bluuebunny/crossref_metadata_2025 huggingface dataset:
Downstream effects of accented speech on memory
Authors: Van Engen Kristin
Published: May 2015

When speech is acoustically challenging, listeners frequently engage additional cognitive processes to effectively perceive it. This increased listening effort can have downstream effects on behavior, impairing listeners’ memory for what they have heard. To date, the listening effort literature has focused on processing speech in challenging listening situations that involve signal degradation due to noise and/or hearing impairment. A common theme in this literature is that acoustic degradation results in speech signals that deviate from listeners' stored phonological and lexical representations—a characteristic that degraded speech shares with speech produced in an unfamiliar accent. In this talk, we bring accented speech into the broader conversation about listening effort. In particular, we present preliminary results investigating the effects of intelligible foreign-accented speech on listeners' subsequent memory for words and sentences, even when these stimuli are intelligible. This work allows us to begin to incorporate listener effort associated with accented and degraded speech into a unified cognitive framework.
Electroencephalographic estimates of listening effort for hearing aid fitting
Authors: Strauss Daniel J. , Bernarding Corinna , Hannemann Ronny , Corona-Strauss Farah I.
Published: May 2015

Objective estimates of listening effort could support hearing aid fitting procedures. For this reason, we have analyzed neural correlates of listening effort using electroencephalographic methods and quantitative neurofunctional modeling in recent years. In particular, we have developed a neurophysical corticothalamic feedback model for electroencephalographic listening effort correlates in event-related potentials (ERP), which allowed us to compare simulated and measured data. However, ERP paradigms suffer from their limited flexibility in hearing aid fitting as they are restricted to a certain class of stimulation protocols. More recently, we have shown that attention related listening effort correlates can also be extracted from the oscillatory electroencephalographic activity when using a circular analysis of the instantaneous phase organization of Hardy space projected versions of the neural signals. In this talk, we are going (a) to review these approaches, (b) present results that show that the oscillatory method allows for the extraction of listening effort correlates in real life fitting settings, and (c) discuss the potential of time-resolved listening effort profiles. We think that the latter will stimulate new ideas what objective methods can do and what subjective psychometric methods cannot do.
Two-dimensional modeling of sound scattering with corrective smoothed particle method
Authors: Li Xu , Zhang Tao , Zhang YongOu
Published: May 2015

Meshfree methods are widely used in solving acoustic problems, since a set of arbitrary distributed particles can easily represent systems with moving boundaries or a variety of media. Among all meshfree methods, the smoothed particle hydrodynamics (SPH) method is suitable in handling problems with large ranges of density and object separation. This paper aims at using the corrective smoothed particle method (CSPM) to simulate the two-dimensional underwater sound scattering in the time domain. First, a novel kind of acoustic boundary for the CSPM is built and tested with a plane wave model. Then, the CSPM code is used to solve sound scattering field of an infinite long cylinder, which has different computational parameters for the boundary condition. Finally, the distribution of sound scattering pressure obtained with theoretical solutions is used to validate the CSPM code, and the efficiency of the code is analyzed by comparing with the SPH results in the fields of computation time and accuracy. The suitable value of computational parameters of the boundary is also discussed.
Understanding the concepts of uncertainty, reproducibility, and repeatability and the application to acoustic testing
Authors: Muehleisen Ralph T.
Published: May 2015

The consideration of uncertainty in measurement has long been an important part of scientific measurement. As measurements became standardized and testing and measurement standards were developed, various forms of uncertainty were sometimes, but not always, considered. Understanding various forms of uncertainty and the basic concepts of uncertainty, reproducibility, and repeatability are important for testing even if the estimation of them is not directly part of the test standard. In this presentation, the concepts of uncertainty, reproducibility, and repeatability for acoustic testing are explained using the ASTM E90 test as an example for explanation.
The influence of test fixture damping on the measurement of sound transmission loss
Authors: Shaw Jennifer A. , Moritz Charles T. , Carrera Armando
Published: May 2015

The sound transmission loss (STL) provided by a material depends on factors such as its mass, damping, and stiffness. In the lab, the damping and stiffness of a panel is influenced by the test fixture. To reduce test to test and lab to lab variation, the test standards give some detail with regards to installing the test specimen and sealing around the edges to prevent leakage between test rooms. However, many times it is not possible to simulate typical installation and sealing methods due to the wide range of installation options for the product, and a heavy layer of clay or other material is used to seal the sample in the fixture. As the size of the sample decreases, the edge damping from clamping and/or sealing the sample can add significant damping to a panel. Too much damping can cause a significant overstatement of the sample STL. This paper examines the influence of edge damping due to sealing clay on the STL of steel and aluminum panels.
The National Voluntary Laboratory Accreditation Program and Acoustical Testing Services Laboratory Accreditation Program
Authors: Harper Kari K.
Published: May 2015

