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Journal of the Acoustical Society of America

Dennis Zelle, Ernst Dalhoff, Anthony W Gummer
Distortion-product otoacoustic emissions (DPOAEs) are presumed to consist mainly of two components, a nonlinear-distortion component and a coherent-reflection component. Wave interference between these two components reduces the accuracy of DPOAEs when used to evaluate cochlear function. Here, short tone pulses are utilized to record DPOAE signals in normal-hearing subjects. DPOAE components are extracted from recordings at discrete frequencies using two different techniques in the time domain. The extracted DPOAE components are compared to recordings obtained with conventional, continuous primary tones...
December 2017: Journal of the Acoustical Society of America
Qipeng Feng, Feiran Yang, Jun Yang
Two types of block sparse models are presented to interpolate the early part of the acoustic transfer functions (eATFs) between the loudspeakers and the target spatial regions in reverberant rooms. The desired eATFs are modeled as a superposition of sound fields generated by a dense grid of equivalent point sources, which exhibit two kinds of block sparse structures under the far-field and small target region assumptions. Simulation results in the two-dimensional case demonstrate that the proposed models can provide accurate eATF interpolation over a broad frequency range using a small number of microphones...
December 2017: Journal of the Acoustical Society of America
Hugo Quené, Rosemary Orr, David van Leeuwen
Second language learners may merge similar sounds from their native (L1) and second (L2) languages into a single phonetic category, neutralizing subphonemic differences in these similar sounds. This study investigates whether Dutch speakers produce phonetically distinct variants of /s/ in their L1 Dutch and L2 English, and whether and how this phonetic categorization develops over time. Target /s/ sounds in matching words in L1 and L2 were compared in their centre of spectral gravity. Speakers varied in their individual learning curves in the categorization of produced /s/ sounds, both in starting points and in longitudinal trajectories...
December 2017: Journal of the Acoustical Society of America
Penelope Menounou, Petros Nikolaou
A time domain model for predicting diffraction around half planes is presented. The model renders the directive line source model [Menounou, Busch-Vishniac, and Blackstock, J. Acoust. Soc. Am. 107, 2973-2986 (2000)] valid for times long after the diffracted signal arrival and for receivers close to the shadow boundaries, where it was not valid before. The presented model unifies diffraction by plane, cylindrically and spherically spreading incident signals (being exact for plane and approximate for cylindrical/spherical) and models diffraction as radiation from a directional line source...
December 2017: Journal of the Acoustical Society of America
Ludovic Tenorio-Hallé, Aaron M Thode, Jit Sarkar, Christopher Verlinden, Jeffrey Tippmann, William S Hodgkiss, William A Kuperman
Ray-tracing is typically used to estimate the depth and range of an acoustic source in refractive deep-water environments by exploiting multipath information on a vertical array. However, mismatched array inclination and uncertain environmental features can produce imprecise trajectories when ray-tracing sequences of individual acoustic events. "Double-difference" methods have previously been developed to determine fine-scale relative locations of earthquakes along a fault [Waldhauser and Ellsworth (2000). Bull...
December 2017: Journal of the Acoustical Society of America
Zhengyu Wei, Hong Hou, Nansha Gao, Yunke Huang, Jianhua Yang
This study presents a method for measuring the complex Young's modulus of viscoelastic materials by extracting the incident wave within a thin bar. A Butterworth impulse is generated by an electromagnetic shaker and is employed to excite a bar-like sample. The experimental results prove that the method proposed in this study can determine the Young's modulus at frequencies ranging from 200 to 6500 Hz under atmospheric pressure and room temperature. The Young's moduli of two types of rubber material determined by the experimental method agree well with those obtained using a standard dynamic mechanical thermal analyzer...
