bluuebunny/crossref_metadata_2025 huggingface dataset:
Investigations of wind-noise reduction at the infrasound test bed in Trafelberg, Austria.
Authors: Gabrielson Thomas B. , Haralabus Georgios
Published: July 2011

The International Monitoring System (IMS) of the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) has a unique infrasound test site (I99AT) with four wind-noise-reduction pipe-array systems in close enough proximity to allow simultaneous measurements under similar environmental conditions. It was designed as a facility to study the effectiveness of various wind-noise-reduction systems so it is clear of trees, vegetation, or other wind breaks. In May 2010, four infrasonic microphones were deployed at the test bed. These reference microphones contributed additional single-point measurements, which could be taken individually or combined into a small array for comparison to the larger pipe-array systems. The test-bed wind-noise-reduction systems in conjunction with the additional sensors permitted observation of the relationship between sensor aperture and wind-noise-reduction effectiveness as a function of frequency. In particular, one 3-day period had varying wind conditions with very low anthropogenic noise. At the lowest frequencies, the turbulence scale sizes exceeded the largest pipe-array dimensions and all sensors converged to similar values of spectral density; as the frequency increased, the wind noise was suppressed first as a function of overall dimension, then as a function of number of inlets. [Work sponsored by the Comprehensive Nuclear-Test-Ban Treaty Organization.]
Wind noise minimization for single infrasonic sensors.
Authors: Webster Jeremy , Raspet Richard
Published: July 2011

One of the main limitations in outdoor infrasound measurements in open areas is the noise generated by turbulent winds. Pipe arrays or arrays constructed using porous hoses are often used to average out the pressure fluctuations from the turbulence. These devices have a limited useful bandwidth, since they also average out the acoustic response at higher frequencies and distort received acoustic waveforms. We have investigated relatively small configurations to reduce wind noise based on our research into low-frequency wind noise over open outdoor surfaces. Such devices may be useful for temporary arrays for which waveform integrity is more important than wind noise reduction at very low frequencies. In this talk, we present results for infrasonic sensors placed bare on the surface, mounted underneath a flush metal foam flat surface, and under two types of hemispherical dome. For reference, these will be compared to and contrasted with wind noise measurements with barriers and pipe arrays previously reported in the literature [J. Acoust. Soc. Am. 114, 1379–1386]
Modeling infrasound propagation using the Fourier pseudo-spectral method.
Authors: Waxler Roger , Velea Doru
Published: July 2011

As part of an undergoing effort to model infrasound propagation in the atmosphere, a pseudospectral time-domain method is employed to solve the linearized equations of thermo-viscous compressible gas dynamics in a two dimensional stratified atmosphere over a flat rigid ground surface. The system of equations is transformed from the spatial to the wavenumber domain using a spatial Fourier transform for the horizontal variables and a generalized trigonometric transform (to account for the ground surface) for the vertical variable. Time evolution is computed numerically in the wavenumber domain using a Runge–Kutta algorithm. In this initial work only viscous and thermal losses are taken into account. To handle the no-slip condition at the ground, acoustic boundary layer theory is used. Numerical results showing the effects of complex meteorology on the the propagation of an acoustic pulse will be presented. [Work supported by US Army SMDC.]
In-situ infrasonic calibrations at Windless Bight, Antarctica.
Authors: Szuberla Curt , Withoff Dave , Fee Dave , Helmericks Jay , Gabrielson Tom
Published: July 2011

The array elements at the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) infrasound station I55US (Windless Bight, Antarctica) are covered with more than a meter of snowfall each year between maintenance visits. During these service trips, in the austral summer, the microphones and their attached wind reduction pipe arrays are brought back to the surface of the Ross Ice Shelf snow. During the November 2010 maintenance visit, an in-situ calibration reference microphone system was used in an attempt to characterize the effect of this compacted snow layer on the performance of the wind reducing elements associated with each microphone. In order to accomplish this, measurements were taken before and after the digging at certain elements. Additionally, one element was measured before and after a meter of fresh snow fell on the dug-up sensor and pipes. This presentation will address the basic technique, developed for the CTBTO arrays, our results, and broader potential applications.
Simulation and analysis of infrasound generated by severe storms.
Authors: Schecter David A. , Nicholls Melville E.
Published: July 2011

Recent observations and longstanding theoretical considerations suggest that a tornado can have a detectable signature in the infrasound of a severe storm. To reliably distinguish the vortex signal from extraneous noise, it is important to advance current understanding of the different mechanisms that produce infrasound in atmospheric convection. Without detailed observations of the acoustic sources within a storm, numerical modeling may be the best method of investigation. This avenue of research is being explored with the Regional Atmospheric Modeling System customized to simulate aeroacoustics. By comparison to analytical results, it has been shown that the model adequately generates the infrasound of vortices and basic diabatic cloud processes. Given these encouraging results, the model is now being used to simulate the infrasound of various convective systems and individual storm features including a towering cumulonimbus (with multiple hydrometeor categories) and artificially forced tornadoes with realistic structure and fluctuations. This presentation will expound a convenient technique for analyzing the sources of infrasound in a complex storm simulation based on an acoustic wave equation (Lighthill analogy) for the perturbation Exner function. It will also provide some computational evidence that moderate-to-strong tornadoes can emit stronger 0.1–1 Hz infrasound than generic storms. [Work supported by NSF-ATM-0832320].
Utah Testing and Training Range 2010: Large scale infrasound sensor deployment to Utah and Idaho.
Authors: Talmadge Carrick L. , Waxler Roger , Kleinert Daniel E. , Nava Sue , Assink Jelle , Buchanan Hank
Published: July 2011

