Validation of an auralization system

Validation of an auralization system
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Validation of an auralization system
Christensen, Claus Lynge; Weitze, Christoffer Andreas; Rindel, Jens Holger; Gade, Anders Christian
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Acoustical Society of America. Journal
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Christensen, C. L., Weitze, C. A., Rindel, J. H., & Gade, A. C. (2001). Validation of an auralization system.
Acoustical Society of America. Journal, 111(5), 2389-2389. DOI: 10.1121/1.1486347
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BENEDUM ROOM, 8:00 TO 10:30 A.M.
Session 3aAAa
Architectural Acoustics: Computer Modeling in Acoustical Consulting II
Lily M. Wang, Chair
Architectural Engineering, University of Nebraska, 200B Peter Kiewit Institute, 1110 South 67th Street,
Omaha, Nebraska 68182-0681
Invited Papers
3aAAa1. Validation of an auralization system. Claus Lynge Christensen, Christoffer A. Weitze, Jens Holger Rindel, and Anders
Christian Gade 共O
” rsted•DTU, Acoust. Technol., Tech. Univ. of Denmark, Bldg. 352, O
” rsted Plads, 2800 Kgs. Lyngby, Denmark,
[email protected]兲
3a WED. AM
The room acoustics program ODEON provides auralization using fully filtered binaural room impulse responses, each reflection
being filtered through nine octave bands and a set of head-related transfer functions. Using the full filtering scheme allows, in
principle, a complete audible presentation of all the properties, time-variant frequency coloration, as well as directional information
predicted by the room acoustics program. Two methods of verification have been applied. The first method is based on direct
measurements on the impulse responses predicted by ODEON, using the room acoustics measuring system DIRAC in order to verify that
the auralization method is actually capable of reproducing the predicted room acoustic parameters. Monaural auralization filters were
used for this purpose. The other method is an audible comparison between in situ recordings of a singing person in real rooms and the
ODEON auralization of the same situations. The latter verification is part of an ongoing European research project, CAHRISMA, on
restoration of the acoustics in old Byzantine churches and mosques in Istanbul.
3aAAa2. Effect of model detail level on room acoustic computer simulations. David T. Bradley and Lily M. Wang 共Univ. of
Nebraska-Lincoln, Peter Kiewit Inst., 1110 S. 67th St., Omaha, NE 68182-0681, [email protected]兲
Computer modeling of room acoustics is limited due to approximations regarding wavelength to surface size ratios and diffraction.
In fact, it is suggested that a model with high geometrical fidelity may actually lead to less accurate predictions. This project seeks to
clarify how the level of model detail affects the accuracy of these simulations. Three models of the University of Nebraska’s Strauss
Recital Hall have been generated at varying levels of detail; low 共a rough model of the essential architectural dimensions兲, medium
共a more accurate representation of the space兲, and high 共a complete rendering of the surfaces within the space兲. The room acoustics
modeling program Odeon is used to calculate objective measures 共i.e., reverberation time and clarity兲 and create auralizations for each
model. Meanwhile, the actual acoustical properties of Strauss Hall have been measured. The objective measure results are compared
between the models and against measured data. Additionally, subjective tests are run with auralizations from all three models and the
original space to determine if the difference in level detail can be perceived psychoacoustically. Quantitative results from these
comparisons are presented to help users of room acoustic simulation software understand how the level of model detail will produce
maximum accuracy.
3aAAa3. The development and use of the diffusion scattering coefficients in room modeling software: The effect of diffuse
reflections on reverberation time. Peter D’Antonio 共RPG Diffusor Systems, Inc., 651-C Commerce Dr., Upper Marlboro, MD
20774兲 and Trevor J. Cox 共Univ. of Salford, Salford M5 4WT, UK兲
In the last 20 years, much progress has been made in the measurement and characterization of sound diffusing surfaces. This
presentation describes how this research might improve the accuracy of computer based geometric room modeling. To model diffuse
reflections, one needs to know the scattering distribution and the portion of scattered energy that is diffusely reflected. AES Working
Group SC-04-02 recently published an information document AES-4id-2001, which describes a measurement procedure to determine
the polar balloons from scattering surfaces. This allows programmers to use actual measured or calculated distributions instead of
Lamberts law, which applies to incoherent optical diffusion. ISO WG 25 is currently addressing a measurement procedure to
determine the random incidence scattering coefficient. This scattering coefficient is used directly in geometrical modeling programs.
The two measurement procedures will be contrasted. It will then be demonstrated by example how the use of diffusion data can affect
the predicted reverberation time.
J. Acoust. Soc. Am., Vol. 111, No. 5, Pt. 2, May 2002
143rd Meeting: Acoustical Society of America
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3aAAa4. Uses and limitations of statistical and geometrical modeling of nonexponential decay curves in performance spaces.
Jason E. Summers, Rendell R. Torres, Yasushi Shimizu 共Prog. in Architectural Acoust., Rensselaer Polytechnic Inst., 110 8th St.,
Troy, NY 12180兲, and J. Christopher Jaffe 共Jaffe Holden Acoust., 114A Washington St., Norwalk, CT 06854兲
The conditions under which the high-frequency, diffuse-field model of coupled rooms is a valid approximation to geometrical
acoustics have been examined by comparison with ray-tracing predictions of decay curves in two and three room systems. Results
particular to coupled rooms were noted. Because nonexponential decay shape is sensitive to both decay rates and relative energy
densities, corrections to these parameters meaningfully improved the diffuse-field model. Variations in the free-path distribution of
each subroom, introduced by coupling, complicated the use of improved decay models. Also, the expected decrease in energy density
with distance from the source was found to result in spatial dependence of decay shape for certain coupling geometries. Insights from
this study were used in the construction of diffuse-field and geometrical computer models of Bass Hall, a 2056 seat multipurpose
auditorium with an acoustically coupled stage house. Preliminary results indicate that high-frequency decay curves in each of the
subrooms predicted by geometrical acoustics are well matched to the predictions of diffuse-field models. The use of both models as
prediction and design tools is assessed by comparison at high frequencies with measurements made during occupied and unoccupied
conditions. 关Research supported by the Bass Foundation.兴
3aAAa5. Case studies of computer model applications in consulting practice. Gary Siebein, Hyun Paek, Mark LoRang, and
Courtney McGuinnes 共Siebein Assoc., Inc., 625 NW 60th St., Ste. C, Gainesville, FL 32607兲
Six case studies of computer model applications in a consulting practice will be presented to present the range of issues that can
be studied with computer models as well as to understand the limitations of the technique at the present time. Case studies of elliptical
conference rooms demonstrate basic acoustic ray principles and suggest remediation strategies. Models of a large themed entertainment venue with multiple amplified sound sources show how visualization of the acoustic ray paths can assist a consultant and client
in value engineering locations and amounts of acoustic materials. The acoustic problems with an angled ceiling and large rear wall
were studied when an historic church was converted to a music performance hall. The computer model of an historic hall did not
present enough detailed information and was supplemented with physical model studies and full size mock-up tests of the insertion of
an elevator door that would open directly into the concert room. Studies to demonstrate the amount of room model detail to obtain
realistic auralizations were also conducted. The integration of architectural acoustic design and audio system design were studied in
computer models of a large church sanctuary.
Session 3aAAb
Architectural Acoustics: Student Design Competition
Lily M. Wang, Cochair
Architectural Engineering, University of Nebraska, 200B Peter Kiewit Institute, 1110 South 67th Street,
Omaha, Nebraska 68182-0681
Robert C. Coffeen, Cochair
School of Architecture and Urban Design, University of Kansas, Marvin Hall, Lawrence, Kansas 66045
The Technical Committee on Architectural Acoustics of the Acoustical Society of America and the National Council of Acoustical Consultants are
sponsoring a student design competition which will be professionally judged at the meeting.
The purpose of this design competition is to encourage students enrolled in Architecture, Architectural Engineering, and other University curriculums
that involve building design and/or acoustics to express their knowledge of architectural acoustics and building noise control in the schematic design of
portions of a building where acoustical considerations are of primary importance.
The submitted designs, which will be displayed at the Pittsburgh ASA Meeting, will be judged by a panel of professional architects and acoustical
consultants. An award of $1,000 will be made to the submitter共s兲 of the design judged ‘‘first honors.’’ Four awards of $500 each will be made to the
submitters of four entries judged ‘‘commendation.’’
J. Acoust. Soc. Am., Vol. 111, No. 5, Pt. 2, May 2002
143rd Meeting: Acoustical Society of America
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LE BATEAU ROOM, 8:00 TO 10:55 A.M.
Session 3aABa
Animal Bioacoustics: Acoustics of Terrestrial Mammals and Birds
Ann E. Bowles, Chair
Hubbs-Sea World Research Institute, 2595 Ingraham Street, San Diego, California 92109
Chair’s Introduction—8:00
Invited Papers
3aABa1. General principles involved in the effect of noise on hearing and vocal communication in birds. Robert J. Dooling
and Michael L. Dent 共Dept. of Psych., Univ. of Maryland, College Park, MD 20742, [email protected]兲
3a WED. AM
Birds provide very useful models for understanding the effects of noise on hearing and acoustic communication. They are
excellent subjects for laboratory studies of hearing in which signals and noise can be precisely defined and delivered and behavioral
responses can be unambiguously interpreted. For this reason, a huge amount is already known about their hearing. Acoustic communication is critically important for most species of birds and some even acquire their communication signals through vocal learning.
For this reason, a lot is already known about how birds perceive complex acoustic signals such as vocalizations. Drawing from both
field and laboratory studies, we review what is known about the effects of noise on hearing and vocal communication in birds. This
includes the effects of intense noise on the ear, the effects of background noise on the detection and discrimination of both simple
sounds and complex vocalizations, and the spatial effects of signal detection in noise in the free-field. As a whole, these studies show
that birds are resistant to damage and interference from noise and have developed a variety of strategies to effectively communicate.
3aABa2. Analysis of auditory spatial receptive fields: An application of virtual auditory space technology. Terry T. Takahashi,
Clifford H. Keller, David R. Euston, and Michael L. Spezio 共Inst. of Neurosci., Univ. of Oregon, Eugene, OR兲
Virtual auditory space technology, typically used to simulate acoustical environments, also allows one to vary one sound localization cue independently of others. VAST was used to determine the contributions of interaural time and level differences 共ITD, ILD兲
to the spatial receptive fields 共RFs兲 of neurons in the owl’s midbrain. The presentation of noise filtered so that only ITD varied evoked
a response along a vertical strip of virtual space, called the ITD-alone RF. Conversely, when ITD was fixed at the cell’s optimum and
the ILD spectrum of each location was presented, the cell responded along a horizontal strip, called the ILD-alone RF. The spatial RF
was at the intersection of the ITD and ILD-alone RFs. The cell’s ILD tuning across frequency, combined with individualized
head-related transfer functions, was transformed into an ILD-alone RF that predicted half the variance in the measured one. This
discrepancy was due partly to the poor response of the neurons to tones, and a new method of inferring frequency-specific ILD tuning
from responses to noise explained about 75% of the variance. By understanding how spatial RFs are constructed, it is possible to infer
the neural image of complex auditory scenes containing multiple sources and echoes. 关Work supported by NIDCD.兴
3aABa3. Sex differences in razorbill „Family: Alcidae… parent–offspring vocal recognition. Stephen J. Insley 共Hubbs-Seaworld
Res. Inst., 2595 Ingraham St., San Diego, CA 92109兲, Rosana Paredes Vela, and Ian L. Jones 共Memorial Univ. of New Foundland,
In this study we examines how a pattern of parental care may result in a sex bias in vocal recognition. In Razorbills 共Alca torda兲,
both sexes provide parental care to their chicks while at the nest, after which the male is the sole caregiver for an additional period
at sea. Selection pressure acting on recognition behavior is expected to be strongest during the time when males and chicks are
together at sea, and as a result, parent–offspring recognition was predicted to be better developed in the male parent, that is, show a
paternal bias. In order to test this hypothesis, vocal playback experiments were conducted on breeding Razorbills at the Gannet
Islands, Labrador, 2001. The data provide clear evidence of mutual vocal recognition between the male parent and chick but not
between the female parent and chick, supporting the hypothesis that parent–offspring recognition is male biased in this species. In
addition to acoustic recognition, such a bias could have important social implications for a variety of behavioral and basic life history
traits such as cooperation and sex-biased dispersal.
3aABa4. Identifying bird species from bird song using frequency component analysis. Jacky Mallett and Irene Pepperberg
共Media Lab., MIT, 20 Ames St., Cambridge, MA 02139兲
The species-distinctive and highly stereotyped nature of bird vocalizations makes birdsong an obvious candidate for computational
analysis. By using techniques from previous work in automatic music recognition and auditory analysis, a database of the detailed
auditory characteristics of a selection of songs from over 150 different birds from the North Eastern region of the United States of
America has been created. Examination of this database has allowed a picture to be built up of species-distinctive characteristics, and
J. Acoust. Soc. Am., Vol. 111, No. 5, Pt. 2, May 2002
143rd Meeting: Acoustical Society of America
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provides a more general picture of bird vocalizations than has previously been available. From this work it appears that frequency use
by birds is of some significance, with evidence that the presence of a particular set of dominant frequencies in a bird’s song can be
used as a distinctive fingerprint for species recognition. This paper reviews previous work in this area, outlines general computational
methods used to extract this information, and presents results of automatic bird recognition using characteristics derived from the
3aABa5. Acoustic surveys for Mexican spotted owls „Strix occidentalis lucida…: An analysis. Ann E. Bowles, Chris Martindell
共Hubbs-Sea World Res. Inst., 2595 Ingraham St., San Diego, CA 92109, [email protected]兲, Kenneth J. Plotkin, Bruce Ikelheimer
共Wyle Labs., Ste. 701, 2001 Jefferson Davis Hwy., Arlington, VA 22202兲, and Tim Lavallee 共GeoMarine, Inc., 11846 Rock Landing
Dr., Newport News, VA 23606兲
During acoustic surveys for Mexican spotted owls, the effective detection range is presumed to be 0.25 mi 共433 m兲. However,
variations within and between surveys are observed, leading to a variance in owl density estimates. While owl behavior may explain
some variation, topography and ambient noise are also likely to be important. To determine the influence of these factors, data from
acoustic surveys for Mexican spotted owls in the Gila National Forest 共April–July, 2000–2001兲 were examined. Measurements of owl
and human call levels were made with a Sony TCD-10 Pro II DAT equipped with an ACO 7013 microphone. Ambient noise was
collected using 40 Larson-Davis 820 and 824 sound level meters in owl activity centers. Wyle Laboratories NMSIM software was
used to model propagation of owl and human calls. Owls produced calls with estimated maximum source levels of 92–98-dB SPL.
