bluuebunny/crossref_metadata_2025 huggingface dataset:
A proposed model for the acoustic reflex
Authors: Gelfand S. A. , Silman S.
Published: October 2005

A qualitative model based upon the relative contributions of the inner and outer hair cells is proposed as a parsimonious basis for acoustic reflex behavior in response to tonal and broad-band activators in normal and impaired ears. It calls upon the localized, divergent innervation of the inner hair cells (IHCs); and the convergent; specially distributed innervation of the outer hair cells (OHCs), which have lower thresholds but are more susceptible to damage than the IHCs. The OHCs are viewed as the basis for the lower reflex threshold, bandwidth effect, and the curvilinear portion of the reflex growth function for broad-band activators in normals. The elevated reflex threshold, and the absence of both the bandwidth effect and the curvilinear portion of the growth function for broad band activators in impaired ears is attributed to the absence/damage of OHCs. The total reflex thresholds in normals and in mildly impaired ears, as well as the linear growth functions for tones and the linear portion of the broad-band growth function, is attributed to the IHCs. The displacement (in terms of activator SPL) of the linear portion of the broad-band growth function in impaired ears reflects the absent curvilinear portion due to OHC damage. The tonal reflex threshold is elevated, so that the growth function is displaced, due to damage of the IHCs in moderate to severe hearing losses. The slope of the growth function is unchanged, however, since energy is integrated (due to the recruitment of additional IHCs as the excitation pattern widens). [Supported by Veterans Administration.]
Method for detecting release of substances from the toad (Xenopus laevis) skin during water flow stimulation of the lateral-line organ
Authors: Bledsoe S. C. , Bobbin R. P. , Morgan D. N.
Published: October 2005

A major criterion that must be fulfilled by any transmitter candidate is to show that it is released following stimulation of the end-organ. The purpose of this study was to detect stimulus-induced release of the transmitter substance from the toad lateral-line organ. Isolated skins were mounted on a plastic cylinder with an O-ring. In this configuration the inner surface of the skin formed the bottom of a collection reservoir containing frog Ringer's. The cylinder with attached skin was positioned on a chamber so that pulsatile water flow could be applied tangentially to the outer (cupular) surface of the skin. The Ringer's was sampled during periods of water flow stimulation and during periods of no stimulation, then frozen and assayed for various substances by Drs. R. and I. Thalmann, Washington University, St. Louis, Missouri. Results from these experiments will be presented and discussed in relation to current hypothesis concerning the nature of the afferent transmitter substance. [Supported in part by NIH and the Kresge Foundation.]
Effects of response criterion on the frequency characteristics of a mechanoreceptor (Pacinian corpuscle)
Authors: Bolanowski S. J. , Verrillo R. T.
Published: October 2005

The vibrotactile frequency characteristic measured psychophysically on humans shows a flat, low-frequency (10–50 Hz) portion and a U-shaped, high-frequency (50–700 Hz) portion. Considerable evidence indicates that the high-frequency portion of the characteristic is mediated by the Pacinian corpuscles population. Neurophysiological measurements on individual corpuscles stimulated directly by sinusoidal displacements also show a characteristic U shape. The neural frequency characteristic decreases in bandwidth, sensitivity, and best frequency when the underlying neural response criterion is increased from low-firing rates to rates approximating 1 spike/cycle. The slope of the lower limb of the curve remains at about 12 dB/octave, regardless of the criterion. The U-shaped portion of the psychophysical frequency characteristic is best approximated by the neural response curve when the 1 spike/cycle criterion is used. The results were obtained on mechanoreceptors excised from cat mesentery and are consistent with physiological and psychophysical results shown by other investigators. This analysis demonstrates the importance of choosing a proper neural criterion when modeling sensory systems and relating physiological and psychophysical results. [Work supported by NIH.]
Binaural masking level differences with a variety of waveforms
Authors: Henning G. Bruce
Published: October 2005

Binaural masking level differences (BMLDs) were measured in a standard two-interval forced-choice detection task. The signals were 250 ms bursts of pure tones, amplitude-modulated waveforms with either high- or low-frequency carriers as well as 20-μs clicks. The pure tones and clicks were presented either with zero phase difference between the ears or with an 180° phase difference between the ears; the AM tones were presented in several different interaural phase conditions, only some of which lead to changes in the apparent location of the signal source. The noise against which all the signals were detected was white, broadband, has a spectrum level of 34 dB, and was identical at the ears. BMLDs were invariably small with high-frequency signals and with clicks. With low-frequency signals the magnitude of the BMLD depended on the observers' ability to lateralize the signal. [This research was supported by the Medical Research Council.]
Dependence of interaural correlation jnds on noise bandwidth
Authors: Gabriel K. J. , Colburn H. S.
Published: October 2005