This presentation provides an overview of NVLAP, the National Voluntary Laboratory Accreditation Program of the National Institute of Standards and Technology (NIST), with particular focus on NVLAP’s Acoustical Testing Services Laboratory Accreditation Program (LAP). Through the Acoustical Testing Services LAP, NVLAP provides third-party attestation of the conformance of its accredited acoustics laboratories to the requirements of ISO/IEC 17025:2005, General requirements for the competence of testing and calibration laboratories; NIST Handbook 150, NVLAP Procedures and General Requirements; and NIST Handbook 150-8, NVLAP Acoustical Testing Services. Specific topics covered in this presentation include a brief history of the Acoustical Testing Services LAP, the accreditation process, proficiency testing, and benefits of accreditation, such as international recognition of the competence of accredited laboratories and the concept of “tested once; accepted everywhere.”
Family and life experiences with Laymon
Authors: Miller Robert L.
Published: May 2015

This talk will bring to light memorable personal recollections growing up with Laymon as husband, father, and mentor. My own memories will illustrate how his love of acoustics, the people he worked with, and the problems he worked on ultimately led to my own career in acoustics. They will include a recounting of childhood business trips, flying experiences, and a summer job opportunity at Bolt Beranek and Newman. The talk also will include his wife, Lucy's, still-vivid recollections of Laymon’s first years at the Harvard Underwater Sound Lab, his nine years at Penn State, and many years later their times together as she accompanied him on his BBN lecture series. Unpublished excerpts from Laymon’s five-volume autobiography will be used to illustrate his own detailed and insightful accounting of other family and life experiences, including his own “ethical will,” written for later generations to better understand and appreciate the values and beliefs for which he most wanted to be remembered.
Reminiscences on Laymon Miller's remarkable twenty seven year consulting career at Bolt Beranek and Newman in Cambridge
Authors: Cavanaugh William J.
Published: May 2015

Laymon Miller joined the noise control engineering consulting staff of Bolt Beranek and Newman (BBN) on August 1, 1954, bringing an impressive record of experience in acoustics from Harvard University's top secret Underwater Sound Lab (HUSL) during WWll followed by ten years as head of the acoustics section at Penn State's Ordinance Research Lab (ORL). Laymon provided invaluable mentoring for many new BBN consulting staff members like this author whose only experience in acoustics were introductory courses in architectural acoustics taught by Physics Professor Richard Bolt at MIT's School of Architecture and the MIT Acoustics Lab, Laymon quickly established a reputation among BBN employees and clients alike as an outstanding teacher and contributed to BBN's unofficial title as the “third important graduate school in Cambridge.” He documented his diverse consulting career through numerous technical papers and articles, through technical brochures he prepared for clients like the US Army Corps of Engineers,manufactures like the Baltimore Air Coil Company and through reports he prepared for thousands of BBN projects on which he served as principal consultant. Laymon retired from BBN in 1981 after a remarkable 27 year career making quieter buildings, concert halls, workplaces, communities, transportation vehicles, and in general, “the world a better place.”
Laymon N. Miller—Contributions to industrial and community noise control
Authors: Wood Eric W.
Published: May 2015

Laymon N. Miller, following graduation in 1939 from the University of Texas in Austin, spent time first at the Underwater Sound Lab at Harvard University and then at Penn State as Head of the Acoustics Section of Ordnance Research Lab (ORL). In 1954, he joined Bolt Beranek and Newman where he was honored as their first Principal Consultant. This presentation describes his contributions to industrial and community noise control while consulting for a wide range of many clients for 27 years, until his retirement in 1981. Laymon Miller, a gentleman, friend, and colleague.
Laymon Miller—An exemplary acoustical consultant
Authors: Brooks Bennett M.
Published: May 2015

Laymon Miller was a “Consultant’s consultant.” He embodied a wonderful example of how to conduct oneself in the engineering consulting business, providing leadership in defining the functions and responsibilities of acoustical consultants. As a leader of our profession, Laymon was also a great friend to the National Council of Acoustical Consultants (NCAC). Former NCAC Newsletter Editor Bill Cavanaugh asked Laymon if he would serve as a guest editor for a continuing series tentatively titled “War stories … from the Consulting Veteran’s files.” Laymon answered the call, and this series continued for many years, capturing the “priceless gems” from which all of us, at all experience levels, can learn about the problems faced by consultants, and importantly about the solutions as applied in the field. Laymon was a talented and generous teacher, in print and in person, of those inside and outside of acoustical consulting. His experiences, related with insight and humor, have provided guidance to generations of those in general industry and to acoustical consulting practitioners alike. Laymon was elected an Honorary Member of NCAC in 1993, received the NCAC C. Paul Boner Award in 2007 and was presented the Institute of Noise Control Engineering (INCE) Outstanding Educator Award in 2008.
Experiences as editor of Laymon Miller’s book An NCAC Anthology in Noise and Vibration
Authors: Shade Neil T.
Published: May 2015

