bluuebunny/crossref_metadata_2025 huggingface dataset:
Ear Differences in the Recall of Vowels Produced by Different-Sized Vocal Tracts
Authors: Darwin C. J.
Published: October 2005

The five vowels /ɪ, ε, æ, a, ʌ/ in the context /əɲ-t/ were synthesized on the Haskins parallel formant synthesizer using two different sizes of imaginary vocal tract. The formant frequencies for one voice were 25% higher than those for the other. Two experimental dichotic tapes were run on two different groups of 18 subjects. On the first tape, the two sounds constituting a dichotic pair could be both low voice or both high voice or one of each. On the second tape, only the high voice was used. Those subjects who listened to the first tape recalled significantly more vowels over-all from the right than from the left ear. On the second tape, subjects showed no significant ear difference. Moreover, this latter (insignificant) ear difference was significantly smaller than that for those trials in the first experiment, which had the high voice on both ears. A right-ear advantage for vowels thus appears when, within an experiment, there is uncertainty concerning size of vocal tract. [Support by NICHD and the Commonwealth Fund is gratefully acknowledged.]
Design Guide for Traffic Noise Prediction
Authors: Kugler B. Andrew , Gordon Colin G. , Galloway William J.
Published: October 2005

There is an increasing interest on the part of local and national authorities on the impact of new highway projects upon the noise pollution of the environment in communities throughout the nation. This paper is a continuation of previous work [“Methodology for Highway Noise Prediction,” D. L. Nelson, C. G. Gordon, and W. J. Galloway, Paper 7A7, 78th Meeting Acoust. Soc. Amer., October 1969, San Diego, California] and discusses a methodology by which the highway designer can predict expected noise levels from a highway during its design stages and compare them with design criteria. The design criteria developed is based on task interference considerations such as speech and sleep. The methodology is presented by means of an example in which noise contours were developed for a proposed highway configuration. The impact of the highway on the community is evluated using the design criteria and the existing ambient noise levels.
Attenuation of Sound in Suspensions and Emulsions
Authors: Allegra J. R. , Hawley S. A. , Holton G.
Published: October 2005

The absorption of sound in suspensions and emulsions, which can be several orders of magnitude greater than that in the pure substances, usually has been attributed to viscous dissipation processes including relative motion, the relaxing bulk modulus of the suspended material, or scattering. A description of these processes is contained in a more general theoretical treatment, which, in addition, indicates that thermal conduction in the vicinity of the interfaces results in substantial sound attenuation. The theoretical results will be discussed for viscous, compressible, thermal-conducting media and compared to observed experimental ultrasonic absorption behavior in a number of aqueous emulsions and suspensions. [This research was supported in part by the U. S. Office of Naval Research and the National Institutes of Health.]
Nearfield Transducer Array for an Anechoic Tank
Authors: Groves I. D.
Published: October 2005

The dimensions (100 in. diam by 25 ft long) of the anechoic high-pressure tank at this laboratory limit the size of transducer that can be accommodated in it and the separation distance that can be achieved. To increase the measurement capabilities of the tank, a nearfield transducer array has been installed. Novel features of the planar array are its circular shape and the manner in which shading has been accomplished: Sensor elements arranged in five concentric rings are cast in an elastomer; shading is provided by six external capacitors. Design details and performance data are presented.
Nearfield Cavitation for a Cylindrical Array
Authors: Porter D. T.
Published: October 2005

Computer calculations were done for the near- and farfields of a cylindrical transducer array of 192 elements. Calculations were done for four different beam depression angles; for each beam depression angle, 12 different phasing sets were used; the sets corresponded to various percentages (0% to 180%) of the phases required to phase the array to a plane at that depression angle. The nearfield pressure maps that were computed show that as the plane wave phasing percentage increased, the peak pressures on the array increased slowly, while the peak pressures in the nearfield off of the array increased rapidly, particularly when the percentage of plane-wave phasing was greater than 100%, which resulted in severe nearfield focusing. An approximate method is presented for predicting the levels of the harmonics generated in the water by the occurrence of cavitation off of the array. When the theoretical acoustic pressure exceeds the ambient static pressure, the acoustic signal is represented as a clipped sine wave, which in turn is represented as a Fourier sine series whose coefficients represent the levels of the fundamental and harmonics.
Large Nearfield Calibration Array
Authors: Pida George
Published: October 2005

Farfield transmitting response, free-field sensitivity, and directivity patterns of both small and large (up to 18 ft in one dimension) underwater audio-frequency transducers have been obtained by direct measurement made in the nearfield with a special hydrophone, the NRL 33 ft × 33 ft nearfield calibration array (NFCA). Some of the measured results will be compared to the results determined by the classical farfield measurements except where only computed results were feasible. The calibrating array hydrophone consists of 2500 acoustic sensors in a square array on 8-in. spacings. These acoustic sensors were amplitude shaded according to the distribution advanced by W. James Trott in a JOURNAL article [36, 1557–1568 (1964)]. Applicable theory and fabrication design data for the special hydrophone will be briefly noted.
Temporal Organization of Higher-Level Linguistic Units
Authors: Lehiste Ilse
Published: October 2005

