bluuebunny/crossref_metadata_2025_split huggingface dataset:
Acoustics and the concert hall
Authors: Beranek Leo L. 
Published: October 2005

Frederick Vinton Hunt profoundly affected the course of architectural acoustics. As the de facto successor to W. C. Sabine, he began his acoustical career by utilizing the Sabine reverberation chamber at Harvard University in the early 1930s to introduce accuracy into reverberation-time measurements. Stimulated by P. M. Morse’s Chap. VIII in Vibration and Sound (1936), Professor Hunt explored the sound field in a rectangular, marble-walled box and published in 1939 a new means for measuring sound-absorption coefficients of acoustical materials as a function of angle of wave incidence and, in addition, the details of a high-impedance, research sound source. As a continuing step he, with his students, expanded the application of the normal-mode-of-vibration theory of acoustics to full-scale rectangular rooms in which acoustical materials were present on one or more walls. Although he subsequently developed research interests in other fields, his papers in architectural acoustics touched off scores of published works by his students and their colleagues. Examples of his contributions that can be found today include techniques for reverberation measurement, the meaning of sound diffusion in spaces, the design of auditoriums for speech and music, and the principles of audio reinforcement and reproduction. This paper summarizes the present-day status of concert hall design, with emphasis on those elements of architecture that must be controlled if satisfactory results are to be obtained.
Subject Classification: 10.60; 55.40.
Theory of air frame noise
Authors: Meecham W. C. 
Published: October 2005

Air frame noise is examined using Curle’s theory for noise from rigid surfaces interacting with turbulence. Measured ’’air frame noise’’ often is open to question because of engine contribution. A large number of examples are considered: model airfoil in a jet, glider noise, jet wing in atmospheric turbulence, boundary layer noise on trailing wing edge, flat-generated noise, landing gear noise, noise from jet impinging on flap, and some others. Of all of these estimated noise sources it appears that for commercial jets the noises from jets on flaps (when present) and from landing gear may be the only sources of possible practical significance.
Subject Classification: 28.65; 40.55, 40.26; 50.55.
Ultrasonic absorption in air at elevated temperatures
Authors: Bass H. E. , Keeton Roy G. 
Published: October 2005

The attenuation of a 1 MHz ultrasonic signal has been measured in 78%N2/22%O2 at temperatures of 302 °K, 467 °K, and 689 °K and pressures from 1 atm to 1/60 atm. The measured attenuation was corrected for classical effects to obtain the attenuation due to rotational relaxation. In addition, the total absorption has been compared to computed values based on a linear combination of viscous, thermal conduction, diffusion, and relaxation losses to check the constants used for each of these terms. The rotational relaxation time of the mixture was found to be 7×10−10, 10×10−10, and 21×10−10 sec atm at 302 °K, 467 °K, and 689 °K, respectively.
Subject Classification: 35.20, 35.35.
Perception of (Hindi) consonants in differentiated clipped speech
Authors: Gupta J. P. , Ahmad Arshad 
Published: October 2005

Twenty nine initial consonants and 31 final consonants of CVC syllables were studied for perceptual confusions under the condition of differentialtion and infinite peak clipping. A quantitative procedure was used to calculate the percentage of information of each of the nine linguistic features (affriction, friction, nasality, aspiration, voicing, liquids, flapped liquids, continuants, and place), and the data so obtained were studied in relation to the data of the two previous studies [J. Acoust. Soc. Am. 45, 758–763 (1969) and J. Acoust. Soc. Am. 45, 770–773 (1969)]. It was found that liquids, voicing and continuants were more affected and that friction, affrication and place of articulation were less affected by the distortion of differentiation and clipping. The relative importance of features in differentiated clipped speech was not found to be the same as that of the normal speech. The study also indicated the perceptual difference between the two distortion conditions with and without pre differentiation.
Subject Classification: 70.30.
Headphone monitoring system for binaural experiments below 1 kHz
Authors: Domnitz R. H. 
Published: October 2005

Binaural experiments are often confounded by variability in the acoustic coupling of the headphones. A simple and convenient system is described for detecting and electrically compensating acoustic imbalances while the headphones are worn by the listener. Application of the system in some binaural experiments is discussed.
Subject Classification: 65.80; 65.62; 85.76.
Force and electrical Thevenin equivalent circuits and simulations for thickness mode piezoelectric transducers
Authors: Martin Roy W. , Sigelmann Rubens A. 
Published: October 2005