This presentation will recount the experiences of serving as editor of Laymon Miller’s book, An NCAC Anthology in Noise and Vibration, published in 2013 by the National Council of Acoustical Consultant’s (NCAC). Ever active in retirement, and at the behest of William Cavanaugh, Laymon contributed 60 papers from 1996 to 2012 to the NCAC Newsletter. These papers, along with his industry publications from 1957 to 2008, were the basis for his book. A committee was formed within NCAC to oversee the compilation and production of his book with this author serving as editor. The “engineer” in Laymon was evident in the meticulous organization of his writings and instructions provided to the editor. An NCAC Anthology in Noise and Vibration is organized in two parts. The first contains industry publications, arranged by topic. The second is Laymon’s NCAC articles arranged chronologically. The book concludes with his autobiography, which he humbly described “as a life of surprises.” Laymon dedicated his book to his friend and colleague Leo Beranek. Through editing the book the author gained insight into Laymon’s seminal contributions to building acoustics, noise and vibration control, community noise, his acoustic consulting adventures, and the work ethic of this remarkable man.
Hearing sensitivity in the Greater Prairie Chicken (Tympanuchus cupido)
Authors: Walsh Edward J. , Whalen Cara , Powell Larkin , Brown Mary B. , McGee JoAnn
Published: May 2015

As their scientific name implies, Greater Prairie Chickens (Tympanuchus cupido) are well known for their vocalizations, particularly those produced by males during courtship. In this report, the auditory sensitivity of a small cohort of Greater Prairie Chickens inhabiting the grasslands of southeastern Nebraska is presented as part of an effort to assess the capacity of wind turbine farm generated noise to mask male courtship vocalizations. Birds were captured from breeding grounds (leks) between March and June of 2014 and sensitivity to tone-burst stimuli was assessed using the auditory brainstem response. While response waveforms were typical of responses observed in other avian species, as was the bandwidth of audibility curves, preliminary data suggest the possibility that Greater Prairie Chickens may be unusually sensitive to low frequency tone-bursts in the vicinity of the dominant spectral component of the “booming” call, a prominent, intense vocalization that males produce during courtship. As part of the larger study that is designed to evaluate the potential impact of wind turbine farm operation on reproductive success, demography and overall survival rates, the potential masking influence of noise produced by turbine operations at wind farms will be discussed in relation to sensitivity findings.
Acoustic monitoring of Bryde’s whales (Balaenoptera edeni) in the northern Gulf of Mexico
Authors: Hodge Kristin B. , Tielens Jamey T. , Rice Aaron N.
Published: May 2015

Bryde’s whales (Balaenoptera edeni) are the most common mysticete species occurring in the Gulf of Mexico, yet due to a dearth of visual sightings and stranding data, little is understood regarding their spatial distribution and seasonal occurrence patterns. Two putative call types unique to this population of Bryde’s whales have recently been identified, providing an opportunity to understand Bryde’s whale spatial and temporal occurrence patterns using passive acoustic monitoring methods. In order to evaluate Bryde’s whale presence in the area, marine autonomous recording units (MARUs) were deployed from June 2010 through September 2011 in the northern Gulf of Mexico where Bryde’s whales have been historically observed. Distribution, seasonality, and diel patterns were examined separately for each of the call types at all sites and days during which acoustic data were collected by the MARUs. Preliminary results show Bryde’s whales were acoustically detected throughout the recording period. Of the two call types associated with Bryde’s whales, one call type was produced consistently more often than the other; however, both call types showed a similar diel pattern. These results suggest Bryde’s whales may reside or visit this area year-round, which may facilitate future monitoring efforts for this poorly studied population.
Newtonian and weighted essentially non-oscillatory models to describe the generation and propagation of the Cicada mating calls
Authors: Hughes Derke , Martinelli Sheri L. , Pierce Allan D. , Katz Richard A. , Koch Robert M.
Published: May 2015

Experiments and analyses of Hughes et al., JASA, 2009 are the origins of this research where we study the in-air waveform generation and propagation of the acoustic signals generated by cicadas. The sound generation is studied in a Newtonian model and the sound propagation is analysis by a numerical solver for viscous Burgers’ equation. The time histories from the tymbal surface velocities recorded by a laser Doppler vibrometer to the microphones positioned near the cicadas provide the test data. The Newtonian model describes the sound production systems process to generate the mating call signal structure. The numerical solver employs weighted essentially non-oscillatory (WENO) reconstruction to approximate the first and second derivatives of the semi-discrete operator. The WENO is utilizes due to the non-smooth structure of the cicada propagating waveform. Principally, the cicada mating signal in question has sharp transitions, since spectral methods tend to produce spurious oscillations as a result of attempting to represent a discontinuous function by a Fourier basis expansion. Thus, these analytical models are computationally tested to determine if the results capture the sound production and the transmission of the cicada mating calls. To verify the models are meaningful, the simulations are verified with real experimental data.
Steady streaming around a pulsating bubble located at the velocity node of a standing wave
Authors: AlHamli Mohammad , Sadhal Satwindar S.
Published: May 2015

