bluuebunny/crossref_metadata_2025 huggingface dataset:
The Distribution of Forty Sounds in an Acoustic Space
Authors: King Ivan R.
Published: May 2012

Mean decibel power spectra were calculated for a half-second sample of each of 40 continuant sounds: 19 vowels, 6 vocalics, 11 fricatives, and 4 sibilants. Eigenvector studies were made of the entire set and of various subsets of the sounds. In every case the first few eigenvectors account for nearly all of the total variance. Similarly, nearly all of the total variance in every case is along the directions of the lowest-order cepstral components. When the 40 sounds are plotted in their principal eigenplane, a clear separation shows between high vowels, low vowels, voiced consonants, and unvoiced consonants. Some of the subsets also show, in their own principal eigenplanes, a geometric arrangement that corresponds to phonetic classes; but some do not. The principal eigenplanes of the various subsets do not coincide; an effort is made to exhibit the geometrical relationship between pairs of such planes. Some of these diagrams show additional separation of sets of sounds. In general, eigenplane plots are instructive and suggest further directions for study. [This work was carried out at the Institute for Defense Analyses, Princeton, New Jersey.]
Computer-Generated Speech Spectrograms
Authors: Yoon Wha Joong , Reeder Kaye , Strong William J.
Published: May 2012

Computer generation of speech spectrograms has become increasingly important because the computer has become one of the most extensively used tools in speech analysis. A method is described for calculating and displaying spectrographic data, along with fundamental-frequency and over-all-intensity data. It represents variations on methods previously described by others. Any 2.5-sec segment of speech data stored on disk can be selected for either a wide-band or narrow-band analysis which is accomplished via the fast Fourier transform. Pitch period, overall intensity, and spectral information are stored on disk and can then be repeatedly displayed with different display options. The basic “display point” is actually a collection of eight points in a two-by-four matrix. Six nonzero intensity levels are available with either 1, 2, 3, 4, 6, or 8 of the available points turned on. The matrix is placed horizontally for narrow-band displays and vertically for wide-band. Display options include a threshold below which spectral values are not displayed, specification of the number of decibels per intensity level of the display, and a high-frequency emphasispecification. Examples of the display output are shown.
Aural Combination Tones and Temporal Masking
Authors: Leshowitz B. , Cudahy E.
Published: May 2012

Greenwood [J. Acoust. Soc. Am. 51, 502–543 (1971)] has shown that for steady-state masker conditions, in which the signal is a long-duration pure tone and the masker is a continuous pure tone, a notch appears in the masked audiogram. This notch at the high-frequency side of the masker is caused by the detection of combination tones on the low-frequency side of the masker. The present study investigated the importance of combination tones in temporal masking. A 5-msec tonal signal was presented at various delays relative to onset of a longer-duration sinusoid. Under the forward-masking condition, the previously described notch in the masked audiogram was not obtained. Signal threshold was found to be a monotonically decreasing function of the difference between signal and masker frequency. In a second study, temporal masking was investigated using two pure tones as a complex masking stimulus. The combination tones that were formed by the masker produced masking effects on the low-frequency side of the masker comparable to those recorded under steady-state conditions. Some implications of these results for the formation of combination tones are discussed. [This research was supported by an NIH grant.]
Monaural and Binaural Frequency Selectivity Using Tonal Temporal Masking
Authors: Yost W. A. , Bergert B.
Published: May 2012

In two experiments, frequency selectivity was investigated using three temporal masking paradigms. In Experiment 1 a 60-msec 70-dB-SPL tone (4-msec rise-decay time) was used to mask a 10-msec (4-msec rise-decay time) 1000-Hz probe tone. The frequency of the masker varied from 250 to 2000 Hz. Masking was measured in the forward masking paradigm in which the time between masker offset and probe-tone onset (ATF was 10 msec, in the backward masking paradigm in which the time between probe-tone offset and masker onset (ΔTB) was 0 msec, and in the combined forward-backward masking paradigm in which ΔTF was 10 msec and ΔTB was 0 msec. In Experiment 2 the combined forward-backward masking paradigm (masker durations 150 msec, probe-tone duration 10 msec, ΔTB and ΔTF 5 msec each, signal frequency 500 Hz, masker frequencies ranging from 200 to 1000 Hz, and masker intensities 75 dB SPL) was used to study masking in three binaural conditions. In the monotic condition the maskers and probe tone were presented to the right ear; in the diotic condition the maskers and probe tone were presented identically to both ears; and in the dichotic condition the maskers were presented identically to both ears, and the probe tone was presented to the right ear 180° out of phase relative to the left ear. In both experiments the function relating the frequency of the masker to the probe-tone threshold (frequency selectivity function) was obtained and compared for the threee temporal paradigms in Experiment 1 and for the three binaural conditions in Experiment 2.
Stoneley- and Franz-Type Surface Waves—An Analytic Approach
Authors: Frisk G. V. , Überall H.
Published: May 2012