Measurements of interaural cross-correlation jnds at reference correlations of +1 and 0 will be reported for five narrow-band Gaussian noise waveforms (with bandwidths of 1 kHz, one third octave, one tenth octave, 10 Hz, and 3 Hz; all centered around 500 Hz) and for a wide-band noise waveform (4.5 kHz). In order to precisely and conveniently control the spectral composition of these noise waveforms, they have been synthesized via sums of random amplitude, random phase cosines (a set of 64 waveforms was generated for each of the six bandwidths). The data will be compared with predictions of correlation-based detection models and with previous experimental work [I. Pollack and W. J. Trittipoe, J. Acoust. Soc. of Am. 31, 1616–1618 (1959)]. Preliminary results at a reference correlation of +1 suggest that the cross-correlation jnd decreases for bandwidths less than or equal to one third octave by approximately a factor of 4. [Work supported by NIH.]
Interaural time discrimination as a function of stimulus frequency and duration
Authors: Grantham D. Wesley , Yost William A. , Passow Betty
Published: October 2005

A 200-Hz-wide noise (96 dB/octave skins), 75 dB SPL, was presented binaurally in a two-interval forced-choice task. Center frequency was 250, 500, 1000, 2000, or 4000 Hz. Signal duration was varied from 20 to 300 ms. In one interval an interaural delay of Δt was introduced to the waveform in the left channel; in the other interval the same delay was introduced to the waveform in the right channel. Observers indicated whether the direction of apparent movement produced by the two bursts was “left” or “right.” Threshold Δt (delay required for 75% correct responses) was 7–10 μs for the three lower-frequency signals for all durations tested. For the higher-frequency signals, performance improved with signal duration: threshold Δt decreased from about 100 μs to about 60 μs for both 2000-Hz and 4000-Hz signals as duration increased from 30 to 300 ms. Extreme variability of responses prevented us from obtaining psychometric functions at 20 ms at the high frequencies. The data support the conclusion that lateralization at low frequencies is based on fine-structure, at high frequencies on envelope, of the stimulus. The data will be discussed in terms of binaural temporal processing.
Interaural envelope discrimination
Authors: Moss P. J. , Colburn H. S.
Published: October 2005

We measured the jnd in the interaural delay of the envelope (onset and offset) of tone bursts. There were no interaural differences in the fine structure. The jnd was determined for three rise times (5, 50, and 140 ms) and two frequencies (500 and 4000 Hz) for four subjects at 74 dB SPL. The jnd is a few hundred microseconds for all subjects at 4000 Hz, with only a slight dependence on the rise time. At 500 Hz, except for one subject, the jnd increases from a few hundred microseconds to about 1 ms as the rise time increases from 5 ms to 150 ms. One subject shows exceptional results at 500 Hz: his jnd is 2 ms, 20 ms, and 35 ms for the three rise times used. For the two subjects tested at several levels, the jnd increases dramatically as the level decreases. In general, these results illustrate the importance of interaural envelope information even for signals with slow onsets and offsets. [Work supported by NIH.]
Effect of one tone burst on the localization of a second tone burst
Authors: Canévet G. , Germain R. , Scharf B.
Published: October 2005

The level of a 1000-Hz tone burst required for localization and that required for detection were independently measured in the presence of a preceding tone burst as a function of the frequency difference between the tones. Three subjects made the judgments in an anechoic room. A 30-ms filtered burst—the signal—was delivered first from one double-cone loudspeaker 15° to the subject's left and then from another to his right. A third speaker directly in front delivered a 30-ms masker, 20 ms prior to each signal. At masker frequencies between 500–930 Hz, signal level had to be about 20 dB higher for perception of a change in direction, than for 80 percent detection. (Change in direction was usually heard as a small shift from left to right in the locus of the fused ensemble comprising masker and signal.) Evidently, the precedence effect applies not only when sounds are identical but also when they differ considerably in frequency. Moreover, even a soft lagging sound contributes to the perceived direction of the fused ensemble.
Effects of binaural maskers on the subjective laterality of diotic targets
Authors: Rubinov Eliot M. , Stern Richard M.
Published: October 2005

The effect of a simultaneously-presented dichotic masker on the subjective lateral position of a 500-Hz diotic target was measured as a function of masker interaural time and intensity differences and target-to-masker ratio. The target-masker complex was presented in temporal alternation with a 500-Hz binaural pointer tone. Subjects adjusted the interaural intensity difference of this pointer to match the perceived laterality of the partially masked target. It was found that the presence of time-delayed maskers at intermediate target-to-masker ratios tended to attract the perceptual image of the target toward that of the masker, while amplitude-shifted maskers tended to displace the image of the target away from that of the masker. At target-to-masker ratios closer to detection threshold, however, the target tended to be perceived at or near the masker in either case. These dependences are discussed in terms of models of binaural interaction and compared to the ability to discriminate interaural time and intensity differences of the target in the presence of similar maskers. [Supported by NIH.]
Interaural time discrimination in noise
Authors: Ito Y. , Thompson C. L. , Colburn H. S.
Published: October 2005

