bluuebunny/crossref_metadata_2025 huggingface dataset:
Acoustic signals induce egg laying in túngara frogs
Authors: Emerson Jenica L. , Tom Karina , Pawek Montana , Shulman Ariana , Watu Brittany , Ha Caitlin , Baek Joshua , Lee Hong S. , Gridi-Papp Marcos
Published: December 2020

Male mating calls generally attract mates and deter competitors. In some vertebrates, however, mating calls can also influence ovarian development. Stimulation of the auditory system shifts the endocrine control of the female gonads but little is known about the underlying mechanisms. We studied túngara frogs because their mate choice responses to sound are well known. We stimulated isolated females with sound and monitored their egg laying to answer three questions: (1) Can egg laying be triggered by sound? (2) Is their response to sound specific? (3) Among conspecific male calls, are the most attractive ones also more likely to elicit egg laying? The results showed that egg laying in isolated females could be elicited by male advertisement calls in the presence of a pool of water. This response occurred within hours but it was abolished if the calls were modified. Among conspecific calls, complex ones known to have enhanced attractiveness to females did not differ significantly from simple ones in their ability to stimulate egg laying. The reproductive state response of the female to sound can therefore match or depart from her mate choice response indicating a complex neuroendocrine coordination with the auditory system.
Modeling underwater propagation of acoustic vortex beams by ray methods
Authors: Zou Zheguang , Fan Xudong , Zhang Likun
Published: December 2020

Acoustic vortex beams have application potentials in the fields of object manipulation and high-speed communication. Due to the additional azimuthal features, modeling the propagation of vortex beams usually requires three-dimensional (3-D) models, which are of high computational cost, especially for large-scale simulations. Here, the two-dimensional (2-D) BELLHOP ray-tracing model is used to simulate the 3-D propagation of acoustic vortex beams in the deep, long-range ocean environment for a low computational cost. The vortex source is constructed by multiple point sources, each with a predefined initial phase to form the vortex wavefront. The 3-D vortex acoustic field is modeled by a sum of the fields simulated for the individual sources in 2-D environments. The results reveal that the traditional 2-D ray-tracing model is an effective tool to study vortex beam propagation in inhomogeneous media, with less complexity compared to finite element simulations using COMSOL Multiphysics.
Weakly nonlinear theory and numerics on pressure wave propagation in a flowing water containing many translational bubbles acting a drag force
Authors: Yatabe Takahiro , Ayukai Takahiro , Kanagawa Tetsuya
Published: December 2020

Focusing on the effect of translational motion of bubbles and drag force acting bubbles, we theotetically and numerically tackle weakly nonlinear propagation of plane progressive pressure waves in a compressible water flow uniformly containing a number of spherical gas bubbles. At an initial state, gas and liquid phases are flowing with each velocity. Drag force and virtual mass force are introduced in an interfacial transport across the bubble–liquid interface. As bubble dynamics, translation and spherically symmetric oscillation are considered. The bubbles do not coalesce, break up, disappear, and appear. The gas viscosity, the thermal conductivities of the gas and liquid are discarded. From the singular perturbation analysis up to the second order of approximation, we have two types of Korteweg–de Vries–Burgers (KdVB) equation with a newly introduced term without a differentiation due to the drag force from the basic equations for bubbly flows in a two-fluid model; the drag term is classified into the linear and nonlinear terms. The translation affects the nonlinear effect of waves and the drag force affects the dissipation effect of waves. We finally numerically solve the KdVB equation to compare three dissipation factors, i.e., acoustic radiation damping due to the liquid compressibility, liquid viscosity, and drag force for various initial void fraction and bubble radius.
Discrimination of interaural intensity differences and monaural intensity increments
Authors: Stellmack Mark A. , Viemeister Neal F. , Byrne Andrew J.
Published: December 2020

This study assessed the equivalence of a binaural task (two-interval discrimination of interaural intensity differences, IIDs) and a monaural two-interval increment-discrimination task, in which each interval consisted of two noise bursts of different intensities, with listeners identifying the interval with the larger intensity change. Stimuli were broadband noise, with trial-by-trial feedback provided. An overall level rove between intervals forced listeners to compare the two signals within each interval (across ears in the binaural task and across bursts in the monaural task). Both tasks involved presentation of four signals of different intensities, yielding the same optimal decision statistic. Assuming (1) discrimination of IIDs across intervals amounts to discrimination of lateral position and (2) variability in lateral position increases with IID leads to a prediction of Weber's law. Functions relating threshold IID delta (or monaural increment delta) in dB to the standard IID (or increment) in dB had nearly equal slopes in binaural (0.054) and monaural (0.058) conditions. While the derived binaural decision statistic is based on discrimination of an emergent percept of the stimulus (intracranial position), the similarity of results suggests that monaural increment-discrimination may be based on discrimination of a similarly emergent percept (a loudness step). [Work supported by NIH R01DC00683.]
X-ray analysis of velum movement in continuous speech
Authors: Islam Jahurul , de Boer Gillian , Lo Chiachih , Smith Hillary , Tse Ernest , Gick Bryan
Published: December 2020

