bluuebunny/crossref_metadata_2025 huggingface dataset:
Acoustical design of the Kyoto Concert Hall
Authors: Ishiwata Chiaki , Oguchi Keiji , Toyota Yasuhisa , Nagata Minoru
Published: October 2005

The Kyoto Concert Hall was planned as the 1200 years’ memorial facility of the ancient metropolis, and was opened in 1995. It consists of two concert spaces: the Main Hall with 1833 seats as the home of the Kyoto Symphony Orchestra (KSO), and the Ensemble Hall of 500 seats. The shape of the Main Hall has essentially come under the category of ‘‘shoe box,’’ with two steps of balconies surrounding both the main audience floor and the stage. The basic room dimensions were fixed following a computer simulation study regarding the distribution of early reflections. Sound scattering elements were introduced on the lower side walls and the ceiling. The diffusing effect, namely, that the elements make the sound field uniform, was confirmed by a 1/10 scale model study. Other design elements are: a heavy concrete ceiling, a timber floor over an airspace, absorptive audience seats, an orchestra riser system, and the selection of a stage timber floor by audition. The Ensemble Hall has a hexagonal plane. In order to compensate for an insufficient ceiling height of 9 m, the walls were tilted 12 deg outward to delay the arrival time of some early reflections, and absorptive curtains were installed temporally to be available for adjusting to a variety of music.
Stage floor of the Kyoto Concert Hall
Authors: Oguchi Keiji , Toyota Yasuhisa , Isiwata Chiaki , Nagata Minoru
Published: October 2005

The orchestra riser system has been installed in the Kyoto Concert Hall, which was newly opened in the autumn of 1995. This paper introduces the design process of the stage riser system and its floor structure in detail. The orchestra, including string sections, could be arranged in a three-dimensional manner with this riser system. Its drastic effect on the acoustics of the hall was confirmed at actual rehearsals and concerts in Suntory Hall. The form, division size, and height of each riser element were discussed with the resident of the hall, Kyoto Symphony Orchestra, using the riser mockup. The extent of the orchestra became more compact for the 3-D arrangement than that for flat one. The stage floor structure was selected through audition of 14 floor samples on which strings and a timpani were played. The samples contained four timber materials of several different thicknesses, and with or without an underneath layer. Some listeners preferred floors that resounded with fullness, but others preferred different floors that resounded tightly and clearly. Finally, a 40-mm Hinoki cypress without an underneath layer was selected as the stage floor structure.
Scale model experiment for the acoustical design of a church
Authors: Mukai Hikari , Satoh Fumiaki , Yano Hiroo , Tachibana Hideki
Published: October 2005

In a church, speech intelligibility is a very important condition together with the reverberance for musical activities. In order to realize these two incompatible conditions, public address (P. A.) systems are often used to improve speech intelligibility. In the acoustical design of St. Ignatius Church in Tokyo, a 1/20-scale model experiment is being made, in which the acoustic conditions, including the effect of the P.A. system, are investigated by applying the hybrid simulation technique. As for the sound sources to measure impulse responses, four types of spark-discharge impulse sources—a simple omnidirectional one and three directional ones which simulate human heads and two types of horn-type loudspeakers—have been developed. In order to investigate the effect of the P. A. system, impulse responses measured under various configurations are convolved with dry sources (speech and music) and judged by means of a subjective hearing test.
The acoustic design of the Takarazuka Grand Theater
Authors: Hase Shigeo
Published: October 2005

The Takarazuka Grand Theater, the home ground of Takarazuka Revue, had closed its 69-year history since 1924, and after reconstruction, it opened as a new theater on 1 January 1993. This new theater is only for the Takarazuka Revue Company which performs musicales, dramas and shows. It has continued more than 80 years, and all the performers are females. The theater has a capacity for 2527 people, and the two-story seating space provides the best view for the audience. As for its acoustic design, the most advanced acoustic technology was employed; especially a sound field control system keeps the acoustical quality at the seats below the deep balcony equal with that at the other seats. As well, the theater features a positional sound image control system, a new acoustic tool where the sound is moved in accompaniment with the actress’ movements. An investigation of the acoustic efficiency shows that the theater has a reverberation time of 1.1 s at 500 Hz. The results of acoustic tests of the sound field control system and the positional sound image control system employed in this theater were very satisfactory. These systems have been also evaluated highly by stage directors and acousticians.
Relationships between subjective and objective acoustical measures in churches
Authors: Carvalho António P. , Morgado António E. , Henrique Luís
Published: October 2005