The just-noticeable difference (jnd) in interaural time delay for a narrow-band noise signal has been measured for ten interaural conditions of wide-band masking noise. The narrow-band signal is a one third-octave noise band at 500 Hz. The masking noise covers 250–1500 Hz. Both signal and masker have an overall level of 56 dB SPL. The masked jnds for narrow-band noise are consistent with those for tones [M. F. Cohen, J. Acoust. Soc. Am. 64, S35(A) (1978)] in that the progression of increasing difficulty (increasing jnds) is interaurally identical musket (NO), uncorrelated masker (NU), and antiphasic masker (Nπ). Note that this progression is exactly opposite to that expected from detectability results. Other interaural conditions of the masker include an interaural delay of τ = 100 μs (Nτ), an interaural attenuation of α dB (Nα), or both (Nτ,α), where α is realized by attenuating one ear and is chosen for each subject to center the masker when both τ and α are present. The jnds with these maskers show that the Nτ,α case is more difficult than Nτ or Nα. [Work supported by NIH.]
The effect of noise on time/intensity trading in lateralization
Authors: Gaskell H. , Henning G. Bruce
Published: October 2005

A standard two-interval forced-choice lateralization task was used to determine interaural delays and interaural amplitude ratios which, when opposed in quiet, led to chance lateralization, i.e., the opposed cues formed time/intensity trades. The signals were 20-μs clicks or 250-ms bursts of: (1) a 304-Hz tone, and (2) a 3952-Hz carrier amplitude modulated to a depth of 100% at a modulation rate of 304 Hz. The addition of various levels of broadband white noise did not influence the relative effectiveness of the two lateralization cues with pure tone signals; however, the addition of noise to clicks and to AM waveforms led to lateralization judgments in which the cue based on interaural delay was less effective than it had been in quiet. This effect can be explained by changes in the frequency region used by Observers listening to clicks but not to AM waveforms. [This research was supported by both Science and the Medical Research Council.]
On the use of multiple perceptual images in binaural discrimination experiments
Authors: Stern Richard M.
Published: October 2005

The results of previous “time-intensity tradability” experiments and binaural detection experiments using phase-coherent targets and maskers have indicated that other attributes of a low-frequency binaural tone besides pitch, loudness, and the laterality of its dominant spatial image are available as cues in interaural discrimination experiments. These results are compared to predictions of simple models based on optimal processing of two partially correlated Gaussian decision variables derived from the interaural time and intensity differences of tonal stimuli. Models in which one decision variable is proportional to time delay and the other to intensity difference fail to describe the experimental data. However, the predictions of a model using one decision variable related to the laterality of a time-intensity-traded image and a second variable proportional to either the interaural time or intensity difference alone are in reasonable agreement with the experimental results. Individual differences across subjects and experiments were found in model parameters related to the correlation of the two decision variables and the time-intensity trading ratio that most closely fit the data. [Supported by NIH.]
Spatial stream segregation
Authors: Judd T.
Published: October 2005

When the tones of a slow (e.g., 1 tone/s) tone sequence alternate between widely placed speakers, observers report hearing a single melody which moves back and forth between the speakers like a pingpong game. When the same sequence is presented more rapidly (e.g., 8 tones/s), observers report hearing two independent melodies or streams, one from each speaker (Spatial Stream Segregation). At intermediate speeds the sequence can be heard in either fashion depending upon attentional biases and other factors. Subjects are poor at discriminating between two rapid tone sequences when the tones alternate between widely placed speakers and the discrimination depends upon appreciating the temporal order of the tones across speakers; but they are good at the discrimination when all of the tones come from a single speaker. Thus, Spatial Stream Segregation impairs across-stream temporal order judgments. All of these observations are analogous to the phenomenon of Primary Auditory Stream Segregation [A. S. Bregman and J. Campbell, J. Exp. Psychol. 89, 244–249 (1971)] where the tones are widely separated in pitch range instead of in space.
Discrimination of dichotic tonal sequences in ear dominance perception of pitch
Authors: Pfannebecker B. , Tolhurst G. C.
Published: October 2005

Four dichotic tonal sequences [B. Pfannebecker and G. C. Tolhurst, J. Acoust. Soc. Am. 63, S1–S51(A) (1978)] were played through headphones to normal hearing listeners. Each listener was instructed to attend a specified ear and to produce graphic responses to the sequences. Discrimination scores for each ear were determined by comparing the graphed responses to graphic patterns of the actual stimulus sequences. An ANOVA indicated that discrimination scores, obtained by averaging scores for both ears, were different as a function of the number of discrete frequency changes (1, 3, 5, or 7) in the stimuli (p < 0.001). However, when the effects of the ear to which listeners were instructed to attend and the number of frequency changes in the tonal sequences were analyzed, there was no difference in response for attended ears. The essentially equilateral sensitivities by the ear to which listeners were instructed to attend did not indicate an ear advantage for tonal sequence pitch information in the compelling ear dominance perception of pitch.
Perception of musical styles
Authors: Marcus K. T. , Mathews G. W.
Published: October 2005