Human callers produced maximum source levels of 88 –95-dB SPL. Detection was possible out to more than 2 km under ideal
conditions, but topography and ambient noise had a large effect. Corrections for these factors would greatly improve estimates of area
surveyed, and thus owl density estimates. 关Work supported by the U.S. Air Force, Air Combat Command.兴
Contributed Papers
3aABa6. Frequency selectivity in canaries with a hereditary hearing
loss. Amanda M. Lauer and Robert J. Dooling 共Dept. of Psych., Univ. of
Maryland, College Park, MD 20742, [email protected]兲
Sensorineural hearing loss is associated with reduced frequency selectivity due to the broadening of the auditory filters in mammals. In European starlings, hearing loss caused by the ototoxic drug kanamycin results
in the widening of auditory filters at 5 kHz 关Marean et al. 共1998兲兴. In the
present study, we examine frequency selectivity in a bird with a permanent
hereditary hearing impairment, the Belgian Waterslager 共BWS兲 canary.
This strain of canary has long been bred for its loud, low-frequency song,
and has been shown to have a hearing loss primarily at higher frequencies
共2 kHz and above兲. Using operant conditioning and the method of constant
stimuli, thresholds for detecting pure tones in flat-spectrum broadband
noise were measured in BWS and non-BWS canaries. Critical ratios were
calculated for comparison with other species of birds. At higher frequencies, critical ratios for BWS canaries were much larger than those of
non-BWS canaries and other birds, suggesting reduced frequency selectivity in the region of the birds’ hearing loss. 关Work supported by NIDCD
R01DC001372 to RJD and Brenda M. Ryals.兴
3aABa7. Narrowband masking in birds. Stacey L. Brown, Robert J.
Dooling 共Dept. of Psych., Univ. of Maryland, College Park, MD 20742,
[email protected]兲, and Marjorie R. Leek 共Walter Reed Army
Medical Ctr., Washington, DC 20307兲
Hearing studies show that zebra finches, Taeniopygia guttata, small
song birds that produce broadband, harmonic vocalizations are unusually
sensitive to the mistuning of a single component in a harmonic complex
关Lohr and Dooling, J. Comput. Psychol. 112, 36 – 47 共1998兲兴. Such a
change in a harmonic stimulus creates both spectral and temporal cues.
Previously it has been reported that these birds have very good temporal
resolution of fine detail within harmonic complexes 关Dooling et al., Hear.
Res. 152, 159–172 共2001兲兴. Here the spectral resolving power is examined
by measuring auditory patterns of masking by narrowband noises. Masking patterns were measured in zebra finches using operant conditioning
and the method of constant stimuli for a 100-Hz band noise masker centered at the birds frequency of best hearing, 2860 Hz. Probe frequencies
were tones between 1000 Hz and 5700 Hz. Results demonstrate a symmetrical masking pattern with less upward spread of masking and a nar2392
J. Acoust. Soc. Am., Vol. 111, No. 5, Pt. 2, May 2002
rower resolution bandwidth in zebra finches than has been observed in
humans. These findings are consistent with other measures of avian spectral resolution. 关Work supported by NIH Grant DC-00198 to RJD.兴
3aABa8. Computer synthesis of bird songs and calls. Mark Kahrs
共Dept. of Elec. Eng., Univ. of Pittsburgh, 348 Benedum Hall, Pittsburgh,
PA 15261兲 and Federico Avanzini 共Universitá degli Studi di Padova,
35131 Padova, Italy兲
We describe the computer simulation of a one-mass source together
with a simple transmission line model for a psittacine bird. The syrinx is
modeled as a lumped mass subject to elastic restoring forces and internal
dissipation. Nonlinear interaction with the airflow follows the Ishizaka and
Flanagan glottal model. This is also used to model complete closure of the
syrinx: during closure an additional restoring force is added and dissipation is increased. During the whole closed phase the syringeal flow is zero,
and consequently its spectrum is broadened and higher partials are generated. The vocal tract transmission lines are implemented with fractional
delay lines and the transmission lines are assumed lossless. The beak is
implemented as two complementary fifth order Butterworth filters. The
pole trajectory for the filters approximates the nonlinear path of the beak
cutoff as discussed by Fletcher. 关M.K. was supported by the Fulbright
Foundation as well as Tekes. F.A. was funded by the Sound Source Modeling Project. Both authors were supported in part by the Academy of
3aABa9. Discrimination of dynamic moving ripples in the zebra finch,
Taeniopygia guttata. Michael S. Osmanski, Robert J. Dooling 共Dept. of
Psych., Univ. of Maryland, College Park, MD 20742兲, and Didier A.
Depireux 共Univ. of Maryland at Baltimore, Baltimore, MD兲
Auditory processing of complex broadband sounds known as moving
ripples has been studied both physiologically at the cortical level in mammals and psychophysically in humans 关Depireux et al. 共2001兲; Chi et al.
共1999兲兴. These stimuli share spectro-temporal properties with many natural sounds, including species-specific vocalizations and the formant transitions of human speech 关Versnel and Shamma 共1998兲兴. One test of the
generality of ripple processing beyond mammals would be to examine a
non-mammalian species. Zebra finches may be excellent subjects for such
143rd Meeting: Acoustical Society of America
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a study because they produce complex broadband harmonic songs and
neuronal responses in their auditory forebrain may be exquisitely tuned to
the specific spectro-temporal patterns of their songs 关Theunnissen and
Doupe 共1998兲兴. We trained these birds to discriminate between flatspectrum broadband noise and moving ripples of different densities that
move up or down in frequency at various rates. Results show that discrimination in zebra finches is better at those ripple densities and velocities which are prominent in their species-specific harmonic vocalizations.
关Work supported by NIH Grant No. DC-00198 to RJD and NIDCD Training Grant No. DC-00046.兴
LE BATEAU ROOM, 10:55 A.M. TO 12:15 P.M.
Session 3aABb
Animal Bioacoustics: General Topics in Animal Bioacoustics
Ann E. Bowles, Chair
Hubbs-Sea World Research Institute, 2595 Ingraham Street, San Diego, California 92109
Chair’s Introduction—10:55
3aABb1. Acoustical and functional analysis of Mountain lion „Puma
concolor… vocalizations. Jacquelyn Potter 共Dept. of Biological Sci.,
Western Illinois Univ., 1 University Circle, Macomb, IL 61455,
[email protected]兲
3aABb3. Extraction of directional pitch change by Japanese monkeys.
Tokuro Takahashi and Hiroshi Riquimaroux 共Dept. of Knowledge Eng. &
Computer Sci., Doshisha Univ., Kyotanabe, Kyoto 610-0321, Japan兲
A 2-year study resulted in acoustic analysis of the structure of over 900
mountain lion vocalizations recorded in a seminatural setting at Wildlife
Prairie Park near Peoria, Illinois. A vocal repertoire was obtained by describing quantitative variables about the sounds, i.e., frequency of the
dominant part of the sound 共beginning, ending, maximum, and minimum兲,
duration, and number of components. Other variables described the tonal,
harmonic, and wideband qualities of the sounds. Behavioral data were
collected during the same period. Further analysis of both acoustic and
behavioral data was completed to develop a correlation matrix between
vocalizations and behavior. This study also looked at the effects of seasons
on vocal behavior. Correlations were found between vocalization types
and rates of usage with specific behaviors. Vocalization type and the usage
rate also varied by season.
Perception of directional pitch change was behaviorally investigated in
Japanese monkeys on an operant Go–Nogo task with water reward. Results show that the difference in the fundamental frequency makes a difference in direction of pitch change. A pair of tone bursts and/or harmonically structured complex tone bursts were sequentially presented. The
monkeys could always discriminate the direction of pitch change by using
the fundamental frequency cue but in a specific case. Their performance
was worse than a chance level, or they oppositely responded to the fundamental frequency cue in the specific case. The case was that the temporal sequence was made of a simple tone burst and a complex tone burst
where the frequency of the simple tone burst was in between the fundamental and the second harmonic frequencies of the complex tone burst,
and the fundamentals of the complex tone were lower than 500 Hz. They
showed amelioration in using the fundamental frequency cue as interval
between two tones was expanded. The results were confirmed with probe
tests. 关Research supported by Special Coordination Funds, and a grant to
RCAST at Doshisha University from the Ministry of Education, Culture,
Sports, Science and Technology of Japan.兴
3a WED. AM
Contributed Papers
3aABb2. Acoustic correlates of human responses to domestic cat
„feliscatus… vocalizations. Nicholas Nicastro 共Dept. of Psych., Cornell
Univ., 243 Uris Hall, Ithaca, NY 14853兲
As part of ongoing research on coevolution of vocal communication
between humans and domestic cats, perceptual data were collected on
participants as they listened to recorded cat vocalizations. In experiment 1,
human subjects were asked to rate the pleasantness of 100 meows along a
7-point scale, from most to least pleasant. In experiment 2, a different
group of participants was asked to rate the urgency of the same meows
along a 7-point scale, from most to least urgent. Linear regression analysis
of the results showed a strong inverse correlation between pleasantness
and urgency. Acoustic correlates of pleasantness included reduced frequency modulation, a downward shift in fundamental frequency, and
fewer noisy segments. Correlates of urgency included increased duration,
higher Wiener entropy, and acute spectral tilt. It is speculated that humans’
affective responses to these acoustic qualities, in conjunction with contextual cues, may form the basis of the communication of more specific
meanings by cats to humans.
J. Acoust. Soc. Am., Vol. 111, No. 5, Pt. 2, May 2002
3aABb4. Sound duration as a perceptual cue influencing vocal
behavior of male bullfrogs. Andrea M. Simmons 共Dept. of Psych.,
Brown Univ., Providence, RI 02912, [email protected]兲
Female frogs of several species use the temporal cue of sound duration
to aid in mate choice. Little is known, however, about the sensitivity of
male frogs to this cue. Male bullfrogs emit a complex advertisement call
to attract females for mating, and to announce territory occupation to other
males. In two experiments, the sensitivity of vocalizing male bullfrogs to
field playbacks of advertisement calls differing in duration was examined.
The number and latency of evoked vocal responses to the stimuli was used
as a measure of perception. Males responded with fewer calls, at longer
latencies, to stimuli shorter in duration than the standard signal 共with a
duration at the mean value for the species兲. Males preferred stimuli longer
in duration than the standard signal, responding with more calls at shorter
latencies. They did not, however, significantly lengthen their own calls in
response to playbacks of long duration signals. This preference for ‘‘supernormal’’ stimuli may be an important factor mediating the evolution of
communication signals. 关Work supported by NIH.兴
143rd Meeting: Acoustical Society of America
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3aABb5. Acoustic communication by ants.
Robert Hickling
共Sonometrics, Inc., 8306 Huntington Rd., Huntington Woods, MI 48070兲
Many ant species communicate acoustically by stridulating, i.e., running a scraper over a washboard-like set of ridges. Ants appear to be
insensitive to airborne sound. Consequently, myrmecologists have concluded that the stridulatory signals are transmitted through the substrate.
This has tended to diminish the importance of acoustic communication,
and it is currently believed that ant communication is based almost exclusively on pheromones, with acoustic communication assigned an almost
nonexistent role. However, it can be shown that acoustic communication
between ants is effective only if the medium is air and not the substrate.
How, then, is it possible for ants to appear deaf to airborne sound and yet
communicate through the air? An explanation is provided in a paper 关R.
Hickling and R. L. Brown, ‘‘Analysis of acoustic communication by ants,’’
J. Acoust. Soc. Am. 108, 1920–1929 共2000兲兴. Ants are small relative to the
wavelengths they generate. Hence, they create a near field, which is characterized by a major increase in sound velocity 共particle velocity of sound兲
in the vicinity of the source. Hair sensilla on the ants’ antennae respond to
sound velocity. Thus, ants are able to detect near-field sound from other
ants and to exclude extraneous airborne sound.
RIVERS ROOM, 8:45 TO 11:00 A.M.
Session 3aMU
Musical Acoustics: General Topics in Musical Acoustics
Uwe J. Hansen, Chair
Department of Physics, Indiana State University, Terre Haute, Indiana 47809
Contributed Papers
3aMU1. The effect of inharmonic partials on pitch of piano tones.
Brian E. Anderson 共Dept. of Phys., Brigham Young Univ., Provo, UT
84602, [email protected]兲
Piano tones have partials whose frequencies are sharp relative to harmonic values. A listening test was conducted to determine the effect of
inharmonicity on pitch for piano tones in the lowest three octaves of a
piano. Nine real tones from the lowest three octaves of a piano were
analyzed to obtain frequencies and amplitude of their partials. Synthetic
inharmonic tones were produced from these results. Synthetic harmonic
tones, each with a twelfth of a semitone increase in the fundamental, were
also produced. A jury of 10 listeners matched each synthetic inharmonic
tone to one of the synthetic harmonic tones. The effect of the inharmonicity on pitch was determined from an average of the listeners’ results. For
the nine piano tones studied, inharmonicity increased pitch from a twelfth
of a semitone to nearly a semitone.