A large scale infrasound deployment was undertaken during the summer of 2010 using large blasts (19.5-tons TNT, 8.8-tons TNT, and 1.9-tons TNT) that were taking place at the Utah Testing and Training Range west of Salt Lake City, UT. A total of four sensors were deployed in the near field and additional 114 infrasound sensors were placed in the “far field.” Six arrays of five elements each were delayed along a “stratospheric arc” 220-km from the source from a bearing of 300° to 355° in 5* increments. Additional six arrays (3 with three elements and 3 with six elements) were deployed in a northern “thermospheric” line, designed to separate the thermospheric line from the stratospheric one. Data will be reported on measurements from 24-explosions. The implications of these measurements on empirical models of atmospheric structure (e.g., G2S) will be discussed.
Interaural time difference processing in birds and alligators: Evolution of binaural circuits.
Authors: Carr Catherine E.
Published: July 2011

The auditory systems of birds and mammals use timing information from each ear to detect interaural time differences (ITDs). In birds, the circuits that encode ITDs are composed of delay lines and coincidence detectors. To determine if these circuits are evolutionarily conserved, we have compared the physiological and anatomical organizations of the auditory nuclei of birds and their sister group, the crocodilians. In both groups, precisely timed spikes in the first order nucleus magnocellularis encode the timing of sounds, and NM neurons project to neurons in the nucleus laminaris that detect interaural time differences. NL neurons act as coincidence detectors, and encode ITDs in both birds and crocodilians. In the crocodilians, however, the range of best ITDs represented in NL was larger than in birds, possibly because of the network of canals that connect the middle ear spaces. These interaural canals are also found in birds, and, for low frequency sounds, may in both groups provide a larger range of ITDs than predicted by actual head size.
On the measurement of angular dependent sound transmission through airborne, supercritical plates.
Authors: Shaw Matthew D. , Anderson Brian E.
Published: July 2011

Angular dependence of sound transmission through airborne plates, at frequencies above their critical frequencies (supercritical), is discussed. Experimental measurements of this angular dependence have been conducted using phased array methods. Theory governing the sound transmission through supercritical plates is already well developed; however, experimental results are known to depart from theory near grazing incidence. The details of the measurement apparatus and issues involved in making this type of measurement will be discussed. The results of the measurements will be compared to theory, focusing on the departure of experiments from theory.
Effects of morpheme type on Deg Xinag ejectives.
Authors: Hargus S
Published: July 2011

Stem-initially in Deg Xinag (Athabaskan), there is a three-way contrast between voiceless unaspirated, voiceless aspirated and ejective stops, and affricates at a variety of places of articulation, including alveolar with lateral release. In prefixes, there is a single lateral ejective affricate, /tɫ’/, historically from *h-s-ɫ-, [Leer (2000)]. In a previous acoustic study [Hargus (2008)], the prefixal lateral affricate had relatively few of the characteristics of ejectives in stems (VOT, f0 perturbation, jitter perturbation, rise time, and normalized fricative energy measures). However, it was not clear whether the reduced number of ejective characteristics of the prefix was a reflection of its evolution from non-ejective *h-s-ɫ- or an expected effect of morpheme type (presumably via concomittant differences in stress). In a follow-up study, the ejective characteristics of a prefixal retroflex ejective affricate (first person plural subject) are compared to those of retroflex ejective affricates in stems. Retroflex ejectives in stems have significantly longer VOT, slower rise time, lesser normalized fricative energy, and/or differences in normalized f0 relative to the prefix. This suggests that the variability of the prefixal lateral ejective affricate is an expected effect of morpheme type, and not a stage in the evolution to ejective. [(Work supported by NSF.)]
Vowel devoicing in Mandarin Chinese spoken in Taiwan.
Authors: Shirai Setsuko
Published: July 2011

The results of the research on vowel devoicing in Mandarin Chinese spoken in Taiwan are presented. In this research, 30 Taiwanese who have lived in Taipei area at least 10 years are served as subjects. They read the sentences written in traditional Chinese, whose final syllables consist of voiceless fricatives or aspirated affricates and high vowels. The results agree with the previous study conducted by Shirai et al. The vowels carry tone 3 (rising and falling tone) tend to undergo devoicing. In addition, some final vowels with frication in high frequency, also known as syllabic sibilants, are partially devoiced. The devoicing of syllabic sibilants is discussed. Furthermore, vowels in penult syllables undergo devoicing. Whether devoicing in Mandarin Chinese is delted or replaced is also discussed.
The theory of adaptive dispersion and acoustic-phonetic properties of cross-language lexical-tone systems.
Authors: Alexander Jennifer A.
Published: July 2011