We carried out an experiment to determine a multidimensional scaling of music styles. A set of short examples of pieces for solo piano were chosen, two each from five style periods: Baroque, Classic, Romantic, 20th Century Modern, and Jazz. The durations of each piece ranged from 1 to 3 min. We played these pieces to 40 subjects ranging from professional musicians to naive listeners. After an initial exposure to the ten pieces, the subjects were asked to listen to and to make 45 similarity ratings on all possible pairs of pieces. The subjects were also asked to rate each piece on 19 bipolar scales. Both data sets were run through the INSCAL program which constructed a two-dimensional similarity space to represent the subjects' judgments. We interpreted the dimensions as a Romantic-Baroque dimension and a Modern-Old dimension. A correlation was noted between musical expertise and the importance the subject attached to the dimensions. The Modern-Old dimension was more important to musicians; the Romantic-Baroque dimension was more important to nonmusicians.
Automatic tone identification in continuously played music
Authors: Piszczalski M. B. , Galler B. A.
Published: October 2005

Successive short-time (32 ms) spectra are calculated either with the FFT or, experimentally, with the C2T CCD to yield the digitized spectra. Pattern matching on the resulting digital spectrogram is done to detect the sharply emerging spectral peaks that often indicate tone beginnings. A check is made for the overlap of previous partials onto the hypothesized new tone at such points and these past partials are filtered out (over time) until they disappear or a new tone is suggested by another emerging spectral peak condition. A pitch and amplitude estimate is then made for each short-time section (described in “Predicting musical pitch from component ratios” available from the authors). The resulting pitch versus time contour is first smoothed and then tone segmentation is performed by seeking tone-transition patterns indicated by abrupt jumps in pitch or associated amplitude crossings over a minimum amplitude threshold. Single notes probably fragmented by spurious octave jumps are compacted and other very short tone-segment fragments are merged into the preceding longer tone. The melodic sequence has been well captured (less than 10% gross errors) with no external modifications required for a variety of instrumental music of varying styles we have processed. Better time resolution and use of context appears necessary for further improvements. [Work supported by NSF.]
Stretched tones with only octave partials: The unsanctified octave
Authors: Cohen Elizabeth
Published: October 2005

Stretched-octave tones whose only partials are stretched octave partials were generated on the Sampson Digital Synthesizer according to the relation Fn = anFo. where n = 1,2,4…. These partials are separated by distances greater than a critical band yet subject reports of difference in tone quality suggest an interaction among the partials. For a = 2. a tone with octave partials only has been traditionally perceived as thin and clear. [J. R. Pierce, J. Acoust. Soc. Am. 40, 249 (1966); IRCAM communication, April 1976]. Departures from a = 2 show progressively greater variance from this percept. The expected beats of mistuned octaves are heard in these tones only with great difficulty and under special conditions. An explanation for the change in tone quality was sought by looking at the rate of phase change between partials. Reasons for interaction phenomena in such widely stretched partials are discussed.
A course in acoustics for the general college undergraduate
Authors: Walkling R. A.
Published: October 2005

Acousticians in the academic profession who have a broad interest in the subject have an excellent opportunity to help increase the public's awareness of acoustical matters. The general college undergraduate is often looking for an isolated course to fill out a schedule. Since the field of acoustics touches on a great many other disciplines, it can catch the interest of students with a variety of backgrounds and experiences. National concern about acoustical problems also sparks interest in the subject. A general survey course in acoustics can capitalize on this interest and serve a wider audience than can a more specialized course like musical acoustics. A course of this type has been taught three times over the last five years at the University of Southern Maine, a two-campus state university serving the southern part of Maine. Several scheduling formats have been tried and a wide variety of students have enrolled, with enrollments almost doubling each time the course has been offered. The course requires only a little background in mathematics, covers most of the major acoustical areas, and concludes with a required 5–10-page term paper, as well as a final exam. Student response has been positive.
Musical acoustics experiments
Authors: Ivey Elizabeth S. , Josephs Jess J.
Published: October 2005

For more than 25 years a course in Musical Acoustics has been offered at Smith College. Demonstrations of some unusual experiments performed by students in this course will be presented. For example: (1) An orchestral piece is played through speakers in a room and tape recorded. The recording is played back in the same room and rerecorded on a second recorder. After repeating this process five times, the last recording provides the room mode vibrations emphasized above all other frequencies. (2) While reading aloud, one's own words are heart through earphones, delayed slightly in time, producing garbled speech. (3) The minimum duration time for pitch perception of a pure tone is shown to depend upon a certain number of cycles being presented, independent of frequency. (4) Binaural hearing is demonstrated using a “dummy head” made of plastic cups and microphones. (5) Two slightly different pure tones are presented binaurally and then stereophonically. The differences in what one hears in pitch resolution are discussed. In addition, plans for a small inexpensive anechoic chamber will be available. Photographs of one built by Smith College students will be shown.
Flexural disk transducers for low-frequency applications
Authors: Fife M. E. , Martin J. E. , Wilder W. D.
Published: October 2005