This study reports on subjective and objective acoustical field measurements made in a survey of 36 Catholic churches in Portugal built in the last 14 centuries. Monaural acoustical measurements (RT, EDT, C80, D50, TS, L, and RASTI) were taken at several source/receiver locations in each church and a group of college students was asked to judge the subjective quality of music and the intelligibility of speech. The listeners in each church evaluated live music performances and speech at similar locations in each room. Evaluation sheets were used to grade the listeners’ overall impressions of room acoustics qualities and also loudness, reverberance, intimacy, envelopment, directionality, balance, clarity, echoes, background noise, and speech intelligibility. This paper complements the one presented at the Indianapolis ASA Meeting and concentrates on the relationships of the subjective parameters with the objective room acoustics measures and with the architectural features of the churches. The results are graphed and analyzed by comparisons. Correlation analyses and statistical modeling identified significant relationships among the measures. For instance, linear correlation coefficients (R) of 0.8–0.9 were found for the relationships: reverberance/RT and clarity/C80; the maximum R found was 0.93 for echoes/RT. Regarding architectural features the maximum R found was 0.87 between intimacy and total volume. [Work supported by CEDEC/FEUP/UP and ESMAE/IPP—Portugal.]
Call repertoires of the Japanese treefrog, Hyla japonica
Authors: Honda Eri , Matsui Masafumi
Published: October 2005

Frogs and toads use acoustic signals for communication. The existence of several call types is recognized, but few studies have been made on them up to the present. The call repertoire of males and females of the Japanese treefrog,Hyla japonica was investigated in the field and laboratory. Six of the call types were confirmed: an advertisement call, an encounter call, a release call, a rain call, a distress call, and an amplexus call. The only call emitted by a female was the release call. Calls were categorized by observing behavior. Of the seven types of calls, only the advertisement call, which is used for mating, was analyzed in detail. The result showed that the temporal parameters (note duration and note repetition rate) were significantly correlated with air temperature; the dominant frequency was positively correlated with air temperature and negatively with snout-vent length; and that the frequency modulation was negatively correlated with the snout-vent length. Detailed acoustical and functional analyses of each type of calls would be expected in this species.
Physiological effects of infrasonic noise on captive fish
Authors: Clark Joseph A. , Young Jane A. , Bart Amrit N. , Zohar Yonathan
Published: October 2005

Infrasonic noise has been found to be a dominant feature of the aquatic environment created by several types of tanks used extensively for farming fish [Clark et al., J. Acoust. Soc. Am. 99, 2558(A) (1996)]. Ground vibrations, pumps and other mechanical systems for cleaning, aerating and maintaining constant flows in the water can generate noise that is transmitted to the tanks by pipes, mounts, and airborne paths. Fluctuations in pressure and particle velocity can be further amplified by vibrations of the flexible tank walls. Fish can sense waterborne noise through both auditory and mechanosensory systems. When the noise occurs at high levels and for extended periods of time, the fish might not be able to adapt to its presence, and undesirable physiological effects such as lowered growth rate and hormone deficiencies could result. This talk describes an experimental study of physiological effects of infrasonic noise in the 5- to 20-Hz region on fingerlings grown in high densities in fiberglass tanks used for commercial fish farming. Comparisons are made with fish grown in tanks that have been acoustically quieted and in tanks where the noise levels are raised above the levels normally found in such facilities.
Low-frequency response of the peripheral auditory organs in the goldfish (Carassius auratus)
Authors: Finneran James J. , Hastings Mardi C. , Derenburger Corrie
Published: October 2005

The amplitude and phase response of individual peripheral auditory organs was measured in goldfish using a noninvasive ultrasonic measurement system. Individual fish were anesthetized and suspended within a low-frequency acoustic field generated by two underwater sound projectors coupled to the ends of a 14-m-long, water-filled acrylic tube. Active control was used to synthesize a plane traveling wave within the tube at frequencies down to 12.5 Hz. Simultaneously, the fish was insonified by a continuous wave ultrasonic source operating at 15 MHz. A separate ultrasonic transducer acted as receiver. Motion of the target due to the low-frequency acoustic field caused the received signal to be phase modulated. Target amplitude information was obtained directly from the receiver output using a high-frequency spectrum analyzer; phase information required demodulation of the received signal. A motorized positioning system allowed the fish to be moved relative to the measurement system so that different organs could be examined. The spatial resolution of the measurement system was about 0.2 mm. Using this system, the responses of the goldfish swimbladder, Weberian ossicles, and otoliths have been measured at frequencies down to 12.5 Hz and compared to existing models. [Work supported by ONR Grant No. N00014-94-1-0337.]
Analysis of mosquito wing beat sound
Authors: Campbell Richard H. , Martin Samuel K. , Schneider Imogene , Michalson William R.
Published: October 2005

Male mosquitos locate their appropriate mating partners by the detection of species-specific wing beat sounds emitted by their females in flight. The wing beat sounds of five military-relevant infectious disease-vector mosquito species—A. freeborni, A. stephensi, A. albimanus, A. gambi, and Ae. aegypti—were recorded and analyzed for amplitude and spectral variation during flight. The post-processing of the recordings resulted in audio files of approximately 1 s of flight suitable for reproduction using a sampling synthesizer and, additionally, matrices of amplitude and frequency data versus time for the fundamental and any useful higher-order harmonics. The accurate cataloging of these unique wing beat sounds can be used effectively in the design of improved sound traps and automatic electronic species identification devices. [Work supported by a Walter Reed Army Institute of Research ILIR award.]
The fetal sound environment
Authors: Abrams Robert M. , Gerhardt Kenneth J.
Published: October 2005

