bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of phase on signal detectability as a function of temporal parameters of a tonal signal
Authors: Hanna Thomas E. , Robinson Donald E.
Published: October 2005

A method of adjustment was used to obtain thresholds for a 500-Hz sine wave added to a 150-ms sample of reproducible noise. Within a track, a single sample of noise was used. Across tracks, ten such samples of noise were examined. Signal phase, signal duration, and the temporal location of the signal in the noise burst were also varied across tracks. Differences in threshold as a function of phase could be described by assuming that the addition of the signal was like adding a sine wave of varying phase to another sine wave of fixed phase, with threshold defined as a constant amplitude resultant. With such a model, parameters of the “noise vector” can be estimated. We will report on changes in these parameters as a function of signal duration and temporal location, and on attempts to establish the spectral-temporal region of the noise burst that determine these parameters. [Work supported by NSF research grant BNS-77-17308 and by a Grant-in-Aid from Indiana University.]
Derivation of distributions of noise-induced hearing levels
Authors: Owens Laurence G. , Melnick William
Published: October 2005

The method for calculating estimates for noise-induced hearing levels (NIHL) adopted by members of the International Standards Organization (ISO) in Draft Proposal 1999/1, Assessment of Occupational Noise Exposure with Respect to Hearing Impairment, is to represent hearing impairment in terms of noise-induced permanent threshold shift (NIPTS) and a correction for the effects of aging. The proposal permits calculations using age-correction data either from a screened population free from otologic pathology and non-noise-induced hearing loss or from an unscreened population subject to all etiologies of hearing loss except working in a given noisy environment. We have modeled the distribution of an unscreened age-correction population from the data available in three sources [E. H. Berger, L. H. Royster, and W. G. Thomas, J. Occup. Med. 19, 10 (1977); USPHS, HEW, Series 11, 11 (1965); HANES I, catalog 4241 (1971–5)]. This model estimates the age-related hearing loss in terms of sex, age, audiometric frequency, and population percentile. These data are then combined with the NIPTS estimates derived from the ISO draft proposal to produce the population distributions of NIHL for the various parametric values.
Sensitivity to interaural intensity differences in tones and noises as measured with a roving-level procedure
Authors: Nuetzel John M.
Published: October 2005

Subjects' sensitivities to interaural intensity differences (IID's) were measured in a two-cue, two-alternative adaptive procedure which presented an IID in either the second or third of four 250-ms signal intervals. Overall level varied randomly over a ±10-dB range around 70 dB SPL. The roving level rendered useless any mortaural comparisons among the intervals. The IID converged on its threshold value in 1/4-dB steps, with the program terminating after a minimum of ten reversals. Results were obtained for interaurally identical and uncorrelated noise bands and for pure tones which were identical, antiphasic, or different in frequency at the two ears. These stimuli were chosen to assess the importance of fused-image lateralization in IID sensitivity. A principal finding was that subjects could perform the task even when they reported no such image. For instance, performance with uncorrelated wideband noise (threshold IID's around 0.4 dB) was only slightly poorer than with interaurally identical noise (thresholds around 0.33 dB). With pure tones from 500 to 4000 Hz, sensitivity to IID's persisted despite interaural frequency differences of over half an octave. The data are consistent with binaural models in which IID's are processed independently of interaural time differences.
Contralateral interferences and relative ear advantages for event timing in three-tone patterns
Authors: Lauter Judith L.
Published: October 2005

Not all listeners can perform above chance in the traditional dichotic-listening paradigm, particularly when sounds such as three-tone patterns are the stimuli. We have previously reported [J. Acoust. Soc. Am. Suppl. 1 69, S22 (1981)] that performance levels in ear-difference testing can be controlled by contralateral “interference” sounds that are not of the same class as the target sounds, e.g., a burst of narrow-band noise. Here we extend those findings to a study of the influence of event timing on ear advantages. Listeners identified the six orders of three pure tones, presented to the attended ear, while an interference sound was presented contralaterally. In one stimulus set, tone onsets were 200 ms apart; three other sets (100, 50, 25-ms onsets) were also tested. Results show: (1) individual performance levels can be adjusted by manipulating target dimensions and/or masker, (2) individuals differ as to absolute ear advantage shown for each stimulus set, and (3) patterns of relative ear advantages indicate that as event timing within a pattern becomes more rapid, ear advantage increasingly favors the right ear. [Work supported by NINCDS NS 03856.]
The effect of stimulus periodicity on frequency discrimination of noise bands
Authors: Arcos John T.
Published: October 2005