The flexural disk transducer has been recognized for many years as a viable candidate for applications requiring low-frequency sound sources. Since the establishment of the theory by Woollett [“Theory of the Piezoelectric Flexural Disk Transducer with Applications to Underwater Sound,” USL Report No. 490, December 1960], much of the development effort has been directed toward improved fabrication and mounting techniques which have resulted in high electroacoustic efficiencies, increased power handling capabilities and greater correlation between theory and measurements. Programs to provide greater depth capability and improved bandwidths are continuing. The combination of specific requirements impose certain limitations upon the design of the flexural disk and dictate tradeoffs where possible. These limitations and tradeoffs are described as they relate to transducer applications at low frequencies requiring high acoustic-source levels, broadband widths, and deep submergence operation. Two transducers have been fabricated, one below 100 Hz to demonstrate potential VLF applications and limitations, and another at 250 Hz for evaluation of the power capabilities of large diameter (33 in.) mosaic disks. The designs, test results, and a summary of possible design trade-offs are presented.
The Helmholtz resonator as a high power deep-submergence source for frequencies below 500 Hz
Authors: Henriquez T. A. , Young A. M.
Published: October 2005

The design criteria for a deep-submergence source utilizing the acoustic principle of the Helmholtz resonator is discussed. For frequencies below 500 Hz, the size of any acoustic source is necessarily large if any great amount of power is to be radiated. The advantage of the Helmholtz resonator becomes apparent when compared to a typical Tonpiltz resonator. Disadvantages are highly reactive electrical loads, which require high driving voltage and reactive power. Trade-offs between physical size and bandwidth can be made for maximum efficiency.
Present status in flextensional transducer technology
Authors: Brigham G. , Glass B.
Published: October 2005

The use of any of the various classes of flextensional transducer has been historically limited by an inability to accurately design them and by their apparent unsuitability to phased and/or conformal arrays. To reliably design any type required the development of a cost efficient, relatively accurate, preferably algebraic mathematical model, but most early analytical research centered around large computer models; generally these were accurate but too complex and expensive to provide important physical insight. More recent work on an equivalent circuit for the class IV transducer produced unrestrained equations of the required accuracy for peak radiated power, resonant half power bandwidth, resonant frequency and the optimum power-bandwidth product design which represents the smallest, lightest transducer of this type for any given acoustic requirements. This paper briefly summarizes the analytical background to the model, recent experimental work, application to several sonars including both expendable and ship systems, and the ultimate capabilities of the class IV type.
Ultrasonic wave scattering from planar discontinuities in solids
Authors: Adler Laszlo
Published: October 2005

Ultrasonic wave scattering was studied from elliptical discontinuities of various aspect ratios (ratio of major to minor axes). The discontinuities are in titanium which is immersed in water. The amplitude of the scattered wave is measured at various angles for broadband (12-MHz wide) pulses. The experiment which is in the ka > 1 region is analyzed based on elastodynamic diffraction theory. This theory offers an inversion process to obtain the size of the discontinuity. There is very good agreement between experiment and theory. [This research was sponsored by the Center for Advanced NDE operated by the Science Center, Rockwell International, for the Advanced Research Projects Agency and the Air Force Materials Laboratory under Contract F33615-74-C-5180.]
Experimental and theoretical study of the scattering of focused ultrasound from microparticles in fluids
Authors: Edwards P. L. , Jarzynski J.
Published: October 2005

The scattering of ultrasonic pulses (frequency ∼10 MHz) from spherical microparticles (∼100-μm diam) was studied experimentally. A method of mounting the microspheres was developed which allows the x, y, and z coordinates of the scatterer to be finely adjusted. Measurements of echo emplitude were made with and without a focusing lens on the transmitting transducer. A quantitative estimate is obtained for the enhancement in sensitivity, by means of focusing, of ultrasonic detection of microparticles in fluids, and a comparison is made with theoretical predictions.
Resonance theory of elastic shear wave scattering from fluid spheres
Authors: Brill D. , Gaunaurd G. , Überall H.
Published: October 2005

A vector spherical harmonic expansion is made of the vector potential for a polarized shear wave in an elastic lossless medium incident on and scattered by a spherical fluid occlusion. The boundary conditions are dealt with in terms of the two Debye shear potentials, s and t, for this incident vector potential. The s potential scatters into both another s potential and also mode converts into a compressional p potential. The t potential scatters only into another t potential with no mode conversion. Scattering amplitudes are cast in a series of resonance terms. The scattered p and s potentials exhibit resonances, however the t potential does not. Plots of the first four scattered amplitudes are shown for the sp, ss, and tt scattering modes. When the background scattering amplitude from an evacuated spherical cavity is removed from each partial wave contribution, the remaining amplitude is a clear series of liquid sphere resonances. This work completes the determination of the scattering matrix elements for a fluid sphere in an elastic medium. [H. Ü. is also at The Catholic University of America, Washington, D.C. 20064, and was additionally supported by ONR, Code 421.]
Intracochlear oxygen tension during and after loud sound exposure
Authors: Nuttall Alfred L. , Lawrence Merle , Burgio Paul
Published: October 2005

