bluuebunny/crossref_metadata_2025 huggingface dataset:
A temporal analysis of acoustic fields by the virtual discontinuity principle of diffraction
Authors: Park Kwanshin , Ueda Mitsuhiro
Published: October 2005

The virtual discontinuity principle of diffraction (VDPD) is a new method for the analysis of diffracted fields by three-dimensional objects that satisfies the wave equation and the boundary condition for obstacles of artitrary geometry [M. Ueda, J. Acoust. Soc. Am. 95, 2354–2362 (1994)]. In this paper, the temporal response of a diffracted field is analyzed using VDPD. To show the validity of the proposed method, the impulse response of the diffracted wave by a semi-infinite plane is calculated and compared with both the exact solution and the experimental result. The experiment is carefully performed by using an ideal discharging point source and a 1/4-in. wideband transducer (B&K, type 4135). The proposed method showed good agreement with the exact solution and the experimental result. It also reduces the computational load by an order of magnitude because it does not require a double integral as required in the conventional technique.
Edge, cavity, and aperture tones at very low Mach numbers
Authors: Howe M. S.
Published: October 2005

The linear theory is developed of self-sustained oscillations of shear layers and jets incident on edges and corners at infinitesimal Mach number. These oscillations are sources of narrow-band sound. Detailed predictions are made of the operating stages for shear flows over wall apertures, shallow wall cavities, and for the classical edge tone, by modeling free shear layers by vortex sheets. Operating stages are identified with the poles of a certain impulse response function; the real parts of these poles determine the operating Strouhal numbers observed experimentally for the real, nonlinear system. The response function coincides with the Rayleigh conductivity of the window spanned by the shear flow for wall apertures and edge tones, and to a drag coefficient for wall cavities. Strouhal numbers predicted for a shallow wall cavity agree well with experimental data in air extrapolated to zero Mach number; edge-tone predictions are in excellent accord with data from various sources. In the latter case, the linear theory also agrees for all operating stages with an empirical, nonlinear model that takes account of the formation of discrete vortices in the jet. [Work supported by the Office of Naval Research.]
Two-dimensional effects in the edge noise of vortices and dipoles
Authors: Schouten Gerrit
Published: October 2005

Expressions for the edge noise of 2-D moving vortices and 3-D moving dipoles (ringvortices) are presented. The integrals, involving Green’s functions in the time domain, are approximated in the far field in terms of the halved derivative of the near-field pseudosound. Attention is paid to the transition from near-field pseudosound to far-field wave behavior, e.g., in the closed form response to a triangular pulse. In 2D the edge sound due to a moving vortex has two components of equal order of magnitude. One is retarded pseudosound from the edge, the other is due to the motion along the trajectory as if the vortex moved in free space. The latter component is deformed as the halfth derivative of free-space pseudosound. In 3D the pressure wave generated by the motion of a dipole near an edge is a factor (r/c)1/2 times stronger than the pressure of the pseudosound. The free motion of a dipole in 3D generates quadrupole sound, the proximity of an edge amplifies it to dipole sound. The vortex sound in 2D does not show this amplification in the edge effect. The time-domain analysis is efficient and illustrative, and seems more attractive than methods using the frequency domain.
A nonstationary Rayleigh wave on the surface of a thermoelastic heat-insulated cylinder
Authors: Rossikhin Yuriy A. , Shitikova Marina V.
Published: October 2005

The influence of heat conduction on the propagation of a surface wave polarized in the sagittal plane along the surface of a thermoelastic cylinder is investigated. The modified Maxwell law is used to take into consideration the small time that is necessary for the establishment of stationary heat conduction after the sudden occurrence of a temperature gradient in a solid. The nonstationary surface wave (Rayleigh wave) is interpreted as the line (in the given case it is a straight line parallel to the generators of the cylinder) on which temperature and the components of the stress and strain tensors experience a discontinuity. The discontinuity line propagates with a constant normal velocity in the direction of cylinder guide along the free from stresses and heat-insulated surface of the cylinder. This line is obtained by the exit onto the cylindrical surface of the three strong discontinuity complex wave surfaces intersecting along this line: quasithermal, quasilongitudinal, and quasitransverse volume waves. Applying the theory of discontinuities, the velocity and the intensity of the surface wave have been found. It has been shown that attenuation of the surface wave intensity is determined by a consideration of the related strain and temperature fields.
Dynamic perception of frequency-modulated tones
Authors: Aikawa Kiyoaki , Tsuzaki Minoru , Kawahara Hideki
Published: October 2005

A dynamic process of perceiving a frequency-modulated (FM) tone has been analyzed. A warped pitch image perceived for a linear sweep and pitch ringing induced by a piecewise linear sweep suggested the existence of a dynamic FM tracking process. The dynamic characteristics of the tracking process are represented by a second-order system. To track multiple FM tones, a neural matrix model was proposed based on the second-order system model. Several interesting perceptual effects were predicted by this model. To further analyze the dynamic process, perceived pitch images for ascending or descending pure-tone sequences were newly examined. A stimulus is a sequence of 20 pure tones. The total duration of the sequence is 632 ms. Rise and fall times of each pure tone are 5 ms each. When the frequency ascends linearly in the logarithmic frequency scale, the frequencies of two adjacent tones are separated by a semitone. Subjective tests revealed that a sequence of pure tones is perceived as a warped pitch sequence. All results are similar to the results obtained for continuous FM tones. The results suggested that the global pitch image of a sequence of pure tones is produced by the dynamic processing of the tone sequence.
Perceived trajectory of gliding tones through interrupting noise and its underlying frequency-extrapolation mechanism
Authors: Kurakata Kenji , Matsui Michinao , Nishimura Atsushi
Published: October 2005

