bluuebunny/crossref_metadata_2025 huggingface dataset:
Phonetic representations and lexical access
Authors: Pisoni David B.
Published: October 2005

In this paper I will consider the available evidence in favor of phonetic and phonological representations in speech processing, particularly as these representations are related to questions of word recognition and lexical access. Several experimental findings will be summarized. These empirical findings along with logical and theoretical considerations provide support for the assumption that phonetic and phonological representations are computed by the human speech processing mechanisms and serve an important function in word recognition and access to the mental lexicon. The arguments in favor of such phonological mediation will be outlined and compared to assumptions made in several contemporary models such as Logogen, Cohort and Lafs. [Work supported by NINCDS Research Grant NS-12179-05.]
Canonical eddies—An estimation of acoustical effects
Authors: Scully-Power P. D. , Malay J. T. , Browning D. G.
Published: October 2005

Because of its inherent stratification, the ocean can be modeled by a canonical sound speed profile which determines an idealized, range-independent waveguide from which the first-order acoustic propagation characteristics can be computed [W. H. Munk, J. Acoust. Soc. Am. 55, 220 (1974)]. Perturbing this stratification on the mesoscale produces a canonical eddy characterized by a first baroclinic mode vertical structure and a Rossby deformation radius horizontal length scale. This parameterization enables the acoustic effects of ocean eddies to be estimated using various range-dependent propagation models—at least as far as first-order characteristics are concerned. [Work supported by NUSC.]
Masking of vibrotactile sensation from a remote site
Authors: Verrillo Ronald T. , Calman Bruce G. , Gescheider George A.
Published: October 2005

The masking of vibrotactile signals delivered to the index fingertip was measured as a function of the intensity of the masker, which was administered to the thenar eminence of the same hand. Combinations of test and masker frequencies were used so that the two signals would occur within the response ranges of the Pacinian and non-Pacinian mechanoreceptor systems. When the frequencies of both masker and test signal were within the range of either system (within channel), masking was effective. A 300-Hz masker (Pacinian) was unable to affect the detection of a 23-Hz signal (non-Pacinian). A 23-Hz masker (non-Pacinian) did effectively mask a 300-Hz signal (Pacinian). It was shown that the cross-channel masking is due to the spread of the mechanical disturbance from the thenar to the fingertip and that the amplitude of the masker was sufficient to excite both systems. Results will be discussed within the context of a duplex mechanism for mechano-reception. [Work supported by NIH.]
Mobility of high impedance structures
Authors: Slack J. W.
Published: October 2005

There are a number of ways of measuring mechanical mobility which are commonly used today. These involve differences primarily in transducer instrumentation, excitation signal, and data processing. As part of the author's doctoral research, a number of mechanical mobility measurements were made on a cast iron engine block. The techniques chosen for mobility measurement are strongly influenced by the structures to be studied. The techniques chosen by the author are presented. An unusual technique for measuring the impedance head stiffness is discussed in detail. Examples are given demonstrating reciprocity and reproducibility of data. Some applications of the mobility measurements are presented.
Human response to train vibrations
Authors: Dixit A. K.
Published: October 2005

Preliminary results of a recent Ontario study are presented in which over two hundred residents rated train noise and vibration at seven sites. Models are analyzed for community annoyance as a function of measured vibration levels. Vibration measurement parameters which correlate well with community response are identified for application in the impact assessment procedure. This work forms the continuation of Train Noise Program of Ontario Ministry of the Environment under which railway yard noise has been previously investigated.
“Modeling” approaches in studying biological effects of ultrasound
Authors: Nyborg Wesley L.
Published: October 2005

Here the term “modeling” is used broadly as any procedure for investigating a complex or difficult topic by treating a simpler or more convenient one. The “difficult topic” addressed here is that of biological changes produced (intentionally or not) in medical applications of ultrasound. In biological modeling, the laboratory animal is usually regarded as a good choice for simulating human tissues. Also, plants, insects, single cells, and cellular or molecular suspensions have proved valuable for special purposes. Physical aspects of the topic can be modeled by applying acoustical theory to simplified or idealized situations. Second-order approximations to the basic nonlinear equations have been fruitful. Especially useful is theory for time-averaged quantities such as heat generation, radiation pressure, radiation torque, and acoustic streaming. Experimental evidence for the significance of these quantities comes mainly from “model” experiments in which special conditions are used. Examples will be discussed. [Supported by Research Grant PHS ROI GM08209.]
Rectified diffusion at megahertz frequencies
Authors: Crum Lawrence A. , Hansen Gary M.
Published: October 2005