We have examined the effect of the no-slip boundary condition on the steady streaming around a radially pulsating bubble, located at the velocity node of a standing sound wave. The no-slip condition can take place on the bubble surface under many circumstances, especially if the surface is contaminated or otherwise coated. We applied the singular perturbation analysis with the oscillation amplitude, ε=U0/(aω)<<1, as a small parameter and took the frequency parameter, M2=iωa2/ν, to be large. Here, a, U0, ω and ν are length scale, velocity scale, frequency, and kinematic viscosity, respectively. We further assumed that the bubble stays spherical in shape, the wavelength is significantly larger than the bubble radius, and no fluid transport takes place from the bubble to the surroundings. Additionally, the lateral and the radial oscillations, while at the same frequency, have a phase difference φ, and the amplitudes of both the oscillations are small compared to the bubble radius. We found that the streaming happened at a lower order than the non-pulsating case and it is more intense than the case of the shear free boundary condition. Furthermore, the phase difference was found to play a significant role in the streaming flow direction and its intensity.
The use of sound speed in downhole flow monitoring applications
Authors: Unalmis Haldun
Published: May 2015

This paper describes the use of sound speed in flow monitoring applications in the high-pressure/high-temperature downhole environment. Downhole flow monitoring is an area that continuously receives attention for many reasons including zonal production allocation in multi-zone intelligent completions with inflow control valves (ICV), detection of production anomalies, as well as reduction of surface well tests and facilities. The propagation speed of a sound wave is a powerful tool to extract useful information from a flowing fluid medium in pipe whether the medium consists of a single-phase or multiphase flow. Considering the complex nature of the flow patterns and changing phase fractions from reservoir to surface, obtaining the propagation speed of sound in this harsh environment is not a trivial task, especially if the interest is real-time flow monitoring. The demanding applications span a wide spectrum from very noisy medium (usually created in gas/liquid flows by the presence of ICV) to very quiet medium, which usually originates from slow-moving liquid/liquid flows. Real-life examples are used for demonstrations. Although most examples are based on strain-based local sensing of the flow, the use of sound speed is independent of the methodology and can be implemented by other methods such as acoustic-based distributed sensing.
Relation between measures of psychoacoustic abilities and masking release for unprocessed, envelope, and temporal fine-structure speech in listeners with normal and impaired hearing
Authors: Leger Agnes C. , Desloge Joseph G. , Reed Charlotte M. , Braida Louis D.
Published: May 2015

Léger et al. [J. Acoust. Soc. Am. 135, 2160, 2014] studied masking release in normal-hearing and hearing-impaired listeners using unprocessed speech and speech processed to convey envelope (ENV) or temporal fine-structure (TFS) cues. Consonant identification scores in speech-shaped background noise (continuous and square-wave interrupted at a rate of 10 Hz) indicated a substantial masking release (MR, better performance in the interrupted noise) for all speech types for normal-hearing listeners but only for the TFS speech in most hearing-impaired listeners. The current study was concerned with relating consonant identification scores and masking release to SRTs for sentences in both types of noise as well as to measurements of basic psychoacoustic abilities. These measures included absolute pure-tone detection thresholds, estimates of auditory bandwidth using a notched-noise procedure, and estimates of cochlear compression obtained using a forward-masking paradigm. For both unprocessed and ENV speech, intelligibility scores and MR were correlated with absolute thresholds and auditory bandwidths in the mid-frequency region (but not at a lower frequency). These correlations were less strong for TFS speech intelligibility and did not predict MR. Cochlear compression was not related to speech intelligibility when controlling for the effect of absolute thresholds. [Work supported by NIH R01 DC000117.]
Dynamic binaural sound source localization with interaural time difference cues: Artificial listeners
Authors: Sun Liang , Zhong Xuan , Yost William
Published: May 2015

When an array of two acoustic sensors is used to localize sound sources based on time differences alone, possible solutions form a cone of confusion. This study, together with a similar one for human listeners, demonstrates that azimuth/vertical planes localization of a sound source using only time difference information is feasible when self-motion measurement of the listener is available. In particular, the case of a static sound source playing that broadcasts low frequency pure tone signals was investigated. A dummy head is mounted on top of a rotating chair to mimic the head and body motion of human beings, as well as to collect audio signals. A gyroscope was mounted on top of the dummy head to collect self-motion data. A mathematical model was constructed to describe the interaural time difference (ITD) change over time, and an Extended Kalman Filter (EKF) was used to estimate the spatial angles of the sound sources with respect to the listener using the developed mathematical model and measured data. The effectiveness and robustness of the developed algorithm are shown by both the numerical and experimental results, which reveal the quick convergence of the estimated spatial angles toward their real values given noisy measured data. The possibilities of using other spatial hearing cues were also discussed.
Effects of harmonic roving on pitch discrimination
Authors: Santurette Sébastien , Le Gal de Kérangal Mathilde , Joshi Suyash N.
Published: May 2015