The continuity effect was investigated using frequency glides preceding and following a noise burst. First, the perceived trajectory of the glides during the noise was obtained by a method of drawing in which subjects were required to express what they had heard by drawing a line. The drawings showed that they did not simply interpolate the two frequency points at the beginning and end of the noise, but extrapolated the preceding glide through the noise. Second, two psychophysical experiments were conducted to examine the possibility of the frequency extrapolation. In the first experiment, subjects compared the duration of one glide with that of another followed by a noise. In the second experiment, they judged the final pitch of glide just before the noise. The results of both experiments showed that they traced the frequency change of the glide and perceived its extrapolated trajectory. The maximum duration of the extrapolation reached about 120 ms. This mechanism may underlie the continuity effect in general other than that with gliding tones, and is included in the cognitive model of auditory scene analysis proposed in another paper [Matsui et al., Proc. Spring Meet. Acoust. Soc. Jpn., pp. 485–486 (1996) (in Japanese)].
A hierarchical structure for adjectives describing timbre
Authors: Ueda Kanzuo
Published: October 2005

An investigation using questionnaires was conducted to find clues to determine the existence of a hierarchical structure for descriptive adjectives having timbre. One hundred sixty-six subjects rated frequency of use for 114 adjectives having timbre on a seven-point scale. Based on the results of the subjective ratings, 50 descriptive adjectives were selected. One hundred sixty subjects then rated their subjective impressions of these adjectives by the following four scales: (1) concrete–abstract, (2) simple–complex, (3) objective–subjective, and (4) difficulty in recalling the expressed timbre. Similarity of the expressed timbre was also measured using a sorting method. The results were analyzed by MDS and clustering techniques. A hierarchical structure for the descriptive adjectives having timbre was interpreted from the results of the analyses. This research should form a basis for further investigation of a human timbre perception mechanism.
An illusory reconstruction of auditory elements
Authors: Sasaki Takayuki , Nakajima Yoshitaka
Published: October 2005

A new pattern of auditory illusion was invented, proving that the perceptual system reconstructs auditory elements, such as onsets, terminations, and pitches. A typical stimulus pattern comprised three harmonic components (fundamental, second, and third), changing their frequencies in the same rate in the same direction. The duration of the lowest component was 1800 ms. The second/third component occupied the first 1000 ms and the third/second component occupied the last 1000 ms, thus making an overlap of 200 ms in the middle. Eight subjects listened to the stimulus patterns and expressed their percepts by drawing and aural reports. The general tendency was that they perceived one continuously ascending or descending tone and a short independent tone with a clear pitch in the middle. Since there was no actual short tone in the middle, it can be concluded that an illusory tone was created perceptually by connecting an onset of one component with a termination of another component. Absolute pitch judgments of the middle tone by absolute pitch possessors showed no consistent tendency. Connection between an onset/termination and its pitch does not seem strong.
A consideration of timbre in broadband harmonic complex tones with different fundamental frequencies and spectral envelopes
Authors: Ozawa Kenji , Suzuki Yôiti , Sone Toshio
Published: October 2005

Similarities in timbre among 36 broadband complex tone stimuli were measured by a rating-scale method to derive multidimensional perceptual space for the stimuli. Fundamental frequencies of the stimuli were 100, 200, or 400 Hz, spectral envelopes were 0, −3, −6, or −9 dB/oct, and the numbers of components were 20, 30, or 40. The obtained similarities were analyzed by the method of multidimensional scaling, and a three-dimensional configuration was drawn. Distances among stimuli in the configuration did not show good agreement with differences in the physical frequency spectrum. The distances in the perceptual space were then compared with differences in the ‘‘masked frequency spectrum’’ [Ozawa et al., Proc. 15th ICAIII , 465–468 (1995)] which was the frequency spectrum in terms of the loudness of the narrow-band frequency component of the stimuli partially masked by each other. The agreement between them was better than that in the case of the physical frequency spectrum. This suggests that the masked frequency spectrum of a sound is a good approximation to the final spectrum perceived in hearing.
A cross-cultural study on timbre perception: Comparison between Japanese and Chinese adjectives which express auditory impression
Authors: Iwamiya Shin-ichiro , Yamaga Youko , Zhan Mingzhi
Published: October 2005

