bluuebunny/crossref_metadata_2025 huggingface dataset:
Semi-supervised source localization in reverberant environments using deep generative modeling
Authors: Bianco Michael J. , Gannot Sharon , Fernandez-Grande Efren , Gerstoft Peter
Published: December 2020

We present a method for acoustic source localization in reverberant environments based on semi-supervised machine learning (ML) with deep generative models. Source localization in the presence of reverberation remains a major challenge, which recent ML techniques have shown promise in addressing. Despite often large data volumes, the number of labels available for supervised learning in reverberant environments is usually small. In semi-supervised learning, ML systems are trained using many examples with only few labels, with the goal of exploiting the natural structure of the data. We use variational autoencoders (VAEs), which are generative neural networks (NNs) that rely on explicit probabilistic representations, to model the latent distribution of reverberant acoustic data. VAEs consist of an encoder NN, which maps complex input distributions to simpler parametric distributions (e.g., Gaussian), and a decoder NN which approximates the training examples. The VAE is trained to generate the phase of relative transfer functions (RTFs) between two microphones in reverberant environments, in parallel with a DOA classifier, on both labeled and unlabeled RTF samples. The performance this VAE-based approach is compared with conventional and ML-based localization in simulated and real-world scenarios.
Effects of medium heterogeneities on direction of arrival estimation
Authors: Real Gaultier , Sklivanitis George , Gemba Kay , Pados Dimitris A.
Published: December 2020

A scaled experiment in a water tank was conducted to study effects of medium heterogeneities on underwater acoustic propagation while controlling the so-called fluctuations. An ultrasonic wave is transmitted (a pulse train at center frequency f = 2.25 MHz) throughout an acoustic lens presenting a plane input face and a randomly rough output face inducing spatial fluctuations of the sound pressure field. The roughness statistics are tuned so that the fluctuating pressure field presents features comparable to what can be observed in the case of acoustic waves propagating through a fluctuating ocean. Generally speaking, disturbances can include path propagation delays, multipath dependent Doppler spreading, scattering from the sea surface or bottom, and coherence loss over the array aperture arising from dynamic wave-front fluctuations due to internal waves. This last topic is the main focus of our study. Signal snapshots received at a virtual, vertical line array of 64 sensors may be corrupted by impulsive (heavy-tailed) additive noise and high resolution outlier-resistant arrival angle identification is desirable. Recent advances in robust techniques such as Sparse Bayesian Learning and L1 -norm Principal Component Analysis motivate this work. We compare the performance of these innovative techniques to the classical MUSIC and Bartlett processors. [This work is supported by DGA, NSF Grant CNS1753406, ONR.]
Bill Cavanaugh—His BBN years and his influence on architectural acoustics education
Authors: Rosenberg Carl , Hoover K. Anthony
Published: December 2020

Bill Cavanaugh was vitally important to the architectural acoustics consulting firm of Bolt Beranek and Newman (BBN) in its early years, during his tenure (1954–1970). He managed its architectural acoustics department, and he hired and mentored many of the best known consultants from that era. He was also enthusiastic and effective in promoting acoustics classes at architectural schools, in the spirit of his mentor Robert Newman, as well as numerous educational outreaches including the celebrated Laymon Miller short courses. This presentation will offer some insight and anecdotes about the early BBN years, with implications for current and future acoustical consulting. Additionally, an overview will be offered of Bill's influence on architectural acoustics education, including the various courses at colleges and universities; the short courses and seminars for architectural firms, government, industry, professional societies, and more; and the origin and continuing good work of the Newman Student Award Fund including its Student Medals, Schultz Grants, Newsletters, and the series of concerts.
Teaching architectural acoustics, as inspired by Bill Cavanaugh
Authors: Hoover K. Anthony , Reuter Eric
Published: December 2020

Bill Cavanagh led by example in teaching architectural acoustics. This presentation will look back at the 1-1/2 credit classes in acoustics that he taught at various colleges, and which inspired and influenced many subsequent acoustics classes and programs. Also, one outgrowth from these earlier classes will be discussed, the acoustics class at Berklee College of Music—its origin, development, and outlook—which over 33 years has provided a three credit class to over 7000 students who are deeply immersed in audio and music, and now have a solid foundation in acoustics.
Influence of environmental and anthropogenic acoustic cues in sea-finding of hatchling Leatherback (Dermochelys coriacea) sea turtles
Authors: Holtz Bethany , Dow Piniak Wendy , Stewart Kelly
Published: December 2020