3aMU2. Prosodic persistence in music performance and speech
production. Melissa K. Jungers, Caroline Palmer 共Dept. of Psych., Ohio
State Univ., 1885 Neil Ave., Columbus, OH 43210, [email protected]兲,
and Shari R. Speer 共Ohio State Univ., Columbus, OH 43210兲
Does the rate of melodies that listeners hear affect the rate of their
performed melodies? Skilled adult pianists performed two short melodies
as a measure of their preferred performance rate. Next they heard, on each
trial, a computer-generated performance of a prime melody at a slow or
fast rate 共600 or 300 ms per quarter-note beat兲. Following each prime
melody, the pianists performed a target melody from notation. The prime
and target melodies were matched for meter and length. The rate of pianists’ target melody performances was slower for performances that followed a slow prime than a fast prime, indicating that pianists’ performances were influenced by the rate of the prime melody. Performance
duration was predicted by a model that includes prime and preferred du2394
J. Acoust. Soc. Am., Vol. 111, No. 5, Pt. 2, May 2002
rations. Findings from an analogous speech production experiment show
that a similar model predicts speakers’ sentence rate from preferred and
prime sentence rates. 关Work supported by NIMH Grant 45764 and the
Center for Cognitive Science.兴
3aMU3. Sound of a cup with and without instant coffee. Andrew
Morrison and Thomas D. Rossing 共Phys. Dept., Northern Illinois Univ.,
DeKalb, IL 60115兲
An empty coffee cup, like an ancient Chinese two-tone bell, emits two
distinctly different tones, depending upon where it is tapped. When it is
filled with hot water, and some instant coffee is added, however, a whole
new set of sounds is heard when the cup is tapped. The pitch rises an
octave or more as the foam clears due to the dramatic change in the speed
of sound in the bubble-filled liquid. A similar, but smaller, effect was noted
in beer by Bragg 关The World of Sound 共1968兲兴 and in hot chocolate by
Crawford 关Am. J. Phys. 共1982兲兴. We describe the modes of vibration in a
coffee cup and the sound emitted by a coffee cup as filled with instant
coffee as the bubble density changes.
3aMU4. Computer-animated illustrations of vibrations and waves.
W. Bruce Richards 共Oberlin College, Oberlin, OH 44074兲
Undergraduate students in a general-education course on musical
acoustics often have difficulty understanding the actual time-domain motions of vibrating systems which textbooks can only depict using static
diagrams. In particular, students have difficulty relating the longitudinal
average displacements of gas molecules in acoustic waves to 共transverse兲
graphs of these displacements as a function of position. To better convey
these ideas, a number of animated graphic diagrams have been programmed on a Macintosh computer. For longitudinal waves, these include
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one-dimensional standing waves in cylindrical pipes with open or closed
ends, various pulse waves reflecting from the open or closed end of a
cylindrical pipe, and standing waves in a conical pipe with an open end. In
addition, the transverse motions of bowed, plucked, and hammered strings
have been programmed. Presented in every case is an exaggerated, slow
motion picture of the system’s displacement as it evolves in time. If desired, an adjacent coordinated and animated graph of displacement, pressure, or other dynamical variable may also be displayed. As part of this
paper the computer programs will be demonstrated.
shape is revealed. It differs significantly from a sinusoid in the vicinity of
either end of the wire because the ends are clamped and the wire has
significant stiffness. The shapes of various harmonics have been determined for a brass harpsichord wire, 70 cm long, from optical detector
measurements made at different distances from a clamped end. Knowledge of shape facilitates the determination of antinode amplitudes of harmonics when the gross motion of the wire is so large that the detectors
must be positioned near an end of the wire because of their very limited
dynamic range. Some observations of harmonics and related phenomena
were reported previously 关Hanson et al., J. Acoust Soc. Am. 108, 2592
共2000兲; 106, 2141 共1999兲兴. The shape information is also needed to help
separate nonlinear effects possibly occurring in the detectors from those of
interest, occurring in the wire itself.
3aMU5. Drumhead contact time measurement using metallic leaf.
José Sánchez and James Irwin, Jr. 共Dept. of Elec. & Computer Eng., 1501
W. Bradley Ave., Bradley Univ., Peoria, IL 61625, [email protected]兲
3aMU8. Regimes of oscillation and reed vibrations in lingual organ
pipes. Eric Cox and Thomas D. Rossing 共Phys. Dept., Northern Illinois
Univ., DeKalb, IL 60115兲
We compare the sound generation in six lingual organ pipes including
two trompette pipes, two oboes pipes, a krummhorn, and a rankett, the
latter two of which were described in a previous paper 关Cox and Rossing,
paper 2aMU8, 142nd ASA meeting兴. With the resonator attached, each
pipe sounds in distinct regimes of oscillation, separated by discontinuities.
The nominal frequencies of the pipes are generally slightly lower than the
resonance frequency of the resonator but slightly higher than the natural
frequency of the reed. The air mass loading of both the resonator and
shallot lowers the reed frequency. Changing the blowing pressure has little
effect on the sounding frequency but a modest effect on sound level.
3aMU6. Mode studies in triangular bellplates. Uwe J. Hansen 共Dept.
of Phys., Indiana State Univ., Terre Haute, IN 47803兲, Daniel Lavan, and
Suzanne Hogg 共Tech. Univ., Sydney, Australia兲
Preliminary results from mode studies in triangular aluminum bellplates using electronic holographic interferometry were reported at the
136th ASA meeting 关Uwe J. Hansen, J. Acoust. Soc. Am. 104, 1767共A兲
共1998兲兴. Since then the TU Sydney co-authors of this paper have performed finite element calculations with results which are remarkably congruent with the holographic data. The first 13 modes will be discussed and
shown in holographic as well as FEM representation.
3aMU7. Shape of a clamped stiff harpsichord wire driven at a
resonant frequency. Roger J. Hanson, Hilliard Kent Macomber, and
Mathew A. Boucher 共Dept. of Phys., Univ. of Northern Iowa, Cedar Falls,
IA 50614, [email protected]兲
A wire transversely driven by a sinusoidal force at the resonant frequency of a vibrational mode vibrates at the driving frequency and at
harmonics generated by nonlinear processes in the wire. If the amplitude
of a harmonic is measured as a function of position along the wire, its
J. Acoust. Soc. Am., Vol. 111, No. 5, Pt. 2, May 2002
3a WED. AM
This work investigates the relationship between mass, diameter, impact location, and energy of steel balls impacting upon the surface of the
drumhead, and the time they remain in contact. The contact time is measured by making the ball and metallic leaf contacts in an electrical switch.
The leaf was applied to the drumhead surface and connected to the circuit
through a wire. The balls were connected to the circuit using a solderattached hair-fine wire. Contact time was measured at a constant drumhead
tension at three distinct locations on the drumhead: the center, halfway
between the center and the rim, and an inch from the rim. In addition, a
single series was measured from the center to the rim at 2-in. intervals.
Initial work indicates that the contact time is not dependent upon energy,
impact location, or diameter, but only upon the mass of the steel ball. The
relationship of the mass-dependent contact time to energy transfer and to
impact spectra is developed, showing mass is the determining parameter
needed for the initial conditions used to simulate drumstick/drumhead interaction 共impact effects兲.
3aMU9. Acoustic analysis of an Olmecan whistle. Sergio Beristain
共President IMA, Lab. Acoust., Faculty of Elec. and Mech. Eng., Natl.
Polytechnic Inst., P.O. Box 75805, 07300 Mexico City, Mexico兲, Rolando
Menchaca 共ESCOM, IPN兲, and Roberto Velazquez 共CIC, IPN兲
Thousands of stone artifacts over 2500 years of age have been found in
the Olmecan area in the southeast region of Mexico. These range from the
famous big heads with helmets 共about 2 m in diameter兲, to small pieces
with precisely drilled holes, which some archaeologists consider to have
some simple uses, much simpler than the work needed to produce the
stone artifact itself. The one studied here 共about 3 cm in size兲, is considered by the acoustics community as an air-phone, and a detailed anaysis
has been done employing FFT techniques in order to find out the frequency spread, the particular tones produced and the sound radiated power
through the different holes and cavities. The artifact is made of a very
solid stone, so-called ilmenite, believed to have titanium, which is very
hard to drill. Nevertheless, many similar pieces have been found in the
area, which means they were built on purpose, and the material used gives
the idea of a sacred application. Attempts have been made to reproduce the
artifacts, which produce sounds similar to those from the original pieces.
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DUQUESNE ROOM, 8:00 TO 11:35 A.M.
Session 3aNS
Noise, Speech Communication and Animal Bioacoustics: Public Policy for Noise
Lawrence S. Finegold, Chair
Finegold & So, Consultants, 1167 Bournemouth Court, Centerville, Ohio 45459
Invited Papers
3aNS1. Public policy and the ASA. E. J. Walsh 共Boys Town Natl. Res. Hospital, Omaha, NE 68131兲
At the Ft. Lauderdale meeting of the Acoustical Society of America, the President of the Society authorized the formation of an
ad hoc public policy committee to be named the Panel on Public Policy 共PoPP兲. The Panel’s mission is to serve the public interest by
addressing and commenting on societal issues that fall within the broad range of disciplines that define the scope of the Society. The
Panel’s goal is to guide the development of ASA policies on, and responses to, questions that arise in relation to those issues. The
operational plan calls for the Panel to execute its responsibility by generating and releasing Executive Council mandated and approved
position statements, reports, or results of in-depth studies on issues affecting public health and welfare for use by appropriate
legislative and policy-making entities. The structure, composition, and operational plan of the Panel will be discussed in general terms
and specific prospective projects will be summarized.
3aNS2. Rationale for noise regulation: How we got here and why we may not stay. Sanford Fidell 共Fidell Assoc., Inc., 23139
Erwin St., Woodland Hills, CA 91367兲
Today’s framework of environmental noise regulation in the United States is the product of a half century’s evolution in understandings of noise effects, and in societal interest and policy interpretations of them. Although it is tempting to associate the evolution
of noise policy with rational adaptations to developments in scientific understanding, this is a myopic and ultimately untenable view.
It is hardly surprising that little of practical utility for regulatory purposes has come from decades of research in this area, considering
the unsystematic and atheoretical nature of much of what has been learned about individual and community response to noise. Today’s
annoyance-based rationale for regulatory policy is only one of several historical perspectives, and not necessarily the most useful of
them. Further changes in the rationale for assessing noise impacts may be expected as court rulings increasingly challenge reliance
upon long-term exposure metrics as predictors of noise effects; as the magnitude of non-acoustic contributions to annoyance becomes
clearer; and as the information that the U.S. Federal Interagency Committee on Noise last reviewed a decade ago becomes more and
more stale.
3aNS3. National policy on the effects of underwater noise on marine mammals and turtles. Roger L. Gentry 共NOAA, Natl.
Marine Fisheries Service, Silver Spring, MD 20910兲
Marine anthropogenic noise is increasing at an unknown rate yet its effects on mammals and turtles are poorly documented. Such
information is central to noise standards for marine animals required by two federal laws 共MMPA and ESA兲. Good policy on
underwater noise would set standards that are neither too liberal 共thereby threatening the well being of marine animals兲, nor too
conservative 共thereby unnecessarily impairing essential human activities at sea兲. This balance must be found using existing data;
standards cannot await new research. Policy must also lay out rules governing the introduction of novel underwater sound sources
whose effects on animals are unknown. Should policy forbid such introductions until all possible consequences are known, or does a
safe, incremental method of introduction exist? Should exceptions be made for novel sources associated with national defense? Policy
must cope with sound sources that are outside the reach of U.S. federal regulations, such as international shipping. Finally, policy must
frame the questions about underwater noise in a way that research can answer. Specifically, how much noise exists, how fast is it
growing, where is it, and what consequences does it have for animals and their ecosystems?
3aNS4. Determination of background sound level for use with Massachusetts community sound level criteria. Gregory Tocci
共Cavanaugh Tocci Assoc., Inc., 327F Boston Post Rd., Sudbury, MA 01776兲
In the early 1970s, the Commonwealth of Massachusetts began the use of their community sound level criteria. In 1990, these
criteria were formalized as Policy 90-001. The policy states that: A source of sound will be considered to be violating the Department’s noise regulation 共310 CMR 7.10兲 if the source increases the broadband sound level by more than 10 dB共A兲 above the ambient.
Ambient is defined as the background A-weighted sound level that is exceeded 90% of the time measured during equipment operating
hours. The Policy also address tonal sound, and this will be described, but the primary concern of this presentation is the measurement
of background sound. A number of background sound measurement strategies will be discussed and a recommendation made on how
background should be measured and analyzed that is easily understood by regulators, developers, and the community.
J. Acoust. Soc. Am., Vol. 111, No. 5, Pt. 2, May 2002
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3aNS5. Noise regulations that serve the community. James D. Barnes 共Acentech, Inc., 33 Moulton St., Cambridge, MA 02138兲
State and local governments have adopted a variety of regulations over the past 40 years to protect the public against unreasonable
noise. These regulations, which may be be qualitative in nature, may prohibit particular activities 共e.g., barking dogs or loud radios兲
or outlaw nuisance noise in general 共e.g., sounds disturbing to a resident兲. In addition, these regulations may be quantitative and define
specific sound limits for a source at property line or community locations. The quantitative approach may typically include absolute
limits that account for many factors, such as the time of day or week, the type of source and receptor, and the character of the sound;
or in the case of Massachusetts, may include relative limits that account for the ambient background sound levels. A significant
increase in community sound levels that is caused by a source is a useful indicator of a potential noise problem, but should this factor
be considered when setting regulatory limits for individual projects? The presentation shall explore this issue and its effect on the
process of siting, permitting, designing, and operating industrial facilities.
