bluuebunny/crossref_metadata_2025 huggingface dataset:
The voicing contrast for language-delayed children: Eighteen months later
Authors: Bond Z. S. , Demerjian Donna
Published: October 2005

In a previous study which compared the acquisition of the voicing contrast by language-delayed and normal children, Bond and Wilson (93rd meeting of the Acoustical Society of America, June, 1977) found that voice onset time (VOT) as a cue for voicing in initial position develops in similar stages for the two groups of children. The purpose of this study was to investigate further the longitudinal development of voicing. Four of the language-delayed children who were tested previously were recorded again, saying near-minimal pairs contrasting labial, alveolar and velar voiced and voiceless stops in initial position. Voice onset time for these stops was determined from spectrograms and compared with the children's previous VOT use patterns. One child showed no progress in achieving control of VOT; three children were making some progress, but the details of their developmental pattern were idiosyncratic.
On the shift in pitch of a sine tone caused by a preceding tone
Authors: Kanistanaux D. C. , Hartmann W. M.
Published: October 2005

The pitch of a brief target sine tone is changed by a preceding tone. The pitch of the target tone is shifted away from the pitch of the preceding tone [A. Jaroszewski and A. Rakowski, Acustica 34, 220 (1976); W. M. Hartmann and B. J. Blumenstock. J. Acoust. Soc. Am. 60, S40 (A) (1976)]. Recent experiments on this effect show the following: (1) The shift is present for tones near 1000 Hz and near 200 Hz and for tones heard at 80 dB and at 40 dB. (2) Smaller shifts exist when 40 dB preceding and target tones are in opposite ears, and for preceding tones 40 dB less intense than the target tones. (3) The shift tends to vanish for missing-fundamental preceding tones with no spectral energy near the target tone. These experiments support a model of pitch perception based upon a central neural excitation pattern which is an intensity-compressed representation of the stimulus spectrum. The results can be understood from a model of short-term neural adaptation and a model for the extraction of pitch from a neural excitation pattern. [Supported by the NSF.]
Discrimination of pitch in minimal duration tonal stimuli
Authors: Howse W. R. , Elfner Lloyd F.
Published: October 2005

Discrimination of pitch for very brief tonal stimuli was measured in a two interval forced choice experiment in which experienced subjects were required to select the stimulus complex that contained acoustic events more disparate in pitch. Within each complex a comparatively long (750 ms) standard tone was followed by a 750 ms interstimulus interval and a brief comparison tone of variable frequency and duration (2, 4, 6. or 8 cycles). Frequencies used for the standard tone were 125, 250, 500, 1000, and 2000 Hz. All stimuli were matched for loudness. Analysis of performance indicates an interaction between number of cycles in the brief tone sample and frequency of the standard tone. Patterns of errors are considered in relation to spectral and periodicity models of pitch perception.
The role of temporal cues in periodicity pitch perception
Authors: Lundeen C. , Small A. M.
Published: October 2005

A computer was used to generate three different waveforms from the same component frequencies by setting the phases of the components so they were either homophasic (all component sinusoids start at 0°), diphasic (sinusoids alternate between − and +45°), or heterophasic (starting phase randomly selected). The pitches evoked by these waveforms were investigated by asking listeners to match a pure tone to all the pitches they could distinguish in a test stimulus, and to rate the saliency of each pitch. Data from three listeners indicated that the pitch of the test stimuli could generally be matched by pure tones whose frequencies are around the fundamental (f1) or the octaves 2f1 and 4f1. Waveform patterning had no significant effect on the overall distributions of periodicity pitch matching responses. However, clear trends could be discerned from the ratings listeners assigned to the saliency of the pitches. A major finding was that the highest ratings of f1 pitch “strength” were always obtained for homophasic waveforms, which among the test stimuli have the most abrupt envelope fluctuations. In contrast, diphasic and heterophasic waveforms, which have smoother envelopes, yielded lower pitch strength estimates at f1 and higher 4f1 ratings. These data seem to reflect a process which uses information concerning the stimulus waveform envelope to determine the relative prominence of competing pitch cues. However, no one-to-one correspondence between pitch and waveform periodicity is apparent.
Economical sound pulse source for demonstrating acoustical phenomena
Authors: Gonter Robert H.
Published: October 2005

An inexpensive source of repetitive sound pulses was built using automotive ignition parts. Using the pulse source and an oscilloscope (having delayed sweep, storage capabilities and spectrum analyzer), it has been possible to perform experiments which are useful in demonstrating a variety of acoustical phenomena. Among the phenomena that can be shown are visualization of direct and reflected pulses, change in pressure amplitude with distance, location of echo sources, insertion loss of acoustical materials (including a piece of paper), frequency response and directivity of microphones, and estimation of temperature fluctuations over a 1.8 m path. Other uses of the pulse source might include in situ measurements of reflectivity of surfaces, measurement of changes in reflectivity with angle, acoustical modeling, and measurement of transmission around barriers of different shapes.
An approach to modeling the relationship between ultrasonic propagation properties and constituent properties of mammalian tissues
Authors: Pohlhammer J. D. , O'Brien W. D.
Published: October 2005