Observed visual and geomagnetic orientation cues on sea turtle hatchlings overlook the impact auditory stimuli may have on orientation. We hypothesized that increased levels of anthropogenic sound, linked to behavioral and physiological cues found in other marine species, impact hatchlings during sea-finding. The responses of hatchling leatherbacks, Dermochelys coriacea, collected from the Sandy Point National Wildlife Refuge, St. Croix, were measured in the presence of aerial acoustic sounds within hatchlings' hearing range of 50 to 1600 Hz. The highest sound energy produced by beach waves occurs at frequencies 50–1000 Hz, which overlaps with the most sensitive hearing range of hatchling leatherbacks (50–400 Hz). Natural beach wave sounds, which peak at frequencies of 50–1000 Hz, may be masked by human conversations (85–650 Hz) and vehicle traffic (60–8000 Hz). In our controlled experimental design, we exposed hatchlings to surf wave sounds (70 dB re: 20 μPa), human conversation (68 dB re: 20 μPa), and traffic noise (70 dB re: 20 μPa). We observed no phonotaxic response (wave sounds: mean angle = 152.1 deg, p = 0.645; human conversation: mean angle = 67.4 deg, p = 0.554; traffic noise: mean angle = 125.7 deg, p = 0.887). This lack of orientation may be due to hatchlings' inability to localize. Visual and auditory cues may also converge to effect sea finding orientation.
Acoustic propagation and reverberation in shallow water with a gassy bottom: Experiments in the Sea of Galilee and preliminary data analysis
Authors: Lunkov Andrey , Katsnelson Boris , Ivakin Anatoliy N. , Katsman Regina
Published: December 2020

Broadband (200—2000 Hz) pulses were transmitted by an omnidirectional source in a shallow lake (Sea of Galilee, Israel, ~40 m depth) in several experiments during last five years. Data analysis and modeling results are presented for acoustic pressure received by a vertical line array located at an anchored station in the deepest place of the lake. Received signal was comprised of a series of arrivals followed by reverberation codas. Modeling of the propagation showed that arrival peaks' magnitudes are controlled by bottom reflectivity affected mostly by averaged (horizontally) acoustic parameters of the gassy sediment. Analysis of reverberation codas can provide further information about random spatial distribution of gas bubbles in the sediment layer and, also, about bottom roughness. Possibilities of inversions for water column and gassy bottom parameters based on these and future experiments are discussed. [Work supported by RFBR, BSF, and ONR.]
Applying acoustic noise to probe the water column in a dynamic shallow-water environment
Authors: Tan Tsu Wei , Godin Oleg A.
Published: December 2020

Acoustic noise interferometry is applied to retrieve empirical Green's functions (EGFs) from the ambient and shipping noise data acquired in the Shallow Water 2006 experiment on the continental shelf off New Jersey. Despite strong internal wave-induced perturbations of the sound speed in water, EGFs are found on 31 acoustic paths by cross-correlating the noise recorded on a single hydrophone with noise on the hydrophones of a linear array about 3.6 km away. Two fifteen day-long datasets are considered. Dispersion curves of three low-order normal modes at frequencies below 110 Hz are extracted from the EGFs with time-warping technique. The dispersion curves from the first dataset were previously employed to estimate the seabed properties [T. Tan et al., J. Acoust. Soc. Am. 147, EL453–EL459 (2020)]. Here, using this geoacoustic model, we invert the differences between the higher-frequency part of the dispersion curves obtained from the two datasets for the variation of the time-averaged sound speed profile in water between the two observation periods. Results of the passive inversion are compared to the ground truth derived from in situ temperature measurements. The effect of temporal variability of the water column during noise averaging time on EGF retrieval is discussed and quantified.
Wave propagation in a one-dimensional bar with rate-independent hysteresis
Authors: Ghodake Pravinkumar R. , Biswas Saurabh
Published: December 2020

A single frequency ultrasonic wave propagation in nonlinear materials generates higher harmonics. The generation of higher harmonics depends on the type of material nonlinearity considered, like odd and even harmonics in quadratically nonlinear materials, and only odd harmonics in cubically nonlinear material. The objective of this study is to present numerical study of one dimensional wave propagation in rate-independent hysteretic media by considering one dimensional chain of spring masses. Preisach-Mayergoyz (1994) and Hodgdon hysteretic models (1988) are commonly used in the theoretical and numerical study of nonlinear wave propagation studies. Here we implement the famous scalar Bouc-Wen model (1976) and a recently developed two-state hysteresis model by Biswas and Chatterjee (2015) to consider hysteresis in the large spring mass system. Number of spring masses are decided based on the spatial resolution needed for the nonlinear wave propagation to capture higher harmonics. The study presents interesting comparison between the wave propagation through an aluminum bar damaged under low cycle fatigue modeled as two different rate-independent hysteretic models. Both models show higher harmonics in responses. However, being a scalar model, the Bouc-Wen model cannot capture small minor loops due to partial reversals, whereas the two-state model captures the minor loops well.
Effect of flow on the acoustic length correction factor of a Helmholtz resonator neck at high Strouhal number: A symmetric three-dimensional numerical parametric study
Authors: Tuozzo Diego M. , Lenzi Arcanjo , Silva Olavo M.
Published: December 2020