3aNS6. The need to revitalize our national noise policy. William W. Lang 共29 Hornbeck Ridge, Poughkeepsie, NY 12603,
[email protected]兲 and Leo L. Beranek 共Cambridge, MA 02138兲
3a WED. AM
At the present time, our Nation does not have a national noise policy. The Congress attempted to define one with the passage of
the Noise Control Act of 1972 as follows: The Congress declares that it is the policy of the United States to promote an environment
for all Americans free from noise that jeopardizes their health and welfare. The Act assigned to the Environmental Protection Agency
共EPA兲 the role of leading Federal agency with the task of coordinating the programs of all Federal agencies relating to noise research
and noise control. Ten years later 共1982兲, all funds for noise control were withdrawn from the EPA, and today the Nation is without
an effective, overall noise policy. Residual responsibility for the control of environmental and occupational noise currently rests with
a dozen agencies of the Federal government, as well as State, municipal, and local authorities. But the activities of these organizations
are largely uncoordinated, and the enforcement of existing noise control regulations is at best sporadic, and in some cases nonexistent.
To assure our quality of life and to minimize the economic impact of potential trade barriers, a study team is recommending that a
national noise policy be developed and then implemented in the immediate future.
3aNS7. Revisiting the NIOSH Criteria for a Recommended Standard: Occupational Noise Exposure. William J. Murphy and
John R. Franks 共Natl. Inst. for Occupational Safety and Health, Hearing Loss Prevention Section, 4676 Columbia Pkwy., M.S. C-27,
Cincinnati, OH 45226-1998, [email protected]兲
In 1998, the National Institute for Occupational Safety and Health 共NIOSH兲 revised the Criteria for a Recommended Standard:
Occupational Noise Exposure 关DHHS 共NIOSH兲 Publication No. 98-126兴. NIOSH reevaluated the recommended exposure limit 共REL兲
for occupational noise exposure and reaffirms support for 85-dBA REL. Based upon scientific evidence, NIOSH recommends a 3-dB
exchange rate. NIOSH recommends that significant threshold shift be identified as an increase of 15 dB in the hearing threshold level
at 500, 1000, 2000, 3000, 4000, or 6000 Hz in either ear, with two consecutive audiometric tests. The new criterion has the advantages
of a high identification rate and a low false-positive rate. In contrast with the former 1972 criterion, NIOSH no longer recommends
age correction on individual audiograms. NIOSH has revisited its recommendations on the using of single-number laboratory-derived
Noise Reduction Rating 共NRR兲 required by the U.S. Environmental Protection Agency for labeling of hearing protectors sold within
the United States. In 1972, NIOSH recommended the use of the full NRR value; however, the new criterion recommends derating the
NRR by 25%, 50%, and 70% for earmuffs, formable earplugs, and all other earplugs, respectively. This presentation will compare and
contrast current regulations against the NIOSH recommendations.
3aNS8. Benefits and disadvantages of self-regulation of environmental noise from military training. George A. Luz 共U.S. Army
Ctr. for Health Promotion and Preventive Medicine, 5158 Blackhawk Rd., Aberdeen Proving Ground, MD 21010-5403兲
In a 1981 Executive decision, the Administration’s Office of Management and Budget 共OMB兲 told the Environmental Protection
Agency to end funding of the Office of Noise Abatement and Control 共ONAC兲. This decision, coupled with a specific exemption for
military equipment contained in the Noise Control Act of 1972, ensured that the military departments would be self-regulating in
regard to noise. This self-regulation for noise stands in contrast to the external regulation of other pollutants, such as air and water
emissions. Two possible disadvantages of self-regulation are 共1兲 reduced funding for noise management compared with funding for
externally regulated pollutants, and 共2兲 lack of an independent and external set of standards for determining acceptable limits on
community noise exposure. Three possible benefits are 共1兲 avoiding the costs of mitigating trivial violations of external standards, 共2兲
maintaining a long-standing policy of preventing noise problems through land use planning, and 共3兲 enabling negotiated solutions
between installations and their neighboring communities. The paper ends with an examination of a negotiated solution for a community subjected to noise from the detonation of obsolete ammunition.
J. Acoust. Soc. Am., Vol. 111, No. 5, Pt. 2, May 2002
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3aNS9. Public policy issues in animal bioacoustics. Ann E. Bowles 共Hubbs-Sea World Res. Inst., 2595 Ingraham St., San Diego,
CA 92109兲 and Mardi C. Hastings 共Biomed. Eng. Ctr., Ohio State Univ., 1080 Carmack Rd., Columbus, OH 43210兲
Control of anthropogenic noise in many terrestrial and underwater environments is crucial for maintaining communication, health,
and normal behavior of animals. Noise can be an issue for any species; usually, however, endangered and threatened species and
marine mammals are the ones provided legal protection under the Endangered Species Act and/or the Marine Mammal Protection Act.
Recent substantiated noise effects in the ocean have received much publicity and generated a more global approach to noise control.
However, there are also cases where publicity was not accompanied by scientific data substantiating effects 共e.g., an incident involving
a $1 million noise barrier installed to protect passerine birds兲. The public and environmental managers have had difficulty developing
adequate guidelines not only because necessary data are often lacking, but also because the manner in which funding is allocated—
noise-producing agencies or private organizations are often pressured to fund studies—gives rise to inevitable conflicts of interest 共or
the perception thereof兲. Examples of recent noise-related controversies will be presented to examine the role of scientists, engineers,
and professional organizations such as ASA in dealing with conflicts of interest and formulating public policy.
3aNS10. Community-based environmental noise management. Lawrence S. Finegold
Bournemouth Ct., Centerville, OH 45459, [email protected]兲
共Finegold & So, Consultants, 1167
After a series of major successes in implementing national environmental noise policies from the 1960s to the 1980s, the U.S. has
not kept up with improvements in environmental noise policies seen in other areas of the world, most notably in Europe during the
past decade. The cessation of funding for the EPA Office of Noise Abatement and Control 共ONAC兲 in 1981 was a defining point in
the history of U.S. environmental noise policy, leading to a virtual stoppage of the development of new noise regulations. The Noise
Control Act 共NCA兲 of 1972, which established EPA ONAC, was never rescinded after ONAC funding was abolished, but it is not
being implemented either. Thus national noise policies are generally not being enforced, except for aircraft certification regulations,
and help for state and local efforts is inadequate. In this paper we describe an evolving concept, community-based environmental noise
management, to provide practical guidance to local communities in developing noise management strategies. This concept includes
components such as local noise ordinances, coordination with State and Federal agencies, incentive and cost-sharing programs, land
use planning, an updated environmental impact analysis process, and a negotiation and dispute resolution process. Each of these will
be briefly discussed.
STERLINGS ROOMS 2 AND 3, 8:00 TO 10:00 A.M.
Session 3aPA
Physical Acoustics: Surface Waves and Ultrasound Spectroscopy
Joseph R. Gladden, Cochair
Physics Department, Pennsylvania State University, 104 Davey Laboratory, University Park, Pennsylvania 16802
Ralph T. Muehleisen, Cochair
Civil, Environmental and Architectural Engineering, University of Colorado, 428 UCB, 441 Ecot,
Boulder, Colorado 80309-0428
Contributed Papers
3aPA1. Acoustically excited surface waves on empty or fluid-filled
cylindrical and spherical shells. A. Claude Ahyi, H. Cao, P. K. Raju
共Dept. of Mech. Eng., Auburn Univ., Auburn, AL 36849-5341兲, M. F.
Werby 共Dept. of Phys., Catholic Univ. of America, Washington, DC
20064-1 and NRL Code 7180, Stennis Space Center, MS 39529兲, X. L.
Bao, and H. Überall 共Dept. of Phys., Catholic Univ. of America,
Washington, DC 20064-1兲
A comparative study is presented of the acoustical excitation of circumferential 共surface兲 waves on fluid-immersed cylindrical or spherical
metal shells, which may be either evacuated, or filled with the same or a
different fluid. The excited surface waves can manifest themselves by the
resonances apparent in the sound scattering amplitude, which they cause
upon phase matching following repeated circumnavigations of the target
object, or by their re-radiation into the external fluid in the manner of head
waves. We plot dispersion curves versus frequency of the surface waves,
which for evacuated shells have a generally rising character, while the
fluid filling adds an additional set of circumferential waves that descend
J. Acoust. Soc. Am., Vol. 111, No. 5, Pt. 2, May 2002
with frequency. The resonances of these latter waves may also be interpreted as being due to phase matching, but they may alternately be interpreted as constituting the eigenfrequencies of the internal fluid contained
in an elastic enclosure.
3aPA2. Acoustic resonances of fluid-immersed elastic cylinders and
spheroids: Theory and experiment. Jan Niemiec 共Naval Surface
Warfare Ctr., Carderock Div., West Bethesda, MD 20817-5700兲, Herbert
Überall, and X. L. Bao 共Catholic Univ. of America, Washington, DC
Frequency resonances in the scattering of acoustic waves from a target
object are caused by the phase matching of surface waves repeatedly encircling the object. This is exemplified here by considering elastic finite
cylinders and spheroids, and the phase-matching condition provides a
means of calculating the complex resonance frequencies of such objects.
Tank experiments carried out at Catholic University, or at the University
of Le Havre, France by G. Maze and J. Ripoche, have been interpreted
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using this approach. The experiments employed sound pulses to measure
arrival times, which allowed identification of the surface paths taken by
the surface waves, thus giving rise to resonances in the scattering amplitude. A calculation of the resonance frequencies using the T-matrix approach showed satisfactory agreement with the experimental resonance
frequencies that were either measured directly 共as at Le Havre兲, or that
were obtained by the interpretation of measured arrival times 共at Catholic
University兲 using calculated surface wave paths, and the extraction of
resonance frequencies therefrom, on the basis of the phase-matching condition. Results for hemispherically endcapped, evacuated steel cylinders
obtained in a lake experiment carried out by the NSWC were interpreted
in the same fashion.
3aPA3. Experimental study of the A-wave axial propagation inside a
fluid filled cylindrical shell: Application to Gelification process
monitoring by surface acoustic wave. Loic Martinez, Brahim Senouci,
Stephane Serfati 共Laboratoire d’Electronique Applique de Cergy
Pontoise, Universite de Cergy Pontoise, 5 mail Gay-Lussac, F 95 031
Neuville sur Oise Cedex, France兲, Marcel Gindre, Jean-Yves Le Huerou
共Laboratoire dImagerie Parametrique, 75270 Paris Cedex 06, France兲, and
Pascal Griesmar 共Laboratoire de Chimie des Materiaux Inorganiques, 95
031 Neuville sur Oise Cedex, France兲
3aPA5. Diffraction correction for precision SAW velocity
measurements. Alberto Ruiz M. and Peter B. Nagy 共Dept. of Aerosp.
Eng. and Eng. Mech., Univ. of Cincinnati, Cincinnati, OH 45221-0070,
[email protected]兲
Surface acoustic wave 共SAW兲 dispersion measurements can be used to
nondestructively characterize shot-peened, laser shock-peened, and other
surface-treated specimens. In recent years, there have been numerous efforts to separate the contribution of surface roughness from those of nearsurface material variations, such as residual stress, texture, and increased
dislocation density. This talk addresses the problem that a perceivable
dispersive effect, similar to the one found on rough shot-peened specimens, is exhibited by untreated smooth surfaces as well. The dispersion
measurements were performed using laser-ultrasonic scanning combined
with special digital signal-processing methods. The observed dispersion
effect is on the order of 0.1%, which is comparable to the expected velocity change produced by near-surface compressive residual stresses in metals below their yield strength. The cause of this apparent dispersion is the
diffraction of the SAW as it travels over the surface of the specimen. It is
demonstrated that a diffraction correction may be introduced to increase
the accuracy of surface wave dispersion measurements. A simple diffraction correction model was developed for surface waves; this correction
was subsequently validated by laser-interferometric surface wave velocity
measurements on 2024-T351 aluminum specimens.
3aPA4. Differential surface acoustic wave IDT gyroscope. Jose K.A,
Anshu Mehta, and Vijay K. Varadan 共212 EES Bldg., Penn State Univ.,
University Park, PA 16802兲
This paper presents the design and experimental evaluation of a gyroscope based on differential design of a surface acoustic wave 共SAW兲 resonator and a sensor on a piezoelectric substrate. The resonator is divided
into two halves, one with metallic dot arrays and other without any metallic dots. Standing waves are formed inside both cavities. The particles at
the antinodes of the standing wave pattern experience large amplitude of
vibration that serves as the reference vibrating motion for this gyroscope.
The metallic dots strategically positioned at the antinode locations experience Coriolis force due to rotation and acoustically amplify the magnitude in the orthogonal direction. However, the other half of the resonator
cannot generate any secondary SAW. A wideband SAW sensor arranged
orthogonal to the SAW resonator picks up these two secondary SAWs and
is fed to a differential amplifier. Any drift in the gyroscope signal can be
completely eliminated by this novel design. The performance of this 74.2MHz gyroscope shows very high sensitivity and dynamic range, which is
ideal for many commercial applications. Unlike other MEMS gyroscopes,
this gyroscope has a planar configuration with no suspended resonating
mechanical structures, thereby being inherently robust and shock resistant.
J. Acoust. Soc. Am., Vol. 111, No. 5, Pt. 2, May 2002
3aPA6. Thin film characterization using resonant ultrasound
spectroscopy. J. R. Gladden, Jin H. So, Rajdeep Pradhan, and J. D.