In speech, the velopharyngeal port (VPP) is closed for oral sounds and open for nasal consonants and nasalized vowels. While VPP opening has been much studied, the stimuli have typically been sustained vowels or short CVC words. To study velum movement in continuous speech, we examined X-ray film database data [Munhall et al., J. Acoust Soc. Am. 98(2), 1222–1224 (1995)] from French and English speakers. The films' speech audio were annotated and velum movement in each frame was tracked using videokymography in ImageJ. Degree of VPP opening was normalized by speaker and plotted in arbitrary units (au). Each velum opening and closure excursion created a peak (max value 1.0) with a corresponding opening and closing slope. Preliminary analysis of two English and six French speakers shows the average VPP opening was greatest during inter-utterance pauses at 0.54 au (SD 0.24), while for nasals the opening was 0.34 (SD 0.17) and for oral sounds the velum was generally closed. There was greater mean opening for utterance-final nasals [0.41 SD(0.21)] than utterance-initial [0.25 SD(0.13)] or mid-utterance [0.32 SD(0.15)] nasals. Across-speaker slope analysis suggests the velum moves at a similar speed for opening and closing movements. Across-language comparison will be reported.
Diadochokinetic speech in individuals at clinical high risk for schizophrenia
Authors: Hitczenko Kasia , Segal Yael , Fuchs Tzeviya Sylvia , Goldrick Matthew , Keshet Joseph , Mittal Vijay
Published: December 2020

Past work has shown that individuals at clinical high risk (CHR) for developing psychosis have difficulty with motor coordination (e.g., Mittal etal., 2013). Here we ask whether these motor disruptions also affect their ability to produce speech, resulting in more variable speech productions. CHR participants and matched controls completed a diadochokinetic speech task, in which they first repeated syllables (i.e., papap…, tatat…, kakak…) and then alternated between different syllables (i.e., pataka....) as quickly and accurately as possible. We detect and localize the acoustic syllables /pa/, /ta/ and /ka/ automatically using a deep learning algorithm that was specially designed for the detection of `acoustic objects', discrete events in the acoustic signal (Segal et al., 2019). We predict that, due to less stable control of their articulators, CHR individuals will show increased acoustic variability and more overlap between different sound categories relative to healthy controls.
Jiri Tichy and his impact on the field of active noise control
Authors: Sommerfeldt Scott D.
Published: December 2020

Jiri Tichy was integrally involved in a number of cutting-edge research areas in acoustics, which gave him keen insights as to where meaningful contributions to the field of acoustics could be made. These insights and connections enabled him to successfully mentor numerous students in these areas by involving them in significant research and introducing them to key contacts. One such area was the field of active noise control, where he was both a mentor and friend to the author. Jiri became actively involved in active noise control in the 1980s, at the time when active control was reborn in the digital age and began to explode as a research area. During this time, the author had the privilege of working with Jiri in this field and being mentored by him. This paper will overview some of the research by the author that was either directly or indirectly influenced by Jiri in his role as both mentor and colleague. Two such research areas include the technique of passive real-time system identification, and the method of actively minimizing acoustic energy density as a means of achieving more global attenuation of the sound field.
Studies on the vibration of Japanese drum wood barrels under material property uncertainty
Authors: Hwang Yun Fan , Suzuki Hideo
Published: December 2020

Unlike isotropic material such as steel, wood behaves as a highly orthotropic composite material. Due to measurement difficulty, only the longitudinal Young's modulus and the specific gravity of the wood were successfully measured at the time the wood barrel was made. In the experiments, mode shapes and modal resonance frequencies were measured. In the numerical modal analysis, the finite-element model of the drum was constructed using orthotropic conical shell elements which require more elastic constants than those being measured. A try-and-error method was used to estimate those unknown constants by comparing the computed and measured modal frequencies and shapes. It was found that the estimated value of the circumferential (cross-grain) Young's modulus, which was unknown at the beginning of the study, turns out to be crucial in determining the lower mode resonance frequencies. The usefulness of this analysis is that the estimated elastic constants can be used for updating the finite-element model which can then be used for calculating the higher order modes. These higher modes cannot be practically determined by measurements. [Work by 2nd author supported by Miyamoto Unosuke Shouten Co.]
Assembling an acoustic catalogue for different dolphin species in the Colombian Pacific coast: An opportunity to parameterize whistles before rising noise pollution levels
Authors: Norena Daniel
Published: December 2020