In order to test the effect of stimulus periodicity on frequency discrimination, we measured the just noticeable frequency change in stimuli with identical power spectra but different temporal characteristics. Our stimuli were made by adding two uncorrelated 50-Hz low-pass filtered Gaussian noise samples which were multiplied by 1-kHz sinusoids differing in phase by 5 degrees. The other condition was the same except that the 1-kHz carriers were 90 degrees out of phase. Stimulus periodicity was quantified by comparing histograms of intervals between zero crossings for the two stimuli. In the first condition, stimulus histograms were much more similar to a histogram obtained from a pure tone at the noise-band center frequency than were histograms of stimuli in the second condition. Preliminary results indicate that for a center frequency of 1 kHz, the difference limen (Δf) obtained from normal hearing adults using a two-alternative forced-choice procedure is half as large with the periodic stimulus as with the other condition. This suggests the importance of stimulus periodicity in frequency discrimination.
Fifteen years experience with a computerized ray tracing program
Authors: Krokstad A. , Strøm S. , Sørsdal S.
Published: October 2005

The computer program, giving a simultaneous picture of the space-, time-, and directional distribution of energy on any room surface, has been used as a design tool both in room acoustical planning and in designing sound reinforcement systems. The newest extension of the program and design cases are presented.
Calculation of subjective preference in concert halls
Authors: Ando Yoichi
Published: October 2005

This paper presents a method of calculating the subjective preference of sound fields in concert halls before their construction. Subjective preference judgments (paired comparison tests) were systematically performed in relation to the fully independent objective parameters of the acoustic information which is included in the signals to both ears. The sound fields with various combinations of listening level, early discrete reflections, subsequent reverberation time, and magnitude of the interaural cross correlation were simulated with the aid of a digital computer. The optimal conditions maximizing the subjective preference could be found for each objective parameter, because the parameter affected almost independently the subjective preference judgments. Based on the linear scale value which is obtained by applying the law of comparative judgment, we can calculate a total preference value according to the “principle of superposition.” Examples of the calculation of preference values using the plan and the cross section of a concert hall are demonstrated. [Work supported by Scientific Foundation of Ministry of Education, Japan.]
Sensitivity of echolocation in the megachiropteran fruit bat, Rousettus
Authors: Summers Carol A. , Suthers Roderick A.
Published: October 2005

The ability of Rousettus aegyptiacus to detect targets was measured in both quiet and white noise, using an obstacle avoidance protocol. Bats were trained to fly through a vertical plane of wires in total darkness; the ability of the bat was assessed by comparing the frequency of misses with the frequency expected by chance. The wires were moved frequently to prevent place learning. Wire sizes ranged from 5.0 to 0.14 mm in diameter. Four bandwidths of white noise were used: 2–12, 16–24, 12–24, and 12–32 kHz. The smallest wire size that the bats could detect in quiet was 0.46 mm in diameter. These results extend earlier findings by Griffin, Novick, and Kernfield (1958). When using noise, bandwidths with higher frequencies interfared with wire detection. Jamming frequencies below 12 kHz had no adverse effect and thus seem unimportant for echolocation. These results will be discussed in light of the auditory sensitivity measurements for Rousettus and the frequency spectra of the orientation clicks. [Supported by NSF grant BNS 79-05606.]
Absolute auditory thresholds in monkeys and humans
Authors: Petersen Michael R. , Sinnott Joan M. , Hopp Steven L. , Owren Magne J.
Published: October 2005

To determine the limitations imposed by the auditory system on the processing of species-specific vocalizations we have conducted a variety of psychoacoustic tests with different monkey species. This paper summarizes measurements of absolute auditory thresholds for three monkey species—the Japanese macaque (Macaca fuscata), de Brazza's monkey (Cercopithecus neglectus), and the vervet (Cercopithecus aethiops)—and four humans tested in the same setting. Human and monkey threshold contours assumed the same general shape but were displaced from one another along the frequency axis: humans were more sensitive than the monkeys below 2 kHz but less sensitive above this frequency. Also, whereas the monkey hearing range extended to 45 kHz, the humans' hearing cutoff in the vicinity of 16 kHz. Previous comparisons of the sensitivity of Old World monkeys have suggested that all species have essentially identical threshold contours. However, we found a small but consistent sensitivity difference for high frequency signals among the species we tested. Frequencies below 22.6 kHz were equally audible to all three species but the vervets were consistently more sensitive (on the order of 3 to 12 dB) to frequencies above 22.6 kHz. Interestingly, this sensitivity difference correlates closely with variations among the species' head sizes and, therefore, interaural distances. These findings are thus consistent with previous reports that close-set ears are highly correlated with enhanced high-frequency sensitivity and they fit nicely with Masterton's et al. [J. Acoust. Soc. Am. 45, 966–985 (1969)] theory that such sensitivity is probably related to selective pressures for sound localization. [Work supported by NSF and NIH.]
Real-ear attenuation characteristics of two protective helmets evaluated under two ANSI Standards methods
Authors: Tolhurst G. C. , Nerbonne G. P. , Russell G. A. , Ivey E. S.
Published: October 2005