Literature values for ultrasonic attenuation, absorption, and velocity in several tissues, including brain, heart, kidney, liver, tendon, fat, and blood at frequencies of 1, 3 and 5 MHz, along with the percent constituency of each tissue (by weight) were used to develope an algorithm relating the acoustical propagation properties of a tissue to it's biological properties. Such an algorithm is hoped to provide the biological content of a tissue sample (e.g., % collagen content, % protein content, etc.…), given the ultrasonic propagation properties within that tissue. A first order model, assuming a linear relationship between constituency and acoustical properties, employs a least squares solution to a system of linear equations. This solution is a set of attenuation coefficients one, for each of the constituents considered. Results show that such a model works for only a limited number of highly structured tissues. A modified first order approach examines scattering (defined as attenuation minus absorption) as a function of collagen content alone. Here it is suggested that, as a function of frequency over the 0.5–7MHz range, the magnitude of scattering increases, but the dependency of scattering on collagen content is decreasing. [This work was supported in part by grants from NIH and FDA.]
Ear dominance for pitch, and dichotic listening to music
Authors: Gregory Andrew H.
Published: October 2005

Although a left ear advantage was originally claimed for the recognition of dichotically presented melodies [D. Kimura, Q. J. Exp. Psychol. 16, 355–358 (1964)], other studies have not always obtained this result. One confounding variable may be that of individual differences in ear dominance, for pitch [R. Efron and E. W. Yund, J. Acoust. Soc. Am. 59, 889–898 (1976)]. When two different tones are presented, one to each ear, for some subjects the pitch of the left ear tone is more salient, for others that of the right ear tone. These individual differences may obscure any more general ear advantage for the perception of melodies. Subjects were therefore tested for their ear dominance for pitch, and this was correlated with their performance on listening to dichotic melodies, which varied in length from 3 to 17 notes in each ear.
Psychophysical tuning curves for aural combination tones
Authors: Formby C. , Sachs R. M.
Published: October 2005

We sought to demonstrate the stimulus-like nature of combination tones by means of a simultaneous masking paradigm. Three musically-sophisticated listeners were instructed to adjust the level of pure tones at various frequencies to just mask a pulsing pitch corresponding to a tone at 1200 Hz and 20 dB SPL. This pitch was produced by four stimulus conditions: (1) a pulsing tone at 1200 Hz; (2) a f2 − f1 condition for which a continuous f1 = 1900 Hz and a pulsing f2 = 3100 Hz; (3) a 2f1 − f2 condition for which a continuous f1 = 1650 Hz and a pulsing f2 = 2100 Hz; and (4) a 2f1 = f2 control condition with a pulsing tone at 1200 Hz and a continuous f1 = 1650 Hz. A common trend was exhibited across subjects. The low-frequency slopes of the four tuning curve conditions were equivalent. The high-frequency slopes were similar but were sometimes contaminated by interactions between the masker and the primary tones in conditions 2, 3, and 4. Condition 1 exhibited the steepest high-frequency slope. These findings provide graphic demonstrations of the stimulus-like nature of combination tones and of a similarity between odd and even order distortion products. [Work supported by NINCDS Grant NS03856.]
The importance of the time constant in duration patterns
Authors: Pinheiro M. L. , Smith A. J. , Schmidbauer L. M.
Published: October 2005

Twenty young adult right-handed subjects, responded half with the right hand and half with the left, to triads of long and short tone bursts. The 175 patterns were subdivided into 9 sets, each with a different pair of durations. Long (L) ranged from 500 to 100 ms; short (S) ranged from 350 to 50 ms. Interburst interval was 200 ms. A significant difference between ear/hand combinations occurred only during the first set of 25 patterns when right hand response to left ear stimuli was superior to left hand response to right ear stimuli. This practice effect disappeared after the first set. The most important finding was the lack of significant differences among sets sharing the same time constant relationship between long and short bursts, but with different durations of long and short bursts. Differences between sets were significant only when this time constant varied; performance was significantly better for longer time constants. There were no significant differences in performance among patterns L-S-L, S-L-S, L-S-S, and S-S-L. However, subjects performed significantly better on L-L-S and significantly poorer on S-L-L.
An overview of the state-of-the-art in Naval underwater acoustic modeling
Authors: Etter P. C. , Flum R. S.
Published: October 2005