The effect of flow on the acoustic length correction factor (ALCF) of a Helmholtz resonator (HR) neck is investigated numerically in order to achieve an expression to calculate the respective flow-acoustic length correction factor (FALCF) as a function dependent on the ratio between the radii of the neck and cavity (up to 0.4) and on the Mach (Ma) number (up to 0.1). The ALCF is of great interest in one-dimensional acoustic applications for achieving better prediction of local effects. In this work, the effects of turbulent flow and radial and axial neck-cavity wave motions are added to improve the one-dimensional HR's resonant frequency prediction model. A symmetric three-dimensional HR model is parameterized and adopted to solve a set of CFD problems (RANS equation and turbulent SST model), with different geometry parameters. The acoustic fluid is air at 20 °C and is considered incompressible. The predictions of the numerical model are validated with experimental studies available in the literature. Different formulations employed to predict the resonance frequency of an HR for the Ma = 0 case are investigated and compared to CFD results as a way to verify its prediction capability related with the HR's geometry. Also, the possibility to obtain the FALCF factor from the neck's acoustic impedance is investigated and compared with the expression derived from the HR's resonance frequency.
Computational aeroacoustics for low Mach number flow using the lattice Boltzmann method
Authors: Wang Song , Scavone Gary
Published: December 2020

Computational aeroacoustics at low Mach number is challenging because of the comparative order of magnitudes between the acoustic perturbations and the numerical errors. The lattice Boltzmann method has been proven to be advantageous for aeroacoustics with a lower dissipation. The recursive and regularized LBM scheme (LBM-rrBGK), which has only been developed recently and tested in aeroacoustic problems, shows advantages over the traditional LBM-BGK. In this paper, results of computational aeroacoustics for low Mach number flow using rrBGK are presented. Two benchmark problems are tested, including the flow passing around a circular cylinder and the sound radiation of a cylindrical duct with uniform flow. The results are compared with either simulation, experiment or analytical results in the literature, and show a good agreement. Finally, the sound radiation directivity of a horn in the presence of mean flow is studied.
Direct numerical simulation and parametric study of the noise generated from particle dispersion in decaying homogeneous isotropic turbulent flow
Authors: Wang Wei , Miller Steven A.
Published: December 2020

The main objective of this study is to understand the noise produced by the dispersion of particles in a simple turbulent flow and to classify the statistics of the particles that influence the noise. The three-dimensional, time-dependent, non-stationary flow-fields of the homogenous isotropic turbulence with microscale Reynold numbers varying from 15 to 50 are computed using direct numerical simulation. 1, 5, 10, 50, and 100 thousand solid particles of varying diameters and densities are randomly injected into the computational domain. The particles' positions, velocities, and temperatures are assessed by integrating the equations of particle motion along each trajectory. The acoustic pressure time history at different far-field observer locations are predicted using the Crighton and Ffowcs Williams (CFW) acoustic analogy for two-phase turbulence. The root mean square acoustic pressures at different observer locations are ensemble-averaged and compared. Three distinct sources of noise from the CFW acoustic analogy are computed, and the effects of particle dispersion on noise sources are presented. The root mean square acoustic pressures increase drastically with an increasing number of particles in the cases of large particles, while the increases in the cases of small particles are not significant comparing to the single-phase flow.
A heat balance model to explain thresholds for thermoacoustic sound production in seawater using metal electrodes
Authors: McBeth Michael
Published: December 2020

Experiments conducted with solid metal wire electrodes in seawater generated second harmonic sound waves thought to be thermoacoustic in origin. Using sine wave bursts of 3 to 25 cycles of 10 kHz voltage across the electrodes, the applied voltage threshold for thermoacoustic sound production was observed to decrease almost linearly for bursts up to ten cycles. At the time of these experiments, around 2014, we were unable to explain these sound production threshold values. A mass density continuity equation with a negative source term is used to explore the observed threshold values. The negative source term represents the decrease in fluid density with each half cycle of applied voltage due to the ohmic heating. This approach builds on an earlier heat balance model that successfully explains an observed delay in thermoacoustic sound production. Model results are compared with the experimental observations.
SpeakEasy: Browser-based automated multi-language intonation training
Authors: Tyler Jeramey , Si Mei , Zhou Helen , su hui , Braasch Jonas
Published: December 2020

Learning to speak a second language involves a cycle of observation, mimicry, and feedback. A student observes a teacher, attempts to copy the teacher's performance, and then the teacher provides feedback on how the student performed. When the students' access to feedback is limited, so is their ability reinforce their learning. In this work a web based application, Speakeasy tools, in introduced to provide remote students with automated visual intonation feedback for multiple languages. For this study, participants are selected from the pool of Speakeasy users and their interactions with the application are observed over a set period of time. The application presents participants with native speaker examples generated via text-to-speech in the form of audio samples, fundamental frequency visualizations, and grapheme and phoneme level timelines. Participants are able to record and review an unlimited number of practice attempts which are processed using the same pipeline used for the native speaker examples. Using the Root-Mean-Square Error (RMSE) between native and participant fundamental frequencies over time, the practice attempt is assigned a score. Practice-attempt scores with respect to time spent using the application provide a metric for measuring a participant's progress. [Work supported by RPI Seed Grant and CISL.]
Ogene Bunch music analyzed through the visualization and sonification of beat-class theory with ski-hill and cyclic graphs
Authors: Calilhanna Andrea
Published: December 2020