As part of a project to assess the sound attenuation characteristics of circumaural hearing protective devices encorporated in two anti-buffet helmets (U.S. Army SPH-4 and DH-132) threshold shift measures were made. These evaluations were accomplished using two ANSI Standard procedures (ANSI Z24.22-1957 and 53.19-1974). Ten normally hearing male listeners per helmet were utilized who made their responses in three separate sessions. The sound stimuli were controlled manually by an experimentor employing a Method of Limits presentation. Mean threshold-shift values and SD were calculated for each frequency or one-third octave band stimulus. A student t statistic compared each helmet at each “frequency” between the two ANSI methods. The results showed only one significant difference (6300 Hz) between Standards for the DH-132. However, for the SPH-4, there were three “frequencies” which were statistically different comparing Standards (500, 3150, and 6300 Hz). An untested assumption for these differences is the helmet pure-tone resonances. The SD valves obtained under Z24 were larger than S3 in 6 out of 18 instances. When comparing two helmets using a single method, the threshold-shift values were highly similar. [Work supported by U.S. Army, Nadick Laboratories, Contract No. DAAK 60-80-C-100.]
Generation and dissipation of heat in the vocal folds
Authors: Titze Ingo R. , Cooper Donald S.
Published: October 2005

The vocal folds may be represented as a viscoelastic system. The power dissipated in the vocal folds (Pf) during phonation results from viscous loss in the vocal fold tissues. It can be approximated on the basis of a simplified representation of the geometry and movement of the fold, and has been estimated to be a significant part of the available pulmonary power [Titze, Tenth Symposium, Care of the Professional Voice (1981)]. Assuming that the energy dissipated is converted into heat, it is added to heat generated by muscle contraction (Pm). Heat is lost by thermal conductivity (Pc) and blood perfusion (Pb). While Pf and Pm increase during phonation, Pb has been shown to decrease during phonation [Hiroto, Otol. Fukuoka 17, 1–5 (1971)]. From estimates of the thermal coefficients of routes by which heat is conducted away from the vocal folds, it is possible to conclude that a temperature gradient should exist between the medial and lateral sections of the folds. Experiments on excised larynges are described in which measurements of this temperature gradient provide an initial estimate of the portion of this temperature gradient due to viscous loss.
The mechanics of abnormal laryngeal devoicing gestures exhibited by deaf persons
Authors: Whitehead Robert L. , Metz Dale E.
Published: October 2005

High-speed laryngeal films were obtained from one normally hearing and four deaf subjects as they produced /ihi/ syllables. Computer assisted frame-by-frame analysis indicated that during /h/ productions the deaf subjects frequently achieved glottal areas that were three times greater than the normally hearing speakers'. These findings are consistent with previously reported data [Metz and Whitehead, J. Acoust. Soc. Am. Suppl. 1 68, S114 (1980)]. Additionally, glottal area changes over time associated with the normally hearing subjects' /h/ productions appear to be continuous in nature. Vocal fold abductory movement away from V1 was virtually contiguous with the adductory movement toward V2. In contrast, glottal area changes over time associated with many of the deaf subjects' /h/ productions appear to be discontinuous in nature. Such area changes were characterized by abrupt vocal fold abductory movements away from V1 and plateaus in the area change. The temporal nature of this motion suggests that each segment of the syllable was produced discreetly on a phoneme-by-phoneme basis. Issues regarding speech air stream economy and speech motor control in the deaf will be addressed. [Work supported by the U.S. Department of Education.]
High-speed filming and acoustic analysis of deaf glottal pulses
Authors: McGarr Nancy S. , Baer Thomas , Löfqvist Anders , Whitehead Robert L. , Metz Dale E.
Published: October 2005

Few studies have examined laryngeal function in hearing-impaired speakers although aspects of abnormal phonation have often been reported in the descriptive and acoustic literature. The purpose of the present study is to characterize the laryngeal vibratory patterns of hearing-impaired speakers and to reconcile these records with acoustic and perceptual descriptions of vocal performance. High-speed films and simultaneous acoustic recordings of hearing-impaired speakers producing sustained vowels were made at the National Technical Institute for the Deaf. Consecutive vibratory cycles were extracted at selected intervals and the glottagraphic records co-analyzed with the acoustics. For one deaf speaker, whose vocal quality was particularly characterized by breathy hoarseness, the acoustic analysis revealed that a turbulent noise component was most pronounced during approximately one-third of the glottal cycle. This portion of the glottal cycle was found to correspond to the region of peak glottal opening in the glottagraphic records. The contribution of the noise component to perceived deaf voice quality will be discussed. [Work supported by NIH Grant NS-13870 to Haskins Laboratories, and the Department of Education to NTID.]
Lingual velocity and onset of voicing
Authors: Ostry David J. , Parush Avraham
Published: October 2005