A survey has been conducted of those basic acoustic models developed by the U.S. Navy acoustic modeling community over the past several years. This survey identifies and briefly describes 23 propagation loss models used for predicting acoustic propagation (primarily for application to passive sonar systems), 11 noise models used for predicting ambient noise and beam-noise statistics, and 14 active sonar and reverberation models used for simulating propagation loss, noise, reverberation, and signal processing (for application to active sonar systems). Matrices cross-referencing models and selected characteristics are presented to summarize the state-of-the-art in Naval underwater acoustic modeling. In parallel with this review, a survey has been conducted to identify potential sources of marine environmental/acoustic data to support these models. The resulting summary provides a brief description of data availability categorized as primary data banks, modified data banks, and data collections which are maintained for limited applications. This compendium of model descriptions and supporting data availability appears to be the most comprehensive available to date in the open literature, and thus may serve as a useful baseline for determining the course of future modeling efforts. Specifically, definite trends in acoustic modeling are shown, and inferences can be drawn which would indicate a future direction for this type of modeling. [Work sponsored by Manager, ASW Systems Project.]
Sound level meters of 50 years
Authors: Young Robert W.
Published: October 2005

The first quantitative noise measurements appear to have been published by Lemon in 1925, in connection with the then new balloon tires. He adjusted a calibrated buzzer until its sound just masked the sound inside an automobile. Others similarly sought a physical measurement directly related to a sensation such as loudness. The reference sound pressure, in the first American Tentative Standards for Sound Level Meters Z24.3-1936, was chosen as the threshold of hearing for an acute ear. For more than 30 years, in Germany the instrument whether of the physical or subjective kind) was named a “loudness meter” whose unit of measurement was the phon. The functional diagram of the sound level meter of 50 years ago is much like that of today: a stable microphone, an amplifier, bandpass filters for optional use, an attenuator, a frequency weighting network (much like the A-), a rectifier, and an indicating instrument. Then and now, the instrument is supposed to respond to the mean-square, frequency-weighted sound pressure, with exponential time averaging. The squaring rectifier long gave trouble; today squaring is often accomplished by doubling the logarithm of the sound pressure. By strong tradition in the U.S.A., the goal for the microphone has been frequency-constant sensitivity on the average of all directions; the goal in Germany has been frequency-constant sensitivity perpendicular to the diaphragm.
Use of “corner microphones” for sound power measurements in a reverberation chamber
Authors: Flynn Daniel R. , Bartel Thomas W.
Published: October 2005

Conventional methods of measuring sound power levels in a reverberation room require determination of the spatial average sound pressure level in the reverberant sound field. At the lower frequencies of interest, it often is not possible to define a microphone array or traverse that provides enough statistically independent samples of the sound field to enable accurate determination of this average level. With a goal of developing a simpler procedure for use at lower frequencies, a study has been carried out of the feasibility of computing sound power level from the sound pressure levels measured using microphones located near the corners of a reverberation chamber. A series of measurements of sound power level have been carried out using both the conventional procedure and the corner microphone procedure. The results are quantitatively compared.
Acoustic harmonic interaction effects in biomedical ultrasonic arrays
Authors: Benjamin K. , Stepanishen P. R.
Published: October 2005

Arrays of piezoelectric transducers are being used in an increasing number of biomedical applications. As a result much work is being done using digital computers to design and develop such arrays. This paper will address the effects on array performance of the acoustic harmonic interactions among elements in arrays of piezoelectric thickness expanders. A distributed parameter transducer model, with acoustic interactions, was used to investigate the effects of the interactions on array beamforming and focusing in the transmit and receive modes of operation. The perturbations due to interactions were studied as a function of frequency, beaming, tuning, transducer backing, and element spacing for various transducer materials. The study which included finite and infinite two-dimensional array configurations showed significant interactions for densely packed elements in the MHz range. This effect generally increased as the array was phase steered off axis. It was also found that the interactions could be significantly reduced by using a matched backing material. Numerical results will be presented to illustrate material. Numerical results will he presented to illustrate typical results of the interactions which were obtained during the study. [Work supported by NIH.]
Acoustic transient interaction effects in biomedical ultrasonic arrays
Authors: Guigli J. , Stepanishen P. R.
Published: October 2005

The transient response of ultrasonic biomedical transducers and arrays is becoming increasingly important as a result of the wideband excitations which are currently envisaged for various biomedical applications. In the present paper, a computer model is developed to evaluate the transient transmit/receive response of multielement beam steered arrays of acoustically coupled piezoelectric thickness expander transducers. Each transducer is represented by a distributed parameter model which includes the effects of mechanical backing and matching materials. A set of coupled convolution integral equations are developed from the model to characterize the transient transmit/receive response of an army and scatterer configuration. These equations are an extended version of earlier work [P. Stepanishen, J. Acoust. Soc. Am. 50, 964–974 (1971)] and can be readily solved using recursire techniques. Numerical results are presented to illustrate typical transient acoustic field and receive phenomena which result from the short pulse excitation of phased arrays of ultrasonic transducers in the MHz range of biomedical interest. [Work supported by NIH.]
Tank coatings for ultrasonic echo reduction
Authors: Corsaro R. D. , Klunder J. D.
Published: October 2005