Inner ear oxygen tension can be a measure of metabolic capacity in the inner ear, in that the energy production of the sensory epithelium could draw upon the available oxygen in the cochlear fluids. During periods of loud sound the metabolic needs of the inner ear presumably increase in order to meet the demands of greater transduced energy. Increased magnitudes of cochlear potentials reflect this higher demand. Additionally, loud sound is also known to have an effect (directly or indirectly) on the state of capillary networks within the inner ear. In the present experiments on guinea pigs, oxygen sensitive microelectrodes were placed into various fluid compartments of the inner ear to measure oxygen changes during the application of intense loud sound. In other experiments, similar electrodes, calibrated for absolute oxygen tension, were placed into the perilymph and endolymph of the first cochlear turn 2 to 7 h after a 4 h period of 120 dBC broad-band noise exposure. Oxygen levels did not change significantly or consistently during acute loud sound exposure. The chronic loud sound exposure. on the other hand, resulted in significantly elevated levels of perilymphatic and endolymphatic oxygen tension. These results will be discussed and related to present and past histological findings. [This work was supported by Public Health Service Grants NS 05785 and NS 11731.]
A set of concatenative units for speech synthesis
Authors: Olive Joseph , Liberman Mark
Published: October 2005

In a previous paper [J. P. Olive, “Rule Synthesis of Speech From Dyadic Units”, IEEE International Conference on Acoustics, Speech and Signal Processing, 568–570, (1977)], we discussed a speech synthesis by rule scheme where the segments used for synthesis were obtained from natural speech. These segments included the consonants and the transitions from consonants to vowels, vowels to vowels, and vowels to consonants. Each synthesis parameter was defined by two sets of LPC area parameters, and in the concatenative process, straight line interpolation was used to obtain the complete set of area parameters. Informal listening and some formal intelligibility testing revealed that this simplified description of the synthesis segments was not sufficient to produce the kind of speech that would satisfy us. Consequently, it was decided to expand the definition of the set of concatenative units. Specifically: (1) the number of phonetic segments defining a synthesis unit can vary from one to three; (2) arbitrary number of area parameter vectors can be stored for a given synthesis unit; and (3) a facility is provided for expressing transition durations and amplitude rules for synthesis units or classes of units. This paper will discuss the details of a more complete and accurate set of concatenative units.
A demisyllable inventory for speech synthesis
Authors: Lovins J. B. , Macchi M. J. , Fujimura O.
Published: October 2005

English syllables can be treated as a syllable core, decomposable into initial and final demisyllables, plus optional word-final phonetic affixes (e.g., /s,z,t,d,θ/) [Lovins and Fujimura, J. Acoust. Soc. Am. 60, S75 (A) (1976)]. An inventory of 835 demisyllables, five phonetic affixes, and 100 reduced-vowel units (CV or VC syllables) has been prepared in the form of LPC parameters. This inventory allows us to generate any of the ten thousand possible English syllables. An initial demisyllable is composed of an initial consonant or cluster, plus a fixed-length segment which includes the CV transition; a final demisyllable contains the major portion of the syllable nucleus, plus postnuclear consonant(s). We have found it generally appropriate to produce “tense” or “long” syllabic nuclei by concatenations such as /Cɪ−/ + /−iyC/ For stressed syllables, this allows a reduction of the set of initial demisyllable vowels to /ɪ,ɛ,æ,a,ʌ,ɔ,ᴜ/. Final demisyllables distinguish all fifteen nuclei. Only two spectral smoothing rules are needed to derive syllable cores from concatenated initial and final demisyllables. Results of naive listeners' perceptual evaluation of a sample set of concatenated monosyllables will be discussed. We will also present a tape recording of sentences produced from the inventory.
A versatile vector processor for multichannel speech recognition
Authors: Osborn R. R.
Published: October 2005

A 32-bit 122-ns cycle time computer has been developed for use as both a speech research tool and as the basis of a speech recognition product. It is structured as a single instruction stream device with three data buses independently controllable during each cycle. Function modules are connected between the buses. The timing and architecture are straightforward, allowing the addition of new functions as independent modules. Pipelines can be configured under software control and the instruction set is well structured and small, eliminating some of the complications of microcoded implementations. A standardized configuration is described which allows eight simultaneous channels of isolated word recognition in real time. The standardized configuration is currently being produced as part of a speech recognition product line.
An in-depth psychoacoustical study of a patient with vestibular schwannoma
Authors: Florentine M. , Thompson C. L. , Colburn H. S. , Durlach N. I.
Published: October 2005

Monaural and binaural capabilities of a thirty-year-old male with a unilateral vestibular schwannoma were studied. His right ear appeared to be within normal limits for all tests. The threshold in his left ear was elevated approximately 20 dB from 250 to 1400 Hz and fluctuated sharply above 1400 Hz. Stimuli were pure tones and one-third-octave noise bands at three frequencies: 0.5, 1, and 3.3 kHz. Alternate-binaural-loudness matches showed decruitment. Frequency discrimination and frequency selectivity were reduced in the impaired ear, as indicated by large difference limens and broad tips of the psychoacoustical tuning curves. Intensity discrimination in the impaired ear was impoverished at all levels and frequencies except near threshold at 1 kHz. Experiments on interaural discrimination failed to demonstrate any sensitivity. For interaural amplitude, all above-chance performance could be attributed to monaural cues in the normal ear. For interaural time and interaural correlation, no sensitivity could be demonstrated. [Work supported by NIH.]
Temporal summation of central auditory stimulation in normal and deafened cats
Authors: Gerken George M.
Published: October 2005

