J Acoust Soc Am. 2020 Jan;147(1):508. doi: 10.1121/10.0000600.
Sound transmission loss of multi-layered infinite micro-perforated plates.
Kim HS1, Kim SR1, Kim BK1, Ma PS1, Seo YH1.
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Abstract
In this paper, the sound transmission loss (STL) of multi-layered infinite micro-perforated plates (MPPs) is studied. A prediction model for the STL of the multi-layered infinite MPPs is developed, where each MPP may or may not have a perforation, and the number of MPPs is arbitrary. When the frequency of interest is well below the critical frequency of the plate such that the effect of flexural vibration can be neglected compared to that of the inertia term, the mass is replaced by an equivalent complex mass. For numerical examples, single-, double- and triple-layered MPPs are studied. As the perforation ratio increases, the magnitude of the equivalent complex mass decreases rapidly, which in turn results in a decrease of the STL. It is observed that for very small perforation ratios, the mass-spring resonance frequencies in double- and triple-layered MPPs move toward a higher frequency as the perforation ratios increase. In addition, the dips at the resonance frequencies become blunt with increases in the perforation ratios due to the artificial damping induced by micro-perforations. It is also found that at a high frequency, the STL shows dips regardless of the perforation ratios when the wavenumber and air gap depths satisfy certain conditions.
PMID: 32007027 DOI: 10.1121/10.0000600
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Select item 320070262.
J Acoust Soc Am. 2020 Jan;147(1):568. doi: 10.1121/10.0000543.
Differences in nasalance and nasality perception between Texas South and Midland dialects.
Bae Y1, Lee SAS2, Velik K1, Liu Y2, Beck C1, Fox RA1.
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Abstract
While previous research has primarily concerned the dialectal influence on speakers' production of oral-nasal balance, quantitatively represented by nasalance, information on cross-dialectal variation in nasality perception is limited. This study investigated the effects of speakers'/listeners' dialectal background on oral-nasal balance characteristics estimated by nasalance, as well as nasality perception measured by direct magnitude estimation with modulus. Represented by two geographically distinct regions, Texas South and Midland dialects were of special interest given that the two dialects lie at opposite ends of normal nasalance variation [Awan, Bressmann, Poburka, Roy, Sharp, and Watts. (2015). J. Speech Lang. Hear. Res. 58, 69-77]. Mean nasalance of various speech stimuli and direct magnitude estimation ratings on synthesized vowel stimuli with varying degrees of simulated nasalization were obtained from 62 participants (31 Texas South, 31 Midland). The results revealed that the two dialectal groups significantly differed in nasalance scores and nasality ratings, with Texas South exhibiting higher nasalance for standardized passage readings and assigning higher nasality ratings on the synthetic auditory stimuli than Midland. These findings indicate that, in addition to production variations of oral-nasal balance characteristics, perceptual variations of nasality exist at a dialectal level.
PMID: 32007026 DOI: 10.1121/10.0000543
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Select item 320070253.
J Acoust Soc Am. 2020 Jan;147(1):206. doi: 10.1121/10.0000567.
Noise acceptance of acoustic sequences for indoor soundscape in transport hubs.
Wang B1, Kang J1, Zhao W1.
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Abstract
Noise acceptance is an aspect of indoor soundscape research. While staying or walking in a transport hub, sequential sounds form sequence sounds sessions, which are referred to as an acoustic sequence. The basic phenomenon and effects of acoustic sequences on acceptance evaluations have been explored. A total of 209 sections of 30 s acoustic units were extracted before performing acceptance evaluations. The acoustic units were divided into strong, medium, and weak levels, and compiled into 37 pieces of acoustic sequences, which were then subjected to four tests for acceptance evaluation: sound content, acceptance level, and effects of weak and strong acceptance units. One piece of an acoustic sequence consists of 20 acoustic units. The results show that all acoustic sequences exhibit "attenuation effects"-as for any acoustic unit that makes up the sequence, general acceptance decreases with time. The lower the acceptance, the faster the decay in score. High acceptance units have an "enhancement effect," and the acceptance increases after a high acceptance unit. Low acceptance units have a "boost effect," and the acceptance increases after a low-level acceptance. Both enhancement and boost effects could improve the acceptance evaluation of acoustic sequences and sound experiences in transport hubs.
PMID: 32007025 DOI: 10.1121/10.0000567
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Select item 320070244.
J Acoust Soc Am. 2020 Jan;147(1):EL37. doi: 10.1121/10.0000562.
Ganong effects for frequency may not be robust.
Politzer-Ahles S1, Lee KK1, Shen L2.