A filled-rubber materials system with selectable and continuously variable acoustic properties is described and used to form broadband anechoic tiles. By applying these tiles to the inside walls of acoustic testing tanks, wall reflections are reduced by 20 to 35 dB at frequencies from 0.5 to 10 MHz. This is advantageous since it allows the use of smaller examination tanks, for example in ultrasonic testing and biomedical applications, and permits the use of cw tanks of tractable size, for example in schlieren and acoustic-visualization studies. The tank coatings developed include one and two layer tiles, 0.15 to 0.65 cm thick. Using a theoretical model of sound propagation in multilayer media, we first calculated the optimum material properties needed to construct tiles meeting specific echo reduction requirements. These materia] requirements were then met by choosing the type and concentration of fillers added to an RTV-602 silicone rubber base. The subsequently measured performance of these tiles agree with that initially predicted by theory.
Generation characteristics of SAW in the excited IDT
Authors: Shu-yi Zhang , Yong-an Shui , Song-ru Fang
Published: October 2005

By utilizing the optical diffraction produced by acousto-optical interaction, the generation characteristics of SAW in the excited interdigital transducer may be observed directly and measured quantitatively. Both the method of dark field imaging and that of simple optical probing have been used. The periodic IDT and LFM IDT deposited on the substrates of YZ-LiNbO3 have been investigated. For the periodic IDT, the experimental investigations show that the SAW generation characteristic are of symmetric growth in both emission directions of the excited IDT, but in the case of LFM IDT, the experimental results indicate asymmetric. Observations of the latter will be described and discussed in some length. Theoretical calculations have been made and their comparison with experimental data are presented. As concluding remarks, it is pointed out that all the intensities (or power flux) of SAW under investigation are represented both in theory and in experiment by the intensities of the superposition of two-directional radiations of each finger pairs, which were considered separatively by Zuliani and Ristic [J. Appl. Phys. 49, 3018–3024 (1978)] for the periodic IDT.
The interelectrode multireflection effect of surface acoustic wave
Authors: Yong-an Shui
Published: October 2005

In general, a series of matrix multiplication is used in the calculation of SAW interelectrode multireflection effect. Usually complicated numerical calculations are required but the relations between the characteristics and the parameters of the arrays are not formulated by such approach. In this report some analytical expressions for SAW interelectrode multireflection effects are given. together with the frequency response and generation characteristics of interdigital transducers including the dispersive transducers discussed. The effect of multireflection of a symmetric periodic transducer could be included by the multiplication of a frequency-dependent weighting factor to the original frequency response. The relation between this weighting factor and the parameters (the number of electrodes and the strip width, etc) is discussed. The unsymmetrical acoustic power output of the dispersive transducer is shown, with the influence of the parameters discussed. It is shown that the reflective arrays of SAW resonators of different strip width could be considered as equivalent to the arrays of different impedance discontinuity with the same reflective characteristics. The reflection outside the forbidden band is also discussed.
High accuracy differential absorption and velocity measurements in relaxing acetate solutions
Authors: Eden Don , Elias John G.
Published: October 2005

Relaxation of acetate ions has been studied in dilute aqueous solutions using an improved differential ultrasonic technique. The technique uses a Carstensen type differential cell which can be completely submerged in the temperature regulated bath. A phase sensitive detection scheme accurate to 2 × 10−4 signal periods permits the measurement of relative velocities with an accuracy of 0.03 cm s−1. A precise waveguide beyond cutoff attenuator has been incorporated into a differential pulse comparison scheme in order to obtain attenuation accurate to 2 × 10−3 dB cm−1. These improvements permit measurements in solutions much more dilute than those previously studied. Results of both velocity and attenuation in very dilute solutions of zinc and copper acetate for frequencies from 1 to 35 MHz will be presented and compared with previous results.
Ultrasonic absorption in dioxane-water mixtures
Authors: Rajagopalan S. , Atkinson G. , Atkinson B. L.
Published: October 2005

Dioxane-water mixtures are a very common solvent system. However, their thermodynamic properties show marked deviations from ideal behavior. The mixtures also show ultrasonic relaxation phenomena in the 10–80-MHz region. In 1966, Hammes and Knoche examined this system in the 10–160-MHz frequency range. They interpreted their data in terms of two chemical relaxations caused by the H-bonding processes: 2 W + 2 D ⇌ D + Q ⇌ Z. We have reexamined the system over a much wider frequency range of 0.2–610 MHz and conclude that the data are more sensibly explained by the concentration fluctuation theory of Romanov and Solovyev. The three parameters of this theory (Q, a thermodynamic parameter; D1, a mutual diffusion coefficient; l, an interaction distance) are examined in terms of the known thermodynamic and transport properties of the system. Finally, an attempt is made to relate this theoretical approach to a molecular model for such water mixtures.
Velocity of sound in arterial tissue
Authors: Rooney J. A. , Gammell P. M. , Hestenes J. D. , Blankenhorn D. H. , Chin H. P.
Published: October 2005