Rectified diffusion studies have in the past been generally confined to kilohertz frequency ranges where experimental confirmation of theoretical predictions can be made. However, since most of the ultrasonic devices used in medicine operate in the megahertz frequency range, it is important to extend these studies of the growth of bubbles by ultrasound to the higher range. We have modified and extended the equations associated with rectified diffusion to apply at megahertz frequencies, and have numerically solved these equations for a variety of conditions such as dissolved gas concentration, distribution of nuclei, and the frequency and intensity of the ultrasound. We have also obtained solutions for both the continuous and pulsed modes of operation. Our results indicate that bubbles can be made to grow at typical levels of exposure used in medical applications. Furthermore, at higher intensities, such as those used in studies on bean roots by Morris and Coakley [to be published in Ultrasound Med. Biol.], the times required for growth to resonance size are on the same order of magnitude as the periods associated with acoustic emissions from the root during insonification. [Work partially supported by the Office of Naval Research and the National Science Foundation.]
Ultrasonic irradiation of multicellular tumor spheroids
Authors: Sacks Peter G. , Miller Morton W. , Sutherland Robert M.
Published: October 2005

In vitro multicell spheroids from a mouse mammary sarcoma (EMT6) were exposed to therapeutic levels of ultrasond (1 MHz, 1–5 W/cm 2, 1–5 min cw) in a polystyrene tube which contains standing waves and promotes cavitationally related damage. Spheroid sizes were varied from 1-day old, 20-micron-diameter cell aggregations (∼11 cells/spheroid) to 25-day, 800-micron-diameter multicell spheroids (∼80,000 cells/spheroid). Damage was assessed by histology, scanning electron microscopy (SEM) and growth studies on individual spheroids and by survival of individual component cells. Dye exclusion (0.05% eosin) and histology indicated that peripheral damage occurred; SEM revealed the presence of surface abnormalities (tears and holes in cell membranes) in exposed spheroids. Additionally, necrotic loci within spheroids were noted after a 3 W/cm2 1 min exposure. Growth studies and surviving fraction indicated that damage is inversely proportional to spheroid size. With initial spheroid diameters ⩾ 200–250 microns, a decrease in spheroid diameter occurred 24 h post-sonication (3 W/ cm2, 5 min cw); the threshold was between 3–5 min of exposure. With initial diameters ⩽200 microns, reduction was produced by a 1-min exposure. Ultrasonically induced surviving fractions of individual cells also increased with increase in spheroid size.
Rotation of exposure tubes as a requirement for ultrasonically induced cell lysis
Authors: Church Charles C. , Flynn H. G. , Miller M. W. , Sacks P. G.
Published: October 2005

This paper is an attempt to explain the need to rotate a tube containing a cell suspension in order to obtain cell lysis. Calculations, based on known physical laws, were performed in order to determine the important forces on cells and bubbles and the movements and interactions which these factors are likely to cause. These calculations support the following conclusions: (1) In the absence of rotation cells and bubbles larger than resonance size are trapped at pressure nodes while bubbles smaller than resonance size are trapped at antinodes. (2} at 1 W/cm2 with rotation lysis is caused by cells sweeping through arrays of trapped small bubbles, and (3) at higher intensities lysis is caused by both trapped and nontrapped small bubbles.
Modal behavior of polymer cones
Authors: Stebbings David W.
Published: October 2005

Polymers were originally utilized in loudspeakers as formed film or sheet materials, usually in sandwiched structures. However, the modal behavior of molded cones can now be controlled well enough to assure uniform radiation characteristics in production more consistent than obtained from pulp-based cones.
Applicability of the partial coherence function to the separation of noise sources in a semi-anechoic field
Authors: Nicolas Jean , Gossdin Blaise
Published: October 2005

Two random noise sources for simulation and two wood product machines have been used to test noise source identification measurements. Noise signals are processed by two single channel FFT analyzers adequately syncronized and by a calculator with appropriate interfacings. The predicted value is compared to the actual value obtained in the absence of the second source. Comparison has been made between coherence due to incoherent noise sources with measurement contamination, and coherence due to partially coherent noise sources with no contamination. It is shown that artificial coherence of a certain level created by the measurement contamination causes more discrepancy on the predicted results than the same level of real coherence. It has also been shown that the smoothing techniques often used to compensate for average number cannot be employed when dealing either with separate noise sources with discrete frequency components or with a ground-reflecting surface which creates an interference pattern. When narrow-band analysis is used with an empirical correction formula the results show that even large and abrupt changes in the dynamic range and also ground effects can be predicted with good correlation.
Pulse propagation in the Central Arctic Ocean
Authors: Kutschale Henry W.
Published: October 2005

Wave-theoretical computer codes have been developed to model pulse propagation in the central Arctic Ocean. Pulse shapes as a function of range and depth are computed from the Pulse Fast Field Program (PFFP) and the pulse parabolic equation (PPE) code. Group- and phase-velocity dispersion and eigenfunctions are computed from the PFFP or from a corresponding normal-mode program. Good agreement has been obtained between measured and computed SOFAR signals. Computer simulations of pulse compression show in detail the possibility of achieving significant signal gain by pulse compression in the Arctic channel. This is accomplished by using predistorted waveforms matched to the dispersion of the channel at specified ranges. The effect of ice roughness on Arctic SOFAR propagation is illustrated from field data and the PFFP. Recent experiments of long-range transmission of explosion sounds over the Pole Abyssal Plain show marked frequency dispersion of bottom-interacting signals following the SOFAR signal. The dispersion of each pulse interacting with the flat ocean bottom of the Plain at a depth of 4100 m can be nearly as strong as that observed in the SOFAR signal for the first mode, but the bottom-interacting pulses appear to correspond to very high-order normal modes. Present efforts are described to model these bottom-interacting pulses, as well as T-phase propagation from earthquakes at the Nansen Ridge.
Propagation anomalies in shallow Arctic water
Authors: MacKinnon Robert F. , Brooke Gary H. , Ozard John M.
Published: October 2005