Performance in pitch discrimination tasks is limited by variability intrinsic to listeners which may arise from peripheral auditory coding limitations or more central noise sources. The present study aimed at quantifying such “internal noise” by estimating the amount of harmonic roving required to impair pitch discrimination performance. Fundamental-frequency difference limens (F0DLs) were obtained in normal-hearing listeners with and without musical training for complex tones filtered between 1.5 and 3.5 kHz with F0s of 300 Hz (resolved harmonics) and 75 Hz (unresolved harmonics). The harmonicity of the tone complexes was varied by systematically roving the frequency of individual harmonics, which was taken from a Gaussian distribution centered on the nominal frequency in every stimulus presentation. The amount of roving was determined by the standard deviation of this distribution, which varied between 0% and 16% of the tested F0. F0DLs for resolved harmonics remained unaffected for up to 6% roving, and increased thereafter. For unresolved harmonics, performance remained stable up to larger roving values. The results demonstrate a systematic relationship between F0DLs and stimulus variability that could be used to quantify the internal noise and provide strong constraints for physiologically inspired models of pitch perception.
Effects of compression channel number and linked compression on masked lateralization performance in simulated bilateral cochlear implant listening
Authors: Spencer Nathaniel , Brown Christopher
Published: May 2015

Bilateral cochlear implants (CIs) are becoming increasingly common. It is hoped for bilateral CI users that audibility in quiet will be complemented by performance benefits in everyday binaural listening tasks, like location-identification of a speech talker presented amid other talkers. While normal-hearing (NH) listeners have typically performed well in such kinds of tasks, bilateral CI users have performed poorly. It is possible that, for bilateral CI users, better performances can be attained through a re-thinking of device signal-processing strategies. In particular, we are interested in evaluating alternatives to single-channel independent compression, as is typically applied at the automatic gain control (AGC) stage. Specifically, we test the hypothesis that for simulated bilateral CI users (listeners with both NH and hearing impairments, HI), lower rms-error in a masked lateralization task will be achieved for multi-channel AGC and linked AGC, than for single-channel independent AGC, with and without pre-emphasis filtering, and for low and high compression thresholds. Preliminary data suggest a lower rms-error for linked compression than for independent compression, in conjunction with no detrimental effect of multi-channel compression. These data support the possibility of linked AGC with multi-channel AGC as an alternative to independent AGC in bilateral CI listening.
The addition of a second lag to the lead-lag precedence effect paradigm for temporally overlapping noise stimuli
Authors: Pastore M. Torben , Braasch Jonas
Published: May 2015

In reverberant conditions, humans routinely perceive sound sources in the direction of the first wavefront despite competing directional information presented by a host of reflections arriving soon after—the so-called “Precedence Effect.” This is often tested over headphones using a “direct sound” (lead) with a single delayed copy (lag) serving as a modeled reflection. Previously, we employed this common experimental paradigm to investigate the lateral extent of the precedence effect using temporally overlapping noise stimuli. The current study extends this inquiry towards the multiple reflections encountered in room-acoustic scenarios by presenting a second lag. Lead and lag stimuli are 200-ms Gaussian noise (500-Hz center frequency, 800-Hz bandwidth) presented dichotically with a programmable amount of delay for both lags. Relative to the intensity of the lead, the two lags are presented at 0, −3, and −6 dB. The lead is presented at the midline, with an ITD of 0 μs. The two lags are delayed by between 1 and 7 ms, with opposing ITDs of ±300 μs. Listeners indicate the lateralization of their auditory event with an acoustic pointer.
Relation between temporal envelope coding, pitch discrimination, and compression estimates in listeners with sensorineural hearing loss
Authors: Bianchi Federica , Santurette Sébastien , Fereczkowski Michal , Dau Torsten
Published: May 2015

