Read by QxMD icon Read

Journal of the Acoustical Society of America

Kam W Lo
When an airborne sound source travels past a stationary ground-based acoustic sensor node in a straight line at constant altitude and constant speed that is not much less than the speed of sound in air, the movement of the source during the propagation of the signal from the source to the sensor node (commonly referred to as the "retardation effect") enables the full set of flight parameters of the source to be estimated by measuring the direction of arrival (DOA) of the signal at the sensor node over a sufficiently long period of time...
March 2017: Journal of the Acoustical Society of America
Daniel C Brown, Shawn F Johnson, Derek R Olson
A numerical model for calculation of the incoherent component of the field scattered from random rough surfaces is described. This model is based on the point scattering approach, where the mean scatterer amplitudes are calculated from deterministic models. These amplitudes are then scaled by a complex circular Gaussian random variable to simulate scattering from a surface with minimal coherence length. The resulting simulated fields are shown to agree with theory for the mean field, mean square field, statistical distribution, and the spatial coherence length...
March 2017: Journal of the Acoustical Society of America
Marta Jussara Cremer, Annelise Colin Holz, Pablo Bordino, Randall S Wells, Paulo César Simões-Lopes
Franciscana dolphin (Pontoporia blainvillei) whistles were documented for the first time during 2003-2013 in Babitonga Bay estuary, South Brazil, together with burst pulses. Recordings were made from small boats under good sea conditions, and recording equipment that allowed analysis of sounds up to 96 kHz. The recordings were made in the presence of 2-31 franciscana dolphins. During 23 h and 53 min, 90 whistles and 51 burst pulse series were recorded. Although Guiana dolphins (Sotalia guianensis) inhabit nearby waters, none were observed in the area during the recordings...
March 2017: Journal of the Acoustical Society of America
Anders Elowsson, Anders Friberg
By varying the dynamics in a musical performance, the musician can convey structure and different expressions. Spectral properties of most musical instruments change in a complex way with the performed dynamics, but dedicated audio features for modeling the parameter are lacking. In this study, feature extraction methods were developed to capture relevant attributes related to spectral characteristics and spectral fluctuations, the latter through a sectional spectral flux. Previously, ground truths ratings of performed dynamics had been collected by asking listeners to rate how soft/loud the musicians played in a set of audio files...
March 2017: Journal of the Acoustical Society of America
Arthur Paté, Jean-Loïc Le Carrou, Arthur Givois, Alexandre Roy
A controversial discussion in the musical community regards the ability of the harpsichord to produce sound level or timbre changes. The jack velocity (controlled in real time within a musical context) and the plectrum shape (modified by the musician or maker prior to the performance) appear to be the two control parameters at the disposal of the harpsichord makers and players for shaping the sound. This article initiates the acoustical study of the control parameters of the harpsichord, presenting a framework for the investigation of these two parameters with means of experimental mechanics measurement...
March 2017: Journal of the Acoustical Society of America
Xiaoyan Kuai, Shengli Zhou, Zhaohui Wang, En Cheng
This paper studies a direct-sequence spread-spectrum communication system with a small spreading factor (e.g., a single digit) in underwater acoustic multipath channels. Exploiting the channel characteristics that the propagation paths can be grouped into distinct clusters, a receiver with a set of parallel branches is proposed, where per-survivor processing (PSP) is applied on each branch to deal with the signal from one cluster while explicitly treating the signals from other clusters as structured interference...
March 2017: Journal of the Acoustical Society of America
Leanna P Matthews, Susan E Parks, Michelle E H Fournet, Christine M Gabriele, Jamie N Womble, Holger Klinck
Source levels of harbor seal breeding vocalizations were estimated using a three-element planar hydrophone array near the Beardslee Islands in Glacier Bay National Park and Preserve, Alaska. The average source level for these calls was 144 dBRMS re 1 μPa at 1 m in the 40-500 Hz frequency band. Source level estimates ranged from 129 to 149 dBRMS re 1 μPa. Four call parameters, including minimum frequency, peak frequency, total duration, and pulse duration, were also measured. These measurements indicated that breeding vocalizations of harbor seals near the Beardslee Islands of Glacier Bay National Park are similar in duration (average total duration: 4...