Maynard 共Dept. of Phys., Penn State Univ., University Park, PA 16803,
[email protected]兲
With mechanical and electrical components approaching nanoscale dimensions, there is great interest in the properties of thin films. Some
properties, such as structure and phase transitions, can be probed with
measurements of elastic constants. We have been using Resonant Ultrasound Spectroscopy 共RUS兲 to probe such properties for a variety of thin
film materials including colossal magnetoresistance 共CMR兲 materials, carbon nanotubes, and a magnetic semiconducting film on GaAs. By accurately characterizing the substrate, the elastic constants and damping of a
deposited film can be determined from changes in the frequency and quality factor (Q) of the sample resonances. Issues of precision and accuracy
in RUS measurements are important for application to thin films. If one is
interested in relative changes in properties 共e.g., resulting from temperature variations, phase transitions, etc.兲, the precision from sharp resonances (Q⬎5,000) is more than adequate. However, since a film may
occupy only 1/1000 of the sample, attaining high accuracy is challenging,
as uncertainty in sample dimensions and crystallographic orientation can
have severe effects on results. Temperature data for the magnetic films
mentioned and attenuation of carbon nanotube films will be presented.
关Work supported by ONR.兴
3a WED. AM
During gel formation, the material passes from the liquid state to the
solidlike state. In order to characterize this liquid-to-solid transition, the
low-frequency fluid-born plate mode A-wave is used. The A-wave has
interesting properties to be nonattenuated—very dispersive at lowfrequency thickness products 共fd兲, and nondispersive for high fd 共the
Scholte wave is the high fd limit兲. The axial propagation of the A-wave is
studied along a glass cylindrical shell in the mid to high fd range 共0.5
MHz mm—1.5 MHz mm兲. The A-wave is generated and received at one
extremity of the tube by a contact broadband transducer excited by a
pulse. In the calibration test, the cylindrical shell is filled with water and
surrounded by air outside. The A-wave dispersion curve is extracted by
short time Fourier transform; comparison with the theoretical dispersion
curves is very good. For the gelification monitoring, the water is replaced
by the gel in its liquid state. A-wave time signals are recorded during the
gelification process. The evolution of the longitudinal speed during the
gelification time is deduced from the A-wave dispersion curves.
3aPA7. Effect of hydrochloric acid on sound absorption and
relaxation frequency in magnesium sulfate solutions. F. H. Fisher
共Marine Physical Lab., Scripps Inst. of Oceanogr., UCSD, La Jolla, CA
The epic work of Kurtze and Tamm on sound absorption spectroscopy
in divalent sulfate electrolyte solutions 共1953兲 from the low-kHz region up
to over 200 MHz revealed astonishing variability at frequencies below 10
MHz and a common relaxation frequency at about 200 MHz. For magnesium sulfate 关Epsom salts兴 solutions, the salt producing 30⫻ the absorption of fresh water below the 100-kHz region in the oceans at low concentrations 关 ⬃0.02 moles/liter兴, Kurtze and Tamm investigated the effects
of adding HC1 or H2 SO4 . They found that as formal pH increased, the
results were different for these acids in reducing the sound absorption.
Fisher 共1983兲 found that if the absorption was plotted against free hydrogen, ion concentration was the same. We used the 100-liter titanium
sphere, a spare ballast tank from the WHOI submarine ALVIN. With precise
143rd Meeting: Acoustical Society of America
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temperature control, we found an increase in the relaxation frequency as
HC1 was added in conjunction with the reduction in sound absorption.
The results will be presented and an explanation will be proposed in the
context of the Eigen and Tamm multistate dissociation model for MgSO4
共1962兲 which explains the effects of pressure on both absorption and conductance. 关Work supported by ONR.兴 The author acknowledges C. C. Hsu
for his work on this project.
results from lattice mismatch with the substrate alters the behavior of the
material. As for CMR materials in bulk form, there should be a correlation
between the CMR behavior and the structural and elastic properties of the
strained thin films. Measurements of the elastic properties of thin films are
obtained using a novel small sample resonant ultrasound spectroscopy
共RUS兲 technique. Thin films of the magnetic material are deposited on a
substrate and the difference in natural frequencies are then used to obtain
the elastic constants of the film. The dominant CMR materials are perovskite manganites, a transition metal oxide. They exhibit a variety of exotic
structural, magnetic and electrical behaviors, which is yet to be understood. In this paper measurements of the electrical resistance and elastic
constants of 200 and 400 nm thin films, as well as unstrained samples, of
the CMR material La共0.7兲Ca共0.3兲MnO3 are presented. 关Work supported by
3aPA8. Using resonance ultrasound spectroscopy to study colossal
magnetoresistance in thin films. Rajdeep Pradhan, Jin H. So, J. R.
Gladden, and J. D. Maynard 共Dept. of Phys., Penn State Univ., University
Park, PA 16803, [email protected]兲
Materials displaying colossal magnetoresistance 共CMR兲 are candidates
for important applications such as high density data storage. When the
CMR material is in the form of a thin film on a substrate, the strain which
GRAND BALLROOM 4, 8:15 TO 11:50 A.M.
Session 3aPP
Psychological and Physiological Acoustics and Speech Communication:
Honoring the Contributions of Ira J. Hirsh
Janet M. Weisenberger, Cochair
College of Social and Behavioral Science, The Ohio State University, 1010 Derby Hall, 154 North Oval Mall,
Columbus, Ohio 43210
Judith L. Lauter, Cochair
Department of Human Services, Stephen F. Austin University, P.O. Box 13019, SFA Station, Nacogdoches, Texas 75962
Invited Papers
3aPP1. Ira at 80: The acronyms of a career in acoustics. Janet M. Weisenberger 共Speech and Hearing Sci., Ohio State Univ.,
Columbus, OH 43210, jan⫹@osu.edu兲
In a career that spans some 54 years to date, the name of Ira J. Hirsh has been associated with significant scientific contributions
to psychoacoustics, outstanding mentoring of research scientists, and dedicated service to the fields of acoustics, audiology, and
psychology. It is a career that can be traced by acronyms that are part of the daily vocabulary of hearing scientists. These include
acronyms of location: Early work at the Psychoacoustics Laboratory at Harvard 共PAL兲, a long tenure in research at the Central
Institute for the Deaf 共CID兲, service as faculty member, chair, and dean at Washington University 共WashU兲; acronyms of professional
societies that have honored him: Acoustical Society of America 共ASA兲, International Commission of Acoustics 共ICA兲, American
Psychological Association 共APA兲, American Psychological Society 共APS兲, American Speech-Language-Hearing Association 共ASHA兲,
American Association for the Advancement of Science 共AAAS兲; acronyms of his service to the National Academy of Science:
National Research Council 共NRC兲, Commission on Behavioral and Social Science and Education 共CBASSE兲; and acronyms of his
contributions to psychoacoustics: Masking Level Difference 共MLD兲, Temporal Order Judgments 共TOJ兲. In large part, these acronyms
are part of our vocabulary because of Ira’s contributions, and tracing them over the past half-century yields a substantive look at the
development of the field of hearing science.
3aPP2. Events, sequences, and patterns: Hirsh’s prescient proposals. Charles S. Watson 共Dept. of Speech and Hearing Sci.,
Indiana Univ., Bloomington, IN 47405, [email protected]兲
Over four decades ago, Ira Hirsh was one of the first to recognize the need for auditory research to expand beyond the study of
single tones, noise burst, and clicks. He wrote, ‘‘We propose to examine auditory perception at a more complex level. The discrimination among and identification of single sounds, which we shall refer to as acoustic events, is undoubtedly an important part of the
perceptual process, but perhaps more important are the rules by which we distinguish and identify sequences of acoustic events.
Auditory psychophysics has been concerned with the acoustic characteristics of the sequence parts, the events; but we need to know
more about the ways in which the parts combine to form patterns which, since they are generated in time, we may call sequences’’ 关J.
J. Acoust. Soc. Am., Vol. 111, No. 5, Pt. 2, May 2002
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Acoust. Soc. Am. 31 共1959兲兴. This must be one of the more prescient proposals of that era, followed as it was not only by Hirsh’s
series of studies of temporal processing, but by a raft of other adventures into the world he forecast, including research on a great
variety of auditory patterns and sequences. Theoretical interpretations of that work and of the general problem areas that Hirsh
pioneered will be discussed.
3aPP3. It’s about time: Presentation in honor of Ira Hirsh. Ken Grant 共Walter Reed Army Medical Ctr., Army Audiol. and
Speech Ctr., Washington, DC 20307-5001兲
Over his long and illustrious career, Ira Hirsh has returned time and time again to his interest in the temporal aspects of pattern
perception. Although Hirsh has studied and published articles and books pertaining to many aspects of the auditory system, such as
sound conduction in the ear, cochlear mechanics, masking, auditory localization, psychoacoustic behavior in animals, speech perception, medical and audiological applications, coupling between psychophysics and physiology, and ecological acoustics, it is his work
on auditory timing of simple and complex rhythmic patterns, the backbone of speech and music, that are at the heart of his more recent
work. Here, we will focus on several aspects of temporal processing of simple and complex signals, both within and across sensory
systems. Data will be reviewed on temporal order judgments of simple tones, and simultaneity judgments and intelligibility of
unimodal and bimodal complex stimuli where stimulus components are presented either synchronously or asynchronously. Differences
in the symmetry and shape of ‘‘temporal windows’’ derived from these data sets will be highlighted.
3aPP4. The times of Ira Hirsh. Pierre L. Divenyi 共Speech and Hearing Res., VA Medical Ctr., Martinez, CA 94553兲
3a WED. AM
Ira Hirsh was among the first to recognize that the auditory system does not deal with temporal information in a unitary way across
the continuum of time intervals involved in speech processing. He identified the ‘‘short’’ range 共extending from 1 to 20 ms兲 as that of
phase perception, the ‘‘medium’’ range between 20 and 100 ms as that in which auditory patterns emerge, and the ‘‘long’’ range from
100 ms on as that of separate auditory events. Further, he was also among the first to recognize that auditory time perception heavily
depended on the spectral context. A study of the perception of sequences representing different temporal orders of three tones, by Ira
and the author 关e.g., Divenyi and Hirsh, J. Acoust. Soc. Am. 64, 1369–1385 共1978兲兴 demonstrated the dependence of auditory
sequence perception on both time range and spectral context, and provided a bridge between Hirsh’s view of auditory time and
Bregman’s view of stream segregation 关Auditory Scene Analysis 共MIT Press, Cambridge, MA, 1991兲兴. A subsequent search by the
author for psychophysical underpinnings of the cocktail-party phenomenon 关e.g., Divenyi et al., Moh. Mtn. Workshop Appl. SPAA
共IEEE, Bellingham, WA, 1997兲兴 suggest that the segregation of simultaneous streams of speech may rely on the ability to follow
spectral changes in the demisyllabic-to-syllabic 共100- to 200-ms兲 range, i.e., Ira’s ‘‘long’’ range.
3aPP5. Ira as a pioneer in audiology: His contributions to the clinical measurement of hearing and hearing impairment. C.
Formby 共Univ. of Maryland, Baltimore, MD 21201兲 and J. P. Gagne 共Univ. de Montreal, Montreal, QC H3C 3J7, Canada兲
Ira Hirsh’s contributions to clinical science and research are diverse and significant. In fact, approximately one-third of the 100⫹
publications that Ira lists in his curriculum vitae 共CV兲 are clinical in nature, dealing with various aspects of audiology, deafness,
hearing aids, aural rehabilitation, and speech and language pathology. The majority of these citations, fully one-quarter of his
publication list, addresses problems specific to the clinical measurement of hearing and hearing impairment. Undoubtedly, the most
influential of these published works appears in his CV under the citation ‘‘The Measurement of Hearing.’’ The forward for this
publication, his only textbook, was penned in June, 1952 共now precisely half a century past at the time of this session兲. The aims of
this presentation are to 共1兲 provide perspective on the fundamental importance of his virtually timeless text in shaping the fledgling
discipline of audiology, and 共2兲 celebrate Ira’s many contributions to the profession and practice of audiology. 关Preparation for this
presentation was supported, in part, by a K24 career development award from NIDCD.兴
3aPP6. Ira Hirsh and oral deaf education: The role of audition in language development. Ann Geers 共Central Inst. for the Deaf,
4560 Clayton Ave., St. Louis, MO 63110兲
Prior to the 1960s, the teaching of speech to deaf children consisted primarily of instruction in lip reading and tactile perception
accompanied by imitative exercises in speech sound production. Hirsh came to Central Institute for the Deaf with an interest in
discovering the auditory capabilities of normal-hearing listeners. This interest led him to speculate that more normal speech development could be encouraged in deaf children by maximizing use of their limited residual hearing. Following the tradition of Max
Goldstein, Edith Whetnall, and Dennis Fry, Hirsh gave scientific validity to the use of amplified speech as the primary avenue to oral
language development in prelingually deaf children. This ‘‘auditory approach,’’ combined with an emphasis on early intervention,
formed the basis for auditory-oral education as we know it today. This presentation will examine how the speech perception, language,
and reading skills of prelingually deaf children have changed as a result of improvements in auditory technology that have occurred
over the past 30 years. Current data from children using cochlear implants will be compared with data collected earlier from children
with profound hearing loss who used hearing aids. 关Work supported by NIH.兴
J. Acoust. Soc. Am., Vol. 111, No. 5, Pt. 2, May 2002
143rd Meeting: Acoustical Society of America
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3aPP7. Personal glimpses of Ira Hirsh: Covariance of perception and reality. William Clark 共Central Inst. for the Deaf, 4560
Clayton Ave., St. Louis, MO 63110, [email protected]兲
No session honoring Ira Hirsh would be complete without a personal reflection of his enormous influence on his colleagues,
students, and friends. During his career in St. Louis that covered the entire second half of the 20th Century 共and still continues兲, Ira
interacted with numerous colleagues at Central Institute for the Deaf, where he served as a senior scientist, Director of Research, and
Institute Director. His second parallel career was at Washington University, where he was Professor of Psychology, and included a
term as Dean of the Faculty of Arts and Sciences. This tribute will provide reflections and reminiscences of what it was like to work
with, and learn from, Ira Hirsh.