Recent physiological studies in animals showed that noise-induced sensorineural hearing loss (SNHL) increased the amplitude of envelope coding in single auditory-nerve fibers. The present study investigated whether SNHL in human listeners was associated with enhanced temporal envelope coding, whether this enhancement affected pitch discrimination performance, and whether loss of compression following SNHL was a potential factor in envelope coding enhancement. Envelope processing was assessed in normal-hearing (NH) and hearing-impaired (HI) listeners in a behavioral amplitude-modulation detection task. Fundamental frequency difference limens (F0DLs) were obtained in the same listeners for complex tones with varying harmonic resolvability. Basilar-membrane input/output functions were measured to assess individual compression ratios. For NH listeners, F0DLs decreased with increasing harmonic resolvability. For the unresolved conditions, all five HI listeners performed as good as or better than NH listeners with matching musical experience. Two HI listeners showed lower amplitude-modulation detection thresholds than NH listeners for low modulation rates, and one of these listeners also showed a loss of cochlear compression. Overall, these findings suggest that some HI listeners may benefit from an enhancement of temporal envelope coding in pitch discrimination of unresolved complex tones, and that this enhancement may be also ascribed to a reduction of cochlear compression following SNHL.
Time-efficient multidimensional threshold tracking method
Authors: Fereczkowski Michal , Kowalewski Borys , Dau Torsten , MacDonald Ewen N.
Published: May 2015

Traditionally, adaptive methods have been used to reduce the time it takes to estimate psychoacoustic thresholds. However, even with adaptive methods, there are many cases where the testing time is too long to be clinically feasible, particularly when estimating thresholds as a function of another parameter, such as in temporal masking curves or when characterizing auditory filters. Here we present a new method, the “grid” method, which adaptively varies multiple parameters during each experimental run. By changing the way the parameter-response space is sampled, the method increases the proportion of experimental time spent in the vicinity of the sought-after threshold curve. The resulting increase in time-efficiency is substantial and can make some measurements clinically feasible. Thresholds from temporal masking curves obtained with the grid method are compared with those from one of the most time-efficient standard methods (single-interval up-down adaptive method of Lecluyse, 2013). Overall, individuals’ results from both methods are very highly correlated, but the grid method was an order of magnitude faster in estimating thresholds. The application of the grid method to other measurements, such as characterizing auditory filters, will also be discussed.
An adaptive procedure for estimating the auditory-filter phase response
Authors: Klyn Niall A. , Feth Lawrence L.
Published: May 2015

Current techniques for psychophysical estimates of the phase curvature of the basilar membrane rely on laborious data collection. For each point on the basilar membrane a separate threshold estimate — more commonly several estimates — must be found for each phase relationship. This practically limits the precision of the estimates and the number of subjects for whom estimates may be obtained. Here, we propose a rudimentary adaptive technique for rapidly estimating the phase curvature of the basilar membrane psychophysically. Consistent with the extant data the procedure assumes that the underlying threshold versus masker curvature function has a U shape. Rather than find thresholds at each value of masker curvature, the procedure seeks out only the value which produces the least masking. It does so by dropping the signal level until only three adjacent masker curvature values fail to mask the signal. New upper and lower boundaries for the masker curvature are then set, the step size between masker curvature values is reduced, and the previous steps are repeated. We present a comparison of the estimates produced by the conventional techniques and the proposed adaptive technique, as well as their relative efficiencies.
A meta-analysis of the effects of hearing impairment and hearing aids on directional hearing
Authors: Akeroyd Michael , Whitmer William M.
Published: May 2015

We report here meta-analyses of all the experiments that have been done since the 1980s on how accurate hearing-impaired listeners are at determining the spatial direction of sound sources. The results demonstrate that their performance is somewhat worse than normal hearing listeners for all directions, and especially so for sounds presented from the side (including distinguishing front vs. back) or for changes in elevation. There is considerable variation across listeners and experiments. In general, hearing aids do not improve performance, and there is overall little effect of differences in hearing aid features or designs (e.g., for left/right accuracy, an across-experiment mean difference of just 1 degree of RMS error). In many situations, a unilateral fitting results in a localization deficit. Though statistically significant effects of aided localization have been observed experimentally, few of them are generalizable as they often occurred for just some source directions, stimuli, or groups of listeners. Overall, there is no experimental evidence for a substantial, universal benefit from hearing aids to directional accuracy.
Effect of listener experience on pitch and rhythm perception with tonal sequences
Authors: Guzman Sandra J. , Elston Cody , Shafiro Valeriy , Sheft Stanley
Published: May 2015

Experience and training can influence discrimination of tonal sequences. Current work investigated pitch and rhythm processing of four-tone sequences by audiology and speech students, audio-arts students experienced in critical listening, and trained musicians. Sequence tones either had a fixed duration (212 ms) with frequency randomly selected from a logarithmically scaled distribution (400–1750 Hz), a fixed frequency (837 Hz) with a randomly selected log scaled duration (75–600 ms), or a random frequency and duration. In initial conditions, the task was to assemble sequence elements to recreate the target sequence for each of the three sequence types. To evaluate effect of extraneous randomization, both frequency and duration were randomized in the final two conditions with only one of the two attributes defining the target sequence. Audio-arts students performed significantly better than audiology and speech students in the reconstruction task. In conditions involving joint processing of sequence pitch contour and rhythm, the performance of audio-arts students was well approximated by the optimal combination of uncorrelated but integral stimulus dimensions. Ongoing work is evaluating the performance of trained musicians in the sequence-reconstruction task, with emphasis on manner in which information is combined across the dimensions of sequence pitch and rhythm. [Work supported by NIH.]
Measures of ear lateralization in a dichotic sample discrimination task
Authors: Tan Alison , Berg Bruce
Published: May 2015