The velocity of sound has been determined for excised human and canine arterial tissues using a time delay spectroscopy technique. Frequency was swept from 0 to 10 MHz with data being taken in the range from 2 to 10 MHz. The velocity was determined using a comparison of the time delay for the received signal between a water path and sample tissue of measured thickness. The velocity was measured as a function of temperature and tissue pathology. Normal tissue is nondispersive and the velocity of sound increases monotonically with increasing temperature from a mean value of 1587 m/s (standard deviation, S.D., 12 m/s) at 25°C to 1609 m/s (S.D., 8 m/s) at 37°C. For fatty lesions the velocity of sound is also nondispersive and for a given temperature increases with increasing attenuation associated with the fatty deposits. In calcified lesions larger than the ultrasound beam area the time delays can vary greatly with frequency and are indicative of multipath effects caused by structure of the precipitated calcium. [Support by the National Research Council and NIH contract N01-HV-729301.]
Effect of phase cancellation artifact on frequency dependence of ultrasonic attenuation measurements
Authors: Frizzell L. A. , Bamber J. C.
Published: October 2005

It is well known that the ultrasonic attenuation coefficient of mammalian tissues, in the low megahertz frequency range, varies approximately linearly with frequency for all measurement methods (recent work has shown that the absorption coefficient of these tissues also varies nearly linearly with frequency). However, the magnitude of the measured attenuation may vary by as much as a factor of three with the measurement technique. In particular it has been shown that measurements with phase sensitive receivers, which are subject to phase cancellation due to an inhomogeneous velocity distribution within the tissue yield higher values than methods utilizing phase insensitive receivers. The frequency dependence of the phase cancellation artifact depends upon the frequency range examined, the range of velocity inhomogeneity, the sample thickness and the receiver aperture.
Absolute threshold and response latency for the chinchilla as a function of stimulus duration
Authors: Clark W. W.
Published: October 2005

An adaptive tracking procedure was used to evaluate thresholds at 0.25, 0.715, 2.0, 4.0, and 8.0 kHz in a group of operantly conditioned chinchillas. Signals were synthesized with 10-ms rise-fall times and varied in ten duration steps from 15 ms to 1.5 ms. Chinchillas reported the signal by releasing a response key within 2.0 s of its onset. Latency was defined as the interval between the onset of the signal and the key release. Threshold measures showed that the chinchilla integrates energy in the same manner as human listeners, but with a longer time constant. Time constants for chinchillas varied from 400 ms at low frequencies to 100 ms at high frequencies. Measures of response latency as a function of signal duration overlapped for all durations at a given frequency. While long-duration signals produced a doubling of latency for a 50-dB reduction of stimulus intensity, short duration signals, as long as they were detected, produced similar latencies as long signals at equivalent SPL's. The implication of this finding will be discussed. [Supported by Grant NS 03856 to the Central Institute for the Deaf.]
Confusion errors in identification of environmental sounds
Authors: VanDerveer Nancy J.
Published: October 2005

The background sounds of everyday life make available much information about activities and objects in the environment. (Consider, for example, familiar footsteps or a sneeze.) In this study, listeners heard a tape recording of 30 such sounds and reported in writing on what they heard (free identification). Their responses showed that they identified many of the recorded events accurately, e.g., paper tearing, keys jingling, clapping, based only on acoustic information. The exception were the “thumps”, such as a door slamming, where accuracy was much poorer. Errors in identification suggest some acoustic properties or features to which listeners may have been responding. Confusion occured only within pairs or small clusters of sounds; for example, blowing-sniffing, scratching-scribbling, and footsteps-knocking-hammering. In particular, confusion occurred among items having quite similar temporal patterning, which might be described in terms of amplitude envelope of the waveform. Understanding acoustic determiners of meaningful-nonspeech-sounds identification may bring new insights into perception generally and may have application to work such as the development of sensory substitution devices for the perceptually handicapped.
Vowel duration in the speech of hearing and deaf children
Authors: Reilly A. P.
Published: October 2005

The duration of vowels in five sentences as read by 16 deaf and 16 hearing children, and one deaf adult, were measured using a computerized, visually assisted, auditory segmentation technique. Data were obtained on absolute and relative durations of vowels with respect to type, the tense-lax feature, lexical stress, and prepausal and sentence-final lengthening. On each sentence, the duration pattern was quantified in terms of the ratios of the durations of successive pairs of vowels. The relationship between the various duration measures and intelligibility was examined. Hearing children produced absolute and relative durations analogous to those reported previously for adults. Deaf subjects produced absolute durations which were two to three times those of the hearing group. However, they also produced relative durations which conformed to normal patterns associated with vowel type, the tense-lax feature, lexical stress, and sentence pattern. Relative duration was closely correlated with intelligibility, but absolute duration was not. Implications for speech training programs for the deaf are discussed. [Work supported by NINCDS.]
Fundamental frequency and formant structure in deaf speech: Influence of a hearing aid in a case study
Authors: Collins M. J.
Published: October 2005