A verbal rating experiment on timbre was conducted to compare the Japanese and Chinese adjectives which express auditory impression. The auditory impression of various kinds of musical sounds was measured by a semantic differential method. The subjects are Japanese and Chinese. The scales used for both groups had the same literal meanings. However, the scales are Japanese for Japanese subjects and Chinese for Chinese subjects. The obtained data were analyzed by principal components analysis. The scales were taken as variables. A four-factor solution is obtained for the Japanese scales. The factors are named sharpness, cleanness, potency, and pleasantness from the loadings of each scale on each factor. A three-factor solution is obtained for the Chinese scales. The factors are named sharpness, cleanness, and potency. The factor of sharpness has the same feature for both groups. However, the features of the factors of cleanness and potency are slightly different. A drastic difference is observed on the scale of ‘‘unpleasant–pleasant.’’ The Chinese scale of unpleasant–pleasant has high loading on the factor of sharpness. On the other hand, the Japanese scale of unpleasant–pleasant is independent of sharpness, cleanness, and potency. This scale makes the independent factor of pleasantness by itself. Furthermore, the acoustic energy in high-frequency region has different effects on timbre perception between Japanese and Chinese.
Dynamic properties of pitch perception of sweep tone
Authors: Shihara Tomonori , Miyazono Hiromitsu , Usagawa Tsuyoshi , Ebata Masanao
Published: October 2005

It is important to investigate the auditory dynamics of pitch perception of a sweep tone in order to make auditory processing clear. In recent years, the trajectory of pitch perception of a sweep tone has been estimated within the viewpoint of auditory scene analysis. However, there are few studies to quantify ‘‘instantaneous pitch’’ in a sweep tone. In this study, instantaneous pitch in the sweep tone was measured by comparing the perceived pitch of a sweep tone with that of a pure tone. The sweep tone used in the experiments had a duration of 4250 ms and a frequency range of 1 oct. As a result, the instantaneous pitch almost matched the pitch corresponding to the actual frequency of the sweep tone at the middle of duration. However, it was higher at the position of 1/4 of the duration, and lower at the position of 3/4 of the duration than the pitch of actual frequency. It seems that the gradient of the perceptual trajectory is gentler than that of the actual frequency. It was suggested that the dynamic property of pitch perception of the sweep tone was affected by forward and backward pitch in the stream.
Integration times for frequency discrimination
Authors: Goodacre Jonathan
Published: October 2005

Frequency discrimination with 40-ms continuous signals was compared to that for signals consisting of two 20-ms tone bursts separated by a 40-ms gap. Performance was impaired for gap signals at the test frequency of 250 Hz but not at frequencies above 1000 Hz. Studies at 250 Hz showed that, by reference to a 40-ms continuous signal, subjects performed poorly with stimuli consisting of two 20-ms bursts, however short the gap duration. A possible explanation within a place mechanism framework is that the bandwidth of the 20-ms bursts limits the sharpness of the excitation pattern at low frequencies. However, there is strong evidence for the use of a timing mechanism at low frequencies [A. Sek and B. C. J. Moore, J. Acoust. Soc. Am. 97, 2479–2486 (1995)]. The results can be interpreted in terms of a timing mechanism that operates on the interspike intervals derived from phase locking in the auditory nerve. The mechanism has a long integration period that can be reset by discontinuities in the ongoing signal. [Work supported by MRC (UK).]
Perceptual segregation by timbre: Streaming by bandwidth but not periodicity
Authors: Cusack Rhodri
Published: October 2005

Alternating tones and noises are rated as segregating into different perceptual streams [Dannenbring and Bregman, J. Exp. Psychol. 2, 544–555 (1976)]. The current study examined segregation by timbre using an interleaved melody task [Dowling, Cognit. Psychol. 5, 322–337 (1973)] in an adaptive, 2IFC procedure. The discrimination threshold for a melody interleaved with distractors was measured. The melodies were five pure tones, randomly chosen from a two-thirds octave range. In experiment 1, the distractors were either: (1) pure tones from the same frequency range; (2) narrow-band noises from the same frequency range; or (3) pure tones from a frequency range 1 oct higher (a comparison condition expected to induce streaming). The timbral difference between the melody and distractors in (2) improved performance, though it was less effective than the frequency difference in (3). In experiment 2, narrow-band noise distractors (aperiodic) were compared with two-component complex tone distractors (periodic), chosen to evoke a similar excitation pattern. Performance improved equally when pure tone distractors were replaced either by narrow-band noises or two-tone complexes. This indicates that differences in bandwidth influence streaming, but provides no evidence for an effect of differences in periodicity. [Work supported by EPSRC, UK.]
Perceptual processing of acoustic gratings
Authors: Miller James D. , Heidbreder Arnold F. , Yuan He
Published: October 2005

