthram
Published: October 2005

Recent developments in the theory of point processes are used to analyze the accuracy by which signals are conveyed by the discharges of single auditory-nerve fibers. It is shown that the only spike trains which can convey a signal without distortion are those well-described by a Poisson process model. Theoretical predictions are made of the distortion present in the transmission of signals by auditory-nerve fiber discharge patterns. Procedures are developed to compensate for these distortions. Computer simulations are used to confirm the theoretical predictions and to assess the accuracy of the compensation techniques. [Work supported by NSF BNS-8022469.]
Subharmonic phenomena in normal and superfluid helium
Authors: Keolian Robert , Rudnick Isadore
Published: October 2005

We have previously reported on observations of subharmonics occurring in parametrically driven shallow water gravity waves [R. Keolian and I. Rudnick, J. Acoust. Soc. Am. Suppl. 1 72, S13 (1982)]. The method depends on oscillating an annular resonator vertically with high enough amplitude so it exceeds the threshold for subharmonic generation. The apparatus has been adapted for low temperature work and liquid helium is now used instead of water. Our preliminary results are similar to those obtained in water including the occurrence of deep and ultradeep subharmonics and the appearance of chaos. Temperatures ranged above and below the lambda point. [Work supported by ONR.]
Relationship between the stress acoustic constants and the ultrasonic nonlinearity parameters for solids
Authors: Yost W. T. , Canttell John H.
Published: October 2005

The ultrasonic characterization of the stress state of a solid is usually based on the measurement of the stress acoustic constant evaluated at the stress free state for each material under investigation. For isotropic and quasi-isotropic solids and for crystals along nonrotated pure mode propagation directions the stress acoustic constant can be obtained from ultrasonic harmonic generation measurements. The relationships among the acoustic constant, the strain acoustic constant, and the ultrasonic nonlinearity parameters for solids will be derived. Experimental results verifying these relationships will be presented for a number of materials.
An improved King integral algorithm for finite amplitude sound beams
Authors: Ginsberg Jerry H.
Published: October 2005

This paper supercedes the previous analysis [J.H. Ginsberg, Acoust. Soc. Am. Suppl. 1 71, S30 (1982)] of the infinite baffle problem for an axisymmetric harmonic excitation, which derived a nonlinear King integral describing the distortion associated with finite acoustic Mach numbers. That analysis was shown [M. B. Moffett and J. H. Ginsberg, J. Acoust. Soc. Am. Suppl. 1 72, S40 (1982)] to exhibit excessive nearfield distortion in comparison to experiment. Using the linear King integral in its conventional complex function form, as opposed to the real function analysis employed previously, leads to formulation of the second order potential in terms of complex functions. Asymptotic integration of this potential function reveals that there may be significant contribution from the evanescent spectrum (small transverse wavenumbers), as well as from the propagating spectrum. A coordinate straining transformation describing the full spectrum is duduced. From it, the previous analysis is shown to be only asymptotically correct. The new analysis reveals that the distortion is governed by a transformation that involves Fresnel integrals for the propagating spectrum and the error function for the evanescent spectrum. Some comparisons of the analytical prediction and the results of Moffett and Ginsberg are presented [Work supported by ONR, Code 420.]
Second-harmonic generation in violins
Authors: Arnold Eric B. , Weinreich Gabriel
Published: October 2005

Measurements of second-harmonic generation in violins have been made with a microcomputer-controlled acoustical spectrometer. Electrodynamic and acoustic excitations are used, and dependences of fundamental and second-harmonic amplitudes on drive level are established. Drive level dependent frequency shifts of the string resonances, attributable to string heating and amplitude-induced tension changes, are observed. Asymmetric resonant curves are found at higher drive levels, becoming hysteretic above a threshold. Possible connections to relevant system parameters will be discussed, and comparison to a modulated-tension model will be made. Comparison of string displacement amplitude and sound level between the experimentally driven violin and a normally bowed instrument played loudly suggests that second-harmonic generation may under some circumstances be a significant channel of energy transfer from string to body. [Work supported by NSF.]
Statistics of short-term spectral characteristics of fluent speech
Authors: Engebretson A. Maynard
Published: October 2005