The importance of auditory monitoring for speech production is well established, particularly as evidenced by the effect of hearing loss on speech. Relatively abrupt changes in speech production have been noted in a hearing-impaired individual with an unusual hearing profile when she uses a “translating” hearing aid. The subject who produced the speech samples exhibits a severe to profound sensorineural hearing loss on traditional audiometric testing (125–800 Hz). Her acuity improves with frequency, such that her thresholds are normal in the range from 11 000 to 14 000 Hz. She has been fitted with an experimental hearing aid which transposes sound upward in frequency to the range where she hears best. Speech samples were obtained with and without the translating hearing aid. Materials used for analysis in the present study were sentences. The vowels /i/, /a/, and /u/, occurring in a variety of consonantal contexts, were analyzed spectrographically. The results indicate a systematic downward shift in fundamental frequency in the aided condition. Additionally, articulatory parameters appear to change concommitantly, and these changes are discussed. [Work supported by NIH.]
Suprasegmentals of deaf speech: Influence of hearing aid in a case study
Authors: Simon Claude
Published: October 2005

The deaf subject in this study wears a frequency transposing aid described elsewhere [H. Halperin, J. Cullen, C. Berlin, and M. Killion, J. Acoust. Soc. Am. 62, S76(A) (1977)]. The method of speech data collection is described in the preceding paper (M. J. Collins, see Abstract 28). Laryngeal vibrations were recorded with the use of an electrical method known as the laryngograph. The suprasegmental characteristics of the speech are compared for the aided and the unaided conditons, in particular, the statistical properties of F0 frequency distributions and the dynamic features of F0 contours. A first examination of the recordings revealed marked differences between aided and unaided conditions in this speaker. In the unaided condition, F0 is consistently higher than in the aided condition. In the unaided condition, the F0 range is reduced and the dynamic features are less marked (rises and falls not so sharp) and less contrasted (used less consistently) than in the aided condition. These first results confirm those obtained in a previous related study of the use of suprasegmental features by deaf children [C. Simon, T. Gold, and H. Levitt, J. Acoust. Soc. Am. 62, S6(A) (1977)]. The detailed nature of the opening and closing movements of the vocal folds is also discussed for both aided and unaided conditons.
Vowel perception: The relative perceptual salience of selected spectral and waveform manipulations
Authors: Carlson Rolf , Granstöm Björn , Klatt Dennis
Published: October 2005

The objective of the preliminary research to be described is to quantify the psychophysical similarity of vowel-like stimuli that differ in certain spectral and waveform characteristics. To that end, the vowel /æ/has been synthesized by adding together sinusoidal harmonics of the appropriate frequencies, amplitudes, and phases. Changes to these parameters and to fundamental frequency are made on a period-by-period basis. The resulting synthetic waveform is essentially indistinguishable from that produced by a conventional cascade formant synthesizer, but the present synthesis technique permits the experimenter to manipulate certain spectral and temporal details more easily. A set of 65 different vowels acoustically similar to /æ/have been synthesized by manipulating formant frequencies, formant bandwidths, spectral tilt, phase relations among harmonics, and filtering passband/stopband. Subjects are asked to estimate the psychophysical distance between each stimulus and a reference vowel in a 380-trial randomized test. Results will be discussed in terms of various theories of vowel perception. [Research supported in part by an NIH grant.]
Tongue-lip coordination in speech production in a deaf speaker
Authors: McGarr Nancy S. , Harris Katherine S.
Published: October 2005

Acoustic electromyographic measures were made of an adult deaf speaker producing 15 repetitions of simple nonsense utterances of the form [əpapipə] with stress on either the [i] and [a] vowel. Conventional hooked wire electrodes were inserted into the genioglossus muscle, while surface recordings were made from the orbicularis oris. The gross acoustic results show that the speaker executes stress variations in a conventional fashion, that is, stressed syllables have greater acoustic amplitude and longer duration, although, as is usual for deaf speakers, durations are prolonged overall. At the muscle activity level, the deaf speaker resembles a normal in some respects, but not in others. The general pattern of onsets and offsets for oris activity was appropriate, although muscle activity levels were abnormally high, as had been previously found [D. Huntington, K. Harris, and G. Sholes, J. Speech Hear. Res. 11, 147–158 (1968)]. The deaf speaker was like normals, also, in showing a somewhat greater activity level for [p] closure preceding stressed than preceding unstressed vowels. For the genioglossus muscle, activity was greater for the vowel [i] than for [a], and greater for stressed than for unstressed vowels, on the average; again, as we would expect from normal data. However, individual tokens showed greater variability for the deaf speaker, thus, genioglossus activity occurred during [a] for some tokens. This result can be interpreted to suggest that the vowel neutralization previously observed for deaf speakers [R. Monsen, J. Phonetics 4, 189–198 (1976)] may result, not from tongue inactivity, but from an inability of the speaker to consistently activate some muscles while suppressing others. Additional light will be shed on this supposition by detailed token-by-token analysis of the physiological and acoustical signals, now in progress. [Work supported by NIH Grants NS-13870, and NS-13617 to Haskins Laboratories.]
Measuring system for the radiation field of a violin
Authors: Weinreich Gabriel , Arnold Eric B.
Published: October 2005