Two stimulus parameters, number of pulses and interpulse interval, were varied to determine temporal summation effects using behaviorally-measured, electrical-stimulation thresholds for eleven permanent electrodes placed in auditory system and other brain loci. Detection thresholds generally decreased with increased number of pulses and with shorter interpulse intervals. Parametric threshold data could be described by a time constant, a sensitivity factor, and a compression factor. For three placements in the vicinity of cochlear nucleus, bilateral cochlear destruction, on the average, reduced the time constant by a factor of 100 and increased sensitivity by 9.2 dB. Classic strength-duration time-constants were shown to be equal in magnitude to the time constants for temporal summation in the deafened animals but not in the normal-hearing animals. The hypersensitivity following deafness is associated with a marked functional alteration in temporal integration, at least in the lower level of the auditory system. [Supported in part by grant NS 08612 from NIH.]
Speech perception of subjects with bilaterally symmetrical and asymmetrical losses
Authors: Nabelek Anna K. , Mason David
Published: October 2005

Four subjects with asymmetrical hearing losses listened to the Modified Rhyme Test in quiet and noise (babble of 20 voices) in the following conditions: binaural, monaural, unaided, and aided. Tests were performed in an audiometric room. Speech and noise were presented through two separate loudspeakers forming ±30° azimuths. The binaural and monaural scores were similar. The binaural scores in quiet were reduced by 19% to 29% and by 12% to 28% in the unaided and aided conditions, respectively, at speech-to-noise ratio, S/N = +5 dB. Four subjects with bilaterally symmetrical hearing losses were selected to match the thresholds of the “preferred” ears and the scores in quiet in the asymmetrical group. The binaural scores in quiet were reduced by 2% to 9% and by 2% to 18% in the unaided and aided conditions, respectively at S/N = +5 dB. In comparison to binaural, monaural scores were slightly lower and decreased more rapidly in noise. It appears that subjects with asymmetrical losses can perform as well as subjects with symmetrical losses in quiet but they may be affected more by the background noise. [Supported by NIH.]
Categorizing hearing loss from speech recognition data II: Results of a check against clinical tests
Authors: Corliss E. L. R. , Moore E. F.
Published: October 2005

Patients with clinically diagnosed hearing losses were given the verbal tests and threshold measurements used in the USPHS Health and Nutrition Examination Survey for 1971–75. A computer program for categorizing hearing losses from recognition data [J. Acoust. Soc. Am. 61, S5(A) (1977)] was applied to the results of the tests. permitting comparison between results of the ordinary clinical tests and computer-aided diagnoses. The program estimates mixtures of losses whereas clinical tests other than hearing by bone conduction primarily diagnose the major component. For minor hearing losses, the speech test does not resolve unequivocal differences between conductive and sensorineural losses, but for higher threshold elevations it appears to resolve conductive, sensorineural, and recruiting components.
Temporal patterning in the perception of spectrally ambiguous speech by deaf and normal listeners
Authors: Stoker R. G.
Published: October 2005

It has been suggested [D. H. Klatt. J. Acoust, Soc. Am. 64, S114(A) (1976): L. A. Streeter, J. Acoust. Soc. Am. 64, 1582–1592 (1979)] that temporal information in speech independently influences syntactic analysis. Under conditions of high spectral ambiguity such as is present in severe sensorineural deafness this temporal pattern analysis might be a primary cue for speech perception. The perception of nonlinguistic temporal patterns by deaf and normal subjects was investigated for the visual, auditory, and auditory-visual modalities using a matching paradigm. These data were compared to data from the same S's regarding their single modal and multimodal perception of speech under conditions of high spectral ambiguity (700-Hz low-pass filtering and modulated white noise). The ability to quickly and accurately perceive nonlinguistic temporal analogs of speech was found to be significantly correlated with the ability to comprehend degraded speech. The correlation was particularly marked for the auditory only condition in the right ear across all subjects. Significant effects were found for age, use of vision and hearing aid usage history of deaf subjects. No similar effects were noted for normal subjects.
Identification of synthetic /bdg/ by hearing impaired listeners in monotic and dichotic listening conditions
Authors: Dorman M. F. , Van de Grift Turek Sandra , Franks John R. , Summerfield Quentin , Raphael L. J.
Published: October 2005

Individuals with sensorineural hearing losses of both flat and sloping configuration evidence difficulty in speech understanding. To assess whether upward spread of masking of F1 is responsible for the poor identification of stop consonant place of articulation, we presented to hearing impaired listeners stimuli from along a [ba da ga] continuum in both monotic and dichotic (F1 to one ear; F2/F3 to the other ear) listening conditions. In the monotic conditions, hearing impaired listeners with similar audiograms evidenced great variability in labeling performance. In the dichotic conditions. performance did not generally improve although for a few listeners the improvement was striking. We suspect that upward spread of masking is not generally responsible for the poor identification of place in listeners with moderate, flat, and sloping sensorineural hearing losses.
The effects of syllabic compression on speech intelligibility for normal listeners with simulated sensorineural hearing loss
Authors: De Gennaro S.
Published: October 2005