Spectral studies of speech sounds have essentially centered around carefully spoken isolated words and phrases. It is well known that the spectral characteristics of these sounds differ from sounds of normal fluent speech. Statistical properties of the spectral characteristics of fluent speech based on short-term, power-spectral-density (PSD) measures of the speech signal were studied. A computer program was written to automatically calculate the PSD of contiguous windows of speech data and to further calculate a variety of histograms of comparative measures of the PSDs. Using cross correlation as a comparative measure, three types of histograms were computed: type(1) differences between adjacent windows, type(2) duration of “steady-state” segments, and type (3) differences between average PSD estimates of “steady-state” segments. Type (1) and type (2) histograms approximate exponential functions. Type (3) histograms resemble uniform distributions before tailing off to zero at large values. Typical values for the mean of the “steady-state” duration and the average rate of these “steady-state” segments is 35 ms and 2.4 segments per second, respectively, which is indicative of syllables. Typical results for a variety of talkers will be presented. [Work supported in part by NS 03856.]
Acoustic correlates of intonation in whispered speech
Authors: Holmes John N. , Stephens Adrian P.
Published: October 2005

Although it is generally accepted that fundamental frequency (F0) is the primary acoustic correlate of intonation, it is well known that intonational distinctions are easily perceived in whispered speech [W. Meyer-Eppler, J. Acoust. Soc. Am. 29, 104–106 (1957)]. Meyer-Eppler reports that analysis of whispered human speech shows different formant frequencies in question/statement oppositions of identical phoneme sequences. It seems plausible that these same formant shifts occur in voiced speech, perhaps as a result of larynx height change, or as a result of learned gestures to maintain the same phonetic quality as F0 varies. However, rule synthesis systems usually use F0 alone to signal intonation. In our experiments we have used speech synthesis by rule in which formant frequencies have been modified in a simple way dependent on the value of F0 as determined by the prosedic rules. When these formants are used with entirely voiceless excitation, subjects are able to make the same question/statement distinctions as with voiced synthesis, although the perceptual difference is less clear. These results may lead the way to achieving more natural-sounding intonation in voiced synthesis.
Classification of tonal quality of speech sound based on the efficiency of generating glottal sound source
Authors: Hiki Shizuo
Published: October 2005

By combining the results of acoustical analysis, synthesis, and a perceptual test of pathological voices [S. Hiki, S. Imaizumi, M. Hirano, and H. Matsushita, J. Acoust. Soc. Am. Suppl. 1 58, S111 (1975) and S. Imaizumi and S. Hiki, J. Acoust. Soc. Am. Suppl. 1, 64, S52 (1978)], a method of classifying tonal quality of speech sound is discussed in terms of the efficiency of generating the glottal sound source. The efficiency is defined here as the ratio of the effective energy of the glottal sound source to the necessary energy for the phonation The effective energy for transmitting linguistic information is estimated by taking into account various factors related to the vibration of vocal folds, the resonance of vocal tract, and the generation of noise components. Application of the method to the composition of perceptual scales and the selection of reference speech samples for the subjective evaluation of the tonal quality of speech sound including both normal and pathological voices is also discussed.
Burmese and the effect of consonant voicing on F
Authors: Maddieson Ian
Published: October 2005

Burmese has a phonemic contrast between voiced and voiceless nasal and lateral continuants. Measurements on tokens from several speakers show that following a voiced continuant F0 is relatively low and rising, whereas following a voiceless continuant F0 is relatively high and falling. The magnitude of these perturbations is affected by the tone of the syllable concerned. Although the tendency for F0 to be low and rising after a voiced consonant and to be high and falling after a voiceless consonant is well known, the reason for this phonetic effect is poorly understood. Moreover, it is often assumed that this effect is restricted to obstruents, and segments such as nasals and laterals do not perturb F0. The synchtonic Burmese data, as well as considerable phonetic and historical evidence from other languages, show that this latter assumption is unsound. This data causes additional problems for both the aerodynamic and laryngeal tension theories which have been proposed for explaining the effect of consonant voicing on the F0 of following vowels. [Work supported by NSF.]
Applications of an algorithm for parsing continuous speech into syllables
Authors: Kahn D.
Published: October 2005

This paper discusses two applications of a previously described algorithm for parsing continuous telephone speech into syllables [D. Kahn, J. Acoust. Soc. Am. Suppl. 1 72, S30 (1982)]. In the first, the parser is used to extract an estimate of the speaking rate, in syllables/rain, of continuous speech input, for use in adjusting rate-sensitive parameters in speech recognition systems. Since the original algorithm is effective as a syllable parser over a fairly wide range of speaking rates, and since the errors made are of both the missed-syllable and false-alarm type, which cancel in the rate-determination application, a good rate estimate is readily possible. In the second application, the algorithm was specifically tuned for the task of segmenting connected-digit strings. Since all English digits except “seven” are monosyllabic, a syllabic analysis of connected-digit strings bears an almost one-one relation to a segmentation into digits. Further, it has proved possible to adjust the algorithm to quite reliably fail to detect the second syllable of “seven.” In the interest of verifying the algorithms in a natural setting, all tests were performed using standard telephone instruments and lines in an acoustically noisy environment (background≈60 dBA).