The timing of tongue movements was studied in relation to oral release and onset of voicing, using pulsed-echo ultrasound. The stimuli were CV syllables, produced at two speech rates and different stress patterns. Relationships between the timing of maximum velocity on tongue lowering, oral release, and voice onset were examined. The interval from oral release to the point of maximum lowering velocity was essentially constant across differences in speech rate, voicing, and vowel height, though estimates differed for stressed and unstressed vowels. For unstressed vowels, peak lowering velocity lagged oral release by approximately 5 ms; for stressed vowels the delay was about 35 ms. The interval from the point of maximum velocity to voice onset was highly correlated with VOT. Further, for stressed vowels, VOT was inversely related to the maximum velocity of tongue lowering and to the distance to the point of maximum velocity from linguo-palatal contact. As reported by others, VOT varied with speech rate, consonantal voicing, and vowel height.
CV detection and identification thresholds for speech/language/learning-disordered listeners
Authors: Clifton Lu Ann B. , Elliott Lois L.
Published: October 2005

This report is a continuation of one by the same authors [J. Acoust. Soc. Am. Suppl. 1 70, S32 (1981)] at the 102nd ASA meeting and will emphasize detection and identification of synthesized CV stimuli [bɑ, dɑ, gɑ]. Responses of children with articulation disorders and of learning-disabled adults deviated from normal performance [L. L. Elliott et al., Percep. Psychophys. 30 (5), 411–416 (1981)]. Poorer detection thresholds, poorer identification thresholds, and aberrant slopes of the identification functions occurred; however, there were large individual differences. Use of standard audiological tests could not have predicted the experimental performance of these listeners. [Supported, in part, by NSF.]
Improvement in consonant recognition with amplification: Correlations with PTA and PTCs
Authors: Dorman M. F. , Hannley M.
Published: October 2005

Presbyacusic listeners with moderate sloping sensorineural bearing impairment were presented the California Consonant Test in three conditions: unaided; with flat frequency response aid; and with high-frequency emphasis hearing aid. Frequency selectivity was assessed using the metric Q1 octave, for a simultaneous pure tone masking paradigm. Three distinct error patterns were found when the data from the unaided and aided conditions were compared: (1) errors on a phone disappeared with amplification (e.g./t∫); (2) errors changed from one phone to another with amplification (e.g./for/s/); and (3) the errors were the same and were not eliminated by amplification (for the stop consonants). In the latter case, the best correlation of PTA for any set of frequencies and improvement in stop consonant recognition was −0.35; the best correlation of Q1 octave and improvement in stop recognition under aided conditions was 0.63. Even though Q1 octave was a better predictor of improvement than was the PTA, the range of improvement with similar Q scores was considerable.
An investigation of the English vowels of intelligible but non-normal profoundly deaf adult male speakers
Authors: Rowe Linda
Published: October 2005

The English vowels of ten intelligible but non-normal profoundly deaf adult male speakers were analyzed using computer techniques to determine ferment frequency values. Spectrographic analysis of the same data was compared to the computer analysis to assure that the computer techniques were applicable to the non-normal speech of deaf speakers. The acoustic data from the deaf speakers was compared to the same data obtained from normal hearing and speaking adult males. Upon completion of the initial research, it is likely that the deaf speakers will miss the acoustic vowel targets. It is reasonable to assume that the deaf speakers are not able to place their articulators accurately enough to achieve the correct targets, and that they are unable to correct the inaccurate articulator placement through auditory monitoring. It will be of interest to examine the relationship between the acoustic data and the physiological correlates and the impact this information should have on the remediation strategies used to improve the speech of profoundly deaf speakers.
Teaching speech to the deaf using computer-assisted instruction
Authors: Osberger M. J. , Lippmann R. P. , Kent R. D. , Watson C. S.
Published: October 2005

At the 98th meeting of the Acoustical Society, we presented a preliminary report on a recently developed computer-based speech training aid for the deaf [Lippmann and Watson, J. Acoust. Soc. Am. Suppl. 1 66, S13 (1979)]. The aid evaluates a child's utterances using a template comparison similar to that used in speaker-dependent word recognition schemes. Characteristics determined from a real-time acoustic analysis of a child's utterance are compared to those of a previously recorded intelligible utterance. The aid is being evaluated in a systematic speech training program with a group of deaf children, 8 to 14 years of age. This report will present preliminary data on the initial clinical trials with the aid. The data indicate that the aid is at least as effective as a teacher in performing the speech drills under study. The children have learned to interpret the feedback, enjoy using the computer, and even after six months of intensive training, remain highly motivated to perform the computerized speech drills. The degree of acoustic variation in the children's productions during the training sessions and its effect on the accuracy of the computer evaluations will also be discussed. [Research supported by NIH/NINCDS-NS16247.]
Identification of an emphasized consonant of a monosyllable in hearing-impaired subjects and its application to a hearing aid
Authors: Ono Hiroshi , Okasaki Tsutomu , Nakai Shoichiro , Harasaki Hidenobu
Published: October 2005