Two anomalous propagation effects in shallow Arctic water are examined. The first effect involves anomalous dispersion (group velocity > phase velocity) associated with modal propagation in an upward refracting water column overlaying a solid bottom. The second effect concerns the anomalous frequency dependence of certain high velocity components of a wideband signal. This latter effect is attributed to the contribution of the continuous spectrum to the total field in a channel with slightly rough boundaries. Theoretical results obtained from a normal mode model are compared, over a wide range of frequencies, with experimental data obtained using explosive sources.
Active noise control at the source
Authors: Burr Paul , Bengisu Turgay , Akay Adnan
Published: October 2005

An active noise control system was investigated to control noise at its source. Much of the previous work on active noise attenuators employed cancellation of sound with sound. In the present work, the radiated acoustic energy was attenuated by counter exciting the radiating surfaces. Appropriate counter excitation was achieved by using an adaptive control mechanism consisting of a feedback control circuit, sensors and exciters. Separate control systems for attenuation of steady-state and random noise sources are described. Active noise control was also applied to increase the transmission loss of panels, particularly at low frequencies which requires only a modest amount of counter-excitation energy. Feasibility of these systems are described through theoretical development of the models and experimental results. [Work supported partially by Bendix Advanced Technology Center.
Industrial saw vibration damper, prototype
Authors: Allen Clayton H.
Published: October 2005

Early models of this saw damper, reported upon previously, gave 15 to 20 dBA of noise reduction when operating in any of several configurations on 10-in. circular saws, cutting various materials. Modifications have been made to harden the design for use in an industrial application for cutting nonferrous metals. The new configuration places the damper inside a conventional saw guard and admits external adjustment of the damper position to accommodate a range of saw blade sizes (from 17 to 20 in. in diameter) and provides for automatic accommodation of various blade thicknesses up to approximately 14 in. At this writing. the new prototype is nearing completion. The design considerations will be discussed and it is anticipated that performance data will be available to present regarding noise reduction and endurance to sustained operation in an abrasive environment.
Temperature considerations in electric motor noise reduction
Authors: Champoux Yvan , Carey John H.
Published: October 2005

Induction motors represent a major noise problem in the petrochemical industry. Retrofit noise reduction frequently requires the use of inlet and outlet mufflers. Be they commercially available units or custom designs, the most severe constraint is often the maximum pressure loss the motor can support without serious reduction of operating lifetime due to excess temperature. Typically, a 10°C increase will reduce the lifetime by half, due to degradation of electrical insulation. One cannot base the true cost of a noise reduction treatment on its capital cost alone if it may reduce the operating life of the machine. This paper presents a technique to simulate the effect of a muffler in order to determine the motor flow characteristics, and at the same time, determine the motor internal temperature versus flow characteristic by electrical resistance measurements. Actual mufflers whose designs were based upon such measurements will be described. The influence of mufflers on the explosion-proof rating of motors will also be discussed.
Dispersion and ranging of transient signals in the Arctic Ocean
Authors: Yang T. C.
Published: October 2005

The Arctic Ocean, because of its unique sound-speed profile, exhibits clear mode structure in long range data of explosive sources. Range estimation can be made from the time-frequency dispersion of wideband pulses received at a single hydrophone. The method is discussed here. From the shot data, we find results using the lowest mode are in agreement with actual ranges within ten percent uncertainty. The method is insensitive to background noise, source spectrum shape, bottom profile, and the source-receiver depths. Relations between the sound-speed profile and the mode dispersions in the Arctic are discussed.
Bottom interaction measurements at FRAM II in the Pole Abyssal Plain of the Eastern Arctic Ocean
Authors: Baggeroer Arthur B. , Duckworth Gregory L.
Published: October 2005

During the FRAM II experiment in the Pole Abyssal Plain of the Eastern Arctic Ocean, an extensive program of refraction shooting was conducted. Multichannel data on an 800 × 800 m hydrophone array and on an ocean bottom seismometer were obtained from shots deployed from a remote camp and by helicopter, at ranges up to 300 km. The multipath of the bottom interacting paths was resolved using high resolution velocity spectra. These spectra were used to determine (i) a crustal model for the seabed at the FRAM II site, (ii) the propagation loss and spreading for both the reflected and refracted bottom interacting paths, and (iii) conversion efficiencies of shear waves identifiable from the OBS. [Work supported by ONR.]
FRAM II ambient noise data
Authors: Dyer Ira , Baggeroer Arthur B.
Published: October 2005