A simple model is reported for thickness-mode piezoelectric elements used as ultrasonic transducers in measurement systems. The model represents the excitation system and transducer as a Thevenin mechanical equivalent for the transmitting mode and a Thevenin electrical equivalent for the receiving mode. Computer programs based on the model have been developed, and computer simulations to study the effects of backing materials, element areas, and excitation sources are reported. The nature in which the source impedance alters the Thevenin mechanical output impedance and its importance in determining peak transmission frequency and in computing acoustic coating layers for matching was found. A total transfer improvement of 28 dB was shown for epoxy-backed elements radiating into fluid with the transducer used as both transmitter and receiver by using high values of source and load impedances in contrast to low values. The model was found to agree closely with experimental data of a 2.7-MHz transducer.
Subject Classification: 85.40; 80.70; 85.52.
Composite sandwich transducers with quarter-wavelength radiating layers
Authors: Ranz-Guerra C. , Ruiz-Aguirre R. Dominguez 
Published: October 2005

The combination of the composite sandwich transducers general equation with a defined gain index suggests that, provided both backing and radiating layers are made of different materials, the optimum performance is obtained when (1) the transducer radiating head is a quarter wavelength thick, as it is known, and (2) the piezoelectric layer is of zero thickness. The last result implies that the optimum design cannot be reached; it can only be approximated by piezoelectric layers of small thickness. In this instance the Langevin’s equation is greatly simplified. Experimental data are presented to decide the limits of use of the simplified Langevin’s equation when the piezoelectric consists of PZT-4 ceramics. The outlined method can be of use in any active layer.
Subject Classification: 85.52.
Measurements of diffraction and interaural delay of a progressive sound wave caused by the human head. II
Authors: Abbagnaro Louis A. , Bauer Benjamin B. , Torick Emil L. 
Published: October 2005

On several occasions the authors have required information on diffraction of sound and interaural time delay caused by the human head, and have measured these parameters in anechoic space. The measurements are of interest since both live subjects and a sophisticated acoustical manikin were used. These measurements are difficult to perform in a reliable fashion at high frequencies on live subjects because of head movement and use of the manikin allowed extension of most measurements to 10 kHz. Different measurement techniques were tried to yield accurate data, and these methods are discussed and results compared.
Subject Classification: 65.60, 65.62, 65.75; 20.30.
Capacitance microphone static membrane deflections: Comments and further results
Authors: Warren J. E. 
Published: October 2005

The biasing of capacitance microphones by a constant voltage or electret charges places electrostatic forces on the microphone’s membrane diaphragm. Due to the dependence of the electrostatic forces on the deflections, the final membrane position is governed by a nonlinear differential equation. Because of this nonlinearity, certain ranges of the parameter values exist for which stable static deflections cannot be obtained. Numerical methods are usually used to obtain the deflections and their critical or highest stable values. The results of two past investigations using different forms for the nondinemsionalized nonlinear differential equation are reviewed and compared [Warren et al., J. Acoust. Soc. Am. 52, 711–719 (1972); Friam et al., J. Acoust. Soc. Am. 53, 1601–1608 (1973)]. A third, and perhaps more appropriate, form for the nondimensionalized differential equation is presented and discussed. Using this third form, deflection and stability results are reviewed for circular and annular membranes. Recent results are then presented for rectangular strip membranes with the tension applied along one axis and supported only on the edges perpendicular to that axis. In general, annular membranes are more stable than the other two types of membrane systems. The effect of openings in the stationary electrode was found to increase the stability in all three types of membrane systems. The amount of increase was found to be dependent upon the size and location of the openings. The static deflections and their stability values are of importance since they determine the operating position of the membrane diaphragm and the operating range of many microphone parameters. Application of the stability results to membrane switches may also be possible [Sessler et al., IEEE Trans, Commun. COM-21(1), 61–65 (Jan. 1973)].
Subject Classification: 85.44, 85.62.
Responses of single units in the cochlear nucleus of the cat to cosine noise
Authors: Bilsen F. A. , ten Kate J. H. , Buunen T. J. F. , Raatgever J. 
Published: October 2005