It is generally known that sensorineural hearing impairment has not only decreased hearing ability but also disorders in various hearing function and for this reason, with the conventional hearing aid which merely loudens sound, failure to catch or miss hearing a consonant often occurs. We have thought to improve audibility by separating a consonant and vowel of a monosyllable then synthesizing each to form an emphasized sound. This synthesized monosyllable was tested for speech discrimination score by 20 sensorineural hearing-impaired subjects. The results show that in the case of voiceless plosives such as /pa/, /ta/, and /ka/, when amplitude of a consonant was increased by 10–20 dB and a silent pause of 30–60 ms was inserted between a consonant and vowel to prevent masking by a following vowel, recognition improved by 46.7%. The improvement is remarkable in the case of /ka/ where original sound was recognized by 40% and synthesized sound by all the subjects. On the other hand, in the case of nasal sound such as /ma/ and /na/, by repetition of consonant and of amplified consonant the audibility improved to 70% from the original recognition of 22.5%. Now we are developing a computer hearing aid which gives the best synthesized monosyllable for bearing-impaired subjects based on speech analysis.
Impaired- and normal-hearing listeners' voicing perception of final fricatives in cue-adjusted syllables
Authors: Revoile S. , Pickett J. M. , Holden L.
Published: October 2005

In the spoken syllables /d∧z/ versus /d∧s/ and /d∧v/ versus /d∧f/, vowel duration differences were reduced, frications deleted, and vowel offsets exchanged or deleted. These adjustments were performed digitally on ten different tokens of each syllable. The voicing cues were adjusted in various combinations to yield different test conditions for identification of the syllables. Hearing-impaired (N = 24) and normal-hearing (N = 11) listeners were tested several times under each condition. For both listener groups, fricative voicing perception was generally unaffected by deletion of the frications from the syllables. The vowel duration adjustments (lengthening vowels that preceded voiceless frication, shortening vowels preceding voiced) significantly reduced fricative voicing perception for about half of the hearing-impaired listeners; none of the normal-hearing listeners was significantly affected by the vowel duration adjustment. When the vowel offsets (final seven pitch periods) were exchanged between voiced and voiceless syllables with vowel durations adjusted and frication deleted, voicing perception went with the exchanged vowel offsets. Deletion of the vowel offsets substantially reduced voicing perception.
Influence of context on measurement of hearing-impaired speakers' intelligibility
Authors: Sitler Ronald , Schiavetti Nicholas , Metz Dale E.
Published: October 2005

Previous research has indicated that hearing-impaired talkers' intelligibility scores are better when sentences are used than when word lists are used as speech material in word identification tests. The speech intelligibility of 20 hearing-impaired talkers was measured with word identification tests using isolated words (W-22 monosyllables) and words in sentence context (CID sentences). Analysis of individual talkers' intelligibility data revealed that sentence intelligibility scores were higher than word intelligibility scores only for the better talkers and that no differences were apparent between sentence and single word intelligibility for the poorer talkers. These findings agree with the results of research with normal speech that has been degraded in intelligibility by noise or filtering and indicate that an interaction may exist between context and overall intelligibility in which only speech that has a certain degree of overall intelligibility may show further intelligibility improvement with increased contextual clues. [Work supported by U.S. Department of Education.]
Multiband syllabic compression for severely impaired listeners
Authors: De Gennaro S. , Braida L. D. , Durlach N. I.
Published: October 2005

Speech reception experiments were conducted to evaluate the benefit of multiband syllabic compression for listeners with severe sensorineural hearing impairments. Three listeners with congenital hearing loss characterized by flat audiograms and dynamic ranges of 20–30 dB were tested on three compression systems and one linear amplification system. The compression systems placed progressively larger amounts of speech energy within the listener's residual dynamic range by raising to audibility and compressing 25%, 50%, and 90% of the short-term input amplitude distribution in each of 16 frequency bands. The comparison linear system was defined by adjusting six octave-wide bands of speech to comfortable levels. System performance was evaluated with nonsense CVC syllables presented at a constant input level and spoken by two talkers. Extensive training was provided to ensure stable performance. The results were notably speaker dependent, with compression consistently providing better performance for one, linear amplification for the other. Averaged over speakers, however, there was no net advantage for any of the compression systems for any listener. The use of high compression ratios and large input ranges tended to degrade perception of initial consonants and vowels. Under some conditions, however, final consonant scores were higher with compression than with linear amplification. Detailed summaries of system performance and analyses of consonant and vowel confusions will be presented. [Work supported by NIH.]
Comparison of two tactile speech codes
Authors: Clements M. A. , Braida L. D. , Durlach N. I.
Published: October 2005

Two methods of encoding speech for tactile displays were compared in experiments which measured the discriminabilty of tactile representations of short speech segments. One display represented the short-term speech spectrum in time-swept mode and used vibration amplitude to encode spectral amplitude. The other represented the vocal-tract shape derived from LPC analysis of the speech waveform and used the number of active vibrators to encode the logarithm of cross-sectional area. Both displays were applied to the thigh via a 12 × 12 matrix of vibrators. The vibrators were driven at 250 Hz during voiced segments and by random noise during unvoiced segments. Overall results show a slight superiority for the spectral display in both vowel and consonant discrimination. Detailed results will be described in terms of an articulatory description of the speech stimuli, and a multidimensional scaling analysis of confusions. Theoretical analysis of the stimuli suggests that the detailed characteristics of the tactile patterns were only crudely discriminated. [Work supported by NSF.]
Vibrotactile communication of consonantal Information: Vowels mask consonants
Authors: Green Barry G.
Published: October 2005