At low frequencies (5 to 50 Hz) ambient noise in the Arctic Ocean appears to be dominated by ice motion effects. During calm periods the noise is of distant origin, but during periods of intense wind or curent stress, nearby cracking, ridging, and/or grinding of the ice causes the observed noise to increase significantly. In the FRAM II program, we used a horizontal 800 × 800 m array to observe the noise, and both frequency and directional spectra have been obtained, with special attention to resolution of nearby events in the near field of the array. [Work supported by ONR.]
Signal versus masker uncertainty with noise maskers
Authors: Spiegel Murray F. , Green David M.
Published: October 2005

Older studies found very little change in threshold when signal frequency was fixed or randomized across trials. However, the maskers were different in each observation interval and listeners had to detect signals based on a departure from an estimation of the maskers' long-term spectra. Signal uncertainty may elevate thresholds up to 6 dB when the procedure allows listeners to compare directly the waveforms in each interval. Furthermore, masker uncertainty, caused by choosing different maskers for each trial, has at least as great an effect as signal uncertainty. The results support the conclusion that a signal is detected not only on the basis of energy in a critical band, but also by comparing it to the levels in adjacent bands. [Work supported by NIH.]
Tuning curves and suppression
Authors: Weber Daniel L.
Published: October 2005

Psychophysical tuning curves measured in forward masking appear more sharply tuned than those measured in simultaneous masking. This difference is often attributed to the operation of the suppression process during simultaneous stimulus presentation and the absence of suppression for nonsimultaneous presentations. An alternative interpretation is that the difference in the tuning curves simply reflects the difference in the effective excitation patterns which results from a filtering process: Simultaneous masking occurs as an interaction of the stimuli prior to filtering, forward masking occurs as an interaction after filtering. If the difference between simultaneous- and forward-masking tuning curves were due to suppression, then the simultaneous, off-frequency “maskers” would actually be suppressing the signal. Thus, suppression effects (e.g., a reduction in forward masking produced by the signal) should result from adding these off-frequency “maskers” to the signal. In fact, the suppression effects predicted from this account are not observed, consistent with the “filter” explanation. [Research supported by NSF.]
Psychophysical tuning curves: Stimulus ensemble and level effects
Authors: Wier Craig C. , Norton Susan J.
Published: October 2005

Monaural masked thresholds were obtained for tone bursts in forward-masking, simultaneous masking, and pulsation-threshold paradigms as a function of masker frequency and probe level. Thresholds were obtained in both the presence and absence of a continuous, broadband background noise adjusted to a constant E/N0 = 15. Probe frequencies were 300, 1000, an 3000 Hz and probe levels were 10, 30 and 50 dB SL (re threshold in the absence of the background noise). Data were collected primarily with a method-of-adjustment psychophysical procedure. Some data were also collected for the limiting conditions with a two-interval forced-choice procedure for comparison. The data were plotted as psychophysical tuning curves. The extent to which physical parameters of the stimulus ensembles are sufficient to account for differences in tuning-curve parameters and the necessity to consider alternative explanations will be discussed. [Research supported by PHS Grant No. RR-07096, and grants from NINCDS and the Deafness Research Foundation.]
Masking curves of tinnitus
Authors: Mitchell Curt , Vernon Jack , Johnson Robert
Published: October 2005

Tones were used to determine masking curves of tinnitus in 32 subjects, These masking curves were classified into four types on the basis of their relation to the subjects audiogram. Also similar audiograms were examined to determine whether they had similar masking curves. Some similarities were noted but in many cases there was no correlation between the audiogram and the masking curves, that is subjects with similar audiograms, and tinnitus sensations, might have quite different masking curves. The findings also supported previous studies where tinnitus masking curves were found to differ significantly from conventional tone-on-tone masking curves. It was also found that in some cases tinnitus sensations could not be masked with tones or noise bands.
Binaural analysis and unmasking effects
Authors: Soderquist D. R.
Published: October 2005

A series of investigations was done examining the homophasic (NOSO) and antiphasic (NOSII) effects in pulsation threshold (PT) and masked threshold (MT) conditions. The initial investigation examined the BMLD by manipulating two variables: (a) Lowpass noise spectrum level and (b) interaural phase of the signal. The results showed increasing phase effects (8–10 dB) for PT as a function of increasing noise level. The BMLD at MT was small and constant (3–4 dB) as a function of noise level. Further investigations showed that homophasic conditions yielded smaller unmasking (lateral suppression) than did the antiphasic condition. The unmasking effects appeared when the signal duration was 125 ms and not when the signal duration was 50 ms. The BMLD occurred in the PT condition regardless of the signal duration. Data in a forward masking paradigm will also be presented.
“Temporal masking” in discrimination of tone glides
Authors: Collins M. J.
Published: October 2005