Lexical-tone languages use fundamental frequency (F0) to convey word-meaning. Nearly half of all languages use lexical tone [Maddieson (2008)], yet those systems are under-studied. To increase our understanding of speech-sound inventory organization, I extend to tone-systems a model of vowel-system organization, the theory of adaptive dispersion (TAD) [Liljencrants and Lindblom (1972)]. This is a cross-language investigation of whether and how tone-inventory size affects acoustic tone-space size. Five languages with different-sized tone-inventories were compared: Cantonese (six tones), Thai (five tones), Mandarin (four tones), Yoruba (three tones), and Igbo (two tones). Six native speakers (three female) of each language produced 18 CV syllables in isolation, with each of his/her language’s tones, six times. Tonal F0 (semitones) was measured at three equidistant points across the vowel. Each language’s tone-space was defined in two ways: (1) the F0 difference between its highest and lowest tones and (2) the configuration of tones in a 2-D space defined by onset F0 x offglide F0. Following the TAD, I predicted that languages with larger tone-inventories would have larger tone-spaces; this was not supported by (1). However, the dispersion of tones in (2) supports the TAD hypothesis that sound-categories will be well-dispersed across the space and highly contrastive.
The vowel tango: Rethinking vowel-inherent spectral change.
Authors: Rogers Catherine L. , Glasbrenner Merete M. , DeMasi Teresa M. , Bianchi Michelle
Published: July 2011

Vowel-inherent spectral change (VISC) refers to vowel-intrinsic formant movement across a vowel steady state. VISC has been shown to (1) be consistent across talkers within a given dialect, (2) vary regularly across vowels within a dialect, (3) vary regularly across dialects, and (4) be necessary for peak vowel-identification accuracy. Hence, VISC has become accepted as a phonetic feature of monophthong vowels of North American English. VISC is typically portrayed using averages across tokens and talkers, highlighting regularity but potentially masking individual differences. To understand vowel production by second-language learners, we were particularly interested in such individual variation. In analyzing individual differences for neighboring target vowels, we found no single time point at which all sets of target vowel tokens were well distinguished from one another. However, looking across three time points, all native-speaker vowel sets were well distinguished from each possible neighbor set at some time point. Thus, VISC can be seen as the steps in a sort of dance, as each vowel moves to avoid overlapping with another, ultimately causing overlap with another and then more movement. This perspective is compatible with models of efficient coding and stochastic and/or exemplar based models of speech production and perception. [NIH-NIDCD #1R03DC005561-01A1.]
Re-examining the effects of perturbation magnitude, direction, and duration on the pitch-shift reflex.
Authors: Allen Patricia J. , Burnett Theresa A.
Published: July 2011

Comparing average voice fundamental frequency (F0) responses to pitch-shifted auditory feedback has revealed effects of some stimulus parameters, but not of others. We hypothesize that some stimulus effects on pitch-shift reflex characteristics are spurious, the result of differences in the incidence of the pitch-shift reflex rather than its inherent characteristics. Using a template correlation analysis technique that allows the pitch-shift reflex to be identified in individual trials, the effects of stimulus magnitude, direction, and duration were re-examined. We presented 30 healthy adults with auditory feedback pitch shifts during sustained phonation of the vowel /u/. Pitch shifts were all combinations of magnitude (50, 300, and 600 cents), Direction (up and down) and duration (100 and 500 ms) for a total of 12 conditions. Results indicate significant effects of pitch perturbation magnitude and direction on the incidence of the pitch-shift reflex. Implications for our understanding of voice F0 responses to changes in auditory feedback are discussed.
Subphonemic planning across syllable and word boundaries.
Authors: Derrick Donald , Gick Bryan
Published: July 2011

Previous research demonstrated that there are no fixed motor programs or tasks in speech, and there is evidence for subphonemic planning in speech within a word across up to two phoneme boundaries [Derrick and Gick (Submitted)]. Because this evidence is word-internal, it could be suggested that speakers simply memorize many motor programs for each word and draw on them as needed. We demonstrate that speech planning extends across three phonemes, two syllables and a morpheme boundary. Participants produce more up-flaps the first flap of words such as “editor” and “auditor”, which often end with the tongue tip up, versus alveolar taps in “edify” and “audify,” which end with the tongue tip down. We also demonstrate planning across word boundaries. Participants also produce more up-flaps in “edit” and “audit” if these words are followed by “a,” which has a double flap sequence, than if the words are followed by “the,” which does not. Planning across morpheme and word boundaries would ultimately require memorization of an infinite number of motor programs or tasks.
Word duration and segment deletion as measures of reduction in a corpus of spontaneous speech.
Authors: Dilts Philip , Baayen R. Harald , Tucker Benjamin V.
Published: July 2011