December 2017: Journal of the Acoustical Society of America
Prakhar Srivastava, Brendan Nichols, Karim G Sabra
This letter demonstrates the feasibility of a passive underwater acoustic marker technology (or "AcoustiCode") for use in underwater navigation. An AcoustiCode tag is a planar surface with machined periodic patterns capable of producing Bragg backscattering beampatterns with engineered spatial and frequency variations, thus having a unique three-dimensional acoustic signature over a selected frequency band. Hence, these AcoustiCodes enable three-dimensional navigation and information signaling in a totally passive manner for existing high-frequency SONAR systems (potentially mounted on autonomous underwater vehicles), which naturally operate in a narrow frequency band and can also be used over significantly longer ranges compared to optically-based systems...
December 2017: Journal of the Acoustical Society of America
Ahmad T Abawi, Petr Krysl
The fluid-structure interaction technique provides a paradigm for solving scattering from elastic structures embedded in an environment characterized by a Green's function, by a combination of finite and boundary element methods. In this technique, the finite element method is used to discretize the equations of motion for the structure and the Helmholtz-Kirchhoff integral with the appropriate Green's function is used to produce the discrete pressure field in the exterior medium. The two systems of equations are coupled at the surface of the structure by imposing the continuity of pressure and normal particle velocity...
December 2017: Journal of the Acoustical Society of America
Mattson Ogg, L Robert Slevc, William J Idsardi
Humans have an impressive, automatic capacity for identifying and organizing sounds in their environment. However, little is known about the timescales that sound identification functions on, or the acoustic features that listeners use to identify auditory objects. To better understand the temporal and acoustic dynamics of sound category identification, two go/no-go perceptual gating studies were conducted. Participants heard speech, musical instrument, and human-environmental sounds ranging from 12.5 to 200 ms in duration...
December 2017: Journal of the Acoustical Society of America
Philip Blom, Roger Waxler
Continuous infrasonic signals produced by the ocean surface interacting with the atmosphere, termed microbaroms, are known to be generated by a number of phenomena including large maritime storms. Storm generated microbaroms exhibit axial asymmetry when observed at locations far from the storm due to the source location being offset from the storm center. Because of this offset, a portion of the microbarom energy will radiate towards the storm center and interact with the winds in the region. Detailed here are predictions for the propagation of microbaroms through an axisymmetric, three-dimensional model storm...
December 2017: Journal of the Acoustical Society of America
Ugur Karban, Christophe Schram
The noise generated by a ducted diaphragm configuration, taken in this paper as a prototype aeroacoustic system, is investigated experimentally using a two-port source identification method [Lavrentjev, Åbom, and Bodén (1995) J. Sound Vib. 183, 517-531]. The method requires successively the determination of the so-called passive scattering properties of the ducted diaphragm system using loudspeakers, and the extraction of the active noise that would be emitted by the aeroacoustic source itself in an anechoic duct...
December 2017: Journal of the Acoustical Society of America
Kya Shoar, Benjamin W Turney, Robin O Cleveland
Shock wave lithotripsy is a non-invasive procedure by which kidney stones are fragmented by thousands of shock waves. Currently, many shock waves are delivered to the body that do not impact the stone, but do result in tissue trauma. This motivates developing a monitoring system to locate kidney stones, with the goal of gating shock waves not aligned with the stone, and hence, reducing renal trauma during lithotripsy. The system consists of a circular array housing twenty-two 0.5 MHz transducers that can be mounted on a clinical lithotripter...
December 2017: Journal of the Acoustical Society of America
Noam Amir, Liat Kishon-Rabin
Many studies have examined the contribution of different spectral bands to speech intelligibility, measuring recognition scores of filtered speech stimuli. For a given filter bandwidth, the influence of filter properties on such experiments has been studied mainly with respect to transition band slopes. The objective of the present study was to determine whether nominal transition band slope is a sufficient characterization of filter properties. Several types of filters, both finite impulse response and infinite impulse response types were examined in three experiments to determine if details of the transition band behavior, as well as group delay properties, had any influence on recognition scores...