This study investigates the ability to lateralize using a dichotic sample discrimination task. On each trial, seven 60-ms tones are drawn from a normal distribution with means of 1000 or 1100 Hz. Even numbered tones are the most informative (d’ = 2) and presented to one ear and the less informative, odd numbered tones (d’ = 0.5) are presented to the other ear. Participants indicate from which distribution the tones are sampled. Task difficulty is manipulated by presenting odd-and even-numbered tones at different intensities. In easier conditions, informative and less informative tones are presented at 70 dB, 50 dB, respectively. In difficult conditions, informative and less informative tones are presented at 50 dB, 70 dB, respectively. Decision weights, efficiency measures, and performance level (d’) all show an unexpectedly wide range in a listener’s ability to lateralize and attend to the most informative tones. Estimates of d’ range from 2.4 to 0.7. Some listeners display high efficiency estimates in all conditions while others show a marked ear preference, achieving high efficiency only when the informative tones are presented to a particular ear. Another group of listeners show a distinct inability to lateralize in any condition. This latter group is most affected by the intensity manipulation.
Integrating Markov random fields and model-based expectation maximization source separation and localization
Authors: Mandel Michael I. , Roman Nicoleta
Published: May 2015

Separation of multiple sources from binaural reverberant audio mixtures has been shown to be a challenging task. Binaural algorithms typically perform separation by employing localization based clustering or classification in individual time-frequency units. By assuming that a single source is active in a particular time-frequency unit, these algorithms produce spectral masks that allow the separation of an arbitrary number of sources. The model-based EM Source Separation and Localization (MESSL) algorithm increases robustness to reverberation by explicitly modeling its effects on interaural phase and level differences and using a consistent estimate of interaural time difference across all frequencies. The current study has extended the MESSL algorithm with a Markov Random Field based mask smoothing procedure that enforces consistency in the assignment of neighboring time-frequency units to sources. The proposed MESSL-MRF algorithm is tested in highly reverberated conditions and shows significant improvements over the original MESSL algorithm as measured by both signal-to-distortion ratios as well as a speech intelligibility predictor.
Prediction of broadband high-frequency acoustic reflection and transmission from subcritical membranes and elastic plates
Authors: Villa Mauricio , Bliss Donald B.
Published: May 2015

Earlier work has shown that distributed broadband excitation of subcritical membranes and plates can yield surprisingly simple closed-form band-averaged directivity patterns, and that the directivity is closely related to energy flow in the structure. A first principles energy-intensity boundary element method (EIBEM) for sound fields in enclosures has also been developed, and shown to be very accurate for impedance reflection boundary conditions. The present work involves the derivation of more realistic reflection and transmission of models for enclosure boundaries with elastic boundaries. For subcritical panels, reflection, radiation, and transmission properties can be characterized by a limited set of parameters, and fairly simple analytical results are derived for the broadband case. Surface reflection and edge re-radiation are both considered. These results facilitate an energy-intensity reformulation of the structural equations, as well as the acoustic field, allowing for the possibility of formalizing the coupling between energy flows in the acoustic and structural systems. The goal is to develop efficient first principles computational models for more accurate modeling of real enclosures.
Detecting building leakages using nearfield acoustic holography technique: A numerical simulation
Authors: Patel Hirenkumar J. , Chelliah Kanthasamy , Raman Ganesh , Muehleisen Ralph T. , Tatara Eric
Published: May 2015

A crack on a building wall and sound generated inside the building using an artificial sound source were simulated using Matlab. Various noise types affecting the pure sound signal, such as background noise in the room, were simulated. The forward problem of sound propagation from the crack surface to a virtual microphone array was simulated using the free-space green’s function. Nearfield acoustic holography (NAH) was applied to perform the inverse problem to calculate the sound pressure at the crack surface and determine the crack location on the building wall. Effects of various errors and noise on the sound pressure reconstruction using NAH were studied. The reconstructed sound pressure levels on the wall surface were compared with the originally simulated sound pressure data at the crack surface. Various crack sizes and shapes were simulated to determine the correlation between the size of the crack and the reconstructed pressure field.
Reconstructing acoustic field based on the normal surface velocity input data
Authors: zhu wu , Wu Sean F.
Published: May 2015