The present study explores phonetic reduction in the Buckeye Corpus [Pitt et al., Speech. Commun. 45, 89–95 (2005)] following up on the work of Johnson [Proceedings of the 1st Session 10th International Symposiam (2004), pp.], who counted the number of segments and syllables deleted from each word in the subset of the corpus that was available at the time. The first experiment presented here provides updated rates of segment deletion (over 25% of words) and syllable deletion (over 6% of words) as measures of reduction rates in the entire completed corpus. The second experiment investigates reduction in the duration of words as a function of several linguistic factors, including frequency, conditional probability, and rate of speech. The data are modeled using multiple mixed-effect linear regression to predict both the duration of each word and the reduction from the median duration of each word. Age, gender, and interviewer gender were not found to affect word duration. Citation length and current rate of speech were both strong predictors of word duration. Frequency and predictability from context also correlate strongly with word duration. Verbs were found to be significantly shorter in duration than other content words with the same citation length.
Diphthong formant transitions in four speaking tasks.
Authors: Kuo Christina , Weismer Gary
Published: July 2011

Diphthongs have been demonstrated to have longer durations and to involve more extensive articulatory gestures, reflected as larger frequency changes, when compared to monophthongs [Lehiste, I., and Peterson, G. E., J. Acoust. Soc. Am. 33, 268–277 (1961); Holbrook, A. and Fairbanks, G., J. Speech Hear. Res. 5, 38–58 (1962)]. However, limited work has documented the nature of diphthong variability. This study describes and examines diphthong formant transitions in the speech production of ten healthy male native speakers of American English, with Wisconsin dialects, to identify and evaluate the pattern, if any, of diphthong variability in four speaking tasks: conversational speech, story reading, sentence in citation form, sentence in clear speech. The study is motivated by the phenomenon of vowel reduction [Lindblom, J. Acoust. Soc. Am. 35, 1773–1781 (1963)], which has been documented widely for monophthongs, as well as speaking rate-induced changes in diphthong formant transitions [Gay, T., J. Acoust. Soc. Am. 44, 1570–1573 (1968)]. Five diphthongs /eɪ/, /ɑɪ/, /ɑU/, /oU/, and /ɔɪ/ in American English are included, and formant transition measures, including transition duration, transition extent, and derived slope (i.e., transition extent/duration) are used for analysis. Findings are discussed within the framework of the acoustic theories of speech production.
Comparison of two and three spatial dimensional solutions of a parabolic approximation of the wave equation at ocean-basin scales in the presence of internal waves: 200–250 Hz.
Authors: Spiesberger John
Published: July 2011

Numerical solutions are given for a parabolic approximation to the acoustic wave equation at 200 and 250 Hz in two and three spatial dimensions to determine if azimuthal coupling in the horizontal coordinate significantly affects horizontal correlation in the presence of internal gravity waves in the sea. Coupling is a small effect at distances of 4000 km or less. This implies that accurate solutions are possible using computations from uncoupled vertical slices. Shapes of horizontal correlation are not far from shapes given by several theories. Estimates of horizontal correlation at 4000 km and 200 and 250 Hz are about 0.4 and 0.3 km, respectively. [Work supported by the Office of Naval Research Contract Nos. N00014-06-C-0031 and N00014-10-C-0480 and by a grant of computer time from the DOD High Performance Computing Modernization Program at the Naval Oceanographic Office.]
Bayesian ambient noise inversion for geoacoustic uncertainty estimation.
Authors: Quijano Jorge E. , Dosso Stan , Dettmer Jan , Siderius Martin , Zurk Lisa M.
Published: July 2011

The noise produced by wind-driven breaking waves in shallow water provides a method for probing the seabed, and drifting vertical arrays have been deployed for remote sensing of geoacoustic parameters by estimating the frequency- and angle-dependent reflection coefficients. In addition, techniques such as spectral factorization allow obtaining the impulse response of the multilayered seabed environment. This impulse response carries information of the sediment acoustic properties that can be extracted and passed as prior information to a Bayesian framework for the estimation of geoacoustic parameters and its corresponding uncertainties, which ultimately determine the resolution of the method. The Bayesian formulation estimates a joint posterior probability density function, from which marginal density functions, moments, and covariances between geoacoustic parameters of interest can be quantified. In this work, Bayesian inversion based on Markov-chain Monte Carlo sampling is applied to simulated ambient noise data for the estimation of layer thicknesses, compressional sound speed, density, and sediment attenuation, and the resolution of the method is explored as a function of qualities of the data such as array design and wind speed. The approach is applied to experimental data collected near Sicily.
Comparative performance of attenuation treatments designed to mitigate underwater noise from pile driving.
Authors: Hastings Mardi C.
Published: July 2011