Phonological units may be of various sizes, ranging hierarchically from a single speech sound through syllables and phonological words to phonological phrases. Evidence for the existence of phonologieal units may be derived from a study of the temporal organization of spoken language. A minimal unit larger than one phoneme consists of a sequence of sounds whose durations are negatively correlated, so that a timing error made in the production of one phoneme is compensated for in the production of an adjacent phoneme. Temporal compensation of this kind was studied in repetitions of the English words steed, staid, stayed, stead, skid, skit, stay, steady, skiddy, and skitty. A negative correlation was always found to exist between the vowel and following consonant in monosyllabic words, as well as between all segments constituting a word taken as a unit. This makes it possible to offer a tentative definition of a phonological word as the domain over which temporal compensation takes place. Higher-level phonological units serving as domains of suprasegmental patterns are described in various other languages.
Mechanical Tuning of the Acoustic Receptor Organ of the Noctuid Moth
Authors: Adams W. B.
Published: October 2005

Mechanical characteristics of the auditory organ of Noctuid moths (Prodenia eridania, Cramer) have been investigated in an effort to define the stimulus at the receptor organ. This organ contains two receptor cells of unequal sensitivity and is suspended from the tympanic membrane. The neural spike rates produced by the more sensitive of the two cells have been recorded as a function of vibration frequency while mechanically stimulating the tympanic membrane. The frequency characteristic obtained in this way is determined by the mechanical properties of the receptor organ itself and is not affected by the system of air-filled cavities surrounding it. The resulting characteristic shows a primary resonance near 2 kHz, an antiresonance near 10 kHz, and one or more higher order resonances above 10 kHz. When the tympanic membrane is exposed to acoustic waves so that the intratympanic cavities become effective, the hearing organ is most sensitive to sound frequencies between 25 and 60 kHz [K. D. Roeder, J. Insect Physiol. 12, 843 (1966)]. Thus it appears that the primary mechanical resonance at 2 kHz is attenuated by the acoustic cavity system. The remaining high-frequency response is adapted to the frequency range of the sonar signals of bats.
Expansion Time of an Underwater Cylindrical Gas Bubble
Authors: Wentzell R. A. , Adlington R.
Published: October 2005

The collapse time of an infinitely long cylindrical cavity under constant pressure is determined. A bubble period-depth relation is determined analogous to the Willis formula for the spherical case. An underwater line charge explosion of known energy is treated as an adiabatic gas and a time equation for expansion from its initial radius to equilibrium is developed. To avoid the difficulties inherent in the cylindrical case due to the potential becoming infinite, the problem is treated as an initial value problem. Experimental results using 90-in. line charges at various depths verify the bubble period-depth relationship. [This work was supported by the DRB, under contract.]
Interaction of Sound with Sound in Water in the Presence of a Solid Surface
Authors: Jones Joie Pierce , Beyer Robert T.
Published: October 2005

Recent experiments involving the scattering of sound by sound have produced negative results for the case of noncollinear beams. When two perpendicularly intersecting finite-amplitude sources (frequencies of 7 and 5 MHz, pressure ampltiudes of 4.5 and 1.8 atm, respectively, at the center of the interaction region) were allowed to interact in water, no scattering at the sum and difference frequencies was observed although pressure levels of 0.07 dyn/cm2 could be measured with a 10 dB S/N ratio. However, scattering has been observed for the same case when solid objects, such as rigid cylinders, are placed in the interaction region. It appears that diffraction of the primary beams by the solid object produces an array of collinear beams, which generate the sum and difference frequencies. Measurements of the interaction at the sum frequency are presented for the case of rigid cylinders (radii 14 and 164 in) in the interaction region. Furthermore, a simple theory is proposed which yields results in good agreement with the experimental data. [This research was supported in part by the Office of Naval Research.]
Improvements in the Complex Exponential Algorithm for Spectral Analysis
Authors: Spitznogle F. R. , Barrett J. M. , Quazi A. H.
Published: October 2005

Research concerning the complex exponential technique of spectral analysis is described. The complex exponential technique has been found to be useful in signal analysis applications where, for sine-wave signal components, a frequency accuracy greater than that obtainable with Fourier techniques is required. The use of the technique for the analysis of several types of signals is discussed, and these results are compared with Fourier techniques. It is shown that almost an order of magnitude improvement in the computational time and memory requirements of the complex exponential algorithm can be obtained by taking advantage of symmetries in the Prony algorithm for obtaining a complex exponential representation. [Research supported under Office of Naval Research contract.]
New Real-Time Spectrum Analyzer
Authors: Owen Robert E. , Solomon Robert D.
Published: October 2005