Identification of vibrotactile transformations of CVs was measured first for eight consonants (stops and nasals) in /_a/ context. The stimuli were 24-channel spectral representations of the acoustic energy in the CVs, presented to the fingertip via the 6 × 24 matrix of an Optacon transducer. Performance reached only 50% to 60% correct, with nasals identified best, followed by voiceless and voiced stops. Confusions were greatest among stops that differed only in place of articulation. Perception of the place feature was examined in another experiment by testing identification of /b/, /d/, and /g/ with five different vowels. Place of articulation was increasingly well identified as the CVs were shortened in duration by truncating the vocalic portion of the stimulus: Performance stood at 54% correct when the CV lasted 258 ms, but rose to 77% correct when the CV lasted only 48 ms. This result indicates that vibrotactile communication of consonants may be poor because of temporal masking induced by the vocalic portion of the stimulus. [Supported by NSF.]
A comparison of the transient acoustical response of Symphony Hall, Boston, Massachusetts and Memorial Chapel, Schenectady, New York utilizing an anthropometric manikin
Authors: Mastracco James M.
Published: October 2005

An anthropometric manikin has been employed to record acoustical transient response in Symphony Hall in Boston, Massachusetts and in Memorial Chapel on the Union College campus in Schenectady, New York, two buildings that appear to have many common architectural parameters and similar architectural histories. Reverberation time curves for the two halls indicate a great similarily in their quality of reverberation. Minimal differences in T60 are observed and mid-frequency reverberation times (the average of T60 at 500 and 1000 Hz) are found to be 2.64 and 2.95 s for Symphony Hall and Memorial Chapel, respectively. Acoustical comparisons between the two halls are also made for three temporal energy levels: Definition, LD [R. Thiele, Acustica 3, 291 (1953)], Clarity, LC [V. L. Jordan, R. Swed. Acad. Music, Stockholm (1977)], and Schultz's parameter, LR [P. J. Schultz, IEEE Spectrum (June 1965)]. As a result, it appears that certain time windows associated with specific temporal energy levels are better suited than others for acoustical comparisons. Similar curves for LR, coupled with similar reverberation curves, rectangular floor plans, and building materials suggest a good possibility that these two halls have a great deal in common acoustically.
Experimental measurements in a variable acoustics hall
Authors: Schrag Richard C. , Holger David K.
Published: October 2005

The experimental measurement of some quantitative acoustic qualities of a variable acoustics concert hall, and their variation with absorber configuration, is discussed. The impulse response of the space, using a electric spark generator as a noise source, was recorded for each configuration at a variety of receiver locations. Digital analysis provided quantitative data for reverberation time, definition, initial time delay gap, and texture. The effect on these parameters of the amount and placement of absorbing material is shown.
Target information obtained from resonant acoustic echoes
Authors: Überall H. , Gaunaurd G. C.
Published: October 2005

Submerged targets may be detected by the echoes they generate in response to an incident acoustic signal; similarly, material inhomogeneities in solids may be detected by ultrasonic echoes. Target identification, i.e., the determination of the scattering object's shape, composition, and orientation, represents a problem of a different order of magnitude. In many cases, the incident signal causes the target to resonate at its eigenfrequencies, and the resonance information is contained in the echo from which it may be extracted. Examples will be shown to demonstrate that the resonance spacings and resonance widths determine the composition of a target of known shape; or that the resonance positions determine the size and shape of a target of known composition. In addition, the relative excitation strengths of the resonances depend on the target orientation so that the latter may be determined. The corresponding method of “acoustic spectroscopy” may thus be used for solving the inverse scattering problem of identifying a target from an analysis of its echo. Relevant experiments (e.g., Maze, Taconet, and Ripoche) will be discussed.
Acoustic monitoring and signature analysis in nuclear and fossil energy generation
Authors: Karplus Henry B.
Published: October 2005

Acoustic monitoring and analysis in nuclear and fossil energy plants has been accompanied by transducer development for the hot environment. The Nuclear Regulatory Commission requires acoustic monitoring systems on nuclear reactors for detecting potential failures. Accelerometers are attached at critical points and their output is automatically analyzed to give warnings of loose parts or excessive vibration. In addition to providing a warning, the system can monitor arrival time to be used for fault location. For use as a potential boiling detector of breeder reactors, the acoustic signature of the sodium coolant boiling has been compared with background noise level. High temperature sodium-immersible microphones and waveguides for smooth energy transfer were developed for this investigation. High-temperature acoustic sensors have been used in a coal gasification plant. The presence of solids in a steam-char line has been automatically determined using passive monitoring of relative sound intensities of different frequency bands.
Computer-aided acoustical pattern recognition of pathological knee joints
Authors: Chu M. L.
Published: October 2005