Traditional Ogene music (metal gong) is a music genre originating in the eastern communities of Nigeria which retains an intrinsic communicative function and music style of Igboland characterized by call and response vocals, polyrhythms and improvisation. Through applying a psychoacoustic approach using visualizations and sonifications of beat-class theory with ski-hill and cyclic graphs, a listener is enabled to represent their experience of both music and mathematics embodied acoustics. This paper demonstrates the evolution of Western music theory to have the capacity to represent rhythm, meter, and pitch by visualizing beat-class theory through ski-hill and cyclic graphs (mathematical music theory). This new approach is suitable for understanding Igbo music which, like the majority of the world's music, is transmitted aurally and not notated. Applying a psychoacoustic approach, this paper illustrates how Igbo music can be accurately preserved for future generations and included in the scholarly discussion. The paper also reveals structural details of the music which may not be accounted for previously through the use of traditional Western music theory.
Interdisplinary Physical Music: A Blind Spot in Education on Acoustics
Authors: Onwubiko Stephen G. , Calilhanna Andrea
Published: December 2020

In attaining a degree in music, education on musical acoustics is multidisciplinary. Musical acoustics contains specialized knowledge, history, methodology, and practices, yet music itself is interdisciplinary. Ideally, acousticians recognize and validate that music is scientific and so, turn a blind eye or pay little attention to interdisciplinary physical music (i.e., migrating from music to musical acoustics). This paper examines the critical fault line erupting beneath the structural foundations of music through musical acoustics to navigate questions seldomly asked. These questions include–who should teach interdisciplinary physical music, e.g., music and mathematics, musical acoustics, psychoacoustics, what are the sets of curriculum standards and evaluation procedures suitable for the inter-multidisciplinary physical music. Finally, the paper proposes the reason why these paths are seldom crossed and provides a solution: a psychoacoustic approach to mathematical music theory as conduit to the intersection of fields with concepts traversing many disciplines.
Analysis of noise reduction methods for supersonic jets in the sideline and upstream directions using a statistical approach
Authors: Patel Trushant K. , Miller Steven A.
Published: December 2020

Jet noise remains a major source of concern for military personnel working aboard aircraft carriers. Broadband shock-associated noise (BBSAN) and fine-scale mixing noise (FSMN) are the main components of noise in the sideline and upstream directions. A decomposition approach based on the Navier–Stokes equations is used to identify the source of BBSAN and FSMN. Statistical models are developed to predict BBSAN and FSMN using the identified source terms. The prediction models use Reynolds-averaged Navier-Stokes solution as an argument. Comparisons of the noise radiated due to BBSAN and FSMN by three different nozzle types, i.e., a method of characteristics nozzle, a bi-conic nozzle, and a faceted nozzle are performed at different operating conditions. Different noise reduction mechanisms such as fluidic injection and corrugations on the nozzle wall are implemented on the faceted nozzle. We examine the change in source statistics and its correlation on the intensity and directivity of the radiated noise for BBSAN and FSMN. Noise reduction predictions relative to the baseline cases are compared for each nozzle modification. Finally, we analyze the noise source locations at different Strouhal number for both components of jet noise in the sideline direction.
Far-field noise radiation characteristics of an afterburning military jet aircraft
Authors: Bassett Michael S. , Rasband Reese D. , Novakovich Daniel J. , Gee Kent L. , Campbell Steven C. , Mobley Frank S. , Wall Alan T.
Published: December 2020

Because of the potential noise impacts of tactical jet aircraft, detailed far-field measurements are valuable in developing and validating models. This paper describes far-field measurements taken of the T-7A Red Hawk trainer aircraft. Data were taken at five microphone arcs, over six engine runups from idle to afterburner. The arcs were of varying resolution, but generally spanned 30 to 160 deg (relative to the jet inlet) at distances from 19 to 230 m. The spectra, sound pressure level, and skewness of the time derivative of the pressure waveform are analyzed according to microphone position and engine condition. Measurement consistency over the different runups and across all conditions validates the dataset for future analysis. [Work supported by AFRL.]
Acoustic standards for high-level impulse noise
Authors: Murphy William J. , Flamme Gregory , Brokaw Elizabeth B. , Gupta Raj K.
Published: December 2020

High-level impulse noise has been a significant source of hearing loss among active duty military personnel, veterans, law enforcement and recreational firearm users. The development of standards for estimating the risk of hearing loss due to such exposures is complicated by a lack of human exposure data. Following World War II, the Army Research Laboratory conducted a limited series of studies that led to the development of MIL-STD 1474, which was based on peak exposure level and envelope duration. In the late 1980s, the US Army recognized that large caliber weapons had different outcomes than small-caliber firearms. The Army conducted the Albuquerque Blast Overpressure Walk-up studies that led to extensive debate about how to estimate the risk of hearing loss from these sounds. The DoD Blast Injury Prevention Standards Recommendation Process evaluated several candidate noise exposure metrics including equivalent energy exposure, Auditory Hazard Assessment Algorithm for Humans, Integrated Cochlear Energy model, and Auditory Model 4.5. Weapon noise measurements were used to highlight how maximum permissible exposures provide a framework that relates the disparate predictions from the models.
A new noise exposure criteria is needed for complex noise
Authors: Qiu Wei , Murphy William J. , Zhang Mebian
Published: December 2020