A new audio-frequency signal-processing system that uses hybrid time-compression techniques is described. An internal computer controls the measurement process as well as the data processing, and it makes the instrument easier to use than a conventional one of similar versatility. Two levels of push-button controls are provided, one simplified set for repeating measurements that have previously been defined, the other, a complete set for research and investigation applications. The computer's digital processing of the spectrum assures quantitative answers over the 54-dB dynamic range with accurate rms averaging and decibel conversion. A self-contained CRT display allows observation of the time domain signal, for setting of trigger level, trigger delay, and weighting function on transients, as well as the normal averaged spectral output. Adjustable constant-bandwidth resolution is provided as well as constant-percentage-bandwidths such as 13 oct. Data output may be on a dc chart recorder, x-y plotter, punched tape, high-speed printer, or in BCD form for a data-link, in addition to the CRT display.
Extracting and Processing Vocal Pitch for Laryngeal Disorder Detection
Authors: Crystal T. H. , Jackson C. L.
Published: October 2005

A peak-following type pitch extractor has been built and used to obtain digital time and amplitude data from the speech of normal subjects and subjects with pathological larynxes. A program in the computer to which the extractor is interfaced refines the extraction by discarding all but the most-significant peak in each pitch period and by screening for time and amplitude regularity. Various statistical measures of the extracted data have been considered as potential indices in the detection of laryngeal dysfunction. Potential indices considered include various measures of pitch time and amplitude jitter, variants of perturbation factor [P. Lieberman, “Some Acoustic Measures of the Fundamental Periodicity of Normal and Pathologic Larynges,” J. Acoust. Soc. Amer. 35, 344–353 (1963)], correlation between time and amplitude, and descriptions of vocal breaks. [This work was supported under contract and performed in cooperation with the personnel of the Neurological and Sensory Disease Control Program, U. S. Public Health Service. Medical and voice data was collected by the Massachusetts Eye and Ear Infirmary, Boston.]
Control of the Jaw in Relation to Stress in English
Authors: MacNeilage Peter F. , Hanson Robert , Krones Robert
Published: October 2005

Current evidence, although fragmentary, suggests that, with high degrees of stress, upper articulators exhibit more movement from natural or prior positions but move no faster. The result is usually increased segment duration. These relationships were investigated in the case of jaw movement. Movement data were obtained by excitation of a photocell by a small light attached to the jaw. Electromyograms were also recorded from muscles controlling the jaw. Movement parameters and relations between electromyograms and movement were obtained by computer. A number of stress environments were examined including noun and verb pairs differing only in stress. In preliminary results, the aforementioned relations between stress and segment duration and amount of articulator movement were replicated. However, contrary to expectations, heavier stresses were usually accompanied by higher rates of jaw movement. Furthermore, studies of the dynamic relations between jaw movements during the entire syllable suggest that for heavier stress a relatively discrete impetus to rapid movement is delivered during part of the syllable, whereas in relatively unstressed syllables a single dynamic function controls rate of jaw movement throughout the syllable.
Differentiation of /p/ and /b/ from Spectrographic-Intraoral Air Pressure Comparison
Authors: Agnello Joseph G. , McGlone Robert E.
Published: October 2005

Recordings of intraoral air pressures nd acoustic signals were obtained from four speakers repeating the syllables [pɑ] [bɑ] [ɑp] and [ɑb]. Intraoral air pressure and formant patterns were simultaneously obtained and displayed on a spectrogram, which permitted measurement of the time relationships of the two events. Comparisons were made of components of the pressure wave trace to either the onset or termination of the formant traces of the vowels. The ratio of the drop in time of pressure from peak to vowel formants onset or termination, which relates to the opening of the lips, significantly differentiated between all four syllables. The pressure rise-time ratio, which corresponds to lip closure, distinguished between /p/ and /b/ in both syllabic positions. These data indicate that the activity during the “silent gap” or stop segment of these utterances contributes significantly to the differences between them.
Auditory Nerve Equilibration in Cat and Guinea Pig
Authors: Wilpizeski Chester , Weiss Betty Goldman
Published: October 2005

Cats and guinea pigs were prepared with permanently implanted stainless-steel recording macroelectrodes located in the auditory nerve. Evoked responses to continuous trains of clicks were displayed on an oscilloscope and photographed over a 5-min period of stimulation. Recordings were made under waking (restrained) and anesthetized conditions at levels from 40 to 100 dB SPL. During anesthetized states, the greatest amount of equilibration (greatest reduction in N1 amplitude over time) occurred with high stimulus intensities and within the first minute of stimulation. Cats showed more pronounced equilibration than did guinea pigs, especially at high sound levels. Wide fluctuations in nerve output were observed in waking cats.
Is Sensitivity (Audibility) Related to Frequency of the Acoustic Stimulus Showing Maximum Efferent Inhibition?
Authors: Nielsen D. W. , Teas D. C. , Konishi T.
Published: October 2005

Certain general features of the data described above (see the two preceding papers) are discussed. In particular, the variation of efferent inhibition as a function of best frequency is similar in the guinea pig to that shown by Wiederhold and Swift [J. Acoust. Soc. Amer. 41, 1585 (1967)] in the cat. Since, in the cat, the frequency region of greatest inhibition was also the region of greatest auditory sensitivity (MAF), were were prompted to compare audibility curves for the two species [Miller and Murray, J. Comp. Physiol. Psychol. 61, 227 (1966) and Miller, Watson, and Covell, Acta Otolaryngol., Suppl. 176 (1963)], as well as their Δu functions. The variation in magnitude of Δu suggests that the audibility curve for the guinea pig may actually be more sensitive in the 5–10 kHz region than previously thought. Our data at present suggest the hypothesis that the audibility curve for the guinea pig is similar in form to that for the cat but less sensitive. The effects of COCB stimulation on the tuning curves will illustrate the effectiveness of COCB stimulation on frequencies around the best frequency. The general use of Δu as a measure of inhibitory effects will be shown to be incomplete especially as a basis for estimating population effects. [Research supported by two PHS grants.]
Medial Geniculate Evoked Responses in Conscious Cat
Authors: Gerken George M.
Published: October 2005