Degenerative joint disorders are, today, the most common nonfatal crippling diseases. In every case these diseases involve progressive destruction of the articular cartilage. At present, there is no available noninvasive clinical tool which will permit on-going objective evaluation of the relative degree of damage to the articular cartilage. Recently a computer-aided, electroacoustical technique was developed to enhance diagnosis of the disease more objectively. The procedure involved the recording of the acoustic energy emitted by the joint during active articulation, as picked up by a dual 1-in. B & K condenser microphones using the principle of “noise cancellation” to minimize high-frequency background noise. The recorded data are then digitized and statistically analyzed both in the time and frequency domain using an IBM computer to extract unique statistical properties which characterize specific pathological disorder and/or cartilage deterioration. Also a three-dimensional spectral history plot was developed to present the extent and relative location of cartilage damage. The respective statistical features of recordings covering normal, rheumatoid arthritic, and degenerative knees apear to be unique and prove to be a promising noninvasive diagnostic tool for early detection of the type and extent of joint damage.
Acoustic signatures of railroad wheels
Authors: Finch R. D.
Published: October 2005

When a railroad wheel is impacted with a hammer blow it emits a characteristic sound. By comparing sounds from the two members of a wheelset a measure of the difference of their mechanical properties is obtained. Both frequency and time domain processing is found to be useful. Reference will be made to both laboratory and field tests and results will be summarized. Considerations in the design of automatic hammers, wheel sensors, and all weather microphones will be discussed. The influence of train speed on the required performance of hardware will be discussed, and parameters in the selection of signal processing hardware will be defined. The principal objective of the work is to recognize the presence of cracks. The main difficulty with meeting this objective is avoiding false alarms due to differential wheel wear, etc. Progress in developing algorithms to reduce this false alarm rate will be described. [Work supported by the Association of American Railroads.]
Ring model of railroad wheel vibrations
Authors: Haran S.
Published: October 2005

A ring model for prediction of the vibration characteristics of railroad wheels is presented. Earlier workers showed that ring theory gave a good explanation of the ratio of resonant frequencies in the railroad wheel, assuming flexural modes are excited in the rim. It was assumed that the massive rim drove the plate of the wheel in forced vibration. In this paper the wheel is modeled by taking the flange, the rim, and the plate as a series of elastically connected concentric rings. The differential equations governing normal mode flexural vibrations are developed for such a system of n elastically connected rings, based on the general equations developed by Love. The free vibration of the system, with displacements both in the plane and out of the plane of the wheel was studied. Modifications were made to include wear on the flange and tread. The effect of hoop stresses in the rim was also modeled. The results agree well with those from other theoretical models and also with experimental values. [Work supported by Association of American Railroads.]
Geometry and Timbre of the English Church Bell
Authors: Perfin R. , Charnley T.
Published: October 2005

Experimental measurements of the frequencies and nodal patterns of all the partials up to about 9 kHz for a good quality English church bell have been made. By matching these with the results of finite-element calculations an understanding of the physical mechanisms generating the various partials has been achieved. This has enabled us to produce, for the first time, a classification scheme for the partials with a firm physical basis, and has given considerable new insight into church bell design. In particular it is now much clearer just how crucial to the production of the bell's characteristic timbre is the thick ring near its rim.
Modes of vibration and scaling of handbells
Authors: Sathoff H. John , Rossing Thomas D.
Published: October 2005

The methods of vibration of handbells can be described by using the nomenclature of circular plates. Thus the [m, n] mode has m nodal meridians extending across the crown and n nodal circles around the periphery [T. D. Rossing and H. J. Sathoff, J. Acoust. Soc. Am. 68, 1600 (1980)]. The frequencies of the modes, with a few exceptions, can be fitted to an equation having the form f = cmk. The most notable exceptions occur in modes having m < 4 and n > 1, where the frequency may increase with decreasing m. Handbells are scaled so that the diameter and height decrease with increasing frequency roughly as f−1/2 rather than f−1, the scaling commonly found in carillon bells. The modes of vibration in handbells tuned over a 10:1 range in frequency are found to be remarkably similar to each other.
The contemporary state of percussion acoustics in China
Authors: Cohen Elizabeth , Hart Michael S. , Furth Vic
Published: October 2005

This paper reports on the results of the author's visits to the People's Republic of China. The authors visited and performed with percussion sections of the opera and National Orchestras. A comparison of the regional differences in instrument design and construction has been made, comparing Wuhan, Beijing, and Kiangsu. The evolution of gong and bell design is discussed. Development and design control of ancient mallets and sticks is also contrasted to contemporary instruments.
The gamelan angklung of Bali
Authors: Hah Kuo-huang
Published: October 2005