Growing ship traffic worldwide has led to a relatively recent increase in underwater noise, raising concerns about effects on marine mammal communication. Many populations of several dolphin species inhabit the eastern Pacific Ocean, along the coast of Colombia. Noise pollution levels in the Colombian Pacific coast (CPC) are very low. Currently, the CPC is slated for the construction of a port in the Gulf of Tribugá. Previous port construction in other countries have shown that this will change the acoustic environment and will compromise marine fauna, such as dolphins. This is the first study focused on the whistle acoustic parameters from several dolphin species in the region before any disturbance. Opportunistic recordings were made in two different locations alongside the coast, reporting five different delphinid species. The results show that the repertoire of four species is different when compared to other populations in more disturbed areas around the globe. An LDA was used to cluster the acoustic parameters and it supported the acoustic niche hypothesis, finding that these species may avoid whistle overlapping. If constructed, the port could force species to adjust their vocal repertoire engaging in an inter-specific whistle overlapping, or could lead to area abandonment, which would cause economic and ecological disasters for the region.
To the beat of a different drummer: Defining the rhythmic traits of humpback whale vocalizations
Authors: Palanca Mar , Walker Lisa , Duque Esteban , Nichols Ross , Sharpe Fred , Seger Kerri , Perazio Christina E. , Friedlaender Ari
Published: December 2020

Tonal signals are useful in behavioral studies as they often represent the building blocks of more complex vocalizations. Their simple structure can be indicative of fundamental processes such as resonant chamber size. Repetitive tones produced by the humpback whales from the Colombian breeding ground are not easily categorized into song nor social calls. These tones display a strong rhythmic quality, yet little is known about the functionality of temporal patterning in its vocalizations. Studies on the temporal structure of song have noted that unit-to-unit duration is relatively consistent within a phrase but that rhythm in song often lacks precision. Taking a musicological approach, we examined potential carrier signals of information within the tones by comparing its rhythmic qualities to those found in social calls (particularly feeding calls) and song, and theorize how rhythmic characteristics may aid the whale in its feeding, communication, and mating pursuits.
Characterization of tissue mimicking phantoms and soft tissues using ultrasound shear wave elastography and power-law models
Authors: Urban Matthew W. , Kijanka Piotr , Wood Benjamin , McGough Robert J.
Published: December 2020

Characterization of mechanical properties of tissue has become an important area of study over the last two decades. Shear wave elastography (SWE) is being used in many clinical applications to characterize, and multiple mechanical properties are being reported. To more comprehensively characterize soft tissues, we have focused on frequency-domain methods for evaluating viscoelasticity. We measure the shear wave velocity and attenuation and the variation with frequency. We will present results with the Kelvin-Voigt fractional derivative model and general power laws to characterize data from SWE experiments in tissue-mimicking phantoms and exvivo and in vivo tissue. Tissue mimicking phantoms from CIRS, inc., that have varying amounts of viscoelasticity will be investigated. Measurements from ex vivo and in vivo liver and kidney will also be used for this study. We will examine the range of the power-law exponents associated with these samples and the different models to provide understanding of the range of these parameters and how well tissue mimicking phantoms realize the parameters measured in soft tissues.
Application of fractional calculus to the ultrasonic characterization of human bone tissue
Authors: Fellah Zine El Abiddine , Roncen Remi , Fellah Mohamed , Ogam Erick , Depollier Claude
Published: December 2020

Transient ultrasonic propagation in human bone tissue is considered according to Biot's theory. The bone is modeled as a porous medium with an elastic structure. The viscous fluid/structure interactions are described by fractional calculus in the time domain. The slow and fast compressional waves, as well as the rotational shear wave predicted by Biot's theory obey fractional propagation equations. The fractional equation system is solved analytically in the time domain, thus obtaining the expressions of the reflection and transmission scattering operators. Inverse identification of the intrinsic microstructure of the pores and of the mechanical properties of the bone is performed in the time domain (waveforms) and frequency domain (attenuation and phase velocities), by adopting a statistical Bayesian inference technique using ultrasonic transmitted and reflected signals, which allows to find the identified parameters and their associated uncertainty.
A comparison of algorithms for the vibroacoustic optimization of a beam: Gradient-based versus evolutionary
Authors: McCormick Cameron A. , Shepherd Micah
Published: December 2020

Two common classes of optimization algorithm used in structural and/or multidisciplinary optimization are gradient-based algorithms and evolutionary algorithms. In the case of smooth, unimodal objective spaces, gradient-based algorithms are generally faster, requiring fewer iterations to reach a solution. Evolutionary algorithms, on the other hand, are more robust against objective spaces that are nonlinear, discontinuous, and multimodal. This talk will present an optimization of the thickness distribution of a cantilever beam, inspired by a similar study carried out by Berggren et al. [“Sound vibration damping optimization with application to the design of speakerphone casings,” in 10th World Congress on Structural and Multidisciplinary Optimization (2013)]. The objective is to minimize the vibration response within a certain region of the beam at discrete frequencies, with constraints on total mass and static compliance. The objective space is expected to be nonlinear and potentially multimodal. A transfer matrix method is used to evaluate the objective function and constraints, and optimal solutions are found using both a gradient-based algorithm and an evolutionary algorithm. Qualitative and quantitative results will be presented in comparing the optimized distribution to that of Berggren et al. and in discussing the benefits and limitations of the two algorithms for vibroacoustic optimization.
Quantitative metrics to experimentally benchmark geoacoustic inversion methods
Authors: Bonnel Julien
Published: December 2020