December 2017: Journal of the Acoustical Society of America
Naveen K Nagaraj, Beula M Magimairaj
The role of working memory (WM) capacity and lexical knowledge in perceptual restoration (PR) of missing speech was investigated using the interrupted speech perception paradigm. Speech identification ability, which indexed PR, was measured using low-context sentences periodically interrupted at 1.5 Hz. PR was measured for silent gated, low-frequency speech noise filled, and low-frequency fine-structure and envelope filled interrupted conditions. WM capacity was measured using verbal and visuospatial span tasks...
December 2017: Journal of the Acoustical Society of America
Marcin Wróblewski, Daniel M Rasetshwane, Stephen T Neely, Walt Jesteadt
The goal of this study was to reconcile the differences between measures of loudness obtained with continuous, unbounded scaling procedures, such as magnitude estimation and production, and those obtained using a limited number of discrete categories, such as categorical loudness scaling (CLS). The former procedures yield data with ratio properties, but some listeners find it difficult to generate numbers proportional to loudness and the numbers cannot be compared across listeners to explore individual differences...
December 2017: Journal of the Acoustical Society of America
Sungmin Lee, Lisa Lucks Mendel
Although the AzBio test is well validated, has effective standardization data available, and is highly recommended for Cochlear Implant (CI) evaluation, no attempt has been made to derive a Frequency Importance Function (FIF) for its stimuli. This study derived FIFs for the AzBio sentence lists using listeners with normal hearing. Traditional procedures described in studies by Studebaker and Sherbecoe [(1991). J. Speech. Lang. Hear. Res. 34, 427-438] were applied for this purpose. Participants with normal hearing listened to a large number of AzBio sentences that were high- and low-pass filtered under speech-spectrum shaped noise at various signal-to-noise ratios...
December 2017: Journal of the Acoustical Society of America
Kevin M Lee, Preston S Wilson, Mark S Wochner
The ultimate goal of this work is to accurately predict the attenuation through a collection of large (on the order of 10-cm-radius) tethered encapsulated bubbles used in underwater noise abatement systems. Measurements of underwater sound attenuation were performed during a set of lake experiments, where a low-frequency compact electromechanical sound source was surrounded by different arrays of encapsulated bubbles with various individual bubbles sizes and void fractions. The measurements were compared with an existing predictive model [Church, J...
December 2017: Journal of the Acoustical Society of America
Jean-François Mercier, Jean-Jacques Marigo, Agnès Maurel
The resonance of a Helmholtz resonator is studied with a focus on the influence of the neck shape. This is done using a homogenization approach developed for an array of resonators, and the resonance of an array is discussed when compared to that of a single resonator. The homogenization makes a parameter B appear which determines unambiguously the resonance frequency of any neck. As expected, this parameter depends on the length and on the minimum opening of the neck, and it is shown to depend also on the surface of air inside the neck...
December 2017: Journal of the Acoustical Society of America
Zhao Li, Liwen Jing, Ross Murch
Acoustic wave propagation (up to 50 kHz) within a water-filled high-density polyethylene (HDPE) pipeline is studied using laboratory experiments and theoretical analysis. Experiments were carried out in a 15 m length of cylindrical HDPE pipeline using acoustic transducers to acquire signals uniformly spaced along the axis of the pipe. By proposing the use of the iterative quadratic maximum likelihood algorithm to this experimental configuration, wavenumbers, attenuations, and mode amplitudes could be accurately extracted from the measurement data...
December 2017: Journal of the Acoustical Society of America
Wenyu Bai, Gerald J Diebold
Although the photoacoustic effect is commonly produced through use of pulsed or amplitude-modulated radiation, it can also be generated by a steady source moving in space. Here, the properties of the photoacoustic effect generated by moving sources in three dimensions are investigated. The mathematics for the moving photoacoustic point source are shown to be closely related to that for derivation of the Lienard-Wiéchert potential for a moving point charge. The cases of rectilinear motion with the speeds lower than, equal to, and greater than the sound speed, as well as a point source oscillating in space are reported...
December 2017: Journal of the Acoustical Society of America
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