Peak sound pressure levels generated by large cast-in-shell steel (CISS) piles being driven by impact hammers into a sedimentary bottom can exceed 180 dB re 1 μa out to a 1-km range. Most solutions for mitigation of sound radiation from piles involve getting air around them. Three treatments are theoretically evaluated: a bubble curtain, a bare steel sleeve, and an “air-wrapped” steel sleeve. Attenuation by bubble curtains is a function of thickness and void fraction; however, to achieve high attenuation at low frequencies, bubbles must large, which complicates the design. A bare steel sleeve provides little attenuation underwater at low frequencies. From 550–800 Hz, frequencies containing the most acoustic energy for radiation from 36- and 48-in. diameter CISS piles, it is only 1 dB. Adding an air wrap on the inside and/or outside walls of the sleeve decouples it from the water so it can act more like a rigid body to provide higher transmission loss. Along with the air-water interfaces, the air-wrapped sleeve results in 35–40 dB attenuation. So how can air be included in an underwater structure to provide sound attenuation? A correlation between this analysis and effectiveness of current field techniques will be presented.
Acoustic transmission loss in industrial pile driving.
Authors: Stockham Mark L. , Dahl Peter H. , Reinhall Per G.
Published: July 2011

Industrial pile driving is a source of high-level underwater noise and new understanding of its effects on the behavior and health of marine mammals and fish has motivated numerous regulations intended to limit these effects. Of primary importance is to identify a suitable transmission loss model to predict where, given a certain source level, the noise produced by the pile driving reaches regulatory thresholds. In November 2009, data were collected from a marine construction site in the Puget Sound. Measurements at two ranges (8 and 12 m) from the pile being driven were taken using a nine hydrophone vertical line array (VLA). Concurrently, at a range of approximately 120 m, there was also a single hydrophone at a depth of 5 m (sensitive to frequencies greater than 10 kHz). By comparing the levels at the VLA to the more distant hydrophone across a number of pile strikes (each forming a identifiable short- and far-range pair), the transmission loss can be estimated. These results are in turn modeled using an approach based on the parabolic wave equation. [Work was funded by the Washington Department of Transportation.]
Standards for measurement and reporting of underwater sound: Application to the source level of trailing suction hopper dredgers.
Authors: de Jong Christ A. F. , Ainslie Michael A. , Jansen Erwin W. , Quesson Benoit A. J.
Published: July 2011

Increasing concern exists for possible effects of low frequency anthropogenic sound in the sea with particular emphasis on shipping, seismic surveys, off-shore construction, and underwater explosives. The need to make like with like comparisons between different sounds, sounds measured in different places, or sounds measured by different monitoring equipment is being addressed by means of a trans-national collaboration between national institutes from The Netherlands, United Kingdom, and Germany with the objective to develop a common measurement and reporting standard. Initial progress is reported with the emphasis on developing a common terminology, including the definition of “source level,” for which no widely accepted definition exists. A method to implement this definition has been developed and is applied to the measurement of seven trailer suction hopper dredgers undergoing various activities involving dredging, rainbowing, sand dumping and pumping ashore, and transit between sites. In the frequency range 30 Hz to 8 kHz, the measured third octave band source levels of the dipole formed by the ship source and its surface image, averaged over three angles between 15 and 45 deg from the horizontal (chosen for consistency with ANSI standard S12.64-2009), range approximately between 133 dB and 185 dB re 1 μPa2 m2.
Underwater radiated noise measurements of a noise-reduced research vessel: Comparison between a U.S. Navy noise range and a simple hydrophone mooring.
Authors: De Robertis Alex , Wilson Christopher D. , Dahl Peter H.
Published: July 2011

[A feasibility study was undertaken to characterize underwater radiated noise for a new class of noise-reduced fisheries research vessels using a field-deployable hydrophone system. Recent studies have demonstrated that vessel-radiated noise can impact the behavior of fish, and that periodic monitoring of survey-vessel radiated noise is desirable to characterize potential biases in fish abundance estimates. Vessel radiated noise is traditionally measured at naval ranges, but lower-cost options are desirable. Beam aspect measurements of a noise-reduced vessel made at a U.S. Navy noise range are compared to those made using an experimental mooring equipped with commercially available instrumentation. Hydrophone depths and distance-to-the-vessel were comparable for the mooring and those used at the Southeast Alaska Acoustic Measurement Facility (SEAFAC). SEAFAC and mooring measurements were taken within a day of one another. Data processing was consistent with the recent American national standard for measurement of underwater sound from ships (ANSI/ASA S12.64-2009/Part 1). The measurements from the experimental mooring were precise and comparable to those made at SEAFAC. This suggests that reliable measurements suitable for monitoring the underwater radiated noise of vessels with low source levels can be made in the field.
A short history: The Newman student awards program.
Authors: Cavanaugh William J. , Vigeant Michelle C.
Published: July 2011

This paper traces the Newman Award Fund programs from the first student medals awarded in 1986 to 13 recent awards in “for merit in the study of Architectural Acoustics” bringing the total to 225 medals awarded to students at over 55 schools of architecture, architectural engineering, and music to date. Any degree granting institution offering a basic course in architectural acoustics and opportunities for students to apply their knowledge in student theses, senior design projects, or research may nominate one graduating student for the Newman Medal from that school each year. In addition, every 2 or 3 years the Fund awards Theodore Schultz Grants to teachers and researchers in architectural acoustics for merit in the development of course materials, innovative course programs, or new texts. A third leg of the Fund program is the Wenger Prizes awarded to student teams for meritorious design in competitions sponsored each year by the ASA Technical Committee on Architectural Acoustics. This paper brings the perspectives and experiences of a charter member of the Newman Fund Advisory Committee as well as those of a more recent member of the Committee, who is a past Newman medalist in her own right. For Newman Fund updates visit www.newmanfund.org.
Acousticatalyst.
Authors: Butko Daniel
Published: July 2011