In the study of acoustic scattering by a solid elastic cylinder inbedded in a liquid, one finds a class of surface waves with speeds close to the sound speed in the liquid. The surface wavenumbers are found from the roots of a 3 × 3 determinant in the complex wavenumber plane. The behavior of these modes for large cylinders has been determined analytically and their dispersion curves calculated. It is found that, as the cylinder radius approaches infinity, one of the surface waves tends toward the Stoneley wave for the solid elastic halfspace. The others, which are the Franz-type modes, tend toward the liquid wavenumber in the limit of infinite radius. Similar analytic techniques are being used to study the Rayleigh and “Whispering Gallery”-type surface waves.
Acoustic Interaction between a Liquid and a Floating Plate
Authors: Barss W. M. , Mckee A. C.
Published: May 2012

Elastic waves in a floating plate have been studied for wavelengths comparable to the plate thickness. The theory has been generalized for unequal Laméé constants. The velocities of wave propagation have been measured for plates of various materials, both in air and with a liquid on one side. Compres-sional waves travelling parallel to the surface of an ice plate (Poisson's ratio 0.3) have a plate velocity, 3.02 ± 0.30 km/sec, 25% less than the bulk velocity (measured normal to the surface) and in good agreement with the calculated value. The reverberation of sound from floating plates, investigated by means of two rotatable transducers mounted together within the supporting liquid, includes a type of reverberation in which sound waves enter the plate from the liquid, are reflected within the plate by a discontinuity in it, and are then re-radiated into the liquid toward their source.
Moire Patterns in Underwater Acoustics
Authors: Barss W. M. , Noble M. R.
Published: May 2012

In some studies of the reflection of sound from submerged models, the sound intensity has been displayed graphically as a function of both frequency and angle. With the frequency swept repeatedly over a chosen range while the angle is swept only once through its range, the intensity is mapped on an XY plotter as a raster of lines varying in width, much as a picture is produced on a TV screen. Many of the patterns obtained in this way exhibit ripples that bear no obvious relation to the expected patterns. The particularly striking ripples observed for reflection from a plate with a corrugated surface led to a study of the reflection from arrays of parallel rods. The ripples are shown to be related to the moiré patterns familiar in optics but have some features that are usually absent from optical demonstrations. Like their optical counterparts, the acoustic moiré patterns may be useful in measuring strains or certain types of displacements.
Introduction to a Nematic Liquid Crystal Acousto-Optic Conversion Cell
Authors: Dreyer John F.
Published: May 2012

Real-time acoustic images have been shown capable of visualization by means of a nematic liquid crystal cell. [P. Greguss, J. Acoust. Soc. Am. 53, 306(A) (1973)]. The cell is composed of a thin film of a nematic liquid crystal in the homeotropic state between polarizers. Irradiation with ultrasonic waves produces birefringence re suiting in a visible pattern. The cell is a combination of a 1-mil-thick layer of a room-temperature liquid crystal between glass which contains a light polarizer and a light diffuser. The most sensitive viewing condition is at 25° from the normal on a diagonal with the polarizers. Two effects are observed. Low-intensity ultrasonic produces a proportionate transparent birefringence with higher energy at a threshold giving light diffusion. It is theorized that the acoustic pressure produces an electric potential due to the piezoelectric property of the liquid crystal and that this potential alters the direction of the molecules. Wavefront patterns obtained are shown.
Determination of Frequency-Dependent Damping Parameters for Composite Structures
Authors: Ni Chen-Chou
Published: May 2012

Employing the mechanical impedance-mobility concept in conjunction with steady-state vibration test, a semianalytical technique for the determination of frequency-dependent structural damping is introduced in this paper. Its major feature is to provide analytical guidance through derivation of governing equations for data acquiring and data processing, as well as physical interpretation. This technique is particularly appealing in determining damping effects on composite structures, which are subject to viscous-like damping environment, provided the damping environment is separable from the composite structures. In other words, these structures can be examined by systematic steady-state vibration test with and without the imposed damping environment.
Evidence that Stressed Syllables are the Most Readily Decoded Portions of Continuous Speech
Authors: Lea Wayne A.
Published: May 2012

Stressed syllables are presumed to be the most carefully articulated portions of speech, and thus the most likely to provide the reliably encoded information needed for automatic recognition of continuous speech. In conjunction with the Carnegie-Mellon Speech Segmentation Workshop, nine research groups used different automatic techniques to segment continuous speech (31 sentences) and identify the phonetic categories or phonemes. These segmentation and classification results were evaluated according to whether major distinguishing features of each of the phonea (such as high/mid/low, front/central/back, and rounded/ unrounded for vowels, and manner of articulation for consonants) were correctly determined. Listeners were asked to classify all syllables in the speech as stressed, unstressed, or reduced, and an algorithm of automatic location of stressed syllables also was used to delimit stressed nuclei. Vowels that were perceived as stressed and/or located by the algorithm were more accurately classified than unstressed or reduced vowels. Similarly, prestressed obstruents were more reliably categorized than other consonants.
Predicting the Location of Grammatical Pauses
Authors: Herman S. , Kloker D.
Published: May 2012