Vibration patterns of the violin body have been difficult to interpret because they vary greatly in radiation efficiency; knowledge of the actual radiation field would do much to clarify the situation. Both magnitude and phase must be measured to allow an interpretation in terms of the wave equation. In our system, the violin string is driven electrodynamically by a sinusoidal oscillator locked to the resonant frequency of the string by a phase-sensitive feedback loop. The violin is mounted in an anechoic chamber, and a pair of microphones sweeps the surrounding space so that the complex sound pressure (using the string vibration as a phase reference) is measured at many points on two concentric spheres. The data is digitally recorded in computer-readable form and then analyzed. Knowledge of the field on two concentric spheres allows a mathematical decomposition into outgoing and incoming waves, so that corrections can be made for the nonideal nature of the anechoic chamber. The apparatus is suitable for analysis of radiation fields of other instruments and of loudspeakers. [Work supported by NSF.]
Humidity changes and eigenmode frequencies in tuned violin plates
Authors: Thompson Rex , Hutchins Carleen M.
Published: October 2005

String players are perennially plagued by the effects of changes in relative humidity on the tone and playing qualities of their instruments. Since the relative frequencies of free plate eigenmodes 5 and 2 in both top and back free plates have been found to have considerable effect on tone and playing qualities in the finished violin, controlled studies are under way to check changes in mode frequencies with changes in relative humidity in pairs of tuned violin plates which have been coated with filler and varnish for more than two years. Details of work in both South Australia and New Jersey will be reported and discussed.
Plate vibrations and resonances of classical and folk guitars
Authors: Ross Richard E. , Rossing Thomas D.
Published: October 2005

It has been shown recently [G. Caldersmith, J. Acoust. Soc. Am. 63, 1566 (1978)] that the two lowest resonances of a guitar act as a resonance doublet whose frequencies are spread apart by acoustic coupling between the top plate and the air in the sound hole. We have investigated the influence on these coupled modes, as well as on the higher modes of vibration, of different patterns of bracing used by guitar makers. In a fan-braced classical guitar, for example, the phase angle between the sound pressure near the top plate and that in the sound hole changes by nearly 180° as one passes through the lowest resonance [I. M. Firth, J. Acoust. Soc. Am. 61, 588 (1977)]. The phase change observed in cross-braced folk guitars tends to be smaller, however. Adding transverse bracing raises the frequency of all the resonances and changes the coupling between “air” and “wood” modes of vibration.
Measurement of decay curves of individual partials of singly excited piano and harpsichord strings
Authors: Arnold Eric B.
Published: October 2005

Curves of relative sound-pressure level versus time for low-order partials (typically up to the fourth) of single piano strings have been obtained. A wide dynamic range contributes to the recognition of a number of characteristic forms which can be related to physical attributes of the piano. These forms appear to be essentially equivalent to forms obtained for the relative energy transmission to the bridge by a two-string system [G. Weinreich, J. Acoust. Soc. Am. 62, 1479 (1977)]. Beats between the two polarizations of each partial are frequently observed, but occur much less often on good pianos in good condition than on other instruments. This suggests the use of these measurements as an indicator of piano quality. Measurements on harpsichords show that beating of the upper partials is the rule rather than the exception [cf. R. W. Pyle, Jr. and T. J. Schultz. J. Acoust. Soc. Am. 39, 1220(A) (1966)], raising the question of what it means to tune these instruments, particularly when the subtleties of different temperaments are involved. Work is in progress to make quantitative comparison with theoretical curves. [Work supported by NSF.]
Acoustical and vibrational measurements on two bells
Authors: Kuntz H. L. , Hixson E. L. , Ryan W. W.
Published: October 2005

The acoustical and vibrational responses of two Coast Guard buoy bells (38.6 and 102 kg) to steady state sinusoidal excitation and to impact excitation are presented. The measurements were made with each bell placed in an anechoic room. The steady state sinusoidal excitation allowed measurement of the driving point acceleration impedance (F/A), the frequency spectrum, the vertical and horizontal directivity patterns (38.6-kg bell), and the bell mode shapes. The impact excitation allowed measurement of the frequency spectrum, the relative acoustical and vibrational amplitudes, and the decay times of the resonances. The frequency spectra determined from the different excitation methods agree. The frequency spectra are shown to agree with some other investigators' bell measurements. Typical results are presented for each type of measurement. Spectrum predictions for a third, untested bell (454 kg) were made by different methods. Limitations on the different predictions are discussed. [This work was supported by the U.S. Coast Guard contract DOT-CG-63441-A.]
Contact microphones: An evaluation
Authors: Schiller E. , Kaufman R. P. , Mah L.
Published: October 2005

Nine contact microphones from eight different manufacturers were systematically evaluated for speech spectrum response, power output. speech-to-wind ratio, speech-to-noise ratio, intelligibility, placement, and physical and electrical characteristics. The methods used for evaluation and the resulting graphs and tabulations obtained will be presented.
Radiation losses in resonant tubes
Authors: Zuckerwar Allan J.
Published: October 2005