Architectural acoustics, generally the result of meticulous calculations and implementation, can occasionally be unintentional byproducts of material choices and spatial relationships. Such an example of fortuitous acoustics exists in downtown Tulsa, OK, commonly known as the center of the universe. This acoustical anomaly has entertained all walks of life for many years, bringing laughter and astonishment to numerous unexpected or doubtful inhabitants. Regardless of someone’s occupation, education, or preconceived thoughts, the acoustical results within this space are noticeable and intriguing. Numerous studies have been performed attempting to decipher the somewhat mysterious amplification of sound as sources radiate outward from the center of the circle. Research has proven both fundamental and advanced acoustical lessons, but the acoustical element as a “found object” in design sparks common interest to investigate further. While visiting Tulsa for an unrelated studio project, a group of University of Oklahoma design students became intrigued to visit the location due solely to the premise of something extraordinary. Those students are now suddenly interested in architectural acoustics. This paper focuses on this type of acoustical phenomenon as a catalyst to spark creative thought and interest in designers that previously placed little or no importance on acoustical design.
Wenger’s history with Newman Fund Award (student design competition).
Authors: Freiheit Ronald R.
Published: July 2011

A unique historical connection exists between Bob Newman and the Wenger Corporation. Before founding the Wenger Corporation in 1946, Harry Wenger was a dynamic band director with a talent for inventing solutions to improve music education. This passion included an appreciation of the fundamental importance of acoustics for rehearsal and performance. He wrote “In all too many cases, the [musicians’] fine preparations are seriously impaired by the poor acoustics of the stage or area from which the group is expected to perform.” To remedy that problem, Wenger began developing portable acoustical shells, engaging Bob Newman as a consultant during the 1960s. Newman visited Wenger’s Minnesota headquarters on a number of occasions, sharing animated discussions with Harry and Harry’s son, Jerry. The same passion for music and acoustics central to the Wenger Corporation’s founder continues today. The relationship with Bob Newman has evolved to encompass well-known names in acoustics such as Ron McKay, Larry Kierkegaard, Bill Cavanaugh, Chris Jaffe, and BBN’s successor firm, Acentech. The Wenger Foundation, funded by the Wenger Corporation, has served as ongoing award sponsor for the Student Design competition. Supporting the efforts of students working in music and acoustics is a logical, natural extension of Wenger’s passion.
Beyond architectural schools.
Authors: Hoover Anthony K.
Published: July 2011

The legacy of Bob Newman and Ted Schultz has benefitted architects, acousticians, and many others. This paper will summarize some of the author’s efforts to carry on their pedagogical spirit. The architectural acoustics class at Berklee College of Music began in 1987, with nearly 3500 total students over the years. A number of those students have been Newman Awardees, and some students have become teachers and even Newman Award mentors. The text “An Appreciation of Acoustics”, with funding support from the Schultz Grant, was written primarily for the Berklee class, and has been used elsewhere. The ASA College of Fellows recently began the Outreach to Undergraduate Students program, which has effectively introduced acoustics as a potential vocation to students in various schools and curricula.
University of Hartford’s Newman Fund Award recipients and the history of its undergraduate acoustical engineering programs.
Authors: Celmer Robert D. , Vigeant Michelle C.
Published: July 2011

The University of Hartford has two ABET-accredited undergraduate engineering programs in the area of acoustics: (1) the Bachelor of Science in Mechanical Engineering with Acoustics Concentration and (2) the Bachelor of Science in Engineering with a major in Acoustical Engineering & Music. Both programs encompass the same engineering vibrations and acoustics courses as well as the same acoustics projects sequence. Alumni of both undergraduate programs have successfully obtained positions in consulting (architectural and environmental), audio product and A/V design, musical instrument design, hearing- and psychoacoustic-related design, noise control, as well as pursued graduate degrees. Projects that have received Newman Fund awards have included investigations of auralization accuracy, just noticeable difference of clarity index (C80), and the relationship between room absorption and late lateral sound level (GLL). Alumni updates on four Newman Medalists will be presented.
A review of the Robert Bradford Newman Student Award Fund’s impact on the University of Nebraska Acoustics Group.
Authors: Ronsse Lauren M. , Wang Lily M.
Published: July 2011