The variables that influence listeners’ perceptions of steady-state acoustic gratings (ripple spectra or profiles) are explored. Subjects identified gratings by the frequency of sinusoidal modulation of their envelopes independently of envelope phases. The gratings or ‘‘profiles’’ were synthesized with 193 log-spaced tones (200–3200 Hz). Sinusoidal modulations of 0.5, 1.0, 2.0, 4.0, and 8.0 cycles/oct and a peak-to-valley depth of 20 dB were used. Three listeners performed the identification task with feedback and completed 75 blocks of 125 trials each. The listeners scores changed from the first ten to the last ten blocks as follows: 91% to 98%, 62% to 91%, and 56% to 70%, respectively. The gratings appeared to vary along perceptual dimensions of (1) noisiness, (2) roughness, (3) tonality, (4) chord quality, and (5) base/treble quality. The first four dimensions allowed identification of the gratings by envelope frequency, while the base/treble quality seemed most related to the envelope phase. Additional experiments explore the effects of the widths of the spectral peaks, the peak-to-valley depth in decibels, and earphone-response equalization. Effects of individual differences and practice are discussed as are relations to the perception of vowels, of musical intervals and chords, and of optical gratings or ‘‘stripe’’ patterns.
Detection of frequency modulation (FM) and amplitude modulation (AM) by budgerigars (Melopsittacus undulatus)
Authors: Nespor Amy A. , Dooling Robert J. , Triblehorn Jeffrey D.
Published: October 2005

Many bird vocalizations contain elements consisting of both frequency-modulated (FM) and/or amplitude-modulated (AM) compo- nents. In humans, differences in perception of FM versus AM sounds are related to other psychoacoustic phenomena and have provided an interesting test of the excitation pattern model of hearing. Here, budgerigars were trained by operant conditioning and tested with the method of constant stimuli to detect FM and AM. The birds were tested at three carrier frequencies (1.0, 2.86, and 4.0 kHz) and the threshold for detecting modulation was measured at eight different modulation frequencies from 5 to 640 Hz. The threshold for detection of frequency modulation decreased with increasing modulation frequency, while the threshold for detecting amplitude modulation was fairly constant over the entire range of modulation frequencies. This pattern of results is similar to that found for humans. Critical modulation frequencies calculated from these functions will be compared to other psychoacoustic phenomena in budgerigars and the relevance of these findings for mechanisms of hearing in birds and the characteristics of vocal signals will be discussed. [Work supported by NIH DC-00198 and MH-00982 to RJD.]
Ultrasonic measurement of the amount of the fibrosis in the liver by using fractal dimensions of the power spectrum shape
Authors: Kikuchi T. , Nakazawa T. , Furukawa T. , Maruyama Y. , Sato S.
Published: October 2005

This paper describes a measurement method for the amount of fibrosis in rat liver by fractal dimensions of the power spectrum shape. Some of the biotissues can be assumed to be an aggregation of point scatterers, and the spatial distribution of them (such as mean spacing or irregularity) may be used to obtain important information on tissue characterization. The power spectra of the scattering ultrasonic wave from random media are strongly affected by the spatial distribution of the scatterers. It was reported that the fractal dimension was one of the tools suitable for analyzing complex figures such as the power spectrum, and that the fractal dimension was sensitive to the spatial distribution of the scatterers. It was found that the amount of fibrosis generated artificially in the rat liver can be estimated quantitatively by the fractal dimension of the power spectrum shape. An attempt has been made to apply this method for ultrasonic measurements of the amount of fibrosis in the human liver.
Naval Research Lab’s multi-mode towed vehicle inertial navigation data acquisition system
Authors: Kennedy Edgar T. , Jorgensen Kevin , Stanic Stephen J.
Published: October 2005

High resolution measurements of acoustic spatial variability in shallow water (SW) and very shallow water (VSW) over a wide range of environmental conditions, were obtained using the towed vehicle described in the following abstract, 3aAO8. To obtain real-time vehicle attitude and current measurements a Doppler velocity log from EDO Corporation, Motion PAK accelerometer from Systron Donner were integrated with pitch, roll, and heading sensors to provide a real-time three-axis navigation system. Real-time data acquisition software was developed by the Naval Research Laboratory utilizing National Instruments LABView object oriented programming language to record vehicle attitude and optionally provide real-time pitch and roll corrections based upon changes in vehicle velocity. The system is designed to measure, record, and monitor up to 16 bins of current velocity between vehicle and bottom surface. Technical detail of data acquisition design, operation, and some results from a high-frequency experiment conducted during 1996 are presented.
Precision acoustic geodetic measurement of seafloor motion over 10 km
Authors: Chadwell C. David , Spiess Fred N. , Hildebrand John A. , Sweeney Aaron D.
Published: October 2005

The technique deploys three or more precision transponders (PXP) on the seafloor, collects simultaneous round-trip travel times (±5 μs) from a hydrophone towed uniformly around the network above the seafloor (300 m), and measures the sound velocity (±10 ppm) and the relative depth of the hydrophone (±10 cm). These observations, modeled as ray traces through a spherical ocean model and ellipsoidal geodesic ray distances, are inverted to determine simultaneously, the centimeter level position of the transponders and towed hydrophone locations. Three PXPs were deployed on the Pacific and three on the Juan de Fuca plate to determine the pattern of deformation around the Juan de Fuca Ridge. Measurements were collected in 1994, 1995, and planned for 1996. Since 1991, at least four PXPs have been maintained seaward of the Cascadia Subduction Zone to measure the subduction rate using the Global Positioning System. No measurable relative horizontal motion among these PXPs is expected providing a test of system repeatabilities. Measurements were collected in 1991, 1993, 1994, 1995, and planned for 1996. This paper discusses the instrumentation, operations, measurement precision, modeling requirements, and current results. [Work supported by NSF.]
Broadband matched-field inversion for integral geoacoustic properties of the ocean bottom: YELLOW SHARK 94 experimental results
Authors: Hermand Jean-Pierre , Gerstoft Peter
Published: October 2005