Geoacoustic inversion schemes are complex methods that combine various experimental designs (e.g., arrays or single receivers, fixed or moving sources,…), different data processing methods (e.g., tracking ray arrivals, filtering modes, estimating spectral matrices,…) and different inversion methods (e.g., brute force grid search, stochastic optimization,…). Because of this complexity and variability, geoacoustic inversion methods are difficult to benchmark. Although simulated benchmarks are possible, experimental benchmarks are more difficult since (1) experimental ground truth is never fully available and (2) different methods may sense different features/scales of the seabed. Nonetheless, assessing the performance of geoacoustic inversion methods is of paramount importance, since the resulting geoacoustic models are used to predict acoustic field for various applications, including Navy operations or noise pollution monitoring. In this presentation, we propose quantitative metrics to assess the experimental performances of inversion methods. The proposed metrics allow inter-comparison of various geoacoustic models, but also comparison of predicted acoustic field with experimental (independently collected) data. The metrics are successfully applied on a subset of data collected during the Shallow Water 2006 experiment.
Microphones that predate modern electroacoustics
Authors: Thompson Stephen C.
Published: December 2020

Our modern understanding of Electroacoustics includes acoustic sensors (microphones) and projectors (loudspeakers) and the electronic amplifiers that form a complete electroacoustic system. The first electronic amplifiers were made with vacuum tubes and became available about a century ago. Thus, we may consider electroacoustics as a technology whose history began at that time. The first microphones were invented before then, but most microphone technologies needed electronic amplification for practical employment. On the other hand, the telephone communication industry, which began in the 1870s, was reasonably mature by the 1920s using a design that did not include vacuum tubes. This presentation will describe the devices used in the early telephone system and how that system could exist without electronic amplification.
Off-axis frequency response in a dual diaphragm, uniphase moving coil microphone
Authors: Grinnip Roger S.
Published: December 2020

When the rear port in a uniphase, unidirectional condenser microphone is modified to include a series compliance element (dual diaphragm) the low frequency performance can be improved. The benefit is most notable in the off-axis response as it relates to source/receiverproximity (proximity effect). Due to the significant operational differences between uniphase moving coil and condenser microphones, incorporating a dual diaphragm element into the rear port of a moving coil microphone requires careful attention to the design. Simplified network models of the uniphase system, proximity effect, and dual diaphragm moving coil design are presented. Measured results of a dual diaphragm, uniphase moving coil microphone are presented with off-axis response comparisons to a single diaphragm, uniphase moving coil microphone.
Acoustics outreach demonstration show: Sounds to astound
Authors: Vongsawad Cameron T. , Vaughn Aaron B. , Wallace Carla , Neilsen Tracianne B. , Anderson Brian E. , Gee Kent L.
Published: December 2020

The sounds to astound acoustics demonstration show is put on twice a year for the local community by the Brigham Young University Student Chapter of the Acoustical Society of America. The show is a free, interactive demonstration show that explores the science of sound for a target audience of 5th to 8th grade students. A variety of introductory acoustics concepts such as waves, frequency, amplitude, and medium are taught in conjunction with an associated demonstration, animation, and/or video. This presentation will describe the planning and execution of the demonstration shows as well as identify several demonstrations and the corresponding acoustics concept(s) taught with it. In addition to these shows, tours of the anechoic and reverberation chambers are also provided for appropriate age groups.
Finite element simulation of reed-resonator coupling: The khaen pipe as an example
Authors: Hassard Brian R. , Cottingham James P.
Published: December 2020

Recently some work has been done on the coupling of a free reed to a resonator using finite element modeling software. This has been focused primarily on the pipes of the khaen, a Southeast Asian free-reed bamboo pipe instrument. The broad goal is realistic modeling of an air-driven reed by simulating fluid-structure interactions in conjunction with air flow and pressure fluctuations. In the current study, coupling between the reed and the resonator has been explored and compared for cylindrical cross-section pipes, including khaen pipes, as well as for Helmholtz resonators. The effects of pressure and fluid flow on the reed motion were studied, and reed-resonator coupling explored for both the Helmholtz resonator and khaen systems. Reed vibration and sound radiation have been analyzed and compared to published models. Preliminary results are realistic, including the sound radiation pattern from a reed driven khaen pipe. Some were unexpected, including a relatively large role of the second transverse mode of the reed tongue. Some unresolved discrepancies remain between results for laminar flow models and pressure physics models, which are the subject of ongoing work. Future goals include modeling a reed-driven simulation of the complete khaen instrument system.
Statistical phase analysis and Lyon statistical mode shape functions
Authors: DeJong Richard
Published: December 2020