The gamelan is a percussion-dominated orchestra of Indonesia. Most of the instruments in the ensemble are gongs and metallophones made of bronze or iron. It is the most representative example of the gong-chime culture. Modern scholarship has attributed the origin of gamelan to two possible practices of the pro-Christian era: the pounding of rice on stonewares and the bronze drum playing in the sacrificial rites—the xylophone theory and the bronze drum theory, respectively. Both practices involve the single-tone principle, i.e., one tone played by one person. Both theories are verified with archeological finds as well as with surviving practices among contemporary people in Southeast Asia, and a connection is made to the Gamelan Angklung, a four-tone gamelan that is very popular as a village ensemble throughout Bali, Indonesia.
Musical and acoustical features of the gamelan angklung
Authors: Hah Kuohuang , Ressing Thomas D.
Published: October 2005

Consistent with the basic slèndro and pèlog scales, the gemelans of Indonesia vary considerably in tuning. The small gamelan angklung is generally tuned to a four-note scale, known as saih angklung, derived from a five-note slèndro scale. We discuss the tunings of the instruments in the N.I.U. gamelan angklung (which will be heard in concert at the banquet), as well as sound spectra of some of the instruments. One of the most interesting characteristics of Balinese gamelan music is the splitting of a melody into two or more parts. In this type of interlocking playing, called kotekan, no one part is independent or more important over the others, a fine reflection of communal cooperation in real life in Balinese society. Another significant feature of gamelan music is its different stratification of texture, i.e., piling up of melodies in order of density, a reflection of their social strata. Both characteristics, along with the emphasis of the fifth-relationship in the vertical direction, the four-note motive, the pair tuning, etc. are demonstrated on gamelan instruments.
Simplified three-dimensional parabolic equation underwater sound propagation algorithm incorporating horizontal refraction and focusing effects
Authors: Pierce Allan D.
Published: October 2005

Usual parabolic equation (PE) formulations ignore azimuthal variations; previous methods of accounting for such are exceedingly time consuming. Present formulation proceeds from variational principle for Helmholtz equation with p replaced by ψ(x, y, z) exp[i φ (x, y)] and discard of second-order terms in ∂ψ/∂x and ∂ψ/∂y. The PE's ko is replaced by k(x, y) = |∇φ|, which is constrained to be same local functional of ψ, ω/c, and ρ as in modal theory. Results of variation are ray equations for x(s), y(s), k(s), and the parabolic equation with range r replaced by horizontal path distance s. Dependent variable in latter is ψ/w1/2 rather than ψ/r1/2, where w is ray strip width. A second parabolic equation gives s dependence of azimuthal derivative of ψ, but is not needed in simplest approximation. Computation proceeds by marching along horizontal ray path, integrating parabolic equation at each step for ψ(s + Δ s), subsequently determining k(s + Δ s) and w(s + Δ s). Computational brevity results because horizontal diffraction effects are ignored. In appropriate limits, formulation reduces to adiabatic mode theory for a single mode or to azimuthal-independent PE. Illustrative results are for point source in ocean where c varies with z and x but not with y. Rough estimates of whether horizontal refraction is important result from approximation of k(x, y) by ω/cmin(x), where cmin is minimum sound speed in the channel, or by the adiabatic mode theory kn(x).
Prediction of the effect of range dependence on convergence zone levels
Authors: Henrick R. F. , Burkom H. S.
Published: October 2005

Convergence zone propagation in a range-dependent environment typified by fronts and eddies is considered. This study addressed the effect of these mesoscale anomalies on convergence zone levels, in particular to determine when catastrophic signal losses may result. Through use of a range-dependent Snell's Law the effects arising from the explicit changes in sound speed as well as implicit effects arising from the presence of horizontal sound speed gradients are quantified. A simple method is developed to first identify whether a mesoscale feature leads to catastrophic losses, and then to determine source position relative to the feature where these losses may be realized. Parabolic equation propagation simulation through a Gulf Stream Eddy Model simulation are then used to present illustrative examples and confirmation of the theory. [Work supported by Department of the Navy.]
Sound propagation through a moderate coastal upwelling: Comparison of modeling predictions with experimental data
Authors: Malay J. T. , Scully-Power P. D. , Browning D. G. , Mooers C. N. K.
Published: October 2005

In a previous paper [J. T. Malay et al., “Modeling sound propagation through a coastal ocean upwelling,” J. Acoust. Soc. Am. Suppl. 1 68, S78 (1980)] modeling predictions were made for the effect of a coastal upwelling on sound propagation. To verify these results, a sound propagation experiment was conducted across a moderately developed upwelling located at the Sur Canyon off the coast of California. A 1-kHz projector was towed through a sonobuoy field which spanned the upwelling region. A supporting oceanographic survey was made to obtain environmental data input for multi-profile modeling predictions. The relative importance of oceanographic and topographic changes on sound propagation were determined. A follow-on experiment in a fully developed upwelling is planned. [Work supported by NUSC.]