The importance of understanding noise exposure effects on pregnant women and domestic animals was made apparent following findings that environmental sounds readily penetrate the abdominal wall, uterus, and fetal fluids. Relatively low-frequency sounds (<0.5 kHz) are transmitted, with sound pressure levels (dB re: 20 μPa) often higher in utero than SPLs in the air surrounding the abdomen. Overall shapes of intra-abdominal isosound pressure contours reveal important differences in the manner in which airborne and vibroacoustic sounds pass through the abdomen. Measurements of fetal cochlear microphonics show attenuation to be 10–15 dB for sounds 0.5 kHz and 40–45 dB for sounds between 0.5–2.0 kHz. Sound transmission is predominantly through bone conduction rather than through the fetal external and middle ear systems. Elevated thresholds for hearing can result from high-intensity noise exposure in fetal sheep. Nonauditory effects in humans include increases in heart rate and heart rate variability and body movements. Changes in behavioral state in the sheep fetus are easily induced with amplitude and frequency-modulated signals produced at the abdominal surface of the ewe. Stimulation in both REM and non-REM sleep led to a change in electrocortical activity, implying central arousal. [Work supported by NIH and March of Dimes Birth Defects Foundation.]
Analysis of broadband echo soundings over a gassy seabed
Authors: Boyle Frank A. , Chotiros Nicholas P. , Pace Nicholas G. , Bergem Oddbjorn , Michelozzi E. , Pouliquen E.
Published: October 2005

Broadband echo soundings, between 1 and 20 kHz, were recorded in shallow water over a fine-grained sediment near Viareggio, Italy. The data-acquisition system was configured to provide a calibrated echo, from which the seabed’s reflection coefficient could be determined. Environmental information, including sediment grab samples and photographs of the seabed, was collected coincidentally. The track traversed a previously charted gas front which was apparent in the displayed data. Anomalously high levels of reflection loss were noticed at the edge of the spectral peak. It is hypothesized that nonlinear conversion of acoustic energy is responsible. The low-energy part of the spectrum is consistent with linear model predictions. An acoustic color-mapping method [Boyle and Chotiros, J. Acoust. Soc. Am. 99, 2553(A) (1996)] was applied to the data, clearly showing the spectral character of certain features. A discussion will be included on the method’s relevance to remote determination of the seabed’s strucure. [Work supported by ONR.]
Long-range ocean mapping by low-frequency sound
Authors: Didenkulov Igor N. , Rodygin Yury L.
Published: October 2005

The development of high-power, low-frequency sound sources and methods of acoustical tomography has been enhancing the range of observation of underwater inhomogeneties in the ocean from local to global scale. In this way, the problem of the role of underwater mountains in sound field formation arises. It also looks attractive to apply a low-frequency sound for large-scale acoustic ocean mapping. The characteristic of sound reflection by underwater mountains has not been studied enough until now. A review of experiments made in the Pacific and Atlantic on long-range sound reflections from underwater mountains and continental slopes is presented. During the measurements, continental slopes were sounded by tone-burst signals of about 240-Hz frequency from distances of 600 and 200 km. Receiving systems deployed at 20–90 km apart from the slopes detected both the forward and reflected signals. The reflection coefficient was found to be about −(20–30) dB. This makes it possible to observe the reflections everywhere in the ocean. Different schemes of long-range ocean mapping based on low-frequency echo sounding and on coherent and incoherent aperture synthesis are discussed. [This work was supported by RFBR Grant No. 96-02-1944.]
Evaluation of sound propagation models used in bottom volume scattering studies
Authors: Li Dan , Tang Dajun , Frisk George V.
Published: October 2005

The proper evaluation of sound propagation between sources/receivers and scatterers is important in characterizing bottom volume scattering. In this work, several sound propagation models used in bottom volume scattering studies are evaluated and their results compared to the exact solution obtained through a numerical wave-number integration technique. It is found that Hines’ approach [J. Acoust. Soc. Am. 88, 324–334 (1990)] works well for the two isovelocity half-space case except when the grazing angle is close to the critical angle. The far-field approximation, given by Ivakin [Sov. Phys. Acoust. 32(6), 492–496 (1986)] and Mourad and Jackson [J. Acoust. Soc. Am. 94, 344–358 (1993)] has a performance depending upon the sound-speed structure in the sediment. For an isovelocity slow bottom, it agrees well with the exact solution. However, discrepancies arise for an isovelocity fast bottom or a bottom with a complex sound-speed structure. In addition, the appropriateness of using the equivalent surface scattering strength as a function of grazing angle in volume scattering characterizations is studied. In conclusion, precautions need to be taken in modeling both the propagation effects and the scattering mechanisms associated with the bottom volume scattering process. [Work supported by ONR.]
Fine-scale acoustic imaging of shallow water sediments
Authors: Tang D. , Chu D. , Auston T.
Published: October 2005