The response of single cells in the cochlear nucleus of the cat to noise with a cosinusoidal power spectrum (cosine noise) was studied. Cosine noise is obtained by adding white noise to the same noise delayed over a time τ; maxima in the spectrum occur at n/τ (n=0,1,2,⋅⋅⋅). The spike rate of a unit was continuously registered as a function of τ (τ diagram). This registration shows a periodic fluctuation having maxima at τ=n/CF and troughs at τ= (n+1/2)/CF, with a decreasing peak–trough ratio for increasing n (CF is the characteristic frequency of the unit). For the majority of the units investigated, a maximal peak–trough ratio was observed not for n=0 but for about n=3. This is ascribed to lateral inhibition. By introducing the mathematical concept of a weighting function in the frequency domain, a quantitative relation with the response of the unit to a pure tone in white noise (iso-intensity curve) could be established. The results are compared with psychophysical results on the internal representation of cosine noise. Possible implications for the existence region of (repetition) pitch and the phenomenon of spectral dominance are discussed.
Subject Classification: 65.44, 65.40.
Fast beamforming techniques for circular arrays
Authors: Farrier D. R. , Durrani T. S. , Nightingale J. M. 
Published: October 2005

This note describes a technique for beamforming on circular arrays which exploits the array geometry to facilitate the use of FFT techniques, and this leads to substantial saving in computing effort. The algorithm described here is particularly advantageous for systems employing a large number of sensors.
Subject Classification: 60.30.
Ultrasonic registration of the fundamental frequency of a voice during normal speech
Authors: Holmer Nils-Gunnar , Rundqvist Hans Erik 
Published: October 2005

A continuous wave of ultrasound through the larynx is used to determine the fundamental frequency of the vocal folds during normal speech. The variation of the ultrasound intensity transmitted between two matched transducers through the vocal fold level is recorded. The apparatus used for these recordings is described. Different transducer positions are investigated and, further, the transducer geometry is discussed.
Subject Classification: 70.20; 80.45.
Comparison of cube-textured and conventional nickel magnetostrictive ring transducers during low-power linear drive
Authors: Huston E. Lee , Sinsky Joel A. 
Published: October 2005

The magnetic and magnetostrictive properties of a scroll-wound ring transducer made from cube-on-face-textured nickel were measured and compared to the corresponding properties of a conventional Nickel 200 ring transducer. Both transducers were separately excited in air at low-power linear drive levels with varying levels of bias induction, and their electrical input impedances were measured. Some in-water measurements were also made on the two rings at nearly optimum values of bias induction. Nickel 200 exhibits larger μT33 and d33 values at all induction levels, while the textured nickel shows larger k33 and g33 values. The data obtained can be used to choose the type of ring and bias induction level of operation which will best satisfy a given requirement.
Subject Classification: 85.46.
Reverberation from plankton at 330 kHz in the Western Pacific
Authors: Castile Brett D. 
Published: October 2005

Acoustic volume reverberation was observed in the open ocean at a frequency of 330 kHz and a depth of approximately 20 m. The instantaneous scattering volumes were small, ranging in size from 0.2 to 0.9 m3. The reverberation was observed primarily as an incoherent return from multiple scatterers (probably greater than 10/m3) but there were also discrete echoes of duration equal to that of the transmitted tone burst, 1 msec. The backscattering strength of the water calculated from the incoherent reverberation was independent of the time of day and varied from about −86 dB relative to 1 m−1 down to −96 dB and is surmised to be due to phytoplankton. The discrete echoes were more numerous at night than during the day and were produced by scatterers most of whose target strengths were on the order of −94 to −86 dB, approximately what would be expected of the small zooplankters such as copepods which were present.
Subject Classification: 30.40, 30.30.
Author’s reply to ’’Comments on ’Measured jet noise compared to California noise codes and health limits’ ’’ [B. G. Hildebrand, J. Acoust. Soc. Am. 58, 1323–1325 (1975)]
Authors: Lane S. R. 
Published: October 2005