From the earliest standards for occupational noise exposure, impulse noise has been recognized as presenting an increased hazard for developing hearing loss. Animal research has focused primarily on the chinchilla as a surrogate for the human ear due to the similarity of sensitivity and frequency range of hearing. Research from the SUNY-Plattsburgh has demonstrated that hearing loss in chinchilla and the kurtosis of the noise exposure are monotonically related for a given equivalent noise exposure level, LAeq. The risk of hearing loss increased with higher kurtosis to a point where the amount noise-induced hearing loss plateaued. SUNY-Plattsburgh, NIOSH, and the Chinese, Zhejiang Provincial Centers for Disease Control researchers have conducted a series of investigations with Chinese workers who have a history of noise exposure in a stable occupational setting. The findings from these investigations confirm the animal research, the risk of occupational hearing loss increases with an increased kurtosis of the noise exposure. This paper will examine the potential for a new noise exposure standard that incorporates both level and kurtosis.
Interfacial tension and acoustofluidics: some connections, instabilities, experimental results, and theory
Authors: Marston Philip L.
Published: December 2020

It is timely to examine early acoustofluidic studies involving surface tension phenomena. The dynamics of fluid cylinders and the Plateau-Maxwell-Rayleigh interfacial instability have been reviewed [P. L. Marston, Phys. Fluids 29, 029101 (2017)]. Here, some related acoustofluidic experiments on liquid cylinders are noted [S. F. Morse et al., Phys. Fluids 8, 3 (1996); M. J. Marr-Lyon et al., Phys. Rev. Lett. 86, 2293 (2001)]. Those were after modulated radiation pressure investigations of the shape dynamics of levitated drops and bubbles [P. L. Marston, J. Quant. Spectrosc. Radiat. Transfer 254, 107226 (2020)]. Especially noteworthy are the subtleties of acoustically trapping and deforming bubbles in water larger than the size for monopole resonance [T. J. Asaki, P. L. Marston, and E. H. Trinh, J. Acoust. Soc. Am. 93, 706 (1993)]. That ability facilitated a series of measurements of bubble interfacial dynamics and shape [Asaki et al., J. Acoust. Soc. Am. (1994-1997); J. Fluid Mech. (1995); Phys. Rev. Lett. (1995)]. A related discussion of the quadrupole projection of the radiation stress is noteworthy [P. L. Marston, Phys. Rev. E 100, 057001 (2019)] along with early publications reporting the break-up of drops and bubbles in water through the application of modulated acoustic radiation forces.
Acoustofluidic equations governing fluid-elastic media with suspended particles and shear elastic properties
Authors: Pierce Allan D. , Siegmann William L. , Brown Elisabeth M.
Published: December 2020

Understanding physics of complex media is generally helped by one's having a complete set of partial differential equations that govern the motion and interactions within the media. A single scalar wave equation is usually not sufficient for understanding all the acoustic properties of interest. An example of such a set of equations are those developed by M. A. Biot (1956) for low frequency propagation of compressional, shear, and other waves in poroelastic media. An analogous set of equations is here developed for a medium that has three primary phases—(1) a fluid, (2) a gossamer array of thin platelets held together by van-der-Waals forces, and (3) a disperse and somewhat random array of larger solid particles held in suspension by the gossamer array. Marine sediment mud is one example of such a medium. Because of the gossamer array. the medium resists static shear, and its compressibility is primarily caused by the fluid. Using various physical principles, one can formulate different elastical-mechanical equations for each of the three phases, or even for subcategories of the phases (such as for suspended particles within different size ranges). The phases interact via different physical mechanisms, such as viscous forces exerted by the fluid on the suspended particles. Examples are given for the use of these equations and of their implications. [This material is based upon research supported by, or in part by, the U. S. Office of Naval Research under award numbers N00014-15-2039, N00014-18-1-2439, and N00014-19-1-2636.]
Direct measurement of small spherical particle rotation driven by the acoustic viscous torque
Authors: Goering Christoph , Lamprecht Andreas , Schaap Iwan A. , Dual Jürg
Published: December 2020

We report a new method for measuring fast rotations up to 13500 rpm of micrometer sized spherical particles utilizing an optical trap [A. Lamprecht et al., Lab Chip 16, 2682–2693 (2016)]. In an acoustofluidic flow cell, a single spherical particle rotates due to the acoustic viscous torque produced by two phase-shifted orthogonal standing waves. The Lorentzian power spectrum of the trapped and rotating particle has additional peaks at frequencies that correlate with its rotational speed. In one of our experiments the thickness of the viscous boundary layer δ around the particle is roughly as large as the particle radius R itself. We use a water glycerol mixture with a dynamic viscosity of μ_ff = 0.06 Pa s to increase δ. Our experiment validates recent numerical research that predicts power rotational speeds for the case δ ≈ R compared to the simplified theoretical formula valid for δ ≪ R [Lee and Wang, J. Acoust. Soc. Am. 85, 1081–1088 (1989)].
Spatial and frequency selective acoustically driven streaming and its application to boundary-induced pattern formation
Authors: Thompson Charles , Chandra Kavitha , Saadatmand Eric
Published: December 2020