The average magnitude of the response evoked by a transient acoustic stimulus may be increased by a background of continuous sound. The phenomenon is dependent upon the intensities and spectra of the two sounds, but cannot be explained, however, in terms of combined instantaneous peak energy. Averaged response amplitude increased over a period of seconds or minutes after the onset of the backround stimulus. The observations are based on bipolar records from four animals. In one cat, for example, the response evoked by a gated 2-msec burst of 3 kHz, 80 dB SPL tone was increased 50% in amplitude by the presence of a 3 kHz, 65 dB SPL background tone. Lesser increases in amplitude were produced by an FM tone centered on 3 kHz, or by a background of 2 or 5 kHz. Neither filtered noise nor white noise enhanced the evoked response. [Work supported in part by a grant from the National Institute of Neurological Diseases and Stroke.]
Simple Electrostatic Transducers for High-Frequency Sounds
Authors: Beavers R. , Palin J. , Simmons J. A.
Published: October 2005

Using aluminized Mylar film for diaphragms and sintered stainless-steel disks for backplates, one can easily assemble electrostatic transducers that operate at ultrasonic frequencies up to 150 kHz. Loudspeakers with 0.15-mil diaphragms and 34-in. diam backplates produce airborne sound from 30 to 150 kHz at 10–20 dyn/cm2 at a distance of 30 cm. Second harmonic distortion varies from −20 to −36 dB with fundamentals from 25 to 100 kHz, and electronic predistortion can considerably reduce these figures. With compensation for the 4–6 dB/oct increase in sound output with rising frequency, these transducer response curves fluctuate by only a few decibels from 30 to 150 kHz. Loudspeakers with 1-in. backplates generate up to 80 dyn/cm2 over their range. As microphones, these transducers yield 0.7 to 1.0 mV/dyn/cm2 ± 2 dB up to 110 kHz. These transducers have been used successfully in studies of echolocation and hearing in bats and, with an additional protective diaphragm, in studies of underwater hearing in marine mammals.
Observation of Wind Wave Generated Doppler Shifts in Surface Reverberation
Authors: Igarashi Yoshiya , Stern Richard
Published: October 2005

Frequency shifts in surface reverberation were consistently observed when a directional transducer was pointed in the direction of ocean wave propagation. The magnitude of the doppler shift systematically decreased to zero as the transducer was rotated 90° to point towards the cross wave direction, and the sign of the shift reversed as the transducer was horizontally rotated from the up-wave to down-wave direction. Doppler shift data were obtained using 110-msec tone transmission at 15 and 60 kHz. The measured shifts were generally in accord with first-order resonance theory with higher order shifts not observed. The spectral width of surface reverberation was independent of wave direction, and roughly three times that of the transmitted pulse for the 60-kHz data and less wide in the case of 15-kHz transmission. It is hypothesized that orbital motions of the water particles forming the larger scale ocean wave, can impart a radial to-and-fro motion of the ultragravity wavetrain riding on it. Rapid up and down dopplers induced by this motion are believed to contribute to the observed spectral broadening.
Convection Velocity of the Pressure Field Induced on a Plane Surface by a Subsonic Turbulent Boundary Layer
Authors: Brackenridge J. B. , Geib F. E. , Maidanik G. , Remmers G.
Published: October 2005

Two convection velocities are defined, the one pertaining to spatial-temporal space, and the other pertaining to spectral space. Assuming the pressure field to be stationary, both spatially and temporally, the pressure field can be described in terms of either the cross correlation φ(x,t) or the spectral density Φ(k,ω) =∫∫dx∫dtφ(x,t) exp[i(k⋅x−ωt)], where x={x1,x3} is the vector separation between two spatial points on the plane surface, t is the time delay, k={k1,k3}> is the Fourier conjugate of x, and ω is the Fourier conjugate of t. Choosing the free-stream velocity U∞ to be U∞={U∞,0}, a convection velocity Uα(t)={Uα(t),0} is defined Uα(t)=x̄1/t, where x̄1 is the value of x1 for any value of t, for which (∂φ/∂t) (x,t)=0; (∂2φ/∂t2) (x,t) <0. Another convection velocity Uβ(k1)={Uβ(k1),0} is defined Uβ(k1)=ω̄/k1, where ω̄ is the value of ω for any value of k1, for which (∂Φ/∂ω) (k,ω)=0; (∂2Φ/∂ω2) (k,ω) <0. The velocities Uα(t) and Uβ(k1) agree with previously so-called convection velocities only if the turbulence pattern is frozen. Otherwise, only these velocities correspond to convection, in the sense that convection velocities will be zero when determined in the way just prescribed in reference frames moving with the velocities Uα(t) and Uβ(k1). Methods for measuring Uα(t) and Uβ(k1) are discussed and assessed. A number of measurements of Uβ(k1) made with wave-vector filters—arrays of flush-mounted transducers arranged in a specific configuration—are reported.
New Inverse-Filtering Technique for Deriving the Glottal Air Flow Waveform during Voicing
Authors: Rothenberg M.
Published: October 2005