Bottom geoacoustic properties were determined from inversion of broadband (200–800 Hz), multitone pressure fields measured at a shallow-water site in the western Mediterranean (YELLOW SHARK 94). Extensive oceanographic and geophysical information was obtained in situ to support and validate the inversion. Matched-field processing was applied for each tone frequency. Optimization of the environmental parameters was performed simultaneously across all propagated frequencies by minimizing a maximum-likelihood objective function with genetic algorithms (SAGA). The following conclusions were drawn from this study. (a) For a fixed source-vertical array configuration broadband tomographic measurements were a sine qua non condition to obtain meaningful inversion results. (b) The broadband inversion provided considerable stability and robustness with respect to volume and bottom variabilities. (c) Corresponding single-frequency inversions performed under the exact same conditions produced erratic results. (d) Integral geoacoustic properties were effectively determined within the constraints imposed by the bottom parametrization. (e) More detailed and accurate properties were obtained by including the range dependence of ocean sound-speed profile (SSP) in the forward modeling. (f) The broadband inversion provided robust, unique, and most likely correct, geoacoustic parameters, i.e., SSP, attenuation, density, and thickness of the top clay layer, and sound speed of the underlying silt layer.
Three-dimensional chirp sonar surveying of SWARM-95 experimental site
Authors: Turgut Altan
Published: October 2005

A full-spectrum chirp sonar system [LeBlanc et al., J. Acoust. Soc. Am. 91(1) (1992)] was used to invert three-dimensional density and sound-speed structure of the subbottom at the SWARM-95 (shallow water acoustics in random media) experimental site on the New Jersey Shelf. Biot’s theory was used in a forward model to calculate normal-incident reflection seismograms for layered marine sediments. Efficient inversion algorithms based on global optimization techniques were used to survey large areas for characterization of sediment properties and their spatial distributions. Chirp sonar inversion results were compared with ground-truth core data at the AMCOR-6010 site and good agreement was observed. Three-dimensional images of sediment density and sound-speed structure were constructed from several parallel runs along the SWARM acoustic track 1003 at the outer-shelf sediment wedge area. Corresponding 3-D wave-number spectra of density and sound-speed variability were also calculated.
Investigation of frequency-angular resonances of sound reflection coefficients from the bottom
Authors: Fokina Margarita S.
Published: October 2005

Features of the behavior of exact frequency-angular dependencies of the reflection coefficients V(fd,tet) (f—frequency, d—thickness of a sediment layer, tet—angle of slid) from a structure and the acoustic properties of various types of the marine bottom are investigated. Angular and frequency resonances of reflection coefficients and change of position of resonance depending on a ratio of acoustic parameters of sediment layers and half-space are revealed. For exact calculations of a reflection coefficients, a matrix propagator was used. Resonant formalism was expanded on the layered elastic bottom case, in terms of the Breit–Wigner variables. The comparisons of resonance and exact calculations of reflection coefficients for two types of resonances show good agreement of the results. Calculations of exact and resonant reflection coefficients for real parameters of the shallow sea bottom was carried out. The relation between resonance position and width and parameters of environment was ascertained. [Work supported by RFFI Project N 96-02-18944.]
Selected measurement issues and data, especially regarding primary and secondary free-field calibrations
Authors: Nedzelnitsky Victor
Published: October 2005

During the last two decades, international research and cooperation have advanced the methods of primary calibration of microphones and developed improved International Electrotechnical Commission (IEC) standards for primary calibrations by the reciprocity technique in pressure fields and in the free field. However, for high-quality primary calibration, a laboratory must carefully investigate its procedures and apparatus to determine their contributions to the various uncertainty components that establish the overall uncertainty. Issues in secondary calibration (for example, comparison) and characterization of measurement microphones and other acoustical instruments also require careful, systematic effort, and increasingly are receiving international attention. Topics of current interest at NIST include acoustic center positions and source–receiver standing waves during primary free-field calibration, the influence of anechoic chamber imperfections on primary and secondary free-field calibrations, and the effects of instabilities and nonlinearities in sound sources and microphones. Recently improved instruments including dynamic signal analyzers capable of FFT and other signal processing, as well as relatively new concepts in their application to acoustical measurements, are necessary to this work.
Principles of operation of condenser microphones
Authors: Zuckerwar Allan J.
Published: October 2005

Following a description of microphone cartridge construction, the topics to be discussed include: electrical and mechanical microphone sensitivities, effect of the polarization voltage, electrical and mechanical stability, membrane damping, electromechanical equivalent circuit, background noise, and response to infrasound. The discussion will be interspersed with little-known factoids on microphone performance which are not found in the traditional literature.
A new traceability system in Japan
Authors: Sato Sojun , Fujimori Takeshi , Horiuchi Ryuzo , Takahashi Tasuke , Murakami Yukio
Published: October 2005