Several studies have demonstrated the importance of grammatical pauses or junctures to the perception and memory of speech. However, little research has been done on the problem of identifying the points where junctures may occur. Bierwisch has proposed that junctures are a function of readjusted surface structure, rhythm, and stress, and has written some complex rules to predict juncture location based on these factors. An alternate theory that claims that junctures are simply a function of surface structure and stress is presented. Both theories were tested against a sample of read sentences. The results support the latter theory, which correctly predicted 90% of the data. Thus the claim that readjusted surface structure and rhythm determine the location of junctures is unwarranted.
Phonological Rule Application in ASR Dictionary Processing
Authors: Hummel J. E. , Aurbach J. , Ret D. , Neu H.
Published: May 2012

Comparison of actual pronunciations of words with dictionary entries is used to study possible occurrences of phonological rules in continuous speech. We have been concerned with the collection of phonological rules and with rule testing techniques to ascertain the statistical counts for the number of times a rule has or has not occurred in recordings of natural speech. The preliminary investigations at this time indicate some of the complex relations that need to be studied in dictionary processing and the application of phonological rules for automatic speech recognition. [The research is supported by the Office of Naval Research, Contract N00014-73-C-022L]
A Locally Organized Parser for Spoken Input
Authors: Miller Perry L.
Published: May 2012

A locally organized parsing system (LPARS) has been developed for use in a continuous speech recognizer, accepting as its input a string of phonemes which contains ambiguity and error. The system is locally organized in the sense that it can construct local parse structures from word candidates recognized fairly reliably in all parts of an input utterance. These local structures are used as “islands of reliability” and serve as context to guide the search for more highly garbled words which might complete the utterance.
Comparative Visual Displays of Time and Frequency Domain Information in Connected Speech
Authors: Baker Janet M. , Ramsey Robert , Miller Mark , Baker James K. , Cooper Christopher
Published: May 2012

Despite the well-known redundancy of speech, certain kinds of acoustic information are uniquely or better seen in either the frequency or time domain. Some of these differences can be clearly seen between different visual displays of digital analyses automatically performed in both domains. In the frequency domain, these include digital spectrograms [Robert Ramey] and spectrum plots [Christopher Cooper and Robert Ramey], and in the time domain, pitch-synchronous plots Qames Baker], instantaneous-frequency plots Qanet Baker], and the waveform [Mark Miller] itself. These displays are produced on a Xerox Graphic Printer as hard copy and on a CRT screen for interaction. For example, formants and other acoustic features of steady and quasisteady states, e.g., stressed vowels, are more apparent when studied in the frequency domain. However, often transient events, encompassing only one or several cycles, are seen exclusively in the time domain. Such events, readily seen in the speech waveform, occur at certain phonemic boundaries and between acoustically distinct portions within some phonemes, e.g., stop consonants. The plots presented illustrate and compare some of these differences. A clear understanding of what kinds of overlapping and unique information are available from each of these domains should aid in their integration for better speech understanding.
A Free-Field Measurement Method for Acoustic Absorbent Characteristics at Oblique Incidence
Authors: Wyerman Barry , McDaniel Oliver , Reethof Gerhard
Published: May 2012

A free-field measuring technique for determining the absorption characteristics of an absorbent material at oblique incidence has been investigated. This method, developed by Ingard and Bolt, compares the pressure and phase of an approximately plane wave measured as a function of incident angle at a point on the surface of the absorbent material to a similar measurement with a reflecting surface. From these results, the impedance and absorption coefficient can be determined as a function of incident angle. Measurements were made with the sample mounted on a 6-ft2 panel and with a smaller panel. The results indicated a low-frequency limit for measurements that was inversely proportional to sample size and a problem of possible diffraction from the edges that made phase measurements difficult. The characteristics of several fibrous absorbents of the Owens Corning 700 fiberglass series were measured and compared with impedance tube measurements. These results were compared with calculations based on derivations by Pyett and Monna for porous layers of absorbent materials. Several recommendations are made on the measuring technique of Ingard and Bolt and factors to be improved upon are also listed. [This work is supported under NSF Grant No. GK-32584.]
Use of a Large-Scale Model to Predict Silencer Performance
Authors: Hendrix D. R.
Published: May 2012

Although gas turbine noise control has been a major problem for many years, it has become particularly severe with the evolution of gas turbines rated at 40 MW and larger for the utility industry. Theoretical modeling and small model testing have not proven satisfactory for accurate prediction of silencer performance. To remedy these shortcomings, large-scale model tests were found necessary. The test hardware required for these large model tests along with procedures for scaling large models to full size is discussed in this paper. Also included are a discussion about an actual test of an exhaust silencer designed for a 2-MW gas turbine. The test utilized a dynamic insertion loss test facility designed to simulate gas turbine or reciprocating engine exhaust and intake noise and flow conditions.
TTS in Man from a 24-h Exposure to Continuous Noise
Authors: Melnick William , Maves Michael
Published: May 2012