It is known that for many conditions of voicing and vocal-tract configurations, the volume velocity waveform at the glottis can be derived by a procedure known as inverse filtering, in which the radiated sound pressure waveform, as picked up by a microphone, is passed through a filter having a transfer characteristic approximately the inverse of the transfer characteristic of the vocal tract at that instant. It is shown that an inverse filter, which uses the volume velocity waveform at the mouth, instead of the radiated pressure waveform, will provide a better replica of the glottal waveform in at least three respects: it provides a reliable zero reference level, much less low-frequency noise, and an easy and accurate amplitude calibration. The required volume velocity waveform at the mouth has been obtained by means of a wire-sceen pneumotachograph based on a specially constructed “circumferentially exhausted” pneumotachograph mask. The mask was designed for a minimal distortion of voiced speech, and when in place will shift formant frequencies less than 10%, as averaged over the different English vowel phonemes. The time resolution of the complete inverse-filter system is presently limited by the pneumotachograph to about 12 msec.
Formant Frequency Measurements in Spontaneous Speech of Children 0–6 yr Chronological Age
Authors: Gilbert John H.
Published: October 2005

Formant construction of the English vowels, /i, æ, a, u/ was investigated. Spontaneous utterances of 30 children ranging in age from 1 to 6 yr chronological age were analyzed on a sound spectrograph and measures made of formants one, two, and three. It was determined that formant construction in children is different from that of the adult and also that there appear to be differences when data are compared on the basis of bone age versus chronological age. [This research was supported by the Medical Research Council of Canada.]
Changes of Human Voice Caused by Age, Disguise, and Simulation
Authors: Endres W.
Published: October 2005

In order to clarify whether visible speech spectrograms can be used to identify human beings, three questions must be studied: Does the formant structure of phonemes uttered by a certain speaker change over a longer interval of time? Does it remain constant if the voice is disguised? Does the formant structure of phonemes uttered by imitators correspond to that of the imitated persons? Spectrograms of phonemes uttered by male and female speakers and recorded over periods of up to 29 years showed that the position of formants of voiced sounds shifts to lower frequencies with increasing age of test persons, and that increasing age results in a decreasing pitch frequency and an increasing indolence to vary it. Speech spectrograms of texts spoken in a normal and a disguised voice revealed strong variations of formant structure. Visible speech spectrograms of utterances of VIPS have been compared with those of imitators. The imitators succeeded in varying the formant structure and the pitch frequency of their voices, but they were not able to adapt these parameters to those of the imitated persons.
Discrimination of Sequential Constraints within Interval-Coded Auditory Displays: Effect of Black Length
Authors: Pollack Irwin
Published: October 2005

Finite-state sequences were translated to interval-coded pulse trains, and converted to sound by earphones. In forced-choice listening tests, listeners heard sequences with common elements, represented equally often over different block-lengths. Interstate interval thresholds were obtained with different block-lengths by an adaptive programming procedure. Such thresholds serve as an experimental measure of the discriminability between block-lengths. Over an impressively wide range of conditions, interstate thresholds are closely related to the difference in informational uncertainty of the sequences.
Dichotic and Monotic Time-Staggered Speech Perception
Authors: Berlin C. I. , Loovis C. F. , Lowe S. S. , Cullen J. K.
Published: October 2005

At the previous meeting of this Society, we reported a lag effect in which the trailing syllable in a dichotic pair was more intelligible with time staggers at 15, 30, 60, and 90 msec. This paper presents data on 12 subjects who listened to time staggers of 90, 180, 250, and 500 msec. A special condition was also added in which the periodic portions of each pair were aligned without concern for the burst onset of the consonant. We called this the “boundary condition” and included it as a result of our observation that the voiceless consonant when paired with a voiced consonant is generally more intelligible in the dichotic condition. Both ears functioned about the same beyond 180-msec staggers. However, we found the boundary condition enhanced the right ear laterality effect and attenuated the voiceless over voiced preponderance seen in ordinary dichotic simultaneous listening. [Supported by the NIH.]
Threshold of Audibility as a Function of Tone Duration: Is There a Frequency Effect?
Authors: Chamberlain S. C. , Zwislocki J. J.
Published: October 2005

The threshold of audibility of pure tones was measured by means of six psychophysical methods: adjustment, limits, constant stimuli, Békésy tracking, forced-choice tracking, and confidence rating. The measurements were made at 250, 1000, and 4000 Hz for stimulus durations of 10, 25, 50, 100, 200, and 500 msec. The results obtained with the methods of adjustment, limits, constant stimuli, and confidence rating show a clear frequency dependence of the threshold shift as a function of stimulus duration—the threshold shift decreases as sound frequency increases. The results of the tracking methods do not show such an effect. An analysis of variance performed for the 10-msec duration indicates a frequency effect at the 5% level of significance and an even more significant method-frequency interaction. This outcome should resolve to some extent the issue of the frequency dependence of threshold-duration characteristics.
Sound Transmission through Single and Double Panels Using Statistical Energy Analysis
Authors: Crocker Malcolm J. , Price A. J.
Published: October 2005