March 2017: Journal of the Acoustical Society of America
Adam Westermann, Jörg M Buchholz
The extent to which informational masking (IM) is involved in real-world listening is not well understood. In the literature, IM effects of more than 8 dB are reported, but these experiments typically used simplified spatial configurations and speech materials with exaggerated confusions. Westermann and Buchholz [(2015b). J. Acoust. Soc. Am. 138, 584-593] considered a simulated cafeteria and found only substantial IM effects when the target and maskers were colocated and the same talker. The present study further investigates the relevance of IM in real-world environments, specifically distractions by nearby maskers and the effect of hearing impairment...
March 2017: Journal of the Acoustical Society of America
Jocelyn Rozé, Mitsuko Aramaki, Richard Kronland-Martinet, Sølvi Ystad
Cello bowing requires a very fine control of the musicians' gestures to ensure the quality of the perceived sound. When the interaction between the bow hair and the string is optimal, the sound is perceived as broad and round. On the other hand, when the gestural control becomes more approximate, the sound quality deteriorates and often becomes harsh, shrill, and quavering. In this study, such a timbre degradation, often described by French cellists as harshness (décharnement), is investigated from both signal and perceptual perspectives...
March 2017: Journal of the Acoustical Society of America
Nathan R Huber, Thomas M Huber, Matthew T Huber
Refracto-vibrometry was used to optically image propagating Mach cones in water. These Mach cones were produced by ultrasonic longitudinal and shear waves traveling through submerged 12.7 mm diameter metal cylinders. Full-field videos of the propagating wave fronts were obtained using refracto-vibrometry. A laser Doppler vibrometer, directed at a retroreflective surface, sampled time-varying water density at numerous scan points. Wave speeds were determined from the Mach cone apex angles; the measured longitudinal and shear wave speeds in steel (6060 ± 170 m/s and 3310 ± 110 m/s, respectively) and beryllium (12 400 ± 700 m/s and 8100 ± 500 m/s) agreed with published values...
March 2017: Journal of the Acoustical Society of America
Natalia Ilyina, Jeroen Hermans, Koen Van Den Abeele, Jan D'hooge
An extension to the angular spectrum approach for modelling pressure fields of a cylindrically curved array transducer is described in this paper. The proposed technique is based on representing the curved transducer surface as a set of planar elements whose contributions are combined at a selected intermediate plane from which the field is further propagated using the conventional angular spectrum approach. The accuracy of the proposed technique is validated through comparison with Field II simulations.
March 2017: Journal of the Acoustical Society of America
You Leo Li, Jeremy J Dahl
The popularity of plane-wave transmits at multiple transmit angles for synthetic transmit aperture (or coherent compounding) has spawned a number of adaptations and new developments of ultrasonic imaging. However, the coherence properties of backscattered signals with plane-wave transmits at different angles are unknown and may impact a subset of these techniques. To provide a framework for the analysis of the coherence properties of such signals, this article introduces the angular coherence theory in medical ultrasound imaging...
March 2017: Journal of the Acoustical Society of America
Liangliang Yang, Xiaomei Xu, Peijun Zhang, Jiabo Han, Bing Li, Per Berggren
Underwater vocalizations were recorded and classified from wild spotted seals (Phoca largha) in Liaodong Bay, China. The spotted seals exhibited an extensive underwater vocal repertoire but with limited complexity. Four major call types, representing 77.8% of all calls recorded, were identified using multivariate analyses of ten acoustic parameters; knock, growl, drum, and sweep. The calls were relatively brief (12-270 ms, mean of -10 dB duration) pulsating sounds of low-frequency (peak frequency <600 Hz) and narrow bandwidth (169-232 Hz, mean of -3 dB bandwidth; 237-435 Hz, mean of -6 dB bandwidth)...