Understanding of the spatial variability of sediment properties is crucial to many applications of underwater acoustics. Although core samples can provide satisfactory resolution of the vertical variability of sediments, horizontal samplings are too sparse to provide a centimeter-scale horizontal resolution. A two-dimensional acoustic tomographic system is under development at the Woods Hole Oceanographic Institution capable of providingin situ 2-D acoustic images of shallow water sediments. The system can provide a spatial resolution up to a few centimeters and differentiate 2% variations in sound speed within the tomographic region. It consists of three identical probes, each includes twenty 5-cm-spaced transducers. Two of the probes are oriented vertically and separated by about 1 m, and the third is positioned horizontally right above the two vertical probes. Improving upon the conventional cross-hole tomographic technique, the horizontal probe greatly helps provide a higher horizontal resolution. The acoustic tomography is performed in a 2-D vertical slice of about 1 m2 (1 m×1 m). To test the robustness and precision of the inversion technique used, numerical simulations are performed in terms of influences from a variety of potential error sources such as transducer position errors. Preliminary experimental results are also presented. [Work sponsored by ONR.]
Prediction of ping-to-ping cross talk in fisheries sonar
Authors: Kirsch Jay
Published: October 2005

Faster ping rates in fish assessment sonars yield higher spatial resolution information, and can reduce the variance of the target strength estimate by taking multiple measurements on single targets [J. E. Ehrenberg and T. C. Torkelson, ICES J. Mar. Sci. 53, 329–334 (1996)]. However, an effect of this corresponding shorter trigger interval is a decrease in spreading time, causing a reduction of spreading loss from the previous ping such that false echoes can result in deep water if the ping rate is too high. This ping-to-ping cross talk is a function of the ping rate, bottom depth and type, applied TVG, and sound absorption. A method has been developed which estimates the energy loss from a previous ping based on those variables, thus allowing one to establish a maximum ping rate for a desired echo-integration threshold. Deep-water measurements of ping-to-ping cross talk were then taken to validate this method. [Work supported by EVOSTC.]
Studies on sound and vibration generated by household appliances. I. The determination of sound power level of a waste disposer by the comparison method
Authors: Koyasu Masaru , Ohkawa Heiichiro , Kaite Masahiro
Published: October 2005

A household food waste disposer is attracting attention as one of the leading disposal systems in Japan, and the possibility that a disposer will be installed at many condominiums from now on is under consideration. Sound and vibration, which are generated by a disposer, are being considered as a new noise source problem. To popularize the disposer in Japan, the reduction of the sound and vibration generated by the disposer is an important matter. In this paper, as a standard method for measurement and evaluation of sound generated by the disposer, the determination of sound power level of a disposer by a comparison method in a hard-walled test room is studied. As a result, the accuracy of measurement for the sound power level of the disposer is practically confirmed. Also it is clear that the sound power level of the disposer is influenced by the kinds of food waste, but frequency characteristics are scarcely affected.
Accuracy in sound power level determination by the scanning intensity method
Authors: Yano Hiroo , Koyasu Masaru , Tachibana Hideki
Published: October 2005

The method of determining sound power levels of noise sources by the sound intensity technique has been specified in ISO 9614 Part 1 (precision, engineering, and survey grades by the discrete point method) and Part 2 (engineering and survey grades by the scanning method). In addition to these, the work of drafting, Part 3 (precision grade by the scanning method) has just started in ISO/TC43/SC1/WG25. In order to obtain data for the specification of the measurement accuracy of the scanning intensity method, a basic experimental study has been done. In this study, an artificial sound source (a loudspeaker array) with complicated sound radiation characteristics and two actual sound sources (a vacuum cleaner and a compressor) were used as the sound sources under test. The sound power level of each sound source was determined in each 1/3 oct band from 50 Hz to 6.3 kHz and those in the octave band and A-weighted values were calculated from the values in the 1/3 oct bands. From these results, the measurement repeatability, the influences of the field nonuniformity, and the temporal variability on the measurement accuracy, and the field indicators were investigated.
Sonoluminescence: Skeletons in the closet
Authors: Putterman Seth J. , Weninger K. , Löfstedt R. , Barber B. P. , Hiller R. A.
Published: October 2005

Now that the exciting measurements of picosecond flash widths, clocklike emission, broadband ultraviolet light, and the role of noble gas doping have generated substantial interest and theories for sonoluminescence, it is time to take a more sober look at the experimental difficulties that stand in the way of the next round of insights. Parameters which control the steady-state motion of the bubble have not yet been elucidated. For instance, measurements of the dipole component of the sonoluminescence (SL) indicate that the bubble collapse can choose states with different ellipticity. Hydrogenic bubbles glow for periods ranging from 30 s to 5 min and are very sensitive to as yet unknown impurities. Tiny amounts of organic impurities dramatically alter the light emission. There is also concern that impurities may partly account for the different spectra observed in light and heavy water. Precise temperature control can be essential to prevent the bubble from hopping between different stable states. [Work supported by the NSF.] a)Current address: UC, Santa Barbara, CA.
Acoustic cavitation and implosion acoustics
Authors: Crum Lawrence A.
Published: October 2005