B. G. Hildebrand’s criticisms of my paper are based on faulty analyses which invalidate the conclusion that my results are ’’unsupported.’’ He ignores the lateral distance factor in the FAA/NAFEC data and the Inglewood data-system limitations, and thus does not make the proper comparisons to the California noise limits or to the peak noise directly beneath the aircraft. The fact that the NAFEC approach noise data were generally less than the legal limit in the 1 mile from threshold region may be attributed to the use of nonstandard noise abatement flight procedures. The additional Inglewood data he shows in his Fig. 1 are not valid indicators of the peak noise levels since the range setting of the measurement system extended to only 100 dBA (i.e., noise peaks above 100 dBA were attenuated). The physical relations of noise source strength and attenuation with distance indicate that my jet aircraft approach noise measurements in the 1 mile from threshold area at LAX were entirely consistent with the Inglewood data measured farther out in the 3 miles from threshold area.
Subject Classification: 50.50, 50.75, 50.55.
Encoding and pitch strength of complex tones
Authors: Hall Joseph W. , Soderquist David R. 
Published: October 2005

Pitch perception in the human was examined with respect to the level of neural analysis and pitch strength of various complex tones. In binaural conditions, three-component complex stimuli were presented to each ear in such a way that if a central processor determined pitch from the combined information from the two ears, one pitch would be perceived. If the pitch processor attended to the information from each ear separately, two pitches would be perceived (corresponding to the fundamental at each ear). Two pitches were perceived and the importance of peripheral encoding for pitch perception was supported. Subjects judged the strength of monaurally and binaurally presented stimuli as a function of the spectral region of the frequency components, number of components per complex, and the spacing between components. Pitch strength was discussed in terms of recent theoretical models of pitch.
Subject Classification: 65.54, 65.56, 65.62.
Input–output functions of cochlear whole-nerve action potentials: Interpretation in terms of one population of neurons
Authors: Özdamar Özcan , Dallos Peter 
Published: October 2005

It is commonly assumed that the two-segmented input–output functions of the whole-nerve action potential are a result of the activity of two sets of primary fibers: a low- and a high-sensitivity group. While anatomical studies show the existence of two populations of fibers, there are no clear-cut electrophysiological signs of two distinct populations responding with different thresholds. In light of this physiological result, it is desirable to construct a scheme for the growth of the whole-nerve action potential that involves only one group of fibers. This can be done in a qualitative fashion by considering the pattern of single-unit tuning curves and assessing the contribution of populations of units to the compound response. Thus the slowly growing low-level segment of the input–output function is identified with the sharp tip region of the tuning curves of the responding units, while the high-level, rapidly growing, segment is associated with the recruitment of higher-frequency units that respond on the tail segment of their tuning curves. Thus the low and high parts of the input–output functions are interpreted in terms of the excitation of narrow and wide segments of the cochlear receptor. Masking experiments that support the scheme are described.
Subject Classification: [43]65.35, [43]65.42, [43]65.59, [43]65.40.
Two-tone suppression in auditory-nerve fibers: Extension of a stimulus-response relationship
Authors: Abbas Paul J. , Sachs Murray B. 
Published: October 2005

Average discharge rate of single auditory-nerve fibers in cats was measured in response to one- and two-tone stimuli. One component (the ’’suppressor tone’’) of each two-tone stimulus was at a frequency (f2) which produced two-tone suppression at some stimulus levels. The other component (excitor tone) produced an increase in rate above the spontaneous rate when presented alone. Fractional response was defined as the driven rate to the two-tone stimulus divided by the driven rate to the excitor alone. Fractional response is thus a quantitative measure of the amount of suppression produced by a suppressor tone. A number of qualitative differences were found in the dependence of fractional response for f2≳CF and f2&lt;CF. For suppressor tone frequencies greater than CF, fractional response depends only on the ratio of suppressor to excitor levels (P2/P1) for a range of excitor levels (P1). For P1 large enough to drive a unit into saturation, fractional response increases with P1. For f2&lt;CF, however, fractional response is a monotonic decreasing function of P2 and P2/P1; it is also a monotonic decreasing function of P1 for P2/P1 fixed. Consistent with these results if the tone level ratio P2/P1 is fixed, rate is a monotonic increasing function of the overall level of a two-tone stimulus for f2≳CF; for f2&lt;CF, rate is typically a nonmonotonic function of overall level. For f2≳CF, slopes of (log) fractional response versus (log) P2/P1 curves are a monotonic decreasing function of suppressor frequency f2. For f2&lt;CF, on the other hand, slope does not depend on f2. If f2 is fixed, and excitor-tone frequency (f1) varied, fractional response decreases with f1 for f2≳CF; for f2&lt;CF, fractional response is independent of f1.
Subject Classification: [43]65.42, [43]65.59.
Equal-sensation functions generated by the method of magnitude estimation
Authors: Stevens Joseph C. 
Published: October 2005