3aPP8. Parameter space of the dichotic speech experiment. Robert C. Bilger 共Dept. of Speech & Hearing Sci., Univ. of Illinois
at Urbana-Champaign, 901 S. 6th St., Champaign, IL 61820, [email protected]兲 and Charles E. Speaks 共Univ. of Minnesota,
Minneapolis, MN 55455兲
The experiment in which different CV nonsense syllables are presented simultaneously to each ear and the listener is asked to
identify both consonants often results in more correct responses to syllables presented to the right than to the left ear, the so-called
right-ear advantage 共REA兲. The REA is generally interpreted as an indication that the left hemisphere processes speech more
efficiently than does the right hemisphere. As the experiment is usually conducted, however, it has the parameter space of 3 共i.e.,
requires three numbers to completely specify the results兲. Using data obtained independently in each of our labs, it will be shown that
the three parameters necessary to uniquely specify the results of the experiment are the probability that the 共1兲 first response is correct;
共2兲 first response is to the syllable presented to the right ear; and 共3兲 second response will be incorrect given that the first response was
correct. The ear advantage 共R, 0, or L兲 is predicted to the nearest percent using the first two parameters; but, as of this moment, the
exact fourfold matrix for a listener cannot be predicted.
3aPP9. Transcending boundaries with Ira Hirsh. Punita G. Singh 共Sound Sense, C6-6046 Vasant Kunj, New Delhi 110070, India,
[email protected]兲
Ira Hirsh has made many contributions to various fields of acoustics from speech, hearing, psychological and physiological
acoustics, to musical and architectural acoustics. It was a privilege for me to have been his student in all these areas, and to have had
him as a guide through masters and doctoral degree programs that focused on topics that lie at the boundaries connecting these
disciplines. Ira was not a prescriptive advisor, imposing particular research topics or procedures on his graduate students. Rather, he
encouraged originality, innovation, and personal goal setting. He would subtly suggest starting points and provide landmarks as
references, rather than explicit directions leading to them. One had to navigate the path by ones own wits. This approach encouraged
lateral, out-of-the box thinking, while also leading to respectful appreciation of historic trajectories in scientific research. During our
time together, we worked on several aspects of music, including, rhythm, melody, pitch, and timber perception. Some of this work will
be recapitulated, highlighting Ira’s role in its exposition and development. His multidimensional personality, astute insights, colorful
remarks, wry humor, care, and concern are qualities to be cherished—beyond the boundaries of campus, city, country, and contemporaneity.
3aPP10. Ad cerebrum per scientia: Ira Hirsh, psychoacoustics, and new approaches to understanding the human brain.
Judith Lauter 共Human Neurosci. Lab., Dept. of Human Services, Stephen F. Austin State Univ., Box 13019, SFA Station,
Nacogdoches, TX 75962兲
As Research Director of CID, Ira emphasized the importance of combining information from biology with rigorous studies of
behavior, such as psychophysics, to better understand how the brain and body accomplish the goals of everyday life. In line with this
philosophy, my doctoral dissertation sought to explain brain functional asymmetries 共studied with dichotic listening兲 in terms of the
physical dimensions of a library of test sounds designed to represent a speech–music continuum. Results highlighted individual
differences plus similarities in terms of patterns of relative ear advantages, suggesting an organizational basis for brain asymmetries
depending on physical dimensions of stimulus and gesture with analogs in auditory, visual, somatosensory, and motor systems. My
subsequent work has employed a number of noninvasive methods 共OAEs, EPs, qEEG, PET, MRI兲 to explore the neurobiological bases
of individual differences in general and functional asymmetries in particular. This research has led to 共1兲 the AXS test battery for
assessing the neurobiology of human sensory-motor function; 共2兲 the handshaking model of brain function, describing dynamic
relations along all three body/brain axes; 共3兲 the four-domain EPIC model of functional asymmetries; and 共4兲 the trimodal brain, a new
model of individual differences based on psychoimmunoneuroendocrinology.
J. Acoust. Soc. Am., Vol. 111, No. 5, Pt. 2, May 2002
143rd Meeting: Acoustical Society of America
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Session 3aSAa
Structural Acoustics and Vibration: Scattering; Composite Materials
Joseph W. Dickey, Chair
Center for Nondestructive Evaluation, The Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218
3aSAa1. Chaos, catastrophe, and critical frequency points on elastic
shells. Michael Werby 共NRL, Code 7181, Stennis Space Center, MS
39529兲 and H. Uberall 共Dept. of Phys., Catholic Univ. of America,
Washington, DC兲
3aSAa3. Visualization of the energy flow for a guided forward wave in
and around a fluid loaded elastic cylindrical shell: Color coding of the
Poynting vector field. Cleon E. Dean 共Phys. Dept., P.O. Box 8031,
Georgia Southern Univ., Statesboro, GA 30460-8031兲 and James P.
Braselton 共Dept. of Mathematics and Computer Sci., Georgia Southern
Univ., P.O. Box 8093, Statesboro, GA 30460-8093兲
Exact equations exist for the determination of the backscattered signals
excited by acoustic signals on submerged elastic shells. In the absence of
resonances these signals may be cast in terms of conservation principles of
inertial components of the interaction of the signal with the object. This
indeed leads to an adequate description of the acoustic background of such
targets. What is determined to be critical is the inclusion of an entrained
mass related to the displacement of the mass equivalent of the fluid due to
the movement of the object. But what happens to such inertial effects in
the presence of elastic resonances? We explore this issue and demonstrate
that the effective or inertial component ranges from zero to infinity over a
small frequency range that characterizes the resonance width. Over this
range there is also a phase shift of 1800. We may as well examine the
effect of radiation loading in this range. It is also possible to investigate a
phase plot of the real and imaginary components of the effective mass
factor which leads to closed trajectories for certain classes of resonances
and to hyperbolic trajectories for other types. The meaning of these observations is discussed. 关Work supported by NRL and ONR.兴
3aSAa2. Backscattered acoustic signal from submerged water filled
elastic shells can be decomposed into body resonances and
eigenmodes of the contained water. Michael Werby 共NRL Code 7180,
Stennis Space Center, MS 39529兲 and H. Uberall 共Dept. of Phys., The
Catholic Univ. of America, Washington, DC 20064兲
Acoustic signals scatter from an elastic shell and excite elastic shell
resonances. For evacuated shells resonances due to proper Lamb waves,
A0 and S0 waves and the pseudo-Stoneley resonances, are the only ones
allowed. When the shell is fluid filled then the eigenfrequencies of the
included fluid may be excited. Further, the presence of the fluid may alter
the elastic body resonances. When the impedance of the entrained fluid is
not much smaller than the mechanical impedances of the elastic material
then the scattered signal is greatly influenced by the entrained fluid, but
only at their allowed eigenfrequencies. Since the fluid is entrained this
leads to a discrete spectrum and an eigenvalue problem which is quite
manageable. In this work we outline a method for determining the eigenfrequencies as well as their nature and use their values to isolate the actual
body resonances due to the elastic material. We also illustrate the influence
of the presence of the entrained fluid on the elastic resonance frequencies.
关Work supported by NRL and ONR.兴
J. Acoust. Soc. Am., Vol. 111, No. 5, Pt. 2, May 2002
Previous work 关Cleon E. Dean and James P. Braselton, ‘‘Visualization
of the energy flow for a guided forward wave in and around a fluid loaded
elastic cylindrical shell,’’ J. Acoust. Soc. Am. 109, 2379 共2001兲兴 showed
the energy flow for a forward propagating fluid loaded elastic cylindrical
shell at the resonance frequency. The results were difficult to interpret
since although the two counterpropagating guided waves were separated
and displayed independently, the conventional grid of vector arrows was
hard to interpret in part because they were hard to see individually. The
current work uses color encoding to show the Poynting vector field. Hue is
used to indicate the direction of the energy flow while intensity of the
color is used to denote the magnitude of the Poynting vector at that point.
3aSAa4. Investigation of the sound transmission behavior of a
chamber core cylinder. Deyu Li and Jeffrey S. Vipperman 共Dept. of
Mech. Eng., Univ. of Pittsburgh, 531 Benedum Hall, Pittsburgh, PA 15228兲
3a WED. AM
Contributed Papers
Several kinds of novel composite structures, such as advanced grid
stiffened 共AGS兲 and chamber core 共CC兲 structures have been designed,
fabricated, and investigated for both civil and military applications. The
chamber core composite is a novel advanced sandwich-type structure that
is created by filament winding an inner shell onto a cylindrical mandrel,
arranging previously fabricated U-shaped channels around the perimeter
of this shell to form the inner chamber walls, and filament winding an
outer shell followed by a co-cure process. In this study, the structural/
acoustic behavior of a normal composite chamber core cylinder is investigated both theoretically and experimentally. Lightly coupled structural
and acoustic modal parameters are identified using experimental modal
analysis techniques. The properties of sound transmission loss 共TL兲 of the
cylinder are also investigated experimentally. The effect of the structural/
acoustic natural frequencies and the damping on the sound transmission
loss is analyzed. Finally, passive control strategies are discussed, and several passive control materials for improving the sound transmission loss
共0–500 Hz兲 of the cylinder are experimentally evaluated. 关Work sponsored
by the Air Force Research Laboratory Space Vehicles Directorate 共AFRL/
VS兲, POC Dr. Steven Lane, 共505兲 846-9944.兴
3aSAa5. Sound absorption characteristics of cenosphere enriched
cement and asphalt concrete. Vikrant Tiwari, Arun Shukla 共Dynamic
Photomechanics Lab., Dept. of Mech. Eng. and Appl. Mech., Univ. of
Rhode Island, Kingston, RI 02881兲, and Arjit Bose 共Univ. of Rhode
Island, Kingston, RI 02881兲
A detailed experimental study has been conducted to determine the
effect of addition of cenospheres on the acoustic properties of cement
matrix and asphalt concrete. Cenospheres are hollow ceramic microballoons, being a waste product of thermal power plants, they are relatively
143rd Meeting: Acoustical Society of America
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inexpensive and their use has the added benefit of decreasing the strain on
the environment. Specimens were made with a different volume fraction
of cenospheres 共0% to 70% in increments of 10兲 to observe the change in
acoustic properties with an increase in the cenosphere content. Specimens
of different sizes were tested to study the acoustic characteristics of the
materials for a wide range 共125 to 4000 Hz兲 of frequencies. The effect of
an increase in the cenosphere content on the dilatational wave velocity in
the specimens was also studied with the help of acoustic transducers. It
was noted that, although the wave velocity remains relatively unaffected
with a change in the cenosphere content, the addition of cenospheres improves the sound absorption characteristics of the cement matrix and asphalt concrete with a considerable decrease 共up to 41%兲 in the density of
the material. It has also been noted that the sound absorption of cement
increases with the addition of cenosphere up to 40% volume fraction and
starts decreasing with the further addition of cenospheres.
Generic Algorithm 共GA兲 was identified as a better optimization method
over the gradient-based methods for this task due to its nature in finding
the combinatorial solutions. This approach is, to the best of our knowledge, novel in applying the GA to this design problem. The performance
of the GA method is compared with the exhaustive search in maximizing
the sound absorption coefficient of an acoustic liner with constraints set
for its cost, thickness, and total weight. The features of the Generic Algorithm and the preliminary proof-of-concept results will be discussed and
9:15–9:30 Break
In this presentation, one proposes a prediction at low- and midfrequencies of the dynamics of fuzzy structures. As introduced by Soize,
the term ‘‘fuzzy structure’’ designates a master structure, whose geometrical, material characteristics, boundary conditions, and excitations are
known, coupled with complex systems, called the structural fuzzy or
fuzzy, whose characteristics are imprecisely known. Previous works done
on this subject analyze the concept of a master structure coupled with a
locally homogeneous fuzzy, composed of a large number of linear oscillators excited by their supports. In the present work, the concept of a
homogeneous fuzzy is extended to an elastic continuum medium. One
theoretically formulates the action of the elastic fuzzy on the master structure: it is shown that the proposed formulation is different from the solution proposed by Soize, derived from the model of a linear oscillator
excited by its support. The proposed theory is successfully applied to the
case of a homogeneous structural fuzzy composed of a large number of
elastic bars whose lengths and cross sections are randomly chosen.
3aSAa6. An equivalent solid „u… formulation for poroelastic
materials. Dominic Pilon and Raymond Panneton 共GAUS, Dept. of
Mech. Eng., Univ. de Sherbrooke, 2500 boul. de l’Universite, Sherbrooke
QC J1K 2R1, Canada兲
Finite element formulations based on Biot’s poroelasticity equations
have been used extensively throughout recent years. The most common
are Biot’s displacement (uគ ,U
គ ) and mixed displacement-pressure (uគ ,p)
formulations. They are used to predict the structural and acoustical behavior of poroelastic mediums within multilayered structures. These models,
while accurate, lead to the resolution of large linear systems: they need,
respectively, six and four degrees of freedom per node in order to efficiently describe the poroelastic medium’s vibroacoustic behavior in 3-D
problems. In this paper, a simplified displacement (uគ ) formulation is presented. It is also based on Biot’s equations, but requires only three degrees
of freedom per node, related to the solid phase displacement field, to
describe the behavior of poroelastic mediums in 3-D problems. The development of the governing (uគ ) equations for the equivalent solid poroelastic formulation is detailed. The limitations of this approach are also
discussed. Numerical and experimental validations are presented in order
to show the accuracy and effectiveness of the formulation within its prescribed field of application.