The ubiquitous cavitation bubble always seems to be around whenever one propagates an acoustic field of moderate amplitude through a liquid. The implosive collapse is a marvelously efficient concentrator of acoustic energy and can result in exotic mechanical and chemical effects. Examples of some of the many ways this acoustic energy can be utilized to accomplish a desirable effect are (a) the generation of a broadband underwater acoustic source, (b) the communication of renal and bilary calculi, (c) the cleaning of contaminated surfaces, (d) the remediation of waste contaminants, (e) the in vivo destruction of carcinomas, (f) the production of exotic materials, etc. A description of a variety of these effects will be presented. [Work supported in part by the NIH and the NSF.]
Recent experimental studies of sonoluminescence
Authors: Moran M. J. , Sweider D. , Rudnitsky R. , Vacca G.
Published: October 2005

Experiments that study sing-bubble sonoluminescence (SL) have frustrated diagnostic capabilities and produced a variety of puzzling results. Recent experiments are addressing this situation with improved diagnostics and by studying new aspects of SL behavior. The experiments range from temporal measurements with improved resolution to attempts to measure trace-gas production. Recent results will be presented and discussed with respect to theoretical studies of SL. [Work performed under the auspices of the U.S. Department of Energy by the Lawrence Livermore National Laboratory under Contract No. W-7405-ENG-48.]
Experimental simulation of shock focusing in a collapsing cavity
Authors: Bourne Neil K. , Proud William G. , Field John E.
Published: October 2005

Recent models have highlighted the effects of shock-focusing in a spherically symmetric collapsing cavity. Several of these simulations have predicted extremely high temperatures in the final stages of the collapse. In order to investigate the feasibility of such a mechanism, an idealized one-dimensional experiment was designed in which a shock wave was introduced by a piston launched from a gas gun into a closed cylindrical cavity. The compressed gas contained within had a quantity of argon introduced. Light was monitored using a fast photodiode and a gated spectrometer capable of resolving nanosecond duration pulses. The piston motion was measured by streak and framing photography using an Ultranac high-speed camera. A threshold in light emission was observed at a piston velocity of ca. 20 m s−1. It is shown that the light emission shows some of the features of the observed luminescence. The effects of colliding waves are discussed.
Impulsive snap-through acoustic projector: A new concept
Authors: DeJaco Jerome F. , Rask Will F. , Rynne Edward F.
Published: October 2005

A new approach for generating impulsive sound in water has been devised. The technology allows for repeatable impulsive sound generation that is depth independent, unlike the technologies of airguns, spark discharge devices, and explosives which create an oscillating gas bubble. One application for this device would be target detection for littoral/clutter-filled environments where repeatable impulsive low-frequency broadband acoustic energy is required. In-water test results of a demonstration device that utilized the snap-through behavior of a spherical shell will be presented. [Work supported by ONR, Code 321SS.]
Experimental microwave radiometry on a sonoluminescence bubble
Authors: Kordomenos John N. , Bernard Miguel , Denardo Bruce
Published: October 2005

Current models of the light emission mechanism for a sonoluminescing bubble are based on experimentally measured spectra in the visible and near-ultraviolet region. Four proposed quantitative theories for the emission mechanism differ by over 25 orders of magnitude in the microwave region. An experimental setup used to measure this predicted microwave emission is described. The sensitivity of the radiometer is greater than the predicted bremsstrahlung emission by a factor of 106 and is insufficient to detect the other mechanisms. Lack of detection of microwaves indicates that bremsstrahlung is not the mechanism of electromagnetic radiation for a sonoluminescing bubble. [Work supported by ONR.]
Investigation of sonoluminescence in a high magnetic field
Authors: Young J. B. , Kang W. , Schmiedel T.
Published: October 2005

A detailed study of sonoluminescence has been made in a high magnetic field. The intensity of emitted light depends critically on both magnetic and acoustic fields. In magnetic field sweeps at constant levels of acoustic drive, sonoluminescence disappears above a pressure-dependent threshold magnetic field. In sweeps of acoustic drive levels at fixed magnetic fields, the upper and lower bounds of forcing pressure that determine the region of sonoluminescence increase dramatically with magnetic field. A near-doubling of the forcing pressures is necessary between 0 and 20 T to sustain sonoluminescence. The pressure and magnetic field dependencies of sonoluminescence suggest that the primary effect of the magnetic field is to alter the condition for bubble stability with increasing pressure compensating for the effects of the magnetic field. This interplay between magnetic and acoustic fields reflects the importance of coupling between electronic and hydrodynamic degrees of freedom in sonoluminescence.
Effect of noble gas doping on sonoluminescence from water oxygen mixtures
Authors: Chow David , Weninger K. , Barber B. P. , Putterman S. J.
Published: October 2005