The transmission of random incidence sound through single and double panels is studied using statistical energy analysis. In the single panel case the analytical model consists of three linearly coupled oscillators, room-panel-room. In the double panel case, the model consists of five oscillators, room-panel-cavity-panel-room. The effects of cavity absorption, panel damping, panel spacing, and edge conditions are included in the analysis. Both resonant and nonresonant transmission are considered. Theoretically, the sound energy transmitted is found to depend strongly on the radiation resistance of the panels and the panel and cavity loss factors. Good agreement is obtained between theory and experiment, and for double panels the agreement is much better than can be obtained using the London or Beranek and Work theories. The radiation resistance and vibration amplitude of the panels are also well predicted by the analysis. [Work conducted when both authors were at the Department of Building Science, The University, Liverpool, England.]
Connection Between the Impact Noise Level and Sound Transmission Loss
Authors: Ver Istvan L.
Published: October 2005

Based on the results presented in the preceding paper, an expression connecting the impact-noise level (Ln) and sound transmission loss (TL) of a floor is derived that takes into account both the resonant and the forced response of the floor; it thus extends the utility of the formulas derived previously by Heckl and Rathe into the frequency range below the critical frequency. It is shown how this connection between impact-noise level and sound TL can be used for the experimental evaluation of the potential TL of a floating floor in the presence of certain types of flanking.
Perception of Rate Changes of Pulsed Stimuli
Authors: Smith Richard P. , Warm Joel
Published: October 2005

This experiment was designed to assess the efficiency of listeners in detecting changes in rate of pulsed stimuli. Each subject was given 50 trials in a counterbalanced order. The following stimulus conditions were used: basal rates of 2, 5, 8, and 11 Hz and linear rate changes of 1, 3, 5, 7, and 9 Hz/sec. Subjects listened to each basal rate for 10 sec, after which a signal light indicated that the basal rate would begin to increase or decrease. Reaction times to perceived increases and decreases of basal rate tempos were recorded. The carrier frequency of the square-wave pulses was 1000 Hz. The intensity was 70 dB (SPL). An analysis of variance indicated: (1) Reaction time was a negatively accelerated decreasing function of rate of change; (2) The over-all effects associated with basal rate and direction of change were not significant. But both parameters interacted with rate of change; (3) Increases in tempo were detected more quickly than decreases in tempo only at high basal rates and slow rates of change. Results are discussed in terms of a postulated ideal detector.
Detection in Non-Gaussian Noises
Authors: Feth Lawrence L.
Published: October 2005

Stimulus-oriented theories of signal detection are based upon an analysis of the detailed statistical character of the stimulus. When the background for detection is band-limited white Gaussian noise, predictions of human performance by these models are generally good. Since the synchronous random telegraph wave and tones, frequency modulated by noise, exhibit flat envelopes and constant energy for all samples of a given duration, a stimulus-oriented detector should perform errorlessly when detecting brief sinusoids in these maskers. Detection experiments were conducted for pairs of Gaussian and non-Gaussian maskers matched for spectrum level and bandwidth. In all experiments, sensitivity and slope estimates obtained for matched maskers did not differ significantly, although in a separate discrimination experiment these matched maskers were perfectly discriminable. [This paper is based upon a PhD dissertation submitted to the University of Pittsburgh. Research supported by National Institute of Neurological Diseases and Blindness, U. S. Public Health Service, and a fellowship from Social and Rehabilitation Administration, Department of Health, Education, and Welfare.]
Latency of Reaction Time when Detecting Sinusoids of Uncertain Frequency in Noise
Authors: Green David M.
Published: October 2005

Several earlier studies of the detection of a sinusoid in noise have reported that uncertainty about the signal frequency causes a small but reliable decrement in detection performance. A reaction-time procedure was employed to study this phenomena in more detail and to determine if another procedure might increase the size and reliability of the effect. The subject attempted to detect as quickly as possible a sinusoidal signal added at a random time to noise. The mean reaction time of these detection responses was measured under two conditions: (1) when the signal frequency was certain and (2) when the signal frequency was uncertain. The amount of uncertainty was varied by changing the number of possible signal frequencies. Increments in mean reaction time due to signal-frequency uncertainty were only about 15% for the two frequency conditions and about 30% when the signal could be any one of 10 possible frequencies. The standard deviation of the reaction-time distributions measured in this experiment was roughly 25% of the mean. [Research supported in part by the National Science Foundation and in part by the National Institutes of Health, Public Health Service, U. S. Department of Health, Education, and Welfare, and by a research grant awarded to the Center for Human Information Processing.]
Rating Scales for Auditorium Acoustics
Authors: Watters B. G. , Beranek L. L. , Schultz T. J. , Johnson R. , Kirkegaard R. L.
Published: October 2005