An earlier series of experiments with human subjects indicated that a noise exposure 16 h in duration was not sufficient to produce clear evidence that an asymptotic level of TTS had been reached. The exposure period was increased. Nine adult males were exposed to a sound field consisting of a 300-600-Hz band of noise at an octave band level of 90 dB for a period of 24 h. Hearing thresholds were measured in one ear at 11 test frequencies from 125 to 8000 Hz prior to exposure and at selected time intervals during and after exposure. TTS appeared to reach asymptote after 8 to 12 h of exposure. Maximum TTS was approximately 11 dB and occurred at 500, 750, and 1000 Hz. TTS was noticeable at 1500 Hz and negligible at other frequencies. Recovery from TTS was complete by 24 h following the exposure period. The magnitude of the asymptote was less than would be expected from previous experiments with man and chinchilla. This observation may be related to pre-exposure threshold hearing sensitivity.
Primary Components of Simulated Air Bag Noise and Their Relative Effects on Human Hearing
Authors: Sommer H. C. , Nixon C. W.
Published: May 2012

Air bag inflation noise contains a positive pressure pulse caused by the air bag volume displacement and a high-frequency noise burst associated with bag unfolding, air turbulence, and the like. Auditory temporary threshold shift (TTS) was measured for 12 discrete frequencies (125-12-kHz range) for volunteers exposed to (1) a positive pressure pulse of 165 dBpk, (2) a high-frequency noise burst of 153 dBrms, and (3) (1) and (2) presented simultaneously. Results indicated that (a) the high-frequency noise burst produced the greatest amount of TTS, (b) the positive pressure pulse produced no measurable TTS, and (c) the two components occurring simultaneously produced less TTS than the high-frequency noise burst alone. TTS associated with air bag inflation noise is primarily the product of the high-frequency noise. It is indicated that the positive pressure pulse reduces the effectiveness of the high-frequency noise in producing TTS. Some implications of these observations relative to the use of air bag restraint systems are discussed.
Effect of the Contraction of the Middle Ear Muscles on Suprathreshold Loudness Judgments
Authors: Morgan D. E. , Dirks D. D.
Published: May 2012

Changes in the threshold of hearing and suprathreshold loudness judgments have been reported under conditions in which the contraction of the middle ear muscles (MEM) has been induced. These psychophysical changes have been accounted for variously on the bases of contributions of contralateral direct masking, contralateral remote masking (CRM), binaural loudness summation (LS), and the effects of changes in transmission caused by MEM contraction. Experimental conditions were devised to determine the influence of the contraction of the MEM on suprathreshold loudness judgments at 250, 500, and 1500 Hz by controlling the possible influences of CRM and LS. The relative loudness of two sequentially presented 50-msec pulses (identical frequency) was judged by subjects with normal sensitivity (hearing and MEM) using the method of constants during three basic experimental conditions. In Condition A (reference condition), the test stimuli were presented monaurally separated by a 1400-msec interstimulus interval. Condition B was identical to Condition A except that a 1250-msec narrow-band noise (2900–5000 Hz) was presented contralaterally with an onset delayed 200 msec relative to the first test pulse. In Condition C an identical contralateral noise was used but with the onset of the first test pulse simultaneous with the onset of the noise. For each of these three conditions two reference tone intensities (60 and 100 dB SPL) and two narrow-band noise stimulus intensities (70 and 105 dB SPL) were employed. Essentially no suprathreshold loudness changes were observed between the two pulses among the various. conditions. We conclude that MEM contractions did not effect the suprathreshold loudness judgment.
SOFAR Propagation in the South Pacific Ocean
Authors: Bannister R. W. , Browning D. G. , Denham R. N. , Guthrie K. M. , Kibblewhite A. C.
Published: May 2012

Some sound speed profiles responsible for SOFAR propagation in the South Pacific Ocean are significantly different from the type most commonly found in the Northern Hemisphere. Near New Zealand the profile is characterized by a broad region of minimum speed; as a result the arrival structure for signals received at the sound channel axis may be opposite to the classic SOFAR pattern. The largest contribution associated with rays nearest the axis arrives first, followed by a gradual decay of the envelope. Recent oceanographic data obtained by the Scorpio Expedition and the Hakuho Maru and Tui cruises are used to define regions of different sound speed structure for the South Pacific Ocean. Mode theory predictions of the arrival structure for each region are compared with experimental data from Project Kiwi One. The corresponding values of attenuation are determined by both peak and energy methods of analysis.
Volume Reverberation in Northern Waters
Authors: Chapman R. P. , Bluy O. Z. , Adlington R. H. , Robison A. E.
Published: May 2012

Spectra of reverberation from deep scattering layers in Baffin Bay, Davis Strait, and the Labrador and Norwegian Seas were measured using explosives and hydrophones operating near the sea surface. Results from four experiments carried out between 1966 and 1972 were used to form a composite picture of reverberation in northern waters in late summer. This reverberation differs from that in the main North Atlantic Basin in that there is usually much less diurnal change in spectrum and considerably more scattering at low frequencies. Exceptions, when they occur, are in the more northerly regions. Towards the south there is a considerable backscattering of sound in the frequency range 1–3 kHz, caused presumably by layers of fish a few tens of centimeters in length. Concentrations of these fish are relatively constant over distances of hundreds of miles but decrease markedly over short distances in the neighborhood of oceanographic boundaries.
Diffusion of Decaying Sound Field in a Reverberation Room with a Highly Absorbing Sample
Authors: Yegnanarayana B. , Ramakrishna B. S.
Published: May 2012