An analysis of radiation losses in a resonant tube—attributable to the escape of acoustic energy through the walls of the tube—is based upon the following model. An acoustic standing wave is established in the test gas inside the tube. The associated pressure fluctuations excite vibrational modes of the tube structure; i.e., end plates and side walls, and these in turn radiate sound into the surrounding atmosphere. Three such modes have been considered: flexural vibrations of the end plates, radial vibrations of the side walls, and longitudinal vibrations of the side walls with rigid end plates. For ordinary tube geometries and operating conditions, the radiation losses are found negligibly small compared to the thermal and viscous wall losses. This conclusion is in disagreement with that obtained from a prior analysis (H. Roesler, Acustica 17, 73–78 (1966)] based on an alternative model. [Work supported by NASA Grant NSG-1324.]
Acoustic behavior in a cavity excited by a waveguide
Authors: Thompson C.
Published: October 2005

The acoustic behavior in a cavity excited by a waveguide, when the cross section of each component is small compared to a wavelength, is examined. The problem is solved by the Method of Matched Asymptotic Expansions. Expansions are made in terms of a small parameter, ε, defined as the ratio of the typical cavity height, H0, to cavity length, L0. A discontinuity in the boundary occurs at the joining point between the duct and the cavity. It is shown that the behavior of the pressure far from the discontinuity satisfies the Webster equation and the pressure boundary layer located about the cavity-duct interface satisfies the Laplace equation to second order in ε. The behavior of the viscous layer near the apex of the discontinuity is also discussed.
A spatial transform diffraction theory for parabolically anisotropic and isotropic media
Authors: Szabo Thomas L.
Published: October 2005

Rome Air Development Center, Hanscom AFB, MA 01731 A transform diffraction theory for either parabolically anisotropic or isotropic media has been formulated under the usual Fresnel region approximations. In rectangular coordinates this approach results in a double inverse spatial Fourier transform integral over the limits of a finite aperture [T. L. Szabo, J. Acoust. Soc. Am. 63, 28–34 (1978)]. For circularly symmetric aperture functions, the integral is a Hankel transform. Both forms have been used to obtain analytic expressions for the near and far fields of tapered sources. More difficult cases have been treated by superposition and FFT routines. Calculations will be presented for the fields of focussing and defective transducers.
Vibration software trends and availability
Authors: Pilkey W. D.
Published: October 2005

The sources of availability of vibration computer programs are listed and reviewed. These include both commercial and public sources, ranging from commercial software houses to users groups. Also, sources of information scruitinizing and surveying vibration software are presented. A major review periodical is the Structural Mechanics Software Series [University Press of Virginia, Box 3608. Charlottesville, VA 22903], which appears anually. Also discussed are recent trends in vibration software development. Special attention is given to the role of the minicomputer and microprocessor. [Work supported by ONR.]
Finite element analysis for the transient response of thin elastic spherical shells
Authors: Singh A. V.
Published: October 2005

This paper presents the development of a finite element for the analysis of spherical shells. Twelve degrees of freedom are taken at each node of the element. The derivation of stiffness and consistent mass matrices is based on the improved shell theory which takes into account the effects of rotary inertia and shear deformation terms. Normal modes and the values of the nondimensional frequency parameter for the free axisymmetric vibration of the spherical shell are calculated using an iterative technique and the orthogonality conditions. These results are then compared with those obtained earlier from the closed form solution of the differential equations of motion. As evident, the present method is found extremely simplified compared to the exact solution of the frequency equation which is transcendental in nature and involves Lagendre functions of complex order. The maximum difference in the results is within 3%–4%. The forced motion of spherical shells subjected to impulsive loadings is also studied in this paper. Detailed numerical results are presented and discussed for various cases of loading conditions.
Computer aided design of passive and active isolators for airborne electro-optical systems
Authors: Whaley P. W.
Published: October 2005

Airborne electro-optical packages are now being considered with increasingly demanding performance requirements. Aircraft linear and angular vibration disturbances thus require more effective isolation and control procedures. Computer aided design of passive vibration isolator locations for two isolators located at arbitrary points along a simply supported beam has been conducted by using a Fibonacci search to minimize the sum of the angular vibration responses at the beam ends [P. W. Whaley and J. Pearson, Shock and Vibration Symposium, 17–19 October 1978].That work is currently being extended to the multiple isolator case, and also to the distributed isolator case. In addition, the distributed optimum control using modern control theory was examined for the simply supported beam and a closed form solution was calculated [W. P. Whaley, ASME Paper No. 78-WA/DSC-39, presented to the 99th ASME Winter Annual Meeting, San Francisco, CA, 10–15 December 1978]. The subject of this paper is future efforts being directed towards a unified vibration control theory utilizing both passive and active isolation and control techniques. The optimization theory, relying heavily on modern control theory, should be utilized to design the optimum vibration isolation configuration given a particular airborne electro-optical system. [This work was conducted while the author was assigned to the Air Force Flight Dynamics Laboratory.]