In 1993, the measurement law was revised and enacted in Japan. The old law had provided only the use of legal metrology units and the approval and verification systems for measuring equipment. The new one has added the provision of a traceability system to match the needs for a high accuracy measurement technique and international mutual recognition. In the Electrotechnical Laboratory (ETL), the national standard of sound-pressure level has been established and maintained in an audible frequency range. The type approval test and verification of sound level meters have been carried out in the Japan Quality Assurance Organization (JQA). Now, in conformity with the law, ETL has started to construct the new traceability system for the acoustical standards in cooperation with JQA. An outline, is made of the traceability system in Japan and of the newly constructed pressure calibration systems for laboratory standard microphones.
Static pressure and temperature coefficients of laboratory standard microphones
Authors: Rasmussen Knud
Published: October 2005

The sensitivity of condenser measurement microphones depends on the environmental conditions due to the changes in the acoustic properties of the enclosed air between diaphragm and backelectrode and in the cavity behind the backelectrode. A theoretical investigation has been performed based on an extended lumped parameter representation of the mechanical and acoustical elements of the microphone, assuming the velocity distribution of the diaphragm to follow the zero-order Bessel function. The extension involves the frequency dependency of the dynamic diaphragm mass and stiffness as well as a first-order approximation of resonances in the back cavity. It was found that each of the coefficients, for a given type of microphone, can be expressed by a single function when the coefficients are normalized by their low-frequency value and the frequency axis normalized by the individual resonance frequency of the microphone. The static pressure and temperature coefficients were determined experimentally for about 20 samples of type BK 4160 and BK 4180 microphones. The results agree almost perfectly with the predictions for BK 4160, while some modifications of the lumped parameter values are called for to make the results for BK 4180 fit the predicted values.
Microphone reciprocity calibrations with adaptive noise cancellation
Authors: Wu Lixue , Wong George S. K.
Published: October 2005

The accuracy of microphone reciprocity pressure calibrations deteriorates due to environmental noise at relatively low frequencies. A computer-controlled automated system that has the potential to reduce calibration uncertainty at low frequencies has been developed. The reciprocity calibration apparatus was placed on a rigid platform with conventional rubber vibration isolators. A lock-in amplifier was employed to assist data acquisition and correlation, with an auxiliary microphone placed near the reciprocity calibration apparatus to measure environmental noise. Calibration results were continuously logged for various environmental conditions during a test period of 2 weeks. Measurements confirmed that the noise signal received by the auxiliary microphone is highly correlated to that of the calibration system, and that adaptive noise-canceling techniques can be used to reduce calibration uncertainties. Preliminary results obtained are encouraging.
Accuracy of pressure calibration of 1/2-in. microphones up to 20 kHz
Authors: Takahashi Tasuke , Murakami Yukio , Ochiai Naobumi , Miura Hajime
Published: October 2005

Specifications of both laboratory standard and measurement microphones are now defined in Parts 1 and 4 of IEC 1094 ‘‘Measurement microphones,’’ respectively. Methods for the absolute pressure calibration of these microphones are also defined in Part 2 of IEC 1094. These standards were published recently. In this report 1/2-in. condenser microphones were used, such as LS2aP/LS2bP: MR112, B&K4180, and WS2P/F: various measurement microphones including those of sound level meters, have been calibrated up to 20 kHz using two couplers: plane-wave and large-volume. Calibration data are compared to each other and the accuracy of the calibrated results are discussed in detail.
High-sensitivity measurement microphone using the laser welding technique
Authors: Sakai Masahiko , Fukushima Susumu , Ohashi Masanao , Ono Takahiko
Published: October 2005

A 1/2-in. bias-typed measurement condensor microphone with high sensitivity as well as its measurement of 1 in. has been developed. In this microphone, the diaphragm is welded to the body by means of a laser welding technique. From this, a reduction of tension of the diaphragm is restrained; therefore, it is able to ensure long-term stability. A wide frequency range (up to 14 kHz) and a high sensitivity are compatible by optimizing the tension of the diaphragm, structure of the back plate, and gap of diaphragm to the back plate. Furthermore, a very low temperature coefficient can be achieved using suitable material for the backplate.
A polymer condenser microphone made with silicon micromachining
Authors: Pedersen Michael , Olthuis Wouter , Bergveld Piet
Published: October 2005

A condenser microphone suited for on-chip integration with CMOS signal conditioning circuits has been developed. The microphone structure consists of a polyimide diaphragm, sensitive to sound, and a perforated polyimide backplate. The structure is similar to previous single-chip microphone designs; however, with the introduction of polyimide, it is possible to realize a low-temperature (<300 °C) fabrication process, consisting of only evaporation, spin-on, and silicon etching processes, which are all compatible with preprocessed CMOS circuits. Microphones with sizes of 1.6 and 2.1 mm, and an air gap of 1.5 μm were fabricated. The devices have been characterized using an acoustical setup, in which the response of the microphone is compared to that of a known reference microphone. The frequency responses are flat within ±2 dB in the frequency range from 100 Hz to 15 kHz, and the open-circuit sensitivities at 1 kHz with a bias voltage of 15 V were −46.1 dBV/Pa (1.6 mm) and −41.8 dBV/Pa (2.1 mm). The A-weighted noise was measured to be −112 dBV for both microphones, yielding an open-circuit equivalent noise level of 28 and 24 dBA SPL.
Conservation and compensation for noise-induced hearing loss in Japan
Authors: Zusho Hiroyuki , Miyakita Takashi
Published: October 2005