Experiments show that the sound field in a room with one wall partially covered with a highly absorbing material is diffuse during the initial portion of the decay. This behavior can be explained by considering the room as a duct with the absorbing material placed on one of its end walls. When a transverse mode is incident on this wall, the reflected wave contains in addition to the incident mode several other transverse modes also, thus contributing to the diffuse state. Maximum power is reflected into modes other than the incident mode if the area of the material is half the area of the wall on which it is placed. This coupling among the modes increases as the specific acoustic impedance of the material is decreased (i.e., as the material is made more absorptive) or as the angle of incidence is increased. An approximate expression for the initial decay rate of the sound is obtained assuming diffuse incidence. The effective absorption coefficient derived from this decay rate depends upon the ratio of the area of the material to the area of the wall. The effective absorption coefficient agrees with the statistical absorption coefficient only when the latter is small.
Sound Radiation from Unbaffled Beams and Plates
Authors: Blake William K.
Published: May 2012

This paper summarizes some recent theoretical and experimental investigations of the sound that is radiated from unbaffled beams and plates. Theoretical analyses include a rigorous treatment of the radiating, unbaffled beam as a vibrating segment of a thin strip of elliptical cross section. The edge mode radiation from unbaffled plates is analytically cast as a two-dimensional Wiener-Hopf problem for radiation from an unbaffled strip. The results were checked by experiment. Reverberant sound power measurements on beams and plates were made in air and in water. The facility used has been described by the author at the 84th Meeting of the Acoustical Society [J. Acoust. Soc. Am. S3, 357(A) (1973)]. The results show that below acoustic coincidence radiation efficiencies of beams are reduced by a factor equal to the product of tht squares of the acoustic wavenumber and the width of the beam. The radiation of edge modes of plates is reduced by factors proportional to the acoustic wave number times the structural wavelength of the plate width.
Use of Voice Changes in the Detection of Deception
Authors: Barland Gordon H.
Published: May 2012

Short-term voice changes from subjects in low-stress and high-stress lie-detection situations were visually displayed by a Psychological Stress Evaluator, model PSE-1. Low-stress subjects (n = 16) picked one of five numbers, then answered “no” to all questions regarding which number they had picked. High-stress subjects (n = 14) were criminal suspects undergoing polygraph examinations in which their verbal answers to the test questions were simultaneously tape recorded for analysis. Under the low-stress condition the detection rate was not significantly different from chance. Under the high-stress condition, using polygraph responses as the criterion for stress, voice changes were clearly able to distinguish between truth and deception. Using a numerical scoring technique with a ±2 inconclusive range, the voice agreed with the polygraph in eight of 14 cases (p<0.01), with the remaining six inconclusive. When inconclusives were restricted to scores of 0, there were 12 agreements (p<0.01), one disagreement, and one inconclusive. Using ranks to compare the effectiveness of voice changes against the three individual components of the polygraph, it was found that the voice was the second most effective single parameter. It is hypothesized that a certain level of stress must be reached in the individual before changes in the voice occur; but once that level of stress is exceded, differential changes in the voice can be used to determine deceptiveness.
Physiological and Voice Indices of Stress in a Simulated Theft Experiment
Authors: Kubis Joseph F.
Published: May 2012

Two voice analysis techniques and a polygraph were used to examine the “no” responses and the concomitant respiration, blood pressure, and psychogalvanic reactions of subjects during an interrogation session. The objective was to determine how accurately the use of these techniques could differentiate the three basic roles in the experiment: Thief, Lookout, Innocent Suspect. The sample of 111 subjects included both males and females. Two experienced examiners were used to evaluate the polygraph and voice records. The results indicate (1) all three physiological indices attain greater accuracy than the voice analysis techniques; (2) there was a slight, though nonsignificant, trend for the records of females to be detected more accurately; (3) while the overall accuracy of the polygraph was statistically significant, the accuracy scores of both voice analysis techniques were within chance expectation. It may be concluded that the two voice-analytic techniques, in their present state of development, cannot be validly used as lie detectors within a simulated theft paradigm.
Electrophysiological Responses Evoked during Loudness Enhancement in Man
Authors: Bauer J. W. , Elmasian R. O. , Galambos R.
Published: May 2012

In a loudness enhancement task, subjects received a tone burst (Tc) followed after an interval (ΔT) by a signal (S1) whose loudness they matched by adjusting the amplitude of another burst (S2) presented 1.5 sec later. All signals were 8 kHz, 0.2 msec, with Tc at 100 dB SPL and 25 dB more intense than S1. As ΔT was decreased in steps from 400 to 100 msec, subjects systematically raised S2 amplitude to a maximum of approximately 15 dB above S1 amplitude. Computer-averaged brain activity evoked by each signal was concurrently recorded between vertex-mastoid electrodes, revealing (1) latencies to the peaks of the brainstem response [which measures activity in auditory nerve and brainstem nuclei; see Jewett and Williston, Brain 84, 681–696 (1971)] for S1 remain constant or increase slightly while those for S2 decrease, and (2) the amplitude of the vertex response (100–300 msec latency) to S1 systematically decreases while that to S2 does not. Hence the electrophysiological results reflect the changes in stimulus parameters, not in the perceptual effects.
Effects of Verbal Conditioning on Averaged Auditory Evoked Response
Authors: Lenhardt M. L.
Published: May 2012