3aSAa7. Genetic encoding for sound package configuration
optimization. Heng-Yi Lai 共Dept. of System and Network, United
Technologies Res. Ctr., 411 Silver Ln., MS129-17, East Hartford, CT
06108, [email protected]兲
The acoustic properties of poroelastic materials can be accurately predicted by the Biot–Allard model if the required acoustic parameters have
been successfully characterized. In conjunction with the transfer matrix
approach, one can use the model to analytically design an acoustic liner
comprising different materials that can provide better performance or cost
reduction advantages over their homogeneous counterparts. However, optimizing the layer configuration remains to a challenging task as it is a
combinatorial problem and the search for the optimal configuration can be
difficult or expensive if simply based on the build-and-test approach. The
J. Acoust. Soc. Am., Vol. 111, No. 5, Pt. 2, May 2002
3aSAa8. On the dynamics of fuzzy structures. Jean-Mathieu Mencik
and Alain Berry 共GAUS, Mech. Eng. Dept., Univ. of Sherbrooke,
[email protected]兲
3aSAa9. Dissipation induced by substructures and distribution of
vibratory energy in a complex system. Sunghoon Choi and Yang-Hann
Kim 共Dept. of Mech. Eng., KAIST, Science Town, Taejon 305-701,
Republic of Korea兲
This work is concerned with the problem of energy transfer that takes
place between a master structure and the substructures attached to it. The
response of the system is characterized by the impedance of the substructures and it determines whether the induced damping is real or apparent.
When the dissipation is real the master structure has a larger loss factor
than that of the substructures and there will be continuous transfer of
vibratory energy from the master structure to substructures. However, in
the case of apparent damping, one can observe that the vibration energy is
transferred back and forth between the master and substructures. Some
combinations of the master and substructures have been considered to
examine this phenomenon and to determine the criteria for damping. It has
found that a modal overlapping condition, which corresponds to bandwidths that exceed the spacing of those natural frequencies, is crucial in
determining the characteristics of the system damping. The result of this
paper is consistent with that found with the fuzzy structure and SEA
framework. 关Work sponsored by Ministry of Education, Korean Government under the BK21 program and Ministry of Science and Tech., Korean
Government under National Research Lab. program.兴
143rd Meeting: Acoustical Society of America
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Session 3aSAb
Structural Acoustics and Vibration and Archives and History:
History of Structural Acoustics and Vibration
Joseph W. Dickey, Chair
Center for Nondestructive Evaluation, The Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218
Invited Paper
3aSAb1. History of structural acoustics and vibrations in the Acoustical Society of America. David Feit, Murray Strasberg
共Carderock Div., Naval Surface Warfare Ctr., 9500 MacArthur Blvd., West Bethesda, MD 20817兲, and Eric E. Ungar 共Acentech, Inc.,
Cambridge, MA 02138-1118兲
GRAND BALLROOM 3, 7:55 TO 9:45 A.M.
Session 3aUWa
3a WED. AM
Structural acoustics refers to the interaction of sound and structures—the response of structures to sound, the radiation of sound
from vibrating structures, and the effect of the acoustic medium on the structural vibrations. Interest in these subjects increased greatly
during the 1930s and 40s because of practical applications in the design of microphones and loud speakers used in telephones, radios,
and electronic phonographs. The combination of electrical and mechanical systems lead to the use of electrical engineering concepts
such as impedance, circuits, and electrical analogies, in the analysis of mechanical systems. In later years, much of the work dealt with
various aspects of underwater structures, prompted by U.S. Navy interests. The field, which began with classical analytical mechanics
applications, has progressed to new approaches, including statistical energy analysis, near-field acoustical holography, fuzzy structures, active control of vibrations, and smart materials. In recognition of these new developments, the name of the technical committee
was changed in 1987 from ‘‘Shock and Vibration’’ to ‘‘Structural Acoustics and Vibration.’’
Underwater Acoustics: Array Performance
Peter Gerstoft, Chair
Marine Physics Laboratory, Scripps Institution of Oceanography, University of California, San Diego, 8820 Shellback Way,
La Jolla, California 92093-0238
Chair’s Introduction—7:55
Contributed Papers
3aUWa1. Acoustic tracking of towed-array hydrophone positions
during tow-vessel maneuvers. Alec J. Duncan 共Ctr. for Marine Sci. and
Technol., Curtin Univ., GPO Box U1987, Perth, WA 6845, Australia,
[email protected]兲, Darryl McMahon 共Defence Sci. and
Technol. Organisation, HMAS Stirling, Garden Island, Western Australia兲,
and Alessandro Ghiotto 共Nautronix Ltd., 108 Marine Terrace, Fremantle,
WA 6160, Australia兲
3aUWa2. Adaptive beamforming of a towed array during a turn.
Peter Gerstoft, William S. Hodgkiss, W. A. Kuperman, Heechun Song
共Marine Physical Lab., Scripps Inst. of Oceanogr., La Jolla, CA
92093-0238兲, Martin Siderius, and Peter L. Nielsen 共SACLANT
Undersea Res. Ctr., 19138 La Spezia, Italy兲
This paper describes an experiment in which a vessel towing an array
of hydrophones executed a series of maneuvers designed to bring the array
into orientations favorable for imaging noise sources on the tow-vessel.
Signals from tracking beacons on the tow-vessel and transient signals from
implosive sources deployed from a second vessel were received on the
array hydrophones and were used to obtain independent estimates of hydrophone position. Array shape estimation and tracking algorithms are
described and the results of applying these algorithms to the experimental
data are presented.
J. Acoust. Soc. Am., Vol. 111, No. 5, Pt. 2, May 2002
During maneuvering, towed-array beamforming will degrade if a
straight array is assumed. This is especially true for high-resolution adaptive beamforming. This problem can be reduced if a proper curved array is
assumed. The tow vessel’s Global Positioning System 共GPS兲 can be used
to estimate this curvature, and this reduces the need for instrumentation in
the array. Based on estimated array shape from GPS, both the conventional beamformer and the white-noise-constrained 共WNC兲 adaptive
beamformer are shown to track the source well. For calculating the steering vector in the WNC approach, a matrix inversion of the cross-spectral
density matrix is involved. This matrix inversion can be stabilized by
averaging the cross-spectral density matrix over neighboring frequencies.
143rd Meeting: Acoustical Society of America
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3aUWa3. Subarray partitions of large aperture planar towed arrays.
Jennifer A. Watson 共Lincoln Lab., MIT, 244 Wood St., Lexington, MA
02420, [email protected]兲, Arthur B. Baggeroer 共MIT, Cambridge,
MA 02139兲, Lisa M. Zurk, and Brian H. Tracey 共Lincoln Lab., MIT,
Lexington, MA 02420兲
The current focus of passive detection and localization is in littoral
regions where acoustic propagation becomes complicated by severe bottom interaction. The resultant high-transmission loss motivates the need
for high-array gain for effective performance over long ranges. Large planar seismic arrays, with aperture dimensions upwards of 3 km⫻0.5 km,
have potential to achieve high gain and good resolution when using
matched field processing. In realistic environments, however, large arrays
are suceptible to signal gain degradation mechanisms, particularly due to
spatial decorrelation of the signal and non-stationary environments. One
approach to overcoming this is partitioning the array. Subarray processing
reduces stationarity requirements and extracts optimum coherent gain,
thus achieving higher gain than that of smaller arrays. This work examines
criteria for partitioning planar arrays to perform localization using MFP.
Trade-offs between spatial resolution, array gain, and resilience to motion
will be quantified and discussed. Performance of different subarray geometries will be presented using adaptive and conventional MFP. 关Work
sponsored by DARPA under Air Force Contract No. F1962800-00-C0002. Opinions, interpretations, conclusions, and recommendations are
those of the authors and are not necessarily endorsed by the Department of
Defense. AB’s work was supported by ONR through the SECNAV CNO
3aUWa4. Passive localization algorithms.
Lawton Brook Ln., Portsmouth, RI 02871兲
Edmund J. Sullivan
An acoustic source can be localized by exploiting the fact that, if the
range is not too great, the wavefront of the incoming acoustic energy can
be assumed to be circular. This is sometimes called ‘‘Wavefront Curvature
Ranging.’’ Here, the estimation of range reduces to the estimation of the
radius of a circle. In fact, if sufficient horizontal and vertical aperture is
available, range, bearing and elevation can be estimated, given a minimum
of four receivers. The technique is based on the measurement of the relative phases between pairs of receivers. In this paper, two methods of
improving the performance of such localizers are investigated. In the case
where the receivers are mounted on a moving platform, it is shown that
exploitation of this motion can improve performance by utilizing information that is usually ignored in phase measurements. Also, since the motion
introduces a time dependence in the true values of the time delays, a limit
on the accuracy of their measurement is incurred. A recursive estimation
process is proposed as a remedy for this problem. These techniques will be
demonstrated by using simulated data.
J. Acoust. Soc. Am., Vol. 111, No. 5, Pt. 2, May 2002
3aUWa5. Beam intensity striations and applications.
共Naval Res. Lab., Washington, DC 20375兲
T. C. Yang
Modal interferences, or striations, are analyzed and modeled for the
beam outputs of a horizontal line array obtained by conventional beamforming. The enhancement of signal levels by the array gain 共over that of
a single element兲 makes the measurement of the invariant parameter more
reliable even in the weak signal cases. It is shown that the signal beams
exhibit the same striation pattern as that predicted 共theoretically兲 for a
single element. Specifically, for a broadside signal, the beam striation is
identical to that of the single element plus a constant signal gain. For a
non-broadside target, the signal beam intensity will be modified by a
frequency-bearing dependent signal gain due to the signal spread over
multiple beams 共the multipath effect兲. Nonetheless the signal beam intensity still retains the same striation pattern 共slope兲 as for a single element.
At non-signal look directions, the sidelobe beams 共those outside the canonical cones containing the signal arrivals兲 exhibit an entirely different
striation pattern. The difference of signal striations between a fast rangerate, close range signal and distant, slow range-rate interferences can be
used to suppress the interferences in array processing. 关Work supported by
3aUWa6. Preliminary results of horizontal array coherence from the
2001 ASIAEX South China Sea experiment. Theodore H. Schroeder,
James F. Lynch, and Arthur Newhall 共Woods Hole Oceanogr. Inst.,
MS#11, Woods Hole, MA 02543, [email protected]兲
The 2001 ASIAEX 共Asian Seas International Acoustics Experiment兲
South China Sea experiment was performed in April–May, 2001 off the
southern coast of the People’s Republic of China. This experiment was a
combined acoustics/physical oceanography/marine geology effort that endeavored to measure basic acoustic propagation and scattering processes
in a well-supported manner. As part of the experiment, a combination
vertical/horizontal autonomous receiving array was deployed in 124 m of
water, where it listened to a combination of moored and towed acoustic
sources spanning a bandwidth of 50– 600 Hz. These acoustic measurements were supported by geological surveys and extensive oceanographic
measurements from fixed and towed instruments, providing a 3-D picture
of the overall oceanography in the experimental area. The initial interest in
this data centers about horizontal array coherence issues, as few experiments have had a horizontal array coupled with extensive environmental
support, allowing for a direct correlation of the array coherence with the
environment. The frequency dependence, time variability, and along-shelf
vs. across-shelf variation of coherence are of particular interest. The latest
results in these topics will be shown. 关Work supported by ONR.兴
3aUWa7. Effect of a ship’s body on the beam pattern of its
hydroacoustic array. Tran H. Dat and V. T. Grinchenko 共Inst. of
Hydromech., Natl. Acad. of Sci. of Ukraine, Zhelyabov Str. 8/4, Kiev
03035, Ukraine兲
143rd Meeting: Acoustical Society of America
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GRAND BALLROOM 3, 10:10 TO 11:30 A.M.
Session 3aUWb
Underwater Acoustics: Shallow Water Propagation and Signal Processing
David M. Deveau, Chair
PSC 1012, Box 701, FPO, AA 34058-9998
Chair’s Introduction—10:10
3aUWb1. Shallow water impact acoustics. David M. Deveau 共Naval
Undersea Warfare Ctr. Det. AUTEC, 801 Clematis St., West Palm Beach,
FL 33401兲
During a series of impact detection and tracking accuracy tests near
Wallops Island, Maryland, an analysis was conducted on the acoustic impacts themselves. Since the impact area was very shallow 共60 ft兲, the
acoustic signature traveled unscathed between the 1000 yard baseline sensors. The initial goal was to implement deep water impact tracking algorithms in the shallow environment. Initially the in-water tracking system
computed positions that were close to those which were laser sighted, but
not close enough. Since the transient acoustic signature was very evident,
hence a stable timing mark, an investigation into the acoustics surrounding
the impact was undertaken. A review of the data showed small transients
which occurred distinctly before the large transient detection that had routinely been considered as the impact itself. Using a threshold detection
scheme, a relative set of timing marks were generated based on these early
transients and were found to produce a more accurate placement.
and dispersion make the Doppler effects far more complicated than in free
space. In a waveguide, multiple frequency components are typically
present in the field scattered from a moving object even if the active
source of radiation is harmonic. Applying a free space Doppler correction
to the field scattered from a moving object in a waveguide is insufficient to
account for the Doppler distortion of the signal in typical ocean
waveguides and active sonar scenarios. Spectral and modal formulations
for the Doppler-shifted field scattered from a horizontally moving target in
a horizontally stratified medium have been developed by Lai and Makris
关J. Acoust. Soc. Am. 110, 2724 共2001兲兴. These formulations are used with
the maximum likelihood method to estimate the velocity of the moving
target by modeling the multiply Doppler distorted scattered signal measured with noise in a shallow water waveguide. The performance of the
maximum likelihood estimate is evaluated by asymptotic analysis of its
bias and mean-square error as a function of signal-to-noise ratio.
3aUWb2. Channel characterization for communications in very
shallow water. Robert J. McDonald, Kerry W. Commander, John S.
Stroud, Jo Ellen Wilbur 共Coastal Systems Station, 6703 W. Hwy. 98,
Panama City, FL 32407-7001, [email protected]兲, and Grant
B. Deane 共Univ. of California, San Diego, La Jolla, CA 92093-0238兲
3aUWb4. Time-frequency analysis and conditional moments of
shallow-water sound propagation. Patrick J. Loughlin 共Dept. of Elec.