While many of us were still trying to figure out the magnitude of SEA predictions, Dick Lyon had moved on to determining the statistics of the phase of frequency response functions. He derived a new set of functions which he named Beranek functions. This was an important element of his work on machinery diagnostics. This presentation will review the development of Statistical Phase Analysis and some following work leading to the definition of Lyon Statistical Mode Shape Functions.
Richard Lyon and the statistics of vibration
Authors: McDaniel James , Liem Alyssa , Kaminski Allison
Published: December 2020

Richard Lyon's pioneering work on the statistics of vibration produced significant insights and tools that profoundly improved our world. This work and its impact will be reviewed. This lecture begins with his 1955 Doctoral Dissertation at the Massachusetts Institute of Technology, which was entitled The Response of Continuous Systems to Random Noise Fields. It was supervised by K. Uno Ingard. His work on Statistical Energy Analysis followed and received widespread interest, resulting in commercial software packages that implemented the theory. For this and related work he received the Gold Medal from the Acoustical Society in 2003, “… for sustained leadership and extensive contributions in the application of statistical concepts to structural acoustics and noise.” To illustrate the impact of his work and to honor his legacy, this presentation reviews recent work by the authors on the statistics of vibrations analyzed by machine learning algorithms. A training set is constructed by computing the responses of a system with randomly generated properties from known distributions. A machine learning algorithm uses this training set to predict the response of a system with known properties.
Of knitting needles and surround sound
Authors: Blair Christopher
Published: December 2020

The author began his association with Dick Lyon in 1972 when he became a graduate student in the Acoustics and Vibration Lab at MIT. Their personal and professional relationship continued, on and off, through the mid 1990s. While early studies of outdoor sound propagation and transportation noise will be discussed, this presentation will focus primarily on their work together at RHLyonCorp in the study of vibration-induced failure mechanisms and in commercial product development, including early efforts in sound quality jury trials.
Dick Lyon's contributions to product sound quality
Authors: Bowen David L.
Published: December 2020

Dick was a firm believer in bringing context of use into any problem involving how to improve the “sound quality” of a product or, as he liked to say, how to make products “sound good.” He first got interested in this field when a sewing machine company approached him at M.I.T. and said they wanted their machine to sound more like their competitor's. Dick took up this challenge in his own way, saying we'll make it better sounding. He did this by incorporating various statistical techniques used in the food and flavor industries to optimize particular aspects of consumer response, substituting the sound levels of different components and mechanisms in the sewing machine for the amounts of different flavorings used in a food product. By exposing a consumer listening panel made up of actual product users to the sounds of a range of “virtual” products made up by combining the original and altered sounds of the different components (but never altered beyond what was physically feasible), and asking panelists to rate these sounds in terms of, say, acceptability, a mathematical model could be formed between changes to the component sounds and consumer ratings, thus providing concrete guidance for improved response. This and other sound quality techniques he pioneered will be discussed.
Spherical reflection for a planar boundary: Inverse Laplace transform of Fresnel's reflection coefficient
Authors: Thompson Charles , Chandra Kavitha , Gandhi Pratik , Bhatta Ambika , Raspopovic Miroslava
Published: December 2020

Numerous investigators have examined the problem of spherical wave reflection from the planar interface between two media. The Sommerfeld's integral can be referred to in this context. Recently the inverse Laplace transform was used by Lindell and Alanen, for the case of an electric dipole above a ground plane, to improve and simplify the analysis of this problem. The current work will focus on the Laplace transform method and the required inversion of the Fresnel reflection coefficient. It is shown that the pole-zero cancellation present the reflection coefficient can result in a significant simplification in the inversion process. Application to the analysis of multilayer media is discussed.
Simulation of N-wave propagation in turbulent atmosphere using standard and wide-angle parabolic equations
Authors: Yuldashev Petr V. , Karzova Maria M. , Khokhlova Vera , Blanc-Benon Philippe
Published: December 2020

Interest to the problem of sonic boom propagation in atmosphere is growing in recent decade due to the development of new generation of supersonic business jets. Important nonlinear wave effects occur in the last kilometer above the ground where sonic boom wave interacts with turbulence of the planetary boundary layer. Focusing and defocusing of the sonic boom on random inhomogeneities of sound speed lead to fluctuations of its peak overpressure and rise time, affecting the perceived loudness. Various one-way model equations of different complexity have been developed and actively used by the research community for analyzing wave propagation in turbulent atmosphere. The basic equation is the nonlinear parabolic equation of the Khokhlov-Zabolotskaya-Kuznetsov-type, which has limitation on diffraction angles. Improvement in accuracy of the diffraction term can be reached using wide-angle formulation. Here, the simulation results for N-wave propagation through homogeneous isotropic turbulence are compared for standard and wide-angle parabolic equations of scalar type. Turbulence wind velocity fluctuations are accounted via effective sound speed. The wide-angle model is based on split-step Pade approximation of the propagation operator. The importance of taking into account large diffraction angles for N-wave propagation in atmospheric turbulence is discussed. [Work supported by RSF-18-72-00196 and ANR-10-LABX-0060/ANR-16-IDEX-0005].
Analytical sound pressure expression of vortices near a ground surface
Authors: Bhatta Ambika
Published: December 2020