Difference limens for tone-glide stimuli are reported to be greater when the glide precedes a contiguous 200-ms fixed-frequency segment than when the glide follows a contiguous fixed-frequency segment [M. J. Collins and H. Stromberg, J. Acoust. Soc. Am. 66, Suppl. 1, S9 (1979)]. The present study was carried out to test the hypothesis that the effect was due, in part, to “temporal masking” of the tone glide by the fixed-frequency segment. Six normal hearing subjects served as listeners. Reference stimuli consisted of 30-ms glide segments, preceded or followed by fixed-frequency (2200 Hz) segments of varied duration. Endpoint frequencies of the reference glide segments were 1680, 2200, and 2710 Hz for both glide-preceding and glide-following conditions. Results indicated that, in general, a greater amount of “masking” was imposed by fixed-frequency segments which preceded glides than by fixed-frequency segments which followed glides. This was particularly evident for the conditions which involved discrimination between no glide and some glide (2200-Hz endpoint frequency): essentially no “forward” masking was observed with significant “backward” masking for the comparable glide-preceding condition. [Work supported by NIH.]
Forward masking of diotic and dichotic clicks by noise
Authors: Hanna Thomas E. , Robinson Donald E. , Shiffrin Richard M.
Published: October 2005

The first part of the present study measured click thresholds during forward masking as a function of masker level and the temporal relation of the 6-kHz low-pass filtered noise masker to the click (300-ms duration with a 20-ms temporal gap or 10-ms duration with a 5-ms gap). Also varied were the spectral content of the click (low-pass filtered at 1 kHz or 5 kHz) and the interaural phase of the click (0° or 180°). The difference in frequency content had no effect on the amount of masking for the 300-ms masker while greater masking was found for the 1-kHz click with the 10-ms masker. This combination (1 kHz, 10 ms) was also the only one to produce masking level differences (MLDs) when the click was presented dichoticly. The second part of the experiment investigated the effects of combining the maskers used in the first part. Additional masking (above that predicted by an energy sum) was found, as has been reported elsewhere [M. J. Penner and R. M. Shiffrin, J. Acoust. Soc. Am. 67, 617–627 (1980)]; however the magnitude was decreased for certain conditions. This result, as well as certain effects on the MLD and results of a final study, can be explained by assuming an interaction between the two maskers [G. P. Widin and N. F. Viemeister, J. Acoust. Soc. Am. 68, 475–479 (1980)]. These data conflict in part with the predictions of additivity of masking obtained from the Penner and Shiffrin model, and suggest modifications to that model may be needed. [Work supported by NSF.]
Forward and simultaneous masking for maskers and signals that differ in frequency
Authors: Jesteadt Walt , Lehman James R.
Published: October 2005

The amount of masking of a 1000-Hz signal was determined for maskers of 694, 833, 1000, 1095, or 1200 Hz, presented at 30, 50, 70, or 90 dB SPL. Forward-masking data were obtained for 10-ms signals with onsets 4, 8, 16, or 32 ms after the offset of the 320-ms masker. Simultaneous-masking data were obtained for 10-ms and 200-ms signals with offsets that occurred 10 ms before the masker offset. The time course of recovery from forward masking was the same for all masker frequencies. As expected, simultaneous masking was greater than forward masking. This difference was particularly large for masker frequencies above the signal frequency. More masking occurred for short-duration signals than for long-duration signals when the signal and masker differed in frequency, in spite of the greater opportunities for off-frequency listening provided by the short signals. This result suggests that the use of longer duration signals will result in narrower simultaneous-masking tuning curves. [Work supported by NIH and NSF.]
Complex acoustic impedance of the human ear
Authors: Parson Ian , Kunov Hans , Alberti Peter , Abel Sharon
Published: October 2005

Instrumentation capable of measuring and displaying the swept-frequency, complex acoustic impedance of the human ear, in the range 200 Hz to 2 kHz, has been built, tested, and shown to provide accurate results (3% to 5%). The mean complex acoustic impedance loci measured in a sample population of 20 normal (screened) subjects is presented. Impedance magnitudes showed a variation of 20% to 40% of the mean. Mean resonant frequencies of 641 and 1140 Hz were observed with mean damping factors of 0.33 and 0.26, respectively. To evaluate repeatability, a population of five normals, evaluated five times, established a variation of 5% to 10% of the mean. Five otosclerotic subjects, having received unilateral stapedectomy were tested, indicating that the operation causes a return to normal resistance levels at the expense of increased resonant responses. [Work supported by Natural Sciences and Engineering Research Council of Canada Grant ♯A4316.]
Determination of the eardrum impedance of human ears with respect to the individual shape of the ear canals
Authors: Joswig Manfred
Published: October 2005

The assumption of a constant shape of the ear canal causes big systematic errors in the computation of the eardrum impedance, as shown by Hudde. He therefore developed a method of determining the impedance and the shape of the ear canal by measurement with probe tube microphones at 3 places within the ear canal. The computation is done completely in the frequency domain [dissertation, Bochum (1980)]. Alternatively a second method was developed, measuring the pressure in a tube, which is fitted to the ear canal entrance. From the impulse response the area function is computed in the time domain and that enables the correct transformation of the input impedance into the plane of the eardrum also for higher frequencies up to 20 kHz. Because of the very effective algorithms of deconvolution and matrix inversion for the determination of the area function the implementation of a micro-computer based system for a mobile diagnostics device should be easy. The measurements of the eardrum impedance, carried out with 20 subjects, confirm the results of Hudde and his conclusions about the physical behavior of the middle ear for higher frequencies. [Work supported by Geers-Stiftung, Germany.]
Synthesis as feedback in field linguistics
Authors: Grimes Joseph E.
Published: October 2005