The problem of spatial and frequency selective acoustic streaming induced in a bifurcated channel using an elastic membrane is examined. The acoustic wavelength is much longer than the channel dimensions. The time-averaged fluid motion can be controlled by adjusting the pressure gradient and the impedance of the membrane. The fluid's dynamic behavior is governed by the relative magnitude of three parameters, the oscillatory Reynolds, Strouhal, and streaming Reynolds numbers. The behavior in the large oscillatory Reynolds and Strouhal number limit is of particular interest. The solution is given by singular asymptotic series expressed in terms of the reciprocal of the Strouhal number and matched using the method of matched asymptotic expansions.
The influence of target/masker fundamental frequency contour similarity on masked-speech recognition for older and younger adults
Authors: Wasiuk Peter A. , Lavandier Mathieu , Buss Emily , Oleson Jacob , Calandruccio Lauren
Published: December 2020

Older adults with sensorineural hearing loss (SNHL) have greater difficulty recognizing target speech in multi-talker backgrounds than young adults with normal hearing (NH). These deficits are due in part to a decreased ability to utilize perceptual differences between target and masker speech to segregate sound sources. For young NH listeners, fundamental frequency (f0) contour (i.e., dynamic f0 movement) has been demonstrated to be an effective stream segregation cue when acoustic-perceptual differences in target and masker f0 contours exist. This project examined if older adults with SNHL can utilize f0 contour differences between target and masker speech to improve target speech recognition. F0 contours of target and masker speech were systematically manipulated to be either flat, normal, or exaggerated. Computational modeling was conducted to estimate differences in energetic masking across listening conditions. Effects of age and hearing loss were differentiated in the statistical model. Results indicated that older adults with SNHL were unable to take advantage of target/masker f0 contour differences to improve target speech recognition in the same manner as young adults, even with prescriptive amplification applied to the speech stimuli. This may contribute to difficulties experienced by older adults in real-world multi-talker environments, even when using amplification technologies.
Remote testing for psychological and physiological acoustics: Initial report of the ASA P&P Task Force on Remote Testing
Authors: Stecker G. Christopher , Beim Jordan A. , Bharadwaj Hari , Bosen Adam K. , Buss Emily , Braza Meredith , Diedesch Anna C. , Dorey Claire M. , Dykstra Andrew R. , Freyman Richard , Gallun Frederick J. , Goldsworthy Raymond L. , Gray Lincoln , Hoover Eric C. , Ihlefeld Antje , Koelewijn Thomas , Kopun J. G. , Mesik Juraj , Peng Ellen , Richards Virginia M. , Shen Yi , Shub Daniel E. , Venezia Jonathan H. , Waz Sebastian
Published: December 2020

Acoustics research involving human participants typically takes place in specialized laboratory settings. Listening studies, for example, may present controlled sounds using calibrated transducers in sound-attenuating or anechoic chambers. In contrast, remote testing takes place away from the lab, in natural settings or in participants' homes. Remote testing can potentially provide greater access to participants, larger sample sizes, and enhanced ecological validity, at the cost of reduced acoustical control, standardization, calibration, and consistency of participant experiences. Emerging technologies can ameliorate some drawbacks, and potentially support new forms of robust research via remote testing. The ASA Technical Committee on Psychological and Physiological Acoustics (P&P) launched the Task Force on Remote Testing in May 2020, with goals of (1) surveying approaches and platforms available to support remote testing by ASA members, (2) identifying challenges and considerations for prospective investigators, and (3) communicating this information via online resources, papers, and presentations. Longer-term goals include identifying best practices and providing resources for evaluating outcomes of remote testing to facilitate via peer review. This presentation will describe the activities of the P&P Task Force on Remote Testing, online resources identified and/or developed by Task Force members, and additional opportunities for ASA members to contribute.
Anonymous multipart web-based psychoacoustics: Infrastructure, hearing screening, and comparison with lab-based studies
Authors: Mok Brittany A. , Viswanathan Vibha , Borjigin Agudemu , Singh Ravinderjit , Bharadwaj Hari
Published: December 2020

Web-based experiments offer the potential to collect large datasets from diverse cohorts of listeners, and can help circumnavigate constraints on in-person testing placed by the COVID-19 pandemic. Here, we (1) outline our infrastructure for multipart web-based hearing studies, (2) describe our approach to screening participants for headphone use and “normal-hearing” status, and (3) compare performance trends in the same task paradigms between lab- and web-based studies. Browser-based psychoacoustic tasks were implemented using jsPsych, a free and open-source JavaScript library. Dynamic sequences of psychoacoustic tasks were combined with consent pages, questionnaires, and debriefing pages using Django, a free and open-source Python library for web applications. Subjects were recruited, pre-screened for demographic characteristics, and compensated anonymously via Prolific.co, a web-based human-subject marketplace. Headphone use was checked by supplementing the procedures in Woods et al. (Atten Percept Psychophys, 2017) with a binaural hearing task. Guided by a meta-analysis of normative data, screening for (near) normal-hearing status (and compliance with instructions) was done by combining scores in a suprathreshold cocktail-party task with survey responses. Individuals meeting all criteria were anonymously re-invited to complete the main psychoacoustic tasks. Preliminary results suggest that performance trends and “main-effects” are comparable to lab-based data.
Normative psychoacoustic data using portable automated rapid testing (PART) iPad application
Authors: Srinivasan Nirmal Kumar , Pfaffe Alyssa , Gallun Frederick J.
Published: December 2020