Eng., Univ. of Pittsburgh, Pittsburgh, PA 15261兲
Broadband acoustic transmissions 共7 kHz to 17 kHz兲 taken from July
4, 2000 to July 8, 2000, in the shallow water near Scripps Pier at La Jolla,
California, are used to extract the time-varying channel parameters of
coherence time and multipath time delay spread, as functions of frequency
and the environmental variables of wave height and tidal fluctuations.
Tidal fluctuations, which have a significant effect on water depth at the
receiver and transmitter, are shown to strongly correlate to variations in
the multipath delay spread. Variations in the coherence time for the channel, as measured by the drop off in correlation between initial and successive impulse responses, are shown to be inversely related to variations in
the measured wave height. The coherence time of the channel was found
to decrease with increasing center frequency. A scatter plot of the receiver
signal-to-noise ratio as a function of wave height and water depth indicates when the shallow water environment allows a viable communications channel to exist.
3aUWb3. Estimating the velocity of a moving object submerged in an
ocean waveguide with active sonar. Yi-san Lai and Nicholas Makris
共MIT, 77 Masschusetts Ave., Cambridge, MA 02139兲
Standard active sonar and radar systems are often used to estimate the
velocity of a moving target in free space by resolving the Doppler shift of
the scattered waveform. In an ocean waveguide, multimodal propagation
J. Acoust. Soc. Am., Vol. 111, No. 5, Pt. 2, May 2002
3a WED. AM
Contributed Papers
Shallow-water sound propagation is inherently nonstationary owing to
such effects as geometric dispersion. The spectrogram has been a principal
means to study the nonstationarities and dispersion characteristics of
shallow-water sound propagation. In this talk, we give the low-order conditional spectral and wave number moments of sound propagation in dispersive environments, and show how they characterize the nonstationarities induced by channel dispersion on the propagating wave. 关Work
supported by ONR 共N00014-02-1-0084兲.兴
3aUWb5. Multipath in synthetic aperture sonar. John E. Piper
共Coastal Systems Station, 6703 W. Hwy. 98, Panama City, FL 32407兲
Synthetic aperture sonar is capable of producing high resolution images. As the detection range increases multipath effects can become important. In this paper we present the results of at-sea tests in the Gulf of
Mexico and St. Andrew Bay with a dual-frequency 共20 kHz and 180 kHz兲
synthetic aperture sonar. Surprisingly, it was found that range to water
depth ratios as small as 4 often produced multipath signals significantly
stronger than direct path signals. These effects on the synthetic aperture
processing and image quality are discussed.
143rd Meeting: Acoustical Society of America
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GRAND BALLROOM 3, 12:55 TO 2:00 P.M.
Session 3pAO
Acoustical Oceanography: Acoustical Oceanography Prize Lecture
Peter F. Worcester, Chair
Scripps Institution of Oceanography, University of California, San Diego, 9500 Gilman Drive,
La Jolla, California 92093-0225
Chair’s Introduction—12:55
Invited Paper
3pAO1. Ocean tomography, inverse methods, and broadband ocean acoustics. Bruce D. Cornuelle 共Scripps Inst. of Oceanogr.,
UCSD, La Jolla, CA 92093兲
Ocean acoustic tomography, as proposed by Munk and Wunsch in 1979, and as implemented by the Ocean Tomography Group,
uses ray travel times to estimate ocean sound speed and currents. Earlier work by Medwin 共1970兲 and Hamilton 共1977兲 used pulse
travel times as measures of integrated sound speed along paths at short and long range, respectively. Munk and Wunsch 共1979兲
recognized that broadband transmissions between many instruments could be used with inverse methods 关Backus and Gilbert 共1967兲;
Liebelt 共1967兲兴 to reconstruct 3D ocean sound speed fields from the travel times along multiple paths. Inverse methods are widely
used in ocean acoustics and in physical oceanography, and the modern challenge is to incorporate time dependence into the inverse
methods to take advantage of the improving ocean dynamical models. In addition, the understanding of broadband acoustic propagation has improved to the point of refining the sensitivity kernel for travel time measurements beyond the simple geometrical optics
of ray paths. This paper will review the evolving use of forward and inverse methods in acoustical oceanography, primarily with
application to acoustic tomography.
GRAND BALLROOM 2, 2:00 TO 3:05 P.M.
Session 3pID
Interdisciplinary: Hot Topics in Acoustics
Mardi C. Hastings, Chair
Biomedical Engineering Center, The Ohio State University, 1080 Carmack Road, Columbus, Ohio 43210
Chair’s Introduction—2:00
Invited Papers
3pID1. Hot topics: Signal processing in acoustics. James Candy 共Univ. of California, Lawrence Livermore Natl. Lab., P.O. Box
808, L-156, Livermore, CA 94551兲
Signal processing represents a technology that provides the mechanism to extract the desired information from noisy acoustical
measurement data. The desired result can range from extracting a single number like sound intensity level in the case of marine
mammals to the seemingly impossible task of imaging the complex bottom in a hostile ocean environment. Some of the latest
approaches to solving acoustical processing problems including sophisticated Bayesian processors in architectural acoustics, iterative
flaw removal processing for non-destructive evaluation, time-reversal imaging for buried objects and time-reversal receivers in
communications as well as some of the exciting breakthroughs using so-called blind processing techniques for deconvolution are
discussed. Processors discussed range from the simple to the sophisticated as dictated by the particular application. It is shown how
processing techniques are crucial to extracting the required information for success in the underlying application.
J. Acoust. Soc. Am., Vol. 111, No. 5, Pt. 2, May 2002
143rd Meeting: Acoustical Society of America
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3pID2. Determining the sources of sounds: Psychological acoustics. William A. Yost 共Parmly Hearing Inst., Loyola Univ.
Chicago, 6525 N. Sheridan Rd., Chicago, IL 60626, [email protected]兲
Perhaps the most important task performed by an organism’s sensory system is determining objects in the world surrounding the
organism. This is a challenging task for the auditory system, especially when many objects exist at the same time. The peripheral
auditory system provides the neural code for the spectral-temporal structure of the complex sound impinging on the ears. It does not
code for the sources of the sound. Neural centers beyond the periphery most analyze this spectral-temporal code in order to form
perceptual images that make up the auditory scene. Recent psychoacoustical and perceptual research on sound source determination
and segregation will be described. This research is just beginning to suggest ways in which the auditory scene is determined. 关Work
sponsored by NIDCD.兴
3pID3. Hot topics in engineering acoustics. Stephen C. Thompson 共Knowles Electron., LLC, 1151 Maplewood Dr., Itasca, IL
From the ASA Handbook, the technical committee on Engineering Acoustics is ‘‘concerned with the evolution and improvement
of acoustical techniques and apparatus, and with the promotion of new applications of acoustics for useful purposes.’’ The interest of
acousticians in apparatus and techniques is at least as old as the society, as can be verified by a quick scan of the first volume of the
journal. Active development continues in areas that include new materials for high power sonar devices, new structures for hearing aid
transducers, the announcement of the first commercial micromachined silicon microphone, multimedia and 3-D audio applications,
and more. This paper is an abbreviated report on a few of these developments.
Session 3pSA
Structural Acoustics and Vibration: Holography
Sean F. Wu, Chair
Department of Mechanical Engineering, Wayne State University, 505 Anthony Wayne Drive, Detroit, Michigan 48202
3pSA1. Spherical wave approximation to arbitrary sound fields.
Nassif E. Rayess 共College of Eng. and Sci., The Univ. of Detroit, Mercy,
Detroit, MI 48219-0900兲
The ability to expand the acoustic field radiated from arbitrarily shaped
objects in the form of a series of spherical wave functions has always been
a point of interest. Despite the paucity of theoretical understanding, experimental and numerical work has repeatedly shown that such expansions
can lead to relatively accurate approximations of the radiated sound fields.
A general understanding of the problem as well as a quantitative approximation of the resulting errors are deduced from the sound radiation model
based on a volume distribution of monopole sources. The errors involved
in the approximation are a direct result of the presence of monopole
sources outside the largest inscribed sphere. It is shown that under many
circumstances, such errors are relatively small and can be mitigated further by the proper choice of the method used to determine the coefficients
of the expansion. The collocation method with an appropriate sampling
scheme has been used with a great deal of success to determine the expansion coefficients in acoustic holography problems.
3pSA2. HELS based near-field acoustic holography for a highly
nonspherical structure. Manmohan Moondra and Sean Wu 共Dept. of
Mech. Eng., Wayne State Univ., 5050 Anthony Wayne Dr., Detroit, MI
The Helmholtz Equation Least Squares 共HELS兲 method 关Wu and Yu,
J. Acoust. Soc. Am. 104, 2054 –2060 共1998兲; Wu, ibid. 107, 2511–2522
共2000兲兴 are validated experimentally in both exterior and interior regions
of a highly nonspherical structure. This is contrary to the common belief
that expansion solutions based on spherical coordinates are valid within
the region bounded by spheres. Detailed explanations for this phenom2409
J. Acoust. Soc. Am., Vol. 111, No. 5, Pt. 2, May 2002
enon, known as the Rayleigh hypothesis, are given in a separate paper.
Shown here are the experimental validations of the acoustic fields reconstructed by the HELS method for a cabinet with overall dimensions 2.05
m ⫻1.05 m ⫻0.75 m. A loudspeaker is placed inside the cabinet. The
white noise produced by the speaker is measured by an array of 48 microphones stationed outside. The acoustic pressures in the near- and farfields are reconstructed and validated with respect to those measured at the
same locations. Also reconstructed is the normal component of the timeaveraged acoustic intensity, from which the transmission paths are identified. Such transmission paths cannot be revealed based on the acoustic
pressure distribution alone because pressure is a scalar quantity. The interior acoustic pressures are reconstructed with the speaker placed outside
and microphone array inside the cabinet. 关Work supported by NSF.兴
3p WED. PM
Contributed Papers
3pSA3. Reconstruction of acoustic radiation from a finite object in
nonfree space. Sean Wu and Xiang Zhao 共Dept. of Mech. Eng., Wayne
State Univ., 5050 Anthony Wayne Dr., Detroit, MI 48202兲
The near-field acoustic holography 共NAH兲 techniques developed so far
have focused on reconstruction of acoustic radiation from a vibrating
structure in either an unbounded exterior region or an enclosed region so
that it can be solved as an interior problem. In practice, many vibrating
structures are mounted on a solid foundation or in the vicinity of reflecting
surfaces. For NAH to become a robust diagnostic tool, the effect of acoustic pressure reflection from nearby surfaces must be considered. In this
paper, the Helmholtz equation least-squares 共HELS兲 method 关Wu, J.
Acoust. Soc. Am. 107, 2511–2522 共2000兲兴 will be modified which expresses the field acoustic pressure as a superposition of both out-going and
in-coming spherical waves. The latter will be used to approximate the
acoustic pressure reflection from nearby surfaces. To guarantee a convergence of the reconstructed acoustic field, a constrained minimization will
be conducted with respect to the expansion functions to determine the
143rd Meeting: Acoustical Society of America
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optimal numbers of expansion terms for both out-going and in-coming
waves. This concept will also be extended to reconstruction of acoustic
radiation from an arbitrarily shaped vibrating structure for which the conventional HELS formulation has been shown to have difficulties to yield
satisfactory reconstruction. 关Work supported by NSF.兴
3pSA4. On the behavior of solutions obtained by the HELS method
inside the minimum sphere. Tatiana Semenova and Sean F. Wu 共Dept.
of Mech. Eng., Wayne State Univ., 5050 Anthony Wayne Dr., Detroit, MI
Previous experimental and numerical studies have shown that the
Helmholtz equation least-squares 共HELS兲 method 关Wu, J. Acoust. Soc.
Am. 107, 2511–2522 共2000兲兴 can be an effective methodology for
nearfield acoustical holography. However, results also demonstrated that
the accuracy of reconstruction on a highly nonspherical surface might be
unsatisfactory. The validity of the HELS method on these highly nonspherical surfaces has become a controversial topic, just like the Rayleigh
hypothesis for acoustic scattering on a corrugated surface. In this paper,
the validity of solutions obtained by the HELS method will be examined
for acoustic radiation from an infinite column with a rectangular cross
section. The acoustic field inside the minimal circle that encircles the
column will be reconstructed. The convergence of solutions both on the
surface and inside the minimum circle will be checked. Moreover, a modified HELS formulation will be used, which describes the acoustic pressure
as a superposition of both out-going and in-coming spherical waves. The
nature of the solutions thus obtained will be examined, and the dependence of convergence of the HELS solution on the validity of the Rayleigh
hypothesis and on the measurement locations will be investigated. 关Work
supported by NSF.兴
Plenary Session, Business Meeting, Awards Ceremony
William M. Hartmann, President
Acoustical Society of America
Business Meeting
Presentation of Certificates to New Fellows
Rachel K. Clifton
David E. Marsh
Kerry W. Commander
Andrzej Rakowski
Brian H. Houston
W. John Richardson
Patrick M. Hurdle
Nicholas Rott
Darlene R. Ketten
Christopher Shera
Birger Kollmeier
Leon H. Sibul
Asbjörn Krokstad
Andrea M. Simmons
David E. Marsh
David C. Swanson
Andrzej Rakowski
Lynne A. Werner
Announcement of Prize
Bruce Cornuelle, 2002 Medwin Prize in Acoustical Oceanography
Presentation of Awards
R. Bruce Lindsay Award to James M. Finneran
R. Bruce Lindsay Award to Thomas J. Royston
Silver Medal in Psychological and Physiological Acoustics to Neal F. Viemeister
Gold Medal to Robert E. Apfel
Gold Medal to Tony F. W. Embleton
J. Acoust. Soc. Am., Vol. 111, No. 5, Pt. 2, May 2002
143rd Meeting: Acoustical Society of America
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