Interim field reports on the phonologies of previously undescribed languages can be tested for consistency using synthesis-by-rule techniques. Such a report on Mura-Piraha of Brazil provided information for the feature rule component of Hertz's Cornell Speech Research System. Values for the parameter rules came from spectrograms made from a tape recorded in the field containing the examples in the report. Both sets of rules were revised to improve the match between the synthesized speech and the recordings. Out of this revision came recommendations about changes to the phonological description that the investigator can follow up on his next opportunity to do field work. In the current absence of such opportunity, two groups of linguists attempted to transcribe the forms phonetically. One had special orientation to Mura-Piraha phonology and the other had only general phonetic background. Both confusion matrices are given.
A new method for the quantitative evaluation of degree of hoarseness
Authors: Yumoto Eiji , Gould Wilbur J. , Baer Thomas
Published: October 2005

A sustained phonation of the vowel /a/ was separated into the harmonic and noise components by the PDP 11/45 computer. The ratio of the acoustic energy of the harmonic components to that of the noise components (H/N ratio) was calculated. The subjects consisted of twenty-five normals and forty-three pathological cases with varying degrees of hoarseness pre- and postoperatively. Sound spectrograms were made from the original phonation and the extracted noise sound. There was a highly satisfactory degree of separation of the noise components from the original phonation. The H/N ratio was a useful tool to quantitatively compare the degree of hoarseness of a posttreatment voice with that of a pretreatment voice. The critical range of the H/N ratio of normals was larger than that of the pathological cases. The theoretical basis of this method will be discussed in detail.
Statistical analysis of cross-linguistic differences between fricatives
Authors: Javkin Hector Raul , Nartey Jonas N. A.
Published: October 2005

The differences between fricatives in different languages have been difficult to determine because of a lack of agreed-upon parameters for characterizing fricatives. The spectra of fricatives in a number of unrelated languages were analyzed into 22 critical bands within the frequencies 0–10 kHz. A PARAFAC analysis was performed within each language across three modes: Fricative, vowel environment, critical band. The analyses of the different languages were compared using PARAFAC and canonical correlation. We hope to answer the question whether the sounds which have been described as the same in different languages are in fact the same.
Spectral characteristics of palato-alveolar affricates in three languages
Authors: Maddieson Ian
Published: October 2005

The spectral characteristics of the fricative portion of palato-alveolar affricates in Spanish, Italian, and (British) English have been examined in order to obtain information on the extent and nature of inter-language differences among similar sounds, as well as on certain intra-language variables. Eight speakers of each language were recorded reading six-syllable sentences at slow and fast speech rates controlled by a metronome. Embedded in each sentence was a word as close to the phonetic form [kat∫a] as the phonotactics of the language permit. In Italian, both single and geminate affricates were recorded. A central portion of the friction noise in each token was analyzed using a program whose output is a simplified spectrum representing relative amplitudes in 22 simulated “critical bands.” Further data reduction was carried out using Harshman's PARAFAC procedure, a 3-mode factor analysis. The results enable comparisons of cross-language and within-language (e.g., speech rate, speaker, sex) differences to be made in terms of differences along a small number of empirically discovered dimensions.
Fricative-stop coarticulation: Acoustic and perceptual evidence
Authors: Repp Bruno H. , Mann Virginia A.
Published: October 2005

Eight native speakers of American English produced 10 tokens of all possible CV, FCV, and VFCV utterances with V = [ɑ] or [u], F = [s] or [∫], and C = [t] or [k]. Acoustic analysis showed that the formant transition onsets following the stop consonant release were systematically influenced by the preceding fricative, suggesting a shift in the place of stop articulation towards the place of fricative articulation. The shift was equally large in FCV (e.g.,/sta/) and VFCV (e.g., /asda/) utterances; that is, it was not reduced when a syllable boundary intervened between fricative and stop. In a parallel perceptual study, the CV portions of these utterances (with release bursts removed to provoke errors) were presented to listeners for identification of the stop consonant. The pattern of place-of-articulation confusions in this identification task will be discussed in relation to the acoustic measurements. [Work supported by NICHD and BRS.]
Dichotic release from low-frequency masking in speech recognition by presbycusics
Authors: Kaplan Harriet , Pickett J. M.
Published: October 2005