In this work, an analytical expression is sought for the sound pressure of aircraft wake vortices near a ground surface. The analytical basis for the mechanisms of aircraft vortex sound generation follows the vortex dynamic models and vortex sound theory. The theory focuses on acoustic signatures of the vortex created from the subsonic flow. Vortex acoustic signature from the ground can mainly be characterized based on the boundary condition and transition of the flow moving away from the ground. Of interest is the acoustic characterization of wake vortex in ground effect. To this end, themethod of images was used to simulate the presence of the ground. The method of images assures that the vorticity is mirrored about the ground plane that contributes to the modified amplitude above the ground. The extension of the presented approach to model the pair of vortices, impedance boundary, and turbulent flow in the ground effect will also be highlighted.
Examining wind noise reduction effects of windscreens and microphone elevation in outdoor acoustical measurements
Authors: Jones Zachary T. , Cook Mylan R. , Gunther Alexander M. , Kimball Taylor S. , Gee Kent L. , Transtrum Mark K. , Lympany Shane V. , Calton Matt , James Michael M.
Published: December 2020

Jones et al. [J. Acoust. Soc. Am. 146, 2912 (2019)] compared an elevated (1.5 m) acoustical measurement configuration using a standard commercial windscreen with a ground-based configuration with a custom windscreen. That study showed that the ground-based measurement method yielded superior wind noise rejection, presumably due to the larger windscreen and lower wind speeds experienced near the ground. This study examines those findings in greater depth by attempting to decouple the effects of windscreens and microphone elevation using measurements at 1.5 m and near the ground with and without windscreens. Simultaneous wind speed measurements at 1.5 m and near the ground were also made for correlation purposes. For the elevated acoustical measurements, three different commercial windscreens were used to further examine impacts of the larger windscreen in the ground-based setup. Results show that the custom windscreen has a more significant noise-reduction impact than microphone elevation, and that the ground-based setup is again preferable for obtaining broadband outdoor acoustic measurements. [Work supported by a U.S. Army SBIR.]
Holographic reconstructions of large-eddy simulations of a highly heated laboratory-scale jet
Authors: Leete Kevin M. , Gee Kent L. , Liu Junhui , Wall Alan T.
Published: December 2020

Near-field acoustical holography allows for the reconstruction of a sound field from a limited measurement. For aeroacoustic noise generated by military aircraft, reconstructions of the pressure field within the jet plume have provided insight into equivalent acoustic noise source distributions, though the relationship between these equivalent sources and actual flow pressures and velocities within the plume remain unknown. This study reconstructs the sound field of a highly heated laboratory-scale jet simulated by the Naval Research Lab's Jet Noise Reduction (JENRE) large eddy simulation solver. The simulated data allow for comparisons of the holographic reconstructions of the pressure and particle velocity fields to points along the nozzle lipline, to the Ffowcs Williams and Hawkings integration surface (FWHS), and to the far field. Pressure field reconstructions outside and inside of the FWHS match well, while particle velocity reconstructions follow similar trends as the velocities generated by the LES but severly underestimate the time harmonic complex amplitdues.
Impacts of component audibility and noise masking on spectral weighting of sound-localization cues
Authors: Folkerts Monica L. , Picou Erin M. , Stecker G. Christopher
Published: December 2020

Spatial localization of complex sound requires appropriate integration of acoustic cues across the frequency spectrum. Spectral weighting functions (SWFs), which quantify the relative weighting of cues across frequency components, have been measured through binaural and free-field methods using observer weighting techniques adapted from Stecker and Hafter [J. Acoust. Sci. Am. 112, 1046–1057 (2002)]. SWFs obtained with equal-amplitude components support a “dominance region” around 400–800 Hz [Bilsen and Raatgever, Acoustica 28, 131–132 (1973); Stecker and Folkerts, J. Acoust. Sci. Am. 145, 1720 (2019)]. The current study extends this work to compare the effects of component intensity on SWFs of stimuli presented with competing noise and stimuli filtered through a high-frequency sloping hearing-loss simulation (HLS). Localization with a white-noise masker deteriorates more for low-frequency than high-frequency noise stimuli [Abel and Hay, Scand. Audiol. 25, 3–12 (1996); Lorenzi et al., J. Acoust. Sci. Am. 105, 1810–1820 (1999)]. Imposition of spectral slopes introduced “level dominance” [Berg, J. Acoust. Sci. Am. 88, 149–158 (1990); Lutfi and Jesteadt, J. Acoust. Sci. Am. 120, 3853–3860 (2006)] in the form of increased weights for the loudest components. Weighting pattern changes in the presence of noise and similar patterns with the HLS due to “level dominance,” if confirmed, may impact spatial hearing by shifting the dominance region. [Work supported by NIH R01-DC016643.]
Listening challenges for service members and veterans with traumatic brain injury: The role of sentence context for speech perception in noise
Authors: Kuchinsky Stefanie E. , Eitel Megan M. , Cohen Julie I. , Lange Rael T. , French Louis M. , Brickell Tracey A. , Lippa Sara M. , Brungart Douglas S.
Published: December 2020