Previous measurements have demonstrated that a small noble gas concentration is essential to the attainment of stable bright sonoluminescence from bubbles formed in a water nitrogen mixture. As the chemical properties of nitrogen and oxygen are quite different, these experiments for mixtures of water and oxygen have been repeated. Again, it is found that noble gas doping is an important aspect of the physics, and that there is a strong similarity between the behavior of the nitrogen and oxygen systems. [Work supported by the NSF.]
Detection of a tonal stimulus masked by a complex with coherent or incoherent frequency modulation
Authors: Ashihara Kaoru
Published: October 2005

The purpose of this study is to investigate if coherent frequency modulation by itself can induce auditory streaming when there are no harmonicity cues. A signal tone was presented with a complex of tones whose frequency fluctuated. To separate the effects of frequency modulation from those of harmonicity, components of the masker were not spaced by a fixed frequency distance but by a critical bandwidth. The detection threshold of the signal was tested in two conditions. In the first, called the coherent condition, all components of the masker were modulated coherently. In the second, incoherent condition, the masker was divided into two parts, the on-signal part and the flanking part. The on-signal part was the bandpass filter of the complex that was centered on the signal frequency and the flanking part was the rest of it. To make the modulation incoherent, the flanking part was moved forward or backward by half a cycle of modulation. The signal was detected with less difficulty in the coherent condition, indicating that the components with coherent frequency modulation were integrated even if they were inharmonic.
Loudness integration and referential intensity coding
Authors: Plack Christopher J.
Published: October 2005

Intensity discrimination was measured in a 2AFC task in which the duration of a 1-kHz sinusoid was randomized, independently for each observation interval, between 40 and 400 ms, while keeping the standard intensity constant. Listeners were required to detect a difference in intensity between the two intervals while ignoring the random changes in total energy (and consequently loudness) caused by the duration randomization. Randomization caused a deterioration in performance consistent with listeners being unable to dissociate the intensity change from the random changes in total energy, implying long-duration temporal integration. When notched noise was added to the stimulus, however, performance improved to a level similar to that seen without the randomization. It is possible that listeners can make a relative comparison of the intensity of the tone with that of the notched noise (possibly in a manner similar to profile analysis) that utilizes a much shorter integration period. It is suggested that when making absolute intensity (in other words, loudness) judgments, listeners generally use a long integration time, but that judgments of relative intensity, which are needed for identifying the features that characterize auditory objects, are made over much shorter intervals. [Work supported by The Royal Society.]
Relative contributions of two neural population responses to intensity coding
Authors: Zeng Fan-Gang , Galvin John J. , Relkin Evan M.
Published: October 2005

Two neural population responses have been proposed to encode the 120-dB intensity range: the spread of excitation along the entire basilar membrane and neurons of different thresholds within a narrow region of the basilar membrane. This study tests relative contributions of the two population codes by measuring forward-masked intensity discrimination of a broadband noise (14 kHz) and pure tones from 125 to 8000 Hz in octave steps. The hypothesis is that the broadband noise and low-frequency tones rely more on the spread of the excitation code, whereas high-frequency tones rely more on the high-threshold neuron code. To obtain appropriate forward masker levels, three normal-hearing listeners balanced loudness of the broadband noise and tones to a 100-ms, 90-dB SPL, 1000-Hz standard. Intensity discrimination was measured for a 25-ms probe which had the same spectral characteristic as the masker and occurred after a 100-ms delay from the masker’s offset. The discrimination data showed that the midlevel hump systematically increases from the broadband noise and the low-frequency tone to the high-frequency tone conditions, indicating a greater contribution of high-threshold neurons to intensity coding [Zeng et al., Hear. Res.55 , 223–230 (1991)]. Backward-masked intensity discrimination was also measured and will be discussed.
Dual effects of notched noise on forward-masked intensity discrimination
Authors: Zeng Fan-Gang
Published: October 2005

A notched noise simultaneously presented with a standard tone reduces the midlevel hump in forward-masked intensity discrimination [Plack and Viemeister, J. Acoust. Soc. Am. 92, 1902–1910 (1992)]. This reduction is difficult to explain based on the assumption that the notched noise would force the listener to use high-threshold neurons within the on-frequency band and thus should produce an increase in the midlevel hump. However, a problem in the Plack and Viemeister study was that the notched noise level was increased as a function of the standard level. In the present study, thresholds of a 25-ms, 1-kHz tone were measured in a 125-ms notched noise and shown to grow nonlinearly as a function of the noise level. The slope of the masking function was less than 1 at low noise levels and was greater than 1 at high noise levels. Compared with data in the absence of notched noise, the notched noise produced a greater midlevel hump at low noise levels and reduced or removed the midlevel hump at high noise levels. These data suggest dual effects of the notched noise on intensity discrimination: (1) restriction of off-frequency listening at low levels, and (2) masking the on-frequency listening through two-tone suppression at high levels.
Equal-loudness level contours below 1 kHz
Authors: Lydolf Morten , Mo/ller Henrik
Published: October 2005