The present situation and outlook of ‘‘Conservation and Compensation for Noise-Induced Hearing Loss in Japan’’ was explained at the Second Joint Meeting of the ASA and the ASJ (1988). After that, a new administrative guideline for prevention of noise-induced hearing loss was issued in 1992. At present, hearing conservation is being done at noisy workplaces in accordance with this guideline. Control of the work environment, work control, hearing conservation, and education of industrial hygiene, in addition to a periodic measurement of the noise levels, are obligatory at workplaces where the equivalent noise level (LAeq) is 85 dB or more. As for compensations covered by Labor Accident Compensation Insurance, various compensations proportional to the degree or hearing loss are paid at the time of their retirement regarding the hearing loss occurring in workers who have worked at a noisy workplace where the noise level exceeds 85 dB(A) for a long period of time. The above is the present situation for conservation and compensation in hearing loss at noisy workplaces in Japan.
The modified power law and hearing conservation
Authors: Macrae John H.
Published: October 2005

The concepts of the modified power law (MPL) and the continuation hypothesis (CH) are outlined and then empirical evidence is presented which suggests that the MPL, not the CH, is the appropriate method for predicting noise-induced permanent threshold shift (NIPTS) in persons with sensorineural hearing impairment. The ISO1999 rule for combining presbyacusis and NIPTS is explained and empirical evidence is presented which indicates that the ISO1999 rule, not the MPL, is the appropriate method for combining NIPTS and presbyacusis. These findings are then used to predict the progression of hearing loss in a person whose thresholds are affected both by aging and by two separate periods of occupational noise exposure. The results are compared with those obtained using the CH instead of the MPL to predict the progression of NIPTS and with those obtained using the MPL instead of the ISO1999 rule to combine presbyacusis and NIPTS.
Evaluation of hazard from intense sound with a mathematical model of the human ear
Authors: Price G. Richard , Kalb Joel T.
Published: October 2005

At its most basic, hazard to hearing is the result of energy arriving at the cochlea. However, the conductive path to the cochlea has many nonuniformities which profoundly shape the driving forces that actually reach it. The normal tuning of the ear as well as the azimuth of the source, an amplitude-dependent nonlinear middle ear, and time-varying middle ear muscle activity are in the conductive path and add to the complexity of interpreting the intracochlear events which culminate in hearing loss. To deal with this complexity, a mathematical model of the ear is being developed to predict hazard accurately. An earlier model for the cat ear [G. R. Price and J. T. Kalb, J. Acoust. Soc. Am. 90, 219–227 (1991)] has been adapted for the human ear and calculational procedures to allow for the effect of the azimuth of the source and middle ear muscle responses have been added. The model allows waveform input from the free field as well as at the ear canal entrance or ear drum position and calculates a hazard based on the stresses at the level of the basilar membrane. This number will be correlated with hearing losses measured from experiments with human ears.
New biological monitoring for organic solvent affect
Authors: Morioka Ikuharu , Kuroda Mototsugu , Miyashita Kazuhisa , Takeda Shintaro , Taniuchi Toshifumi , Luo Wei-Zhi
Published: October 2005

To clarify the effects of organic solvents on auditory function, the upper limit of hearing was measured with 93 male workers exposed to organic solvents in six factories producing buttons and one factory producing fiber-reinforced plastic baths. Special medical examinations and environmental monitoring of the organic solvents were also done. The upper limit of hearing was significantly lower than the standard upper limit age curves for males, although the levels of environmental monitoring were lower than the permissible concentration of the organic solvents. It deteriorated in workers exposed to the organic solvents for more than 5 yr. Its deterioration was related to the levels of environmental monitoring of styrene and the mandelic acid concentration in urine. It deteriorated dose dependently as the levels of environmental monitoring of styrene increased. The chronic exposure to styrene may cause the deterioration of the upper limit of hearing. Those whose special medical examinations for organic solvents were normal, showed the deteriorated upper limit of hearing. It is suggested that the upper limit of hearing is a sensitive method for the biological response monitoring of styrene on workers.
The validity of predicting the field attenuation of hearing protectors from laboratory subject-fit data
Authors: Berger Elliott H. , Franks John R.
Published: October 2005