Psychoacoustic tasks have been used to evaluate auditory processing capabilities throughout many decades. Here, we present data for Spatial Release from Masking (SRM), gap detection thresholds (GDTs), and spectrotemporal modulation (STM) sensitivity on a large group of listeners varying in age and hearing acuity collected using the PART iPad application (https://braingamecenter.ucr.edu/games/p-a-r-t/). Coordinate Response Measure (CRM) sentences were used to quantify SRM. A 4 Hz-2 c/o spectrotemporally modulated broadband noise was used to quantify STM sensitivity. Broadband Gaussian noise was used to measure gap detection thresholds. Initial analyses revealed similar thresholds between traditional methods found in the literature and data collected through the PART application for all psychoacoustic tasks. The ease with which the data is collected using PART application is expected to aid clinicians in rapidly characterizing difficulties perceived by individuals in everyday listening scenarios and in evaluating patient progress with hearing aid adjustments and aural rehabilitation over time.
Basic auditory skills evaluation battery for online testing of cochlear implant users
Authors: Shafiro Valeriy , Hebb Megan , Oh Jasper , Sheft Stanley , Vasil Kara J. , Moberly Aaron C.
Published: December 2020

Cochlear implant (CI) performance varies considerably across domains of auditory function, but clinical testing is typically restricted to speech intelligibility. Although other domains, including environmental sound and music perception or speech comprehension, are considered important to quality-of-life and personal safety, their adaptation into clinical use has been limited. The basic auditory skills evaluation (BASE) battery was developed to provide online access to such comprehensive assessment using the Internet as a test delivery platform. It includes 17 3–5 min tests to evaluate (1) basic spectro-temporal processing, (2) processing of environmental sounds and music, and (3) speech perception and comprehension in quiet and background noise. Two groups of 18 and 25 postlingual adult CI users were tested either at home following online instructions or in the lab by an audiologist. Results revealed a range of performance across tests from near ceiling to close to chance. No significant differences in group performance on any of the tests were observed, suggesting that BASE battery can assess a diverse array of abilities online, with varying difficulty levels. These findings provide preliminary support for the use of the test battery for an Internet-based comprehensive assessment of ecologically relevant aspects of auditory perception in adult CI users.
Evaluating tests of binaural hearing for hearing impaired listeners using a portable device
Authors: Diedesch Anna C. , Bock Sheng Jie Adelaide , Gallun Frederick J.
Published: December 2020

Individuals with sensorineural hearing loss may have similar monaural thresholds (i.e., pure tone audiogram) but perform quite differently on tests of speech-in-noise. Additional testing using complex, binaural signals may be able to differentiate individuals with similar pure-tone hearing. Here, individuals with mild-to-moderate hearing losses were evaluated using tests of spectral, temporal, and spectrotemporal modulation, diotic and dichotic frequency modulation, gap detection, 2 kHz tone-in-noise, and spatial release from masking. Binaural psychoacoustic measurements were evaluated on an iPad using the Portable Automated Rapid Test (PART) app. Normal hearing listeners were evaluated as controls. Normal hearing results were similar to normative data previously collected by Lelo de Larrea-Mancera and colleagues (2020) and hearing-impaired results were elevated for most binaural measurements evaluated compared to normal hearing controls. Binaural psychoacoustic data were successfully measured for individuals with mild-to-moderate amounts of hearing loss using a portable system. Results show that evaluating complex stimuli on clinical populations using a portable device is feasible. Additionally, if accomplished on a larger scale the current test battery may likely add useful information on how hearing-impaired listeners process complex binaural stimuli and could compliment current clinical diagnostic test battery and, potentially, guide hearing aid fittings.
Telepractice in pediatric speech therapy: Characteristics of patient, parent, and provider vocal interaction
Authors: Kondaurova Maria V. , Donaldson Cheryl W. , Betts Abigail L. , Zheng Qi , Lowman Joneen , Bush Matthew L.
Published: December 2020

How does the use of modern technology, such as telepractice, affect the characteristics of vocal interaction between the speech-language pathologist (SLP), the child, and the caregiver? This study examined the prevalence and temporal structure of vocal turns between the SLP, mothers and their children with cochlear implants (CI) (n = 7, mean age 59 months, range 43-81 months) during one 30- minutes in-person and one sequential tele session, order counterbalanced. The frequency of vocalizations, vocal turns, simultaneous speech and between-speaker pause duration in tele versus in-person sessions were examined. Results indicate that the SLP vocalized more during in-person than the tele session; mothers demonstrated an opposite result. The child vocalization frequency was not depended on session type. There were more turns between the SLP and the child during in-person than tele session; opposite results were found for mother-child turns. The number of turns between the SLP and the mother and the occurrence of simultaneous speech were not affected by session type. Pauses were longer between the SLP and the child and between the child and her mother in tele- than in-person session. Results suggest that vocal interactions between the patients, parents and providers are impacted by the intervention delivery modality.
Tunable vibration control in a microelectromechanical resonator array by means of parametric coupling between mechanical and electrical modes
Authors: Surappa Sushruta , Degertekin F. Levent
Published: December 2020