Binaural equal-loudness level contours and the threshold of hearing have been measured on 25 otological normal-hearing subjects. In the frequency range from 50 Hz to 1 kHz the measurements were made in the free field for frontal sound incidence. From 20 to 100 Hz the experiments were made in a pressure field chamber with an inner volume for the test subjects of approximately 1 m3. The experiment is made with pure tones at each of the third octave frequencies in the frequency range. Loudness levels between 20 and 100 phon are measured. The data are going to be used for the standardization work in the Working Group ISO/TC43/WG1 for a revision of the international standard ISO 226.
Air versus bone conduction: An equal loudness investigation
Authors: Stenfelt Stefan P. Y. , Hakansson Bo E. V.
Published: October 2005

Air versus bone conduction loudness balance testing was performed at the frequencies 0.25, 0.5, 0.75, 1, 2, and 4 kHz in three groups of subjects: normal-hearing subjects, subjects with pure sensorineural hearing loss, and subjects with mixed hearing loss. The subjects were fitted with earphones (Koss portaPro) and a percutaneous bone transducer (HC-380) or an audiometric transducer (B71). Narrow-band noise was presented interchangeably between the earphones and the bone transducer. Balance testing was performed at each frequency and at different levels (30–80 dB HL in 10-dB steps) in the following manner: The sound pressure from the earphones was fixed and the subject under test adjusted the output level from the bone transducer for equal loudness similar to the procedure used in the conventional ABLB test. Preliminary results and their interpretation will be presented.
Estimation of the new equal-loudness level contours
Authors: Takeshima Hisashi , Suzuki Yôiti , Kumagai Masazumi , Sone Toshio
Published: October 2005

The current international standard of the equal-loudness level contours specified in ISO 226 is found to involve large errors, epecially for frequencies below 1 kHz. In the past 10 years, a series of experiments has been conducted for full revision of ISO 226 in ISO/TC 43. At the final stage of this project, the new equal-loudness level contours should be drawn from available data points. To do this, the use of an appropriate model for loudness perception is actually useful. A loudness function is proposed by combining that proposed by Lochner and Burger to express the steepness near threshold with the two-stage model proposed by Attneave to consider the loudness-comparison process. Equal-loudness levels are then estimated according to the following procedure. (1) Parameters of the loudness function are estimated from the experimental data by the nonlinear least-squares method. (2) The estimated parameters are smoothed along the frequency axis with B-spline functions. (3) The equal-loudness level contours are calculated by using estimated parameters and the threshold of the hearing curve. Through this procedure, the new equal-loudness level contours are determined from the experimental data obtained hitherto.
On the pitch identification of complex tones by the autocorrelation function (ACF) model
Authors: Sumioka T. , Ando Y.
Published: October 2005

The pitch of the complex tone consisting of harmonics without the fundamental frequency is investigated. The pitch is called ‘‘residue pitch.’’ If the pitch of the complex tone is insensitive to the relative phases of the spectral components, then the pattern transformation model [F. L. Wightman, J. Acoust. Soc. Am. 54, 407–416 (1973)], which corresponds to the autocorrelation function (ACF) of a signal, may be identified. In this study, subjects were asked to control the frequency of a sinusoidal wave to match the pitch of a test stimulus with a different waveform which is generated by setting the different phases of each component. The components consist of frequencies 600, 800, 1000, 1200, and 1400 Hz with the same amplitude. The measured pitch of the stimulus was almost the same as that of the fundamental frequency (average: 201–202 Hz). The result, therefore, indicates that the ACF model is acceptable.
Intermediate scale measurement system: A state of the art facility for Naval structural acoustics research; system overview and measurement results
Authors: Schreppler Stephen C. , Jebsen Gary M. , Kneessi S. Lawrence
Published: October 2005

The intermediate scale measurement system (ISMS) is a state-of-the-art measurement range for Navy structural acoustics research. The range is located in Lake Pend Oreille at the Acoustic Research Detachment (ARD) of the Naval Surface Warfare Center, Bayview, Idaho. The system is designed to accommodate ‘‘high fidelity’’ 1:10 to 1:4 scale models of submarines. The ISMS has several unique measurement modes, including: (1) generation of plane-wave ensonification using a phased planar array of 36 projectors; (2) radiated signature measurement using a full 360-deg azimuth, 158 hydrophone, near-field receive array; and (3) acquisition of data from up to 1000 model-mounted sensors. Through use of high precision acoustic location measurement, the ISMS has an integral capability to project near-field bistatic target strength and radiated noise signatures to the far field. Based on these measurement modes, the ISMS can make very accurate, precise and repeatable target strength, radiated noise, and structural response measurements. The receive array is also used for the spatial imaging of the radiated pressure fields. Selected analysis products from a 1:4 scale model test series will be presented. [Work supported by ONR.]
A comparison between in-water scattering measurements made on low and moderate complexity two-dimensional structures and high-fidelity numerical predictions
Authors: Herdic Peter , Simpson Harry J. , Houston Brian H.
Published: October 2005