Simulation experiments, involving normal listeners, were conducted to gain a better understanding of the effects of multichannel syllabic compression on a hearing loss characterized by reduced dynamic range and recruitment. Spectrally shaped noise was used to modify normal thresholds. Two impaired listeners from a previous study [R. P. Lippmann, L. D. Braida, and N. I. Durlach, J. Acoust. Soc. Am. 62, S90(A). (1977)], one with a sloping high-frequency loss and one with a flat loss, were simulated. Two linear systems and one compression system were studied under conditions which replicated the investigation with impaired listeners. The results of these experiments, like those with the impaired, showed no advantage for compression over a well-chosen linear system. However, the patterns of error response were different for the two types of processing for the features duration and frication. Voicing, place, and affrication were equally well perceived under both systems. In general, the accuracy of the simulation, measured in terms of speech reception performance, was much greater for the sloping-loss case than for the flat-loss case. [Work supported by NIH.]
Labiometrics I: Analysis of articulatory dynamics in relation to perception of vowels through lipreading
Authors: Erber N. P. , Sachs R. M. , DeFilippo C. L.
Published: October 2005

Vowel intelligibility is important in communication through lipreading. We studied articulation as one source of vowel confusion. An adult female was filmed frontally at 18 fps as she spoke a random list of ten vowels (/i, ɪ, ɛ, æ, a, ɔ, ᴜ, ᴜ, ʌ, ɝ/) and six diphthongs (/aɪ, eɪ, ɔɪ, aᴜ, oᴜ, jᴜ/) in /b/-V-/b/ context (five tokens each). This silent film was shown to twenty normally hearing adults for visual vowel identification. Confusion matrices indicated distinction between rounded (back) vowels, spread (front) vowels, and most diphthongs. High intelligibilities for /i, a, ɔɪ, aᴜ, oᴜ, jᴜ/ and low intelligibilities for /ɪ, ɛ, æ, ɝ/ were obtained, as in several previous studies. Not all tokens of a given vowel were equally intelligible. To examine the relation between articulation and vowel intelligibility, the film images were studied frame-by-frame. Measurements were made of frontal articulatory parameters presumed to be important for visual identification of vowels (vertical and horizontal mouth opening, lip thicknesses, teeth visibility, and jaw displacement). Data suggest that highly intelligible tokens are characterized by extreme articulatory changes and quasi steady-state segments. Tokens which evoke similar response distributions (regardless of intended vowel) exhibited similar patterns of articulatory change. The results suggest articulatory rules for optimizing communication of vowels through lipreading. [Work supported by NINCDS grant NS03856.]
Consonant recognition with the MESA
Authors: Sparks David W. , Grant Ken W.
Published: October 2005

Two moderately trained normal-hearing adults were tested in the identification of 22 consonant-vowel tokens presented live-voice in three unimodal and three multimodal receptive conditons: lipreading-alone, auditory-alone (low-pass filtered at 300 Hz), tactile alone (using the MESA system described by Sparks et al., 1978). tactile-visual (TV), audio-visual (AV) and tactile plus audio plus visual (TAV). Preliminary testing indicated that the identification of these CV tokens is poor when they are presented unimodally. The purpose of the present study was: (1) to determine which segmental speech “features” are extracted by subjects from specific auditory, visual and tactile inputs, and (2) presuming that features arriving from different modalities are complimentary, to determine if subjects could learn to integrate these features across modalities in order to identify speech tokens. Our results suggest that subjects extract complimentary features from within each modality and that these features can be integrated inasmuch as multimodal receptive performance far exceeds unimodal reception. Further, features extracted via tactile and auditory modalities are similar. Models of the ways in which listeners extract and utilize segmental features, independently and in combination. in making an absolute identification decision are discussed. [Work supported by NINCDS.]
The effect of occluded ear impedance on the eardrum SPL produced by hearing aids
Authors: Gilman Samuel , Dirks Donald
Published: October 2005

Experiments were designed to measure the effect of eardrum impedance on the SPL response at the eardrum for several earmold and hearing aid-receiver arrangements. Three ear simulators were used representing the eardrum impedances of the 10th, 50th, and 90th percentile of the population with normal middle ear function. Data from five commercially available hearing aid receivers were obtained using eardrum SPL and receiver input phrase responses as criteria. In addition to differences in SPL due to simulator impedances, there were significant variations due to interaction between receivers and simulators at the receiver resonant frequencies. Effects as large as 10 dB were measured at receiver resonances within the range of simulator and earmold impedances tested. Receiver input phase resonances of the simulators were compared to the responses from three equivalent real ears. Real ear data corresponded generally with the simulator data in interaction effects.