Communication of scientific ideas is aided if the essential “dimensions” of the topic being discussed are first identified, and then quantified or scaled. This is as true for subjective as for objective dimensions. We report our most recent efforts to scale the more important subjective dimensions of the effect of the acoustic character of auditoria upon speech and music. Approximately a dozen dimensions have been found useful in communicating subjective evaluations of various halls. Examples are: brassiness, brilliance, and over-all loudness resulting in a hall for a standard speech or music source.
Auditorium Acoustics Simulator
Authors: Horrall T. R. , Blanchard B. E. , Watters B. G.
Published: October 2005

An acoustics simulator is a complex of signal processing equipment by which the acoustical characteristics of one space may be simulated in another. Artificial reverberation systems, theater surround systems, and four-channel stereo systems are familiar examples of relatively simple simulators. A more comprehensive simulator can be useful in auditorium acoustics research because it enables the experimenter to control and rapidly alter important acoustical parameters, thus permitting facile psychoacoustical testing. We describe a recently completed auditorium acoustics simulator, which has loudspeaker channels for up to 12 arrival directions. The impulse response for each channel is individually programmable from combinations of “direct” sound, “reverberation,” and “discrete echoes” generated from magnetic tape delays. Design features are convenient programmability of desired directional impulse responses, and the facility for instantaneous comparisons among a number of combinations of such preprogrammed sounds.
Binaural Detection as a Function of Signal Frequency and Noise Level
Authors: Wilbanks W. A. , Cornelius P. T. , Houff C. D.
Published: October 2005

The present study is a continuation of work by Wilbanks and Whitmore [J. Acoust. Soc. Amer. 43, 785–797 (1968)], and by Wilbanks and Cornelius [J. Acoust. Soc. Amer. 46, 126 (1969)], on the dependency of binaural masking-level-differences (MLDs) upon signal frequency and noise spectrum level. Monaural and binaural signals of 150, 225, 250, 500, and 1200 Hz were employed. The spectrum level of the noise was varied between +10 and +55 dB. The results show that, with very low noise levels (+10 dB), the largest MLDs for monaural and binaural signals are obtained at 500 Hz (4 dB and 9 dB, respectively). As the noise level is raised to +55 dB, the signal frequency at which the largest MLDs occur shifts to 250 Hz (15 dB and 21 dB). At 150 Hz, the MLD increases from less than 1 dB and 3 dB to about 10 and 18 dB as the noise level is increased from +10 to +55 dB. At 1200 Hz, the MLD is relatively independent of noise level. Some theoretical implications of these results are discussed. [Research supported by National Science Foundation.]
Towards a Theory of Melody
Authors: Lindblom B. , Sundberg J.
Published: October 2005

Given a certain well-defined class of melodies, what are the principles and laws by means of which the metric, harmonic, and tonal facts of these melodies can be derived? The present paper describes an attempt to formulate such a system of rules that specify the logical organization of melodic structure in a set of Swedish nursery songs. Our approach is based on the assumption that fundamental rules of linguistic prosody underlie the composition of such melodies. A large body of metric, harmonic, and tonal data can be accounted for with the aid of this assumption. Our results indicate many parallels between the organization of linguistic and musical structure and support the idea that musical processes cannot be adequately described in terms of Markovian or stochastic models; rather, our results indicate that available evidence suggests that the formal machinery developed within the study of language may turn out to be of value also in the construction of future theories of music. The paper contains taped illustrations of melodies that can be generated with the present system of rules.
Acoustic Criteria and Procedures for Adjusting Tone and Response in Woodwinds
Authors: Benade A. H.
Published: October 2005

Bore and tone hole proportions of three clarinet types (Oehler, Albert, and Boehm) were obtained for instruments including those of outstanding players here and abroad. Resonance curves were measured for many. Measured resonances closely match those calculated via bore, tone hole, and bundary-layer perturbations plus reed dynamics. Acoustical features of these clarinets are correlated with musical strengths and weaknesses. Acoustical “diagnosis” can be based on playing experiments. Systematic reaming and lacquering of an instrument is possible, to give qualities preferred by the player. Low-register pitch stability, full tone, and solid attack requires tuning of the second-mode resonance (with the reed in action) to within 5 cents of the third harmonic of the played frequency. Higher harmonics including those of clarion register frequencies mostly lie in the “open-holes passband,” where the resonance frequencies are pseudorandom. It is sufficient to tune one of these resonances to some harmonic of the played note. Elimination of all sharp corners reduces damping at low sound levels, and gradualizes the onset of turbulence at high levels, giving an increase in dynamic range. Related procedures are known for flute and recorder; bassoons and oboes respond similarly.
Two Processes in Melody Recognition
Authors: Dowling W. J.
Published: October 2005