The influence of affective association on the auditory averaged evoked response (AER) was investigated. By using verbal conditioning, affective loadings of pleasant, unpleasant, and neutral were grafted onto pure tones. Auditory AER were obtained for frequencies of 0.5, 1.0, 2.0, and 4.0 kHz. The N1P2 amplitude change (re the 0.5-kHz response) was found to be significant when the pleasant and unpleasant quantities were grafted to the low or mid frequencies. The results suggest that only pure tones that produce the largest disturbance in the cochlea will reflect significant electroencephalic effects. In the significant conditions the pleasant quantity was found to evoke a greater amplitude change than the unpleasant quantity. It was concluded that previous conditioning can result in stimuli attention by verbal association.
Pitch without Place?
Authors: Pierce J. , Zweig G. , Hansen E. , Molzon B. , Thomas K.
Published: May 2012

Psychophysical experiments involving the perception of amplitude-modulated tones are discussed and the results compared with earlier findings. The implications of the data for current models of periodicity pitch are also indicated.
Random-Access Programmable Recorder of Complex Sounds (RAP): A Digital Instrument for Auditory Research
Authors: Spenner B. F. , Engebretson A. M. , Miller J. D. , Cox J. R.
Published: May 2012

The design, construction, and operation of a self-contained, movable, digital recorder of sounds is described. After analog-to-digital conversion (20-kHz sampling rate and 12-bit amplitude encoding) the waveform is stored in one of two buffer memories (4000, 12-bit words). While one buffer stores incoming data, the other writes in the mass memory (25-megabit, digital disk unit with removable disk packs). The mass memory is organized into 406 cells, each of which can accept 250 msec of sound for a total capacity of 101.5 sec. Playback is achieved by transferring data from the mass memory to one of the buffer memories while the contents of the other buffer memory are being converted from digital to analog form. With appropriate filters at the input and output a bandwidth of 8 kHz and a signal-to-noise ratio of 60 dB are achieved. Edit, load, and replay modes of operation allow isolation of recorded sounds and transfer of sounds from one location to another. The replay mode, a 16-item memory, and an interface allow any arbitrary cell or sequence of cells to be played without interruption. Replay begins instantaneously when a play command is received. A variety of peripheral devices allows the instrument to be broadly useful in acoustical and auditory research. Controls are designed so that persons capable of operating a quality tape recorder are able to use the digital recorder.
Theoretical Performance of a Parametric Array with Phase-Reversed Primary Radiation
Authors: Lockwood James C.
Published: May 2012

Finite-amplitude attenuation of an intense sound wave may be diminished by reflection from a pressure release surface. Muir has suggested that this effect might be utilized to lengthen the region of interaction of a high-intensity parametric array and, hence, improve its performance. A theoretical analysis of a reflected parametric array has been performed. In this analysis a modification of the Mellen-Moffet model for parametric array performance has been utilized. The modifications consist of introducing the appropriate finite-amplitude taper function for reflected primary radiation into the model and of performing vector summations of difference frequency components generated with different phases. The results of the investigation indicate that the far-field difference frequency source level may, in some cases, be increased by more than 3 dB by reflecting the primary radiation from a pressure release reflector placed near the point of initial shock formation. Theretical data have been obtained for comparison with the experimental results presented at this meeting by Muir and Mellenbruch.
Laboratory Measurements of Acoustic Characteristics of Ocean Bottom Sediments
Authors: Martin F. D. , Winokur R. S.
Published: May 2012

Sound attenuation and velocity in ocean bottom core samples were measured by using a pulsed impedence tube at frequencies from 3 to 8 kHz, hydrostatic pressures from 1000 to 10 000 psi, and temperatures of 4° and 22°C. The data were analyzed using a theory for sound interaction with rigid porous material in which the wet static density of the sample is replaced by a complex dynamic quantity. The results indicate that observed attenuation and velocity fluctuations as a function of frequency, which are similar to those reported by Lastinger [J. Acoust. Soc. Am. 47, 285 (1970); 52, 1465 (1972)] and Sabin [J. Acoust. Soc. Am. 40, 1345 (1966)] for measurements made on a variety of porous samples with the same experimental arrangement, can be eliminated by treating the sample density as a complex number. Corrected attenuation values for various sediment samples of about 75% porosity vary from 0.5 to 3.0 dB/m at 3 kHz, increasing linearly with frequency, while the corrected velocity values are relatively constant at about 1500 m/sec.
Differences in the Dichotic “Lag Effect” as a Function of the Type of CV Syllables Presented
Authors: Porter Robert J.
Published: May 2012