Service Members and Veterans (SMVs) with a traumatic brain injury (TBI) often report difficulties understanding speech in noise. This study assessed the impact of TBI history on speech-in-noise recognition and benefit from sentence context. Participants were SMVs (ages 20–62) who had a history of at least an uncomplicated mild TBI (n = 122) or who had no TBI history (n = 58). For each listener, an interleaved, adaptive procedure was used to obtain an overall Speech Reception Threshold (SRT) and a difference in accuracy for high and low context sentences at that threshold. Penalized LASSO regressions revealed larger context benefits for individuals with TBI, poorer high frequency thresholds, poorer executive function, and self- reported tinnitus. Age, Post-Traumatic Stress Disorder, and neurobehavioral symptom severity did not predict context benefit. These results suggest TBI is associated with greater reliance on context in noise, even when accounting for variation in hearing acuity and cognitive function. [This project was funded by the Defense and Veterans Brain Injury Center (DVBIC) as part of a Congressionally-Mandated Longitudinal TBI Study. The views expressed in this abstract are those of the authors and do not reflect the official policy of the Department of Army/Navy/Air Force, Department of Defense, or U.S. Government.]
Examining bilingual speech perception and the role of background noise
Authors: Morini Giovanna
Published: December 2020

Over the years there has been much debate regarding how bilingualism influences performance on linguistic tasks. One specific question is whether growing up with one versus two languages is related to variations in the ability to process speech in adverse listening conditions. This talk will include findings from studies with both adults and young children that compared monolinguals' and bilinguals' ability to recognize and learn words in the presence of white noise. The adult data suggest that bilinguals are less accurate than monolinguals at identifying familiar words in noise. However, the bilingual “disadvantage” identified during word recognition is not present when listeners were asked to acquire novel word-object relations that were trained either in noise or in quiet. Similar group differences were identified with 30-month-olds. Bilingual children performed significantly worse than monolinguals, particularly when asked to recognize words that were accompanied by noise. This work suggests that linguistic experience and the demands associated with the type of task both play a role in the ability for listeners to process speech in noise. Furthermore, it suggests that bilingualism not only plays an important role in speech processing in noise, but that this effect is preset from a very early age.
Predicting children's word recognition accuracy from accent distance metrics
Authors: Bent Tessa , Holt Rachael F.
Published: December 2020

Compared to adults, children show lower word identification accuracy under both environmental- and source-related listening challenges (e.g., speech in noise or unfamiliar accents). Early school-aged children have difficulty understanding both unfamiliar native and nonnative accents. Although adults typically have difficulty only when unfamiliar accents are mixed with noise, children show word identification decrements for some unfamiliar accents under quiet conditions. Furthermore, children's word recognition accuracy varies widely across accents in both quiet and noise-added conditions. The developmental differences appear to stem partially from children's less robust use of semantic/syntactic contextual cues; less well understood is the role of specific accent characteristics leading to reduced word identification. We are currently assessing the relation between a number of accent distance metrics and children's word recognition accuracy. These metrics, which quantify the distance from the home dialect, include segmental (i.e., Levenshtein distances), holistic signal (i.e., dynamic time warping), holistic perceptual (i.e., listener rankings from the native dialect standard), and suprasegmental (e.g., articulation rate, speech rhythmic metrics) measures. This work may provide insight into what aspects of the signal cause children more difficulty than adults when mapping unfamiliar pronunciations onto their lexical representations. Work supported by the National Science Foundation, Grant No. 1941691.]
Long term acoustic time series of the Lofoten–Vesterålen ocean observatory
Authors: Pedersen Geir , Zhang Guosong , Aniceto Sofia , Johnsen Espen
Published: December 2020

Lofoten-Vesterålen (LoVe) is a productive coastal shelf-slope area and an environment sensitive to external stressors. This is a region with complex dynamics where the Norwegian Coastal Current and the Norwegian Atlantic Slope Current meet and mix, and commercially and ecologically important species of fish go through early vulnerable life stages drifting through during planktonic life stages. The LoVe Ocean Observatory is a cabled multi-purpose observation network in development, where the first node was installed and has been in operation since 2013. The main objective of the observatory is to significantly increase knowledge of the physical, chemical, and biological environment of the LoVe shelf-slope-system. The observatory nodes are equipped with a range of sensors including active and passive acoustic sensors. Echosounders monitor vertical distribution and density of marine organisms and flux of biomass across the observatory transect. Hydrophones provide continuous monitoring of anthropogenic noise and vocalizing marine mammals and fish. In this work we examine the active and passive acoustic time series from the first years of operation of the observatory, with emphasis on periods of co-occurrence of lower trophic level organisms and top predators.
Model for explosive shock waves in fluids with relaxation
Authors: Willis William A. , Cormack John M. , Muir Thomas G. , Hamilton Mark F.
Published: December 2020