March 2017: Journal of the Acoustical Society of America
Youngmin Choo, H C Song, Woojae Seong
The time-domain Helmholtz-Kirchhoff (H-K) integral for surface scattering is derived for a refractive medium, which can handle shadowing effects. The starting point is the H-K integral in the frequency domain. In the high-frequency limit, the Green's function can be calculated by ray theory, while the normal derivative of the incident pressure from a point source is formulated using the ray geometry and ray-based Green's function. For a corrugated pressure-release surface, a stationary phase approximation can be applied to the H-K integral, reducing the surface integral to a line integral...
March 2017: Journal of the Acoustical Society of America
M A Poletti
This paper derives a generalized spherical harmonic description of Bessel beams. The spherical harmonic description of the well-known cylindrical Bessel beams is reviewed and a family of spherical Bessel beams are introduced which can provide a number of azimuthal phase variations for a single beam radial amplitude. The results are verified by numerical simulations.
March 2017: Journal of the Acoustical Society of America
William A Yost
Spatial Release from Masking (SRM) was measured for identification of a female target word spoken in the presence of male masker words. Target words from a single loudspeaker located at midline were presented when two, four, or six masker words were presented either from the same source as the target or from spatially separated masker sources. All masker words were presented from loudspeakers located symmetrically around the centered target source in the front azimuth hemifield. Three masking conditions were employed: speech-in-speech masking (involving both informational and energetic masking), speech-in-noise masking (involving energetic masking), and filtered speech-in-filtered speech masking (involving informational masking)...
March 2017: Journal of the Acoustical Society of America
Y K Chiang, Y S Choy, S K Tang
The noise attenuation of fan-ducted noise at low blade-passage frequency remains a challenge. The present study investigates the noise reduction mechanism of a tensioned membrane housing device that directly controls the sound radiation from the doublet which is enclosed in an infinitely long duct with a point vortex. The time dependent sound radiation mechanism and the vibro-acoustics coupling mechanism of the systems are studied by adopting the potential theory and matched asymptotic expansion technique. The silencing performance of such a passive approach depends on the amplitude and phase of the sound field created by the doublet and the acoustic pressure induced by the membrane oscillation in order to achieve sound cancellation...
March 2017: Journal of the Acoustical Society of America
Dorian S Houser, William Yost, Robert Burkard, James J Finneran, Colleen Reichmuth, Jason Mulsow
This document reviews the history, development, and use of auditory weighting functions for noise impact assessment in humans and marine mammals. Advances from the modern era of electroacoustics, psychophysical studies of loudness, and other related hearing studies are reviewed with respect to the development and application of human auditory weighting functions, particularly A-weighting. The use of auditory weighting functions to assess the effects of environmental noise on humans-such as hearing damage-risk criteria-are presented, as well as lower-level effects such as annoyance and masking...
March 2017: Journal of the Acoustical Society of America
J S Egerton, M J S Lowe, P Huthwaite, H V Halai
Knowledge of acoustic properties is crucial for ultrasonic or sonic imaging and signal detection in nondestructive evaluation (NDE), medical imaging, and seismology. Accurately and reliably obtaining these is particularly challenging for the NDE of high-density polyethylene (HDPE), such as is used in many water or gas pipes, because the properties vary greatly with frequency, temperature, direction and spatial location. Therefore the work reported here was undertaken in order to establish a basis for such a multiparameter description...
March 2017: Journal of the Acoustical Society of America
Yi Shen, Dylan V Pearson
Modulation masking is known to impact speech intelligibility, but it is not clear whether the mechanism underlying this phenomenon is an invariant, bottom-up process, or if it is subjected to factors such as perceptual segregation and stimulus uncertainty thereby showing a top-down component. In the main experiment of the current study (Exp. II), listeners' ability to recognize sequences of synthesized vowels (i.e., the target) in sinusoidally amplitude-modulated noises (i.e., the masker) was evaluated. The target and masker were designed to be perceptually distinct to limit the top-down component of modulation masking...
March 2017: Journal of the Acoustical Society of America
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"