Subjects were asked to identify pairs of dichotically asynchronous (by 0–165 msec) “encoded” CVs [ba, da, ga] or relatively less encoded CVs [wa, la, ja]. For encoded CV pairs, subjects tended to identify most accurately the temporally lagging syllables. As in previous studies [e.g., M. Studdert-Kennedy, D. Shankweiler, and S. Schulman, J. Acoust. Soc. Am. 48, 599–602 (1970)], this “lag effect” was found at asynchronies up to 120 msec, with a maximum effect at 60 msec. Whereas all subjects displayed lag effects for the encoded CVs, only six of the 11 subjects displayed similar lag effects for the less encoded CVs. The six remaining subjects displayed results similar to those obtained with non-speech or vowels under similar conditions in other studies. These observations are consistent with an interpretation of the lag effect in terms of an interaction between signals during a special decoding process which is necessary for the perception of the highly encoded consonants but which is optional, in some sense, for other speech sounds. [Work supported by NIH predoctoral fellowship.]
Flyover Noise Prediction from Static Data
Authors: Veldman Henry F.
Published: May 2012

The use of static ground test data to describe the acoustic characteristics of an aircraft flyover can result in a significant savings both in time and money, providing good correlation with actual flight test measurements is assured. This paper addresses itself to the elements associated with the calculation of EPNL values from static ground test data. Farfield noise level measurements were made over a range of engine thrust settings from idle to takeoff power of a JT3D-3B engine mounted on a test stand. Two key engine operation parameters were used to correlate the SPL values: low-pressure compressor rotor speed, which controls fan noise; and net thrust, which controls jet noise. The SPL spectrum, used to simulate a flyover, is generated by interpolating the measured data at the appropriate in-flight values of rotor speed and net thrust. The extrapolation to inflight condition also considers airplane parameters such as altitude, climb gradient, and number of engines, as well as Doppler shift effects, spherical divergence, atmospheric and extra ground attenuation, and ground reflection. Comparisons are made between EPNL values predicted from static ground test data and values obtained from flight tests. A tape will be played which demonstrates the difference between flyovers of a production B-707 airplane and a B-707 airplane equipped with quiet nacelles.
Nozzle Geometry and Forward Velocity Effects on Noise for CTOL Engine-Over-Wing Concept
Authors: Von Glahn U. , Goodykoontz J. , Wagner J.
Published: May 2012

Wing acoustic-shielding benefits for CTOL application were studied for a variety of exhaust nozzles, including convergent circular, bypass, six-tube mixer, and the mixer with ejector. The equivalent diameters for the nozzles ranged from 1.6 to 2.9 in. while the wind chord was 13 in. A 13-in.-diameter free jet was used to provide forward velocity. Farfield noise data were obtained at subsonic jet pressure ratios from 1.3 to 1.7 and forward velocities up to 260 ft/sec. The data are presented in terms of SPL and PWL spectra, directivity, and total power. The studies showed that jet noise shielding benefits were attained at a directivity angle of 90° with all nozzle-wing configurations. Forward velocity, except for local regions that were a factor of nozzle geometry, did not alter the shielding benefits obtained statically; the absolute magnitude of noise shielding varied in a manner similar to that for nozzle-only operation. The shielding effectiveness (configuration SPL minus nozzle-only SPL) are discussed and compared for the nozzle-wing configurations tested. In terms of sound power spectra, the presence of the wing had only a second-order effect on noise generation.
Water-Table Visualization of Flow-Induced Pressure Oscillations in Shallow Cavities for Simulated Supersonic Flow Conditions
Authors: Heller Hanno H. , Widnall Sheila E. , Jones William
Published: May 2012

Intense periodic pressure fluctuations can occur in the fluid in and above a cavity that is exposed to high-speed external airflow. Water table visualization provides an excellent tool to study the flow pattern in and near a cavity because all nonstationary phenomena are slowed by a factor of several hundred. Direct observation by eye or high-speed movie camera reveals for an oscillating cavity (1) the periodic deflection of the shear layer above the cavity, (2) the cavity internal upstream propagation of an “acoustic” wave originating at the trailing edge bulkhead, (3) the downstream propagation of a pressure wave in the cavity originating at the leading edge bulkhead, and (4) the propagation of a “shock wave” pattern away from the cavity into the surrounding fluid. The effect of geometric and fluid dynamic changes on these non-stationary phenomena is most easily visualized. In particular, oscillation-suppression techniques can be readily implemented and studied, before elaborate wind-tunnel and flight tests are conducted to substantiate findings and evaluate the feasibility and effectiveness of certain devices. A motion picture of water table visualized pressure oscillations in shallow cavities for simulated supersonic flow conditions shown during the presentation, illustrates the effects of the following geometric changes: length-to-depth ratio, curvature of leading-edge and trailing-edge bulkheads, upstream and downstream spoilers, attached and detached upstream and downstream cowls, and upstream and downstream bulkhead impedance and floor impedance. [This work has been supported in part by the Air Force Flight Dynamics Laboratory, Wright-Patterson AFB, Ohio 45433.]
Sonic Boom Structural Damage Prediction
Authors: Hershey Robert , Higgins Thomas
Published: May 2012