The method of magnitude estimation has been adapted to measure successfully various kinds of equal-sensation functions in several sense modalities. These successes may help to evaluate a recently reported severe failure of the method to yield satisfactory duration-intensity trading functions for equal loudness.
Subject Classification: [43]65.50, [43]65.22, [43]65.75.
On an invariance property of acoustic waveguides
Authors: Davis Sanford S. 
Published: October 2005

The acoustic power transmitted by a variable-area duct section which carries a steady subsonic flow is investigated under the conditions of both upstream- and downstream-propagating incident plane waves. It is found that the ratio of the power transmitted by incident waves moving against the flow to the power transmitted by incident waves moving with the flow bears the simple relation (1−M2)/(1+M)2.
Subject Classification: [43]28.60; [43]20.45.
California sea lion underwater auditory detection and variation of reinforcement schedules
Authors: Schusterman Ronald J. 
Published: October 2005

A sea lion (Zalophus californianus) was trained to report the presence of a pure tone under water in a yes–no psychophysical procedure. The payoff matrix was varied by altering the probability of fish reinforcement [P (SR)] contingent on two classes of response—hits and correct rejections (CR). The P (SR‖Hit) and the P (SR‖CR) were 1.00, 0.75, 0.50, and 0.25. In baseline, both P (SR‖Hit) and the P (SR‖CR) were = 1.00. In the asymmetrical payoff matrices P (SR) was held constant at unity for one response and varied over three values for the other response. Thus, seven different payoff matrices were used. The sea lion showed rapid acquisition of a stable response bias independent of its ability to detect the underwater auditory signal. These results demonstrate that varying reinforcement probability is functionally equivalent to varying amount of reinforcement in the control of response bias in underwater signal detection by sea lions [see R. J. Schusterman, B. Barrett, and P. Moore, J. Acoust. Soc. Am. 57, 1526–1532 (1975)].
Subject Classification: [43]80.50, [43]80.60.
Frequency-dependent influence of the sea bottom on the near-surface sound field in shallow water
Authors: Murphy E. L. , Wasiljeff A. , Jensen F. B. 
Published: October 2005

The influence of the sea bottom on shallow-water sound propagation can be especially pronounced for the sound field near the boundaries. Comparison of the near-surface sound field with the mid-depth field, for example, can serve as a useful diagnostic tool for understanding the frequency-dependent influence of the sea bottom on sound propagation in shallow water. Broad-band shallow-water sound-propagation data analyzed in one-third octave bands are compared for a very shallow receiver (2 m) and a mid-depth receiver (50 m). The data are also compared with results from modal calculations. The interplay between the behavior of the modal depth functions and modal attenuations, as frequency is varied, provides a convenient model for interpreting the results.
Subject Classification: [43]30.20, [43]30.30.
Absorption of sound by sound
Authors: Westervelt Peter J. 
Published: October 2005

Earlier studies [J. Acoust. Soc. Am. 29, 934 (1957)] of the mutual nonlinear interaction of two plane waves of sound with each other exhibited a singularity when the waves became collinear. The singularity is removed in this study, which leads to a method for calculating the pressure absorption coefficient α of a wave with wave vector k1 resulting from interaction with isotropic acoustic waves having the energy density spectrum u (k). Thus, α= (4ρ0c20)−1(1+1/2Λ)2π ℱk1 0 ku (k) dk+k1ℱ∞d1 2u (k) idk+k21ℱk11k−1u (k) dk], in which ρ0 and c0 represent the density and velocity of sound of the fluid which is assumed to be dispersionless. The constant 1/2Λ =ρ0c d0−1(dc/dρ)ρ0.
Subject Classification: [43]25.22, [43]25.35.