Nonlinear propagation of sound from underwater explosions has been treated empirically and analytically since the work of Cole [Underwater Explosions (1948)]. A semi-analytical solution for propagation of a weak shock followed initially by an exponential tail was obtained by Rogers [J. Acoust. Sci. Am. (1977)] under the assumption of no relaxation. Here, an efficient algorithm is presented for calculating the propagation of a weak shock followed by a tail with arbitrary waveform in a fluid with multiple relaxation mechanisms. The model is based on an evolution equation in intrinsic coordinates for nonlinear propagation in a relaxing fluid [Hammerton and Crighton, JFM (1993)]. Intrinsic coordinates permit the waveform to become multivalued, which avoids having to discretize thin shocks. At distances where output is desired, a shock is inserted according to Landau's equal-area rule, rendering the waveform single-valued. Waveforms calculated in this way agree with numerical solutions of a Burgers equation augmented to include relaxation, with the proposed method requiring less computation time. When an exponential tail following the shock decays faster than the shortest relaxation time, explicit solutions are obtained for the amplitude and arrival time of the shock. [W.A.W. is supported by the ARL:UT Chester M. McKinney Graduate Fellowship in Acoustics.]
From statistical room acoustics and acoustic intensity to spatial audio
Authors: Elko Gary W.
Published: December 2020

Jiri Tichy was my graduate student advisor at Penn State. Jiri introduced me to statistical room acoustics and sound power measurements using a single pressure microphone in a reverberation room. From there we moved on to the measurement of sound power using acoustic intensity. We developed spatial microphone array probes with 2–4 microphones that measured the complex vector acoustic intensity in one to three dimensions. After graduation, the fundamentals developed analyzing the estimation of the complex acoustic intensity were applied to the development of a spherical microphone array that realized any first-order superdirectional directivity pattern pointing in any direction. It later became clear that higher-order arrays were needed to achieve higher directional gain. This led to the development of the Eigenmike® spherical microphone array with 32 pressure microphones and capable of 4th order spherical harmonic decomposition of the sound field. This array is finding application into AR/VR and statistical room acoustic analysis … bringing the technology full circle. I am incredibly lucky and grateful to have had Jiri as my mentor. He showed me how to look at acoustics problems and set the foundations of the many acoustic signal processing areas I have worked on in my career.
Psychoacoustics and classroom acoustics: New possibilities for interaction
Authors: Zahorik Pavel
Published: December 2020

For more than a century, psychoacoustics has contributed to our understanding of how humans perceive sound and how the human auditory system encodes sound. Although general knowledge from psychoacoustics is clearly relevant to classroom acoustics, relatively little research has directly linked these two areas of study. Perhaps the closest link is in the detection and perception of a single ideal acoustic reflection, where psychoacoustics has documented effects of various factors, such as reflection delay, reflection direction, and source material. Of course, real rooms are vastly more complex acoustically, and thus, the psychoacoustic complexities already evident with single reflections surely multiply in real rooms. Historically, there have also been challenges in the experimental control of relevant room acoustic parameters. Virtual acoustics has largely solved this problem, but detailed scientific study of the perceptual aspects of room acoustics still involves exploring a very large parameter space, which can be prohibitively time-intensive for human subjects testing. Here, a computational modeling approach based on psychoacoustic principles is described that greatly facilities parameter space exploration. The modeling is applied to the problem of determining reverberation detection threshold, which provides critical and missing basic information regarding the limits of human sensitivity to room reverberation.
Song and hearing in different canary strains (Serinus canarius)
Authors: Dooling Robert J. , Brown Jane , Brittan-Powell Beth , Ball Greg , Conte Matthew , Carleton Karen , Madison Farrah
Published: December 2020

Canaries have been selectively bred for specific song characteristics (song canaries) or for morphology or plumage (type canaries) for centuries. Type canaries (e.g., Border and Gloster strains) retain song characteristics that are quite similar to those of wild canaries. By contrast, song canaries (e.g., Belgian Waterslager and Roller strains) have been selected for song types pleasing to the human ear, resulting in songs that, in most cases, are less complex, lower-pitched, and narrower in a frequency range than songs from wild canaries. We now suspect that song selection in the Belgian Waterslager song canary has either directly or indirectly resulted in high-frequency hearing loss associated with hair cell abnormalities. Here, we compare hearing in the Belgian Waterslager and several other type and song canaries including the American Singer Canary. Though bred only since the 1930s, American Singer canaries may also have a high-frequency hearing loss that looks very similar to that of the Belgian Waterslager and may involve similar pathologies. Illumina whole-genome sequencing has preliminarily identified a number of high-impact SnpEff variants in Belgian Waterslager and American Singer Canaries, some of which are related to deafness genes in mammals.