A technique has been developed for predicting the probability of sonic boom structural damage. This technique utilizes the probability density functions (pdf's) of the sonic boom induced stress and the material strength. Analysis of the data from experiments performed at Oklahoma City, White Sands, and Edwards Air Force Base has shown the stresses produced by sonic booms on windows to have lognormal pdf's. Similarly, analysis of the breaking strength distribution for glass plates has shown it to be log-normal. From these pdf's a statistical model has been developed for predicting the probability of window breakage as a function of nominal pressure, window size, aircraft flight path direction, and boom duration. Calculations from the model indicate a breakage probability of 1.1 breaks per million panes in good condition boomed at a nominal overpressure of 1 lb/ft2. Results predicted by the model agree well with experimental data at both high and low overpressures. [Work supported by Federal Aviation Administration.]
Some Aspects of the Evolution of the Reptilian Cochlear Duct
Authors: Baird I. L.
Published: May 2012

Anatomical studies of the reptilian ear have demonstrated phylogenetic and adaptive modifications at morphological, histological, and cytological levels. Morphologic differences in the cochlear duct appear to form orderly patterns, distinctive to familial levels. Limited but increasing evidence suggests that those differences are accompanied and extended by specialization in the basilar papilla. In turtles, early derivatives of stem reptiles, the organization of that receptor fits the concept of “primitive sensory epithelia” (Wersall and Flock, 1965). Snakes and amphisbaenians, derived from stock leading to lizards, show stages of neuroepithelial specialization, particularly in sustentacular cells. Lizards show additional cytoskeletal specialization of supporting elements; their hair cells frequently exhibit ciliary elongation and specific patterns of polarization, usually combined with tectorial modifications and absence of efferent innervation. In iguanid lizards, and possibly other families, different genera show stages of papillar specialization that correlate with accepted phylogenetic concepts and reported differences in auditory capabilities. Alligators, stemming from stock leading to birds, have unique sensory and sustentacular cells within a receptor clearly related to avian conditions. [Supported by Research Grant NS-07860, NINDS.]
Coherent Transmission of Signals in the Ocean
Authors: Clay C. S.
Published: May 2012

The purpose is to review the coherent signal transmission experiments and theory that were associated with Columbia University's Hudson Laboratory. They are (1) continuous wave transmission (Berman, Clay, Guthrie, Frosch, Poss, Shaffer, Sherry, and Tolstoy); (2) reproducible signal transmissions (Clay, Parvulescu, and Williams); and (3) theory of coherent transmission in the ocean (Clav). The first experiments were made between a source suspended from a drifting ship and bottom-mounted hydrophones. These showed the fluctuations to be extremely small for the frequency band greater than 10−2 Hz. Bottom source-receiver transmissions showed phase fluctuations that were accountable to ocean surface waves. Reproducible signal transmissions using the matched signal technique were made by Parvulescu and Clay [“The Tongue of the Ocean,” Radio Eng. Electron. 29, 223–228 (1964)] and they suggested the concept of a correlation space for coherent transmission. Clay applied the adiabatic approximation to modes in the ocean and derived the magnitude and spatial correlation function of the coherent transmission [Rev. Geophys. 4, 475–507 (1966)].
A Comparison of Transmission Fluctuations in Deep Ocean and Coastal Waters
Authors: Clark J. G. , Kronengold M.
Published: May 2012

Over the past ten years, several fixed-system acoustic transmission ranges have been established in coastal waters and extensive data from these ranges have been analyzed. From the Straits of Florida in particular, very long time series of acoustic and environmental parameters have been available, enabling investigations of transmission fluctuations to be carried out on all time scales up through the seasonal scale of events. Time series of comparable length are now being obtained from a deep-ocean fixed system range in the Eleuthera-Ber-muda region, and significant comparisons with the coastal zone results are now being established. These comparisons will be discussed with reference to the statistical characteristics of the data, the fluid dynamical processes to which the acoustic fluctuations are related, and to their relevance to selected theoretical concepts.
A Flexible Piezoelectric Material for Hydrophones and Other Dynamic Pressure Transducers
Authors: Pauer Lyle
Published: May 2012

A family of flexible piezoelectric materials has been developed and used successfully in several hydrophone designs as well as in other types of dynamic pressure transducers. Polar and frequency responses for the hydrophones are presented. Data from experiments to determine the change in receiving voltage sensitivity with hydrostatic pressure are given. Dielectric, piezoelectric, and mechanical constants of the material have been determined and are compared with piezolelectric materials in general use. Transducer applications other than hydrophones which take into account the unique properties of the material are explored.
A New Continuous-Line Hydrophone
Authors: Miller G. Kirby
Published: May 2012

A promising new line mechanoelectrical transducer based on the electret phenomenon is considered for use as a variational pressure sensor in the underwater environment. Theoretical design considerations are developed for the coaxial configuration with regard to sensitivity, geometry, frequency, input electronics type, and ambient pressure. Results of limited underwater tests show favorable performance characteristics.
A Model Community Noise Ordinance
Authors: Szecsody Alex J.
Published: May 2012

A condition necessary for quality of life is the control and regulation of noise. To serve this need, a model community noise ordinance for communities of moderate size has been developed. Extensive use is made of incorporating existing rules and specifications in a manner that compliments and utilizes their provisions at the community level. This ordinance, as presented, is recommended for adoption in principle. Each community will be required to place this ordinance in its appropriate legal form before it is adopted.