Speech discrimination in the presence of competing cafeteria and speech babble noise was measured in elderly subjects with bilaterally symmetrical sensorineural hearing losses. All demonstrated at least one central or retrocochlear audiometric sign. The purpose of the study was to investigate whether low-frequency attenuation, dichotic or diotic presentation of speech in noise would improve speech discrimination in this population. Previous work by Pickett and associates using synthetic formants, had demonstrated release from low-frequency masking in some younger subjects as a function of these conditions. An as yet unpublished study by Kaplan and Pickett demonstrated similar results in presbycusics. It was hypothesized that comparable release from low-frequency masking would occur if speech in noise were presented under attenuated low-frequency, dichotic and diotic conditions. Speech discrimination was measured under earphones with noise and speech in the preferred ears under the following conditions: unaltered monotic, and monotic with attenuation of the band below 1000 Hz by 5, 10, and 15 dB; in addition, dichotic (band split) and diotic. For the dichotic condition, the band was split at 1000 Hz with filter skirts of 55 dB per octave. The high-pass band was delivered to the preferred ears. Modified Rhyme Test stimuli in open and closed set formats and SPIN Test sentences were used. For the group as a whole, dichotic and diotic conditions were significantly superior (0.05 and 0.01 levels) to unaltered monotic. When subjects were grouped according to degree of loss, the mild, loss group showed greater dichotic-monotic and diotic-monotic superiority than the moderate loss group. When subjects were grouped into “SSI Normal” and “SSI Abnormal” categories (two different types of central involvement), based on performance on the Jerger Synthetic Sentence Inventory (SSI) in ipsilateral competing message, there were no significant differences between groups, except for larger dichotic-monotic differences for the SSI Abnormal group. [Work supported by NINCDS.]
Ideal performance of the ear requires quantum-mechanical description
Authors: Bialek William , Schweitezr Allan
Published: October 2005

Brownian motion of hair cell stereocilia greatly exceeds the apparent threshold displacement, and must be reduced by active filtering (Schweitzer and Bialek, November 1980 ASA meeting). Active filtering requires amplification and the determination of a characteristic frequency. Absolute quantum-mechanical limits to the noise performance of amplifiers exist, and these limits must be achieved if the observed threshold performance of the ear is to be attained. Similarly, the factors which determine the characteristic frequency must have an accuracy comparable to quantum-mechanical limitations, and far greater than available classically. These arguments demand a quantum-mechanical view of auditory transduction, and such a view will be briefly presented (see also Bialek and Schweitzer, these abstracts).
A “Stereocilium laser”? Ideal amplification and finite-delay tuning attain theoretical limits to auditory performance
Authors: Bialek William , Schweitzer Allan
Published: October 2005

Does Nature employ the most remarkable of all amplification processes—amplification by the essentially quantum-mechanical phenomenon of stimulated emission—in a living system? We believe the performance of the ear may, in fact, require such a description. Considerations leading us to this view, and a model of hair cell transduction incorporating “laser-like” amplification, and tuning resulting from propagation delay within the stereocilium, will be presented. Synopses (largely self-contained) of the following topics will be displayed: thermal motions of the stereocilia, reduction of thermal noise by an active “second filter”, quantum-mechanical limits to amplifier performance, the limiting threshold attainable by a hair cell filter, amplification in an actin-myosin “maser” and the generation of a feedback force, tuned mechanical stereocilium response arising from force feedback with a propagation delay, saturation nonlinearities. and the quantum-mechanical origin of “essential” auditory nonlinearities.
Role of the forebrain in sound localization
Authors: Heffner Henry
Published: October 2005

The ablation-behavior method has been used to study the role of the auditory forebrain in the localization of sound. Bilateral ablation of auditory cortex in carnivores and primates results in a severe impairment in the ability to locate the source of a sound. Though the animals do, under certain conditions, show a residual ability to discriminate sounds on the basis of locus, the cortical sound localization deficit is nonetheless quite severe and can be demonstrated even in tasks which do not require the animal to approach the source of the sound (i.e., conditioned suppression). Furthermore, unilateral auditory cortex lesions cause an impairment in the localization of sounds in the auditory field contralateral to the lesions. Bilateral lesions of the medial geniculate body produce a less dramatic deficit in which the animals are only mildly impaired on two-choice sound localization when the loudspeakers are centered around the animal's midline with a more severe deficit appearing when both speakers are placed to the left or right of the animal. However, if the lesions extend into the brachium of the inferior colliculus, the animals may be completely unable to localize sound. Finally, experiments with opossums, the domestic rat, and feral pack rats have indicated that cortical ablation may not have a dramatic effect on sound localization in all mammals. [Work supported by NIH.]
Responses of inferior colliculus neurons in a masking level difference stimulus paradigm
Authors: Roth G. Linn , Sinex Donal G.
Published: October 2005

We have investigated the responses of single neurons in the inferior colliculus (IC) of anesthetized cats to stimuli often used in psychoacoustic masking level difference (MLD) studies. Typically we derived rate-intensity curves under diotic (S0N0) and dichotic (SπN0) stimulus conditions. In addition, we were often able to obtain interaural time difference (ITD) functions over the S0 to S±2π range, with and without background noise present. Preliminary analysis of our data indicates: (1) Some IC neurons respond at lower rate and/or phase-locking thresholds to SπN0, than to S0N0, but many IC neurons prefer S0N0 to SπN0; (2) an 1C's neuron's response in a MLD stimulus paradigm can be predicted from ITD curves derived using binaural tone bursts with no background noise (i.e., the presence of noise usually does not alter a neuron's ITD sensitivity); and (3) some IC neurons that appear to be insensitive to ITD's do exhibit lower thresholds to SπN0 than to S0N0, but only within a restricted range of noise levels.
Theoretical studies of the influence of head shape and ear-canal acoustics on binaural signal detection
Authors: Koshigoe Shozo , Tubis Arnold
Published: October 2005