Vibration control in flexible structures at both the micro and macro scale has been a subject of considerable research interest over the last few decades. Various active, semi-active and passive vibration control schemes have been proposed for applications ranging from attenuating unwanted vibrations in structural components to controlling the ring down time in high-Q mechanical oscillators. Here, we present a simple, yet highly effective method to passively attenuate large amplitude resonant vibrations in an array of membrane-based microelectromechanical (MEM) resonators. By capacitively coupling the MEM array to a resonant electrical circuit tuned to half the mechanical resonance frequency, the vibrational energy in the array can be converted to electrical energy via parametric mode coupling between the mechanical and electrical resonator. Simulation and experimental studies indicate that both the rate of vibration attenuation and the degree of suppression can be effectively controlled by tuning electrical parameters such as the resistance and the initial voltage in the circuit. The extension of the control scheme to multi-mode vibrations by making use of multiple shunted electrical resonators will also be briefly discussed.
Switchable acoustic metamaterial design through instability-driven microstructure transformations in soft composites
Authors: Rudykh Stephan
Published: December 2020

Soft materials can sustain large deformations, and, thus, can be used as a platform for tunable and switchable systems capable of wave manipulations. The fascinating elastic instability phenomenon in soft materials can be used to design new (meta-) materials with switchable microstructures, properties, and functions. Examples include the emergence of tunable band gaps at low-frequency ranges, the appearance of negative group velocity, and extreme wave slowing-down. Here, we investigate the elastic instability phenomenon in soft heterogeneous materials, and the applications of the phenomenon to design of soft acoustic metamaterials. The deformable composites typically combine soft matrix and stiffer phases (such as fibers or inclusions). We will start by considering the effect of experimentally observed wrinkling on elastic waves band-gaps in soft laminates. Next, we will discuss the emergence of the negative group velocity in 3-D fiber composite brought to the “marginally stable” state. Then, we will turn to the so-called auxetic or negative Poisson's ratio materials comprising of soft- matrix-void-stiff-inclusion systems, and illustrate the mechanisms leading to the emergence of low-frequency band gaps. Finally, a new type of instabilities giving rise to anti-symmetric domain formations will be illustrated on the examples of 3-D printed soft composites.
More “rhythmic” speech is more intelligible in noise: Evidence from Lombard-inspired speech modifications
Authors: Bosker Hans Rutger , Cooke Martin
Published: December 2020

When listening in challenging circumstances, such as in loud background noise, speakers may adjust their voice, known as Lombard speech. These acoustic adjustments facilitate speech comprehension in noise relative to plain speech (i.e., speech produced in quiet). However, exactly which characteristics of Lombard speech drive this intelligibility benefit in noise remains unclear. This study assessed the contribution of enhanced amplitude modulations to the Lombard speech intelligibility benefit. We demonstrate that (1) across a range of cross-language speech corpora, talkers show greater power in the modulation spectrum for speech produced in noise as compared to RMS-matched speech-in-quiet; (2) more enhanced amplitude modulations (i.e., more `rhythmic' speech) correlate positively with intelligibility in a speech-in-noise perception experiment; (3) transplanting the amplitude modulations from Lombard speech onto plain speech leads to an increase in keywords correct scores, suggesting that enhanced amplitude modulations in Lombard speech contribute towards intelligibility in noise. Results are discussed in light of recent neurobiological models of speech perception with reference to neural oscillators phase-locking to the amplitude modulations in speech, guiding comprehension.
The effects of word status and vocoding on voice cue perception
Authors: Koelewijn Thomas , Gaudrain Etienne , Tamati Terrin N. , Başkent Deniz
Published: December 2020

Talkers' voices play an important role in speech perception, a process affected in CI-users. While previous research has suggested top-down influence of linguistic content on talker perception, how this affects perception of individual voice cues when vocoded remain unclear. Fifteen young, normally hearing participants performed a three alternative forced choice adaptive task. They listened to words presented normal (forward) or reversed (word status), while for one of the three words the fundamental frequency (F0) and/or vocal-tract length (VTL) was manipulated. In addition, either the same or three different words/reversed-words (token homogeneity) were presented in sequence, without or with (low or high simulated stimulation-spread) vocoding. Results show that JNDs for F0 and VTL were significantly smaller (better) for words compared to reversed-words, for fixed than for variable conditions, and for without than with vocoding. A four-way ANOVA and post hoc analysis revealed the word status was mostly affecting VTL JNDs in the variable word conditions. This suggests the phonotactic properties of vowels impact VTL perception. In all, linguistic (phonological) processing seems to have a top-down effect on voice cue perception especially when linguistic variability is high. These cognitive compensation mechanisms might also benefit CI-users, especially when it comes to VTL discrimination.