The Robert Bradford Newman Student Award Fund has significantly impacted the acoustics group within the Architectural Engineering Program at the University of Nebraska-Lincoln over the past 10 years since the group was founded. Many of our students have received the Newman Student Medals. Students have also participated in the annual Student Design Competition, co-sponsored by the Newman Fund and the ASA Technical Committee on Architectural Acoustics. A Schultz Grant, disbursed by the Newman Fund, was awarded to our group in the year 2000 through which the webpage “concerthalls.org” was developed. This paper will review the positive influence that these three initiatives sponsored by the Newman Fund have had on the Nebraska Acoustics Group.
Auditory scene analysis in the echolocating dolphin.
Authors: Moore Patrick , Finneran James J.
Published: July 2011

Auditory scene analysis (ASA) refers to an animal’s ability to organize acoustic information in order to construct an understanding of its environment. In most mammals, vision is the primary sensory system and audition plays a secondary role; however, in the echolocating dolphin the reverse is likely true. One underlying tenant of ASA is stream analysis. This is the ability of an animal to integrate acoustic information over time and depends on short term memory for acoustic events. Moss and Surlykke [J. Acoust. Soc. Am. 110, 2207 (2001)] demonstrated that the bat echolocation perceptual system possesses the minimum requirements for stream analysis. This experiment replicates the bat study and tests the dolphins ability to assemble information about changing echo delay by discriminating between phantom targets of varying delays. Phantom targets are presented using a Phantom echo generator system. Emitted signals are received via contact melon hydrophone and delayed echoes transmitted directly to the dolphin lower jaw. Will the dolphin perform as well as the bat?
Critical bandwidths in echolocating porpoises, dolphins and whales.
Authors: Nachtigall Paul
Published: July 2011

Odontocete cetaceans may differ from most mammals in their response to noise. A close look at the published data [Popov et al. (2006)] of the critical bandwidths of two species of porpoises, the harbor porpoise (Phocaena phocoena) and the finless porpoise (Neophocaena phocaenoides), shows constant bandwidth critical bands in the high frequency area where echolocation signals are processed. A further look at harbor porpoise critical band data [Kastelein et al. (2009)] can be interpreted to show a mixture of constant Q bandwidths at lower frequencies and constant bandwidth data at higher frequencies. Data from Lemonds et al. [1997] indicate that the bottlenosed dolphin shows typical mammalian constant Q filters in lower frequency whistle areas but shifts to constant bandwidths in the areas of high frequency where echolocation discrimination processing is assumed to occur. Recent work (Kloepper et al.) has shown substantial loss in echolocation discrimination performance in the false killer whale with the loss of high frequency hearing. General high frequency hearing loss due to noise in the environment may particularly affect the echolocation processing capabilities of odontocetes and thus the foraging capabilities and fitness of odontocete echolocators. [Work funded by the Office of Naval Research.]
Biosonar beam formation in the bottlenose dolphin: Evidence for focusing in stages.
Authors: Cranford Ted W. , Krysl Petr , Trijoulet Vanessa
Published: July 2011

The idea that a dolphin biosonar beam is focused in a series of stages was put forth by Dr. Norris more than 50 years ago. Development of our finite element modeling (FEM) tools allowed us to test this hypothesis. We constructed an FEM model of a bottlenose dolphin (Tursiops truncatus) head from CT scans and tissue property measurements, and simulated the formation of the sonar beam. The sound transmission system within the dolphin forehead contains several tissue elements. The model allowed us to tease apart the functional contributions that these structures make to the formation of an echolocation beam. The simulations showed that the direction of the beam was consistent with prior biosonar investigations and illustrated that the narrowing of the sound transmission beam increases with various levels of refinement in structural (tissue) complexity. It appears as if each additional structure such as the melon, the air spaces, source location, and configuration adds to the effect of narrowing the beam, and their combined contribution is significant. [Work supported by the Chief of Naval Operations (Grant No. CNO45).]
Dolphin echolocation signals measured at extreme off-axis angles: Insights to sound propagation in the head.
Authors: Au Whitlow W. L. , Moore Patrick , Branstetter Brian , Finneran James
Published: July 2011

Echolocation signals radiated along the beam axis of an Atlantic bottlenose dolphin resemble single transient-like oscillations. As the azimuth of the measuring hydrophones in the horizontal plane progressively increases with respect to the beam axis the signals become progressively distorted. At approximately ± 45 deg, the signals begin to divide into two components with the time difference between the components increasing with increasing angles out ± 90 deg. The time difference between the two pulses measured by the hydrophone on the right side of the dolphin’s head is on the average approximately 10 μs larger than the time differences observed by the hydrophone on the left side of the dolphin’s head. The center frequency of the first pulse is generally lower by 33 to 47 kHz than the center frequency of the second pulse. When considering the relative locations of the two phonic lips, the data suggest that the signals are being produced by one of the phonic lips and the second pulse resulting from a reflection within the head of the animal. The data also indicate that the process of generating echolocation signals is a complex one and the exact mechanisms are not yet known.
Harmonic beamforming: Categorical perception segregates targets from clutter in bat sonar.
Authors: Simmons James A. , Bates Mary E. , Zorikov Tengiz V.
Published: July 2011