Melodies can be recognized (a) by recognition of the exact pitches in the melody and (b) by recognition of melodic contour—the sequence of ups and downs. Recognition memory for brief melodies shows that subjects use process (a) when melodies are repeated without transposition, and process (b) when the melody to be recognized is transposed in pitch. On each trial a pair of computer generated five-note melodies was presented. In different sessions the second melody of the pair was (1) either identical to the first or random; (2) either identical to the first or had the same contour with different interval sizes; or (3) either had the same contour or was random. In separate sessions the second melody was either transposed to another part of the pitch scale or not. Results show that without transposition conditions 1 and 2 are comparable (d′ = 2.8 and 3.0), suggesting that melody recognition is based on exact pitch recognition. With transposition Conditions 1 and 3 are comparable (d′ = 1.7 and 1.5), suggesting that contour recognition is important even in recognizing identical transpositions. Discriminating identical from contour preserving transpositions is difficult (Condition 2, d′ = 0.3). Performance in Condition 3 is comparable with and without transposition (d′ = 1.5 and 1.3).
Acoustic Ray Theory Calculations
Authors: Wright Evan B.
Published: October 2005

An acoustic ray trace program has been developed at the Naval Research Laboratory based upon a smoothed fit of sound speed profile data to an inverse quadratic function of depth. The program computes closed-form solutions for ray trajectories, travel times, and propagation losses between discrete layer boundaries in the profile. There is provision for range-dependent changes in sound speed profile, and for representation of the sea bottom as either flat or linearly segmented. Receiver intensities can be calculated as random or phase-dependent ray series, or by a technique of statistical distribution of arrivals. Results are given for the application of the program to a bistatic reverberation problem. Separate ray traces from source and receiver were made and arrivals on the bottom were matched to yield the receiver arrival pulse structure.
Employee Reactions to a Landscaped Office Environment
Authors: Riland Lane H.
Published: October 2005

An anonymous questionnaire study of 136 employees at various organizational levels in five departments regarding their reactions to various aspects of a landscaped office environment three months after occupancy revealed quite favorable reactions over-all, particularly compared to conventional office environments. Some of the more important improvements over conventional office environment as perceived by the individuals involved in improved over-all psychological climate, including acoustical and communication factors, as well as others. Some critical reactions also involved acoustical as well as other variables. Many of the measured reactions appeared to be functions of the organizational level of the respondant. Specific reactions to the importance of privacy at the work place were measured. Acoustical as well as visual factors were noted as both improvements and problems regarding privacy. A follow-up of the same areas approximately one year later indicated continued over-all favorable reactions to the landscaped environment compared to conventional office environments.
Jet Aircraft Noise in Metropolitan Los Angeles under Air Route Corridors
Authors: Hurdle P. , Lane S. R. , Meecham W. C.
Published: October 2005

Airport community noise exposure to jet aircraft takeoff and landing activity at Los Angeles International Airport (LAX) has been extensively measured and documented. However, the noise intrusion problems due to overflights of jet aircraft in the approach and departure air routes over the communities of the Los Angeles Metropolitan area have largely been ignored. Preliminary measurements indicate that in at least 10 peripheral residential communities (at distances of 15 to 30 miles from LAX), the noise levels caused by jet aircraft overflights exceed 20 dBA above the average ambient noise levels. There are four major approach and departure corridors to LAX with a total number of 500 commercial jet aircraft overflights each 24 hours. Many communities are thus subjected to about 100 overflights during the peak traffic periods (about 3-h duration). As a result, hundreds of thousands of individuals are subjected to a significant noise annoyance every 2 min for sustained periods. In most of these instances, the noise levels exceed the municipal codes on allowable residential noise disturbances. However, these noise ordinances are not enforced against the air carriers. It is estimated that if the aircraft operators were fined accordingly, the total of such fines in the Los Angeles area would be several million dollars per year.
Noise Survey of Houston, Texas
Authors: Cook B. D. , Dhingra H. C. , Donlin W. P. , Werchan R. E.
Published: October 2005

The results of a recent noise survey in the Houston area are presented. This survey, conducted along the guidelines of a Draft Method for Measurement of Community Noise ANSI S3-W-50, was restricted primarily to designated census tracts. The acoustical time profile of one area is demonstrated by a motion picture of computer generated maps. [Research supported by the Institute of Urban Studies, University of Houston.]
Comparative Effects of Auditory and Extra-Auditory Acoustic Stimulation on Human Equilibrium and Motor Performance
Authors: Sommer H. C. , Harris C. S.
Published: October 2005

Human equilibrium and psychomotor performance of subjects exposed to free-field broad-band noise were compared to those for subjects exposed to similar spectra of noise presented through earphones. The noise spectra and levels presented through earphones approximated those delivered to the ear canals of subjects wearing various ear protector combinations in a free-field broad-band noise of 140 dB re 0.0002 dyn/cm2. The major difference between exposures was the extra-auditory acoustic stimulation received by the free-field exposure group. Performance of 32 subjects was measured during three different noise exposure conditions. Performance with ordinary mechanic tools was adversely affected by free-field noise and unaffected by noise presented through earphones. Rail task performance in free-field noise exposure exhibited approximately twice as much decrement for the subjects wearing binaural ear protection and four times as much with monaural ear protection as compared to the comparable auditory exposure presented through a headset. Auditory stimulation combined with extra-auditory stimulation produced more decrement in performance and equilibrium than auditory stimulation alone.