The human head is modeled as a rigid sphere or spheroid with ear-canal chambers directly opposite one another. A Green's function formalism is used to calculate the transformation in amplitude and phase from the free field sinusoidal sound pressure to the pressure at the entrances of the auditory canals. Comparisons between the calculated and experimental results show good agreement for realistic head shapes and ear-canal parameters. Applications of the model to sound-source localization studies will be discussed.
Probe measurement of SPL in hearing-aid occluded ear canals
Authors: Gilman Samuel , Dirks Donald D.
Published: October 2005

A minature probe microphone was developed for use with earmolds to measure eardrum SPL. The probe has been designed using the earmold as an integral part of its acoustic system and no part of the probe itself projects into the ear canal. Previous ear simulator data indicated accurate (±2 dB) eardrum SPL measurements at frequencies up to 5.0 kHz. To determine the effects of ear-canal variations on probe measurement accuracy, tests were performed on normal hearing adults. Assuming that pure tone thresholds are not different for the ear either open or occluded, thresholds measured (tracking procedure) with an earphone were compared to those measured via a hearing-aid receiver and earmold-probe assembly at frequencies between 500 Hz and 6.0 kHz. Both systems were calibrated on the same simulator. No significant differences were observed between the two sets of threshold measurements up to frequencies of 6.0 kHz. Subsequent measurements indicated that a large parallel vent in the earmold had no effect on the probe microphone accuracy. Results suggest that the probe-earmold procedure can be used to measure occluded eardrum SPL up to frequencies of 6.0 kHz.
Mechanisms of flow-excited cavity tones at low Math number
Authors: Elder S. A. , Farabee T. M. , DeMetz F. W.
Published: October 2005

Experimental studies on a wall-mounted cavity in laminar and turbulent subsonic flow provide new insights into mechanisms of tone generation as wind speed is varied. Contributions to tone generation from turbulent boundary layer fluctuations, acoustic background noise, sheartone feedback coupling, and cavity resonator feedback coupling, respectively, can now be quantitatively sorted out on the basis of theoretical models. Effect of turbulent eddy size on random-noise cavity excitation is found to agree qualitatively with wave filter hypothesis, A new theory of laminar pipetones will be presented which is similar to but complements an earlier model of turbulent pipetones. This includes an improved method of estimating phase velocity of interface waves at pipetone resonance frequencies. [The work was supported by a GHR contract with the Naval Ship Systems Command, administered by the David W. Taylor Naval Ship Research and Development Center, Carderock, MD.]
The perception of intervocalic /t/ and /d/: A comparison of child and adult listeners
Authors: Norwood John A.
Published: October 2005

Child and adult listeners were presented with two sets of stimuli to be judged as either petal or pedal. One set was constructed by editing a naturally produced token of petal, and the other, a token of pedal. Construction of each set involved systematically varying three acoustic cues important for the voicing distinction between intervocalic stops: (1) preceding vowel duration, (2) stop closure duration, (3) voice onset time. Besides the silent closures used in each set, some tokens with glottal buzz were used in the pedal set. Preliminary analysis shows that, for silent closures, VOT had the strongest effect on the subjects' responses, except for the adults' responses to stimuli created from petal. There closure duration had a slightly greater influence. Closure duration otherwise had a strong effect just secondary to VOT. The effect of preceding vowel length, though observable, was weak. Stimuli with buzz-filled closures were heard almost entirely as pedal, regardless of other cue values. Adults and children showed similar overall patterns of responses, but with the adults being more sensitive to changes in vowel and closure duration.
Effects of two sources of interference in speeded classification for normal and language disordered children
Authors: Greyerbiehl Dianne H. , Yeni-Komshian Grace H. , Meltzer Richard H.
Published: October 2005

Two speeded classification tasks were conducted with 32 normal and language disordered children, 7–9 years of age. In the first task, the control conditions were (ba vs da) and (ab vs ad); and the orthogonal condition was (ba,ab vs da,ad). In this task subjects tracked the phonemes, /b/ and /d/, while ignoring the syllable type, CV and VC. In the second task, the control conditions were (ba vs ab) and (da vs ad); and the orthogonal condition was (ba,da vs ab,ad). In this task they tracked the syllable type while ignoring the phonemes. Within each task the stimuli were presented in quiet or in noise, and a 40- or 80-ms transition rate. Results indicate no group differences on the control tasks. In the orthogonal conditions, the normals were better than the language delayed. In general the task that required the subjects to track the phoneme and ignore the syllable was easier than the task in which they tracked the syllable and ignored the phoneme. The effects of background noise and formant transition rate were significant in the phoneme tracking task but not in the syllable tracking task.