In order to assess the level of fidelity in the state-of-the-art numerical predictions of scattering cross sections associated with two-dimensional fluid-loaded structures, a series of experiments was conducted and compared to the numerical predictions. These comparisons were done for low and moderate complexity structures in the midfrequency band, 2<ka<20. The low-complexity structure was a simple hollow cylinder with hemispherical end caps that was carefully crafted to be as axisymmetric as possible. Unlike the simple shell, the moderate complexity shell had faceted conical ends with internal structures that included two bulkheads and two regular straight frames. These shells were numerically modeled as axisymmetric two-dimensional structures and scattering cross sections were generated using a finite-element–infinite-element formulation (SARA2D). How well the numerical calculations predicted the scattering cross sections is both qualitatively and quantitatively discussed and will include the use of direct visual comparisons of cross-section data, statistical analysis, and supersonic imaging techniques. [Work supported by ONR and NRL.]
Vibratory power flow through a nonlinear path into a multiresonant receiver
Authors: Royston Thomas J. , Singh Rajendra
Published: October 2005

Vibratory power flow through a nonlinear path into a multiresonant support structure is considered via an example case, a hydraulic engine mount. System equations for the nonlinear source–path–receiver system are developed for periodic excitation and an efficient solution method is formulated for the calculation of the steady-state stable response based on a multiterm harmonic balance approach with condensation and continuation. In this study it is shown that while modeling the isolation path with a ‘‘softened,’’ nonlinear expression may only moderately alter the predicted system behavior at the excitation harmonic, it can significantly alter it at higher harmonics. With respect to isolation performance, studies of multiharmonic motion and power transmission show that audible structure-borne noise may be generated from subaudio frequency excitations due to path nonlinearities. It is also shown that support base (receiver) dynamics can significantly affect the isolation performance. For instance, with a multidegree-of-freedom base model, significant levels of vibratory energy at higher harmonics of the excitation are transmitted, especially when superharmonics coincide with receiver resonances.
Analysis of structural intensity of complex structures
Authors: Hayek S. I. , Miller A. , Agarwala V.
Published: October 2005

The prediction and computation of the vibration structural intensity have been accomplished for simple structures, such as beams, rods, plates, and shells. These structures, even when connected to other simple structures, were amenable to analytic solutions, which allowed the researchers to obtain exact analytic expressions for the power flow and the structural intensity vector maps for these structures. A calculation of the structural intensity by the use of finite-element methods (FEM) is proposed. This hybrid method requires that one must delve into the FEM codes to retrieve all the resultant moments, shears, normal forces, as well as the transverse, tangential, and rotational velocities. These quantities are processed to result in complete structural intensity maps. The influence of mesh size, the use of resultants at the mid of the elements, and mesh size requirements as a function of axial, flexural, and torsional wavelengths are explored. An example of a connected branched structure undergoing coupled flexural, longitudinal, and torsional vibration is analyzed to illustrate the influence of these parameters on the accuracy of the structural intensity calculations.
Vibration and nonstationary wave localization within elastic constructions
Authors: Abramian A. K.
Published: October 2005

The phenomenon of vibration and nonstationary wave localization within beams, plates, and shells has been studied using a linear and a non-linear approach. Using a linear approach, wave localization within finite constructions with inclusions (mass, frames, etc.) can be explained by the phenomenon of trapped modes. Necessary and sufficient conditions for low-frequency trapped modes are: (1) The continuous spectrum of a boundary value problem for an elastic construction without inclusion must be shifted from zero; (2) an inclusion which contacts with an elastic construction must possess a mass element. It has been proved that trapped frequencies can be the natural frequencies within the finite length construction. Peculiarity of the trapped frequencies of the finite-length construction is the fact that they are multiple natural frequencies of the second order. The nonlinear approach has been used to explain the nonstationary wave localization in the domain of a shell dent. The dent has been modeled as a set of nonlinear springs. New design principles for active and passive isolation of such constructions based on linear and nonlinear localization are outlined.
Japanese production of English segmentals using visual feedback
Authors: Lambacher Stephen G.
Published: October 2005

This paper focuses on the use of visual feedback as a tool in helping Japanese learners improve their production of English segmentals. Each student was equipped with a Sony workstation containing a sound analyzer able to measure frequency, duration, pitch, and intonation. Subjects received training in the pronunciation of English stop, fricative, affricate, and liquid sounds using visual feedback during a 13-week period. A pre- and post-test consisting of English words containing the target sounds within a varied-vowel environment in sentence frames was administered before and after the subjects received instruction. Critical-band analysis was performed on a short segment within the steady state of the target sounds, and the resulting acoustic properties of Japanese production of the target sounds were examined and compared. Formant frequencies were calculated from an FFT frequency response with a pre-emphasized, low-pass filter. A sampling frequency of 19 kHz with a frequency range between 0 and 5000 Hz was used. Results from the post-test show general improvement in production of each of the target consonants after students are instructed and exposed to visual feedback. These results will be discussed, along with some practical ideas of how to effectively utilize visual feedback to improve production of English segmentals.