Beaming for FM biosonar transmissions of big brown bats is broad and frequency-dependent (70 deg at 25 kHz to 30 deg at 80 kHz). In flight, sound reception is directional and frequency-dependent, too, being oriented to the front and centered on-axis. A broadcast beam defined by the harmonic ratio of FM2 to FM1 depicts the frontal zone for flat-spectrum ensonification surrounded by increasingly lowpass ensonification for objects located off to the sides and farther away. The width and flat front of the central lobe of this harmonic-ratio beam predict the bat’s acoustic behavior during flights in obstacle arrays of different densities [Petrites et al., JCP-A (2009)] and the spatial unmasking of target detection by relocating clutter to progressively larger horizontal separations from the target [Sumer et al., JCP-A (2009)]. Amplitude-latency trading for responses to FM2 relative to FM1 in lowpass echoes causes echo-delay acuity to defocus, which also prevents masking from clutter. Only focused delay images can mask other focused images, which effectively excludes clutter echoes from causing masking. [Work supported by the ONR and the NIMH.]
Changes in spectrotemporal features of echolocation signals in multiple bat assemblages.
Authors: Bates Mary E. , Knowles Jeffrey M. , Barchi Jonathan R. , Simmons James A. , Fujioka Emyo , Watanabe Yu , Furusawa Yuto , Hiryu Shizuko , Riquimaroux Hiroshi
Published: July 2011

Echolocating bats face potential acoustical interference when flying and foraging near echolocating conspecifics. Quantifying changes in the signal structure of echolocation emissions between bats flying alone and within a larger group has proven difficult. Here, we use two new methodologies, an onboard radio telemetry microphone and a multiple microphone array to record the sounds of big brown bats (Eptesicus fuscus) flying alone and in small groups both in the laboratory and in the field. In a laboratory flight room, bats changed the ending frequency of their first harmonic when the conspecific with which they were paired emitted calls at a similar frequency. In the field, ending frequency and sweep shape were more variable among groups of bats flying together than among single bats compared to one another. The presence of other nearby bats did not have any effect on the timing of emissions or the interpulse intervals [Work supported by NIH, NSF, ONR, and JSPS.]
A shear wave elastography system for cetacean tissues and its potential application in fish bioacoustics.
Authors: Gray Michael D. , Martin James S. , Rogers Peter H.
Published: July 2011

A system is being developed to determine the in vivo, low-frequency elastic properties of cetacean head soft tissues. The system consists of two ultrasound-based components: a shear wave generation source and a vibrometer that monitors the induced tissue motions. Processing of the tissue motion data yields estimates of the frequency dependent shear speed and loss as a function of tissue depth. This work builds upon developments by other researchers in the area of radiation force elastography, with the addition of novel design features intended to enable the examination of tissue volumes that are relatively thick and/or obstructed by bone. Potential applications of the technology to fish bioacoustics investigations will be discussed. [Work supported by ONR.]
Tracing tonotopy in teleosts.
Authors: Smith Michael E.
Published: July 2011

It is not known whether the auditory hair cells of fishes possess a tonotopic organization in the saccule. To investigate this question, we exposed groups of six goldfish (Carassius auratus) to one of four tones (100, 800, 2000, and 4000 Hz) at 176 dB re 1 μPa for 48 h. The saccules of each fish were dissected and labeled with phalloidin in order to visualize hair cell bundles. The hair cell bundles were counted at 19 specific points in each saccule to determine the extent and location of hair cell damage. In addition to quantification of anatomical injury, hearing tests (using auditory evoked potentials) were performed on each fish immediately following sound exposure. The location of hair cell loss varied along the length of the saccule in a graded manner with the frequency of sound exposure, with lower and higher frequencies damaging the more caudal and rostral regions of the saccule, respectively. Similarly, fish exposed to lower frequency tones exhibited greater threshold shifts at lower frequencies, while high-frequency tone exposure led to hearing loss at higher frequencies. These data suggest that the frequency discrimination ability of goldfish is at least partially driven by peripheral tonotopy in the saccule.
Localization of monopole and dipole sound sources by midshipman fish (Porichthys notatus).
Authors: Zeddies David G. , Fay Richard R. , Alderks Peter W. , Gray Michael D. , Coffin Allison B. , Bandiwad Ashwin , Mohr Rober A. , Brown Andrew D. , Rogers Peter , Sisneros Joseph A.
Published: July 2011

A series of experiments was undertaken to investigate methods of sound source localization by fish. In these experiments, positive phonotaxic responses of gravid female plainfin midshipman fish (Porichthys notatus) to low-frequency, playback tones (80–90 Hz) were studied as they approached sound sources. The sound fields for simple (monopole) and relatively complex (dipole) sources within the behavioral arena were measured and characterized in terms of pressure and particle motion. Results indicate that female midshipman fish are able to locate sound sources in the near field using acoustic cues alone, and that they used the particle motion vectors to locate the source in both the monopole and dipole sound fields. It was also found that neither the lateral line nor the swim bladder was necessary for localization behavior, and that the fish were able to solve the 180 deg ambiguity inherent in the particle motion vectors. [Work was supported by the National Science Foundation.]