The mandate of ANSI Working Group S12/WG11 has been to develop ‘‘laboratory and/or field procedure(s) that yield useful estimates of field performance’’ of hearing protection devices (HPDs). A real-ear attenuation at threshold procedure was selected, devised, tested via an interlaboratory study [Royster et al., ‘‘Development of a new standard laboratory protocol for estimating the field attenuation of hearing protection devices. Part I. Research of Working Group 11, Accredited Standards Committee S12, Noise,’’ J. Acoust. Soc. Am. 99, 1506–1526 (1996)], and incorporated into a draft standard that is currently under review [ANSI S12.6-199X]. The procedure utilizes a subject-fit methodology with listeners who are audiometrically proficient, but inexperienced in the use of HPDs. A key factor in the decision to utilize the subject-fit method was an evaluation of the representativeness of the laboratory data vis-à-vis attenuation values achieved by workers in practice. Twenty-two field studies were reviewed to develop a database for comparison purposes. Results indicated that laboratory subject-fit attenuation values were equivalent to or greater than the field attenuation values, and yielded a better estimate of those values than did experimenter-fit or experimenter-supervised fit types of results. Recent data, not available at the time of the original analyses, further confirm the findings.
Evaluation of hearing handicaps and quality of life in subjects with noise-related hearing loss
Authors: Miyakita Takashi , Ueda Atsushi
Published: October 2005

Hearing impairment interferes with normal communication and reduces the quality of life for the affected individual and significant others. In the workplace, noise-induced hearing loss has been one of the most prevalent work-related diseases, but both employees and employers have not yet accepted it as a serious health hazard. In order to promote an understanding of the social consequence of hearing loss, establishment of methods for evaluating hearing handicaps and for implementing workplace health promotion are indispensable. For this reason, the Japanese version of the Hearing Disability and Handicap Scale (HDHS) and a questionnaire on the quality life (QOL) were developed. Based on the preliminary results obtained among present and retired workers, the relationship between hearing handicaps and QOL will be discussed.
Using audiometric database analysis to evaluate hearing conservation programs: Current status
Authors: Royster Julia D. , Royster Larry H.
Published: October 2005

Since the publication of Draft ANSI S12.13-1991, evaluating the effectiveness of hearing conservation programs, additional data have been collected from audiometric monitoring programs and subjected to analysis. Of the three methods proposed in the draft standard, the two simpler procedures (the percent worse and the percent better or worse) have proved more robust in differentiating program effectiveness than the more complex third method (standard deviation of differences). The S12 Working Group 12 is preparing a revised draft for ballot, and its features will be presented in this paper together with new analyses. Results of other commonly employed methods, such as the percentage of OSHA standard threshold shifts and comparison of group mean thresholds to expected age-effect hearing levels, will be shown for comparison.
Performance of a digital active noise reduction hearing protector in a reverberant chamber
Authors: Pan G. J. , Brammer A. J. , Crabtree R. B.
Published: October 2005

High-intensity, low-frequency noise in modern helicopters and land vehicles degrades the communication reliability and endangers the hearing of the crew. Passive noise attenuation is not effective in terms of the performance/cost ratio in such environments. While active noise reduction (ANR) headsets that use analog feedback control have been commercially available for some time, this paper will focus on digital ANR hearing protector/headsets, which apply a feedforward control approach. A prototype ANR hearing protector has been developed in the laboratory using a floating-point digital signal processor (DSP) and an adaptive feedforward control algorithm. The ANR performance will be discussed based on recent experimental results measured on five human subjects in a reverberation chamber. For the experiments, 12 to 300-Hz broadband white noise and simulated helicopter noise were used. The results showed good control stability and active noise reduction performance.
Chairman’s challenge to sonoluminescence theorists
Authors: Apfel Robert E.
Published: October 2005

Sonoluminescence phenomena are highly complex, involving physical and chemical processes operating up to 12 orders of magnitude in energy, and involving emissions that depend delicately on some of the initial conditions. It is therefore not surprising that several competing theories exist to ‘‘explain’’ what experimentalists have observed. Some of these theories are speculative, some quasiquantitative, and some quantitative. None has been accepted universally. Therefore, since the special session on implosion acoustics will feature several theorists, the chairman issues the following challenge to the theorists: Define for the audience, in general, and for experimentalists, in particular, a specific experiment or set of experiments that will permit one to distinguish the author’s theory from the others. Implicit in this challenge is the theorist’s ability not only to describe what has already been observed, but also to make predictions for regions of the experimental parameter space not yet visited. The theorist’s proposal to experimentalists should be outlined in a slide, and also in hard copy in advance of the conference so that the chair can circulate a compendium of proposals at the session.
Acoustic energy storage in single bubble sonoluminescence
Authors: Brenner Michael P. , Rosales R. Ruben , Hilgenfeldt Sascha , Lohse Detlef
Published: October 2005

A gas bubble trapped in water by an oscillating acoustic field can emit visible bursts of light. Currently the energy focusing of this phenomenon (sonoluminescence) is understood as the converging of a shock toward the interior of the bubble. A complementary but alternative possibility is presented which stems from a linear hydrodynamic instability of the entire gas inside the bubble, leading to the storage of acoustic energy inside the bubble. This mechanism suggests a qualitatively different method for estimating the light intensities from the bubble than those given previously, identifying the hydrodynamic parameters which are important for determining the light intensity. A natural consequence of the theory is the presence of abrupt transitions in the light intensity as a function of experimental parameters, such as those previously observed by Weninger et al. [J. Phys. Chem. 99, 14195 (1995)]. These transitions are where energy input during the bubble collapse exactly balances energy dissipation throughout a cycle.