Traditional NAH relies on the acoustic pressure collected on a hologram surface in the near field of a vibrating structure. To ensure accuracy in reconstruction, it is necessary to have a conformal array of microphones, which is not an easy task in practice. On the other hand, it is easy to use a scanning laser vibrometer to measure the normal surface velocity. This paper presents a modified Helmholtz Equation Least Squares (HELS) formulation to reconstruct the acoustic field based on the normal surface velocity input data. This approach is advantageous in that: (1) it enables one to collect input data in the far field; (2) measurement setup is very simple; and (3) the normal surface velocity contains all near-field information for reconstruction of an acoustic field. To ensure the accuracy in reconstruction, the normal surface velocity is supplemented by a few measurements of the acoustic pressure in the far field. With this combined input data, the acoustic field in three-dimensional space can be accurately reconstructed. Numerical simulations for reconstructing an acoustic field generated by arbitrarily shaped objects are demonstrated. Experimental validations on using this modified HELS formulation to reconstruct the acoustic field from a loudspeaker are also presented.
Symmetric and asymmetric reversible quasi-holographic processing of dual transducer sonar for feature extraction and analysis
Authors: Zartman David J. , Plotnick Daniel S. , Marston Philip L.
Published: May 2015

Two independent transducers in a side-by-side configuration may transmit and/or receive in-phase or out-of-phase with each other. In the transmit mode, the transducers are driven individually; in the receive mode the transducers are recorded independently, allowing the phase relationships to be determined in post-processing. This results in both monostatic and weakly bistatic data. When the transducers are scanned together, as for synthetic aperture sonar, the scattering results from glory target features of a small solid sphere in water are seen to be sensitive to different combinations of in-phase and out-of-phase sources/receivers. Certain combinations function as a spatial derivative and may be generated synthetically from scans using a single transducer. This spatial derivative is shown to be highly sensitive to the alignment of a solid cylinder in water. Imaging via reversible quasi-holographic processing [D. J. Zartman, D. S. Plotnick, T. M. Marston, and P. L. Marston, Proc. Meet. Acoust. 19, 055011 (2013)] was applied to this target and used for target isolation, feature extraction, identifying and separating system effects from target physics, and for self-normalization. Though transmitting and receiving in-phase improves ordinary SNR, it can reduce some feature sensitivity relative to differential processing. [Work supported by ONR.]
Study on the interference structure of vector acoustic field in shallow water
Authors: Sun Dajun , Shi Junjie , Mei Jidan , Xu Haizhu
Published: May 2015

The application of vector sensors is closely associated with the characteristics of vector acoustic field in shallow water, whose study is the foundation for target detection, positioning, and classification. Beginning from Normal Mode theory, theoretical studies are presented about the amplitude of different components of vector acoustic field involving the pressure, horizontal and vertical particle velocity, as well as the phase relation between the pressure and the vertical particle velocity. The main factors considered here are the source depth and the range relative to the vector sensor. These interference structures were observed during the experiment that took place in July of 2013 in South China Sea of nearly 90m depth. The results indicated that the interference structures of vector acoustic field are not only influenced by the sound speed profile but also by seabed parameters including stratification depth and its corresponding acoustic properties. Moreover, the phase relation between the pressure and vertical particle velocity is remarkably impact by these parameters. [Work supported by the National 863 Project (No. 2011AA090502) and Defense Industrial Technology Development Program (B2420132004).]
A wave structure based method for recognition of marine acoustic target signals
Authors: Meng Qingxin , Yang Shie
Published: May 2015

The loudness and timbre of propeller are remarkable features of ship-radiated noise. The information of loudness and timbre is indicated in the wave structure of time series, and the feature of wave structure can be applied to classify various marine acoustic targets. In this paper, the feature extracting method of time series wave structure is studied. A nine-dimensional feature vector is constructed through statistical characteristics, containing zero-crossing wavelength, peek-to-peek amplitude, zero-crossing-wavelength difference and wave train areas. The feature vectors are inputted into SVM classifier to identify marine acoustic targets. The kernel function is set radial basis function (RBF).The penalty factor and kernel width of RBF are selected by the method of grid search. Finally, the recognition rate of test data reaches over 89.5%, with the help of cross validation. The sea-test data show the validity of target recognition ability of the method above.
Seismic sources in parabolic equation solutions for beach and island propagation scenarios
Authors: Frank Scott D. , Collis Jon M.
Published: May 2015

Seismic events at and under the seafloor can be detected by seismometers on a beach. Events occurring in the earth's crust without ocean cover can also be detected at sea. Parabolic equation solutions for environments that include seismic sources in conjunction with island topography demonstrate that results for propagation moving away from or onto land can be obtained. Transmission loss results are given in the context of the (ur,w) parabolic equation formulation of elasticity. Horizontal and vertical displacement values, as would be measured on land-based or ocean bottom seismometers, can also be obtained. Examples involving underwater volcanic events are considered, as are shore-bound events that generate oceanic T-waves that would be measured at sea.