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Abstract
The Ganong effect-more identifications of a certain phoneme in a context where that phoneme would yield a real word than a context where that phoneme would yield a pseudoword-has been widely replicated. Few studies, however, have tested whether this effect occurs for frequency contrasts. In the present study, participants' likelihood of identifying an ambiguous sound as aspirated was tested in acoustically identical continua in contexts where the identification of the sound as aspirated would either yield a lower- or higher-frequency word than the identification of the sound as unaspirated would. No frequency-based Ganong effect was found.
PMID: 32007024 DOI: 10.1121/10.0000562
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Select item 320070235.
J Acoust Soc Am. 2020 Jan;147(1):529. doi: 10.1121/10.0000544.
Sociophonetic trends in studies of Southern U.S. English.
Thomas ER1.
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Abstract
Although the U.S. South was usually avoided for phonetic studies in earlier years, phonetic analyses of Southern U.S. English have expanded in numerous directions in recent years. Studies of vocalic variation have dominated the enterprise, with a broad range of studies that have examined the phonetic peculiarities and distribution of variants within the region, the characteristics of particular communities, and the phonetic attributes of African American and Latino groups. However, other phonetic phenomena are finally seeing more study. Several consonantal variables have attracted acoustic analysis. Other studies have focused on intonation and certain timing-related phenomena. Numerous experimental studies have tested the abilities of listeners to identify dialects and a few other perceptual issues. These developments are outlined here, including advancements in segmental, prosodic, and perceptual analyses.
PMID: 32007023 DOI: 10.1121/10.0000544
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Select item 320070226.
J Acoust Soc Am. 2020 Jan;147(1):EL13. doi: 10.1121/10.0000501.
Sediment interval velocities from a monostatic multibeam sonar.
Holland CW1, Pinson S2.
Author information
Abstract
Interval velocities for marine sediments are generally obtained from source-receiver separations at various offsets. A method is described for estimating interval velocities using a monostatic configuration. Testing is performed using simulated data from rough layered seabeds and interval velocity is estimated within less than 1% of the true value. Monostatic multibeam data from the Gulf of Lion are also presented which exhibit many characteristics similar to the simulated data. The method applied to the measured data yield an interval velocity of 1569 m/s in an 18 m sediment layer. This accords with nearby independent data from cores and wide-angle reflection analysis.
PMID: 32007022 DOI: 10.1121/10.0000501
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Select item 320070217.
J Acoust Soc Am. 2020 Jan;147(1):EL19. doi: 10.1121/10.0000499.
Voice fundamental frequency differences and speech recognition with noise and speech maskers in cochlear implant recipients.
Meister H1, Walger M2, Lang-Roth R2, Müller V2.
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Abstract
Cochlear implant (CI) recipients are limited in their perception of voice cues, such as the fundamental frequency (F0). This has important consequences for speech recognition when several talkers speak simultaneously. This examination considered the comparison of clear speech and noise-vocoded sentences as maskers. For the speech maskers it could be shown that good CI performers are able to benefit from F0 differences between target and masker. This was due to the fact that a F0 difference of 80 Hz significantly reduced target-masker confusions, an effect that was slightly more pronounced in bimodal than in bilateral users.
PMID: 32007021 DOI: 10.1121/10.0000499
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Select item 320070208.
J Acoust Soc Am. 2020 Jan;147(1):231. doi: 10.1121/10.0000589.
A system for controlling the directivity of sound radiated from a structure.
Kournoutos N1, Cheer J1.
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Abstract
Directional sound fields can be generated by arrays of multiple sound sources such as loudspeaker drivers. These systems, though potentially capable of high levels of directivity control over a broad bandwidth, may prove prohibitively expensive, fragile, or impracticable in certain applications. To overcome these limitations, this paper presents an investigation into the design and limitations of a directional structural-actuator-based array. This provides an affordable and robust alternative to conventional loudspeakers, particularly when the actuators can be used to radiate via a pre-existing structure and where the required audio quality is lower, or the bandwidth somewhat limited. In the first instance, an analytical model is formulated and used to perform a simulation-based parametric study, which provides insights into the design trade-offs. Based on this study, a physical prototype is constructed using six actuators and a flat panel, which enables the model to be experimentally validated and an evaluation of the directional radiation capabilities of the proposed system to be carried out. Experiments show that a simple analytical model is an effective tool in designing such arrays, predicting the trends in the behaviour of the prototype and that the structural actuator-based system is capable of controlling directivity within its intended operational bandwidth.
PMID: 32007020 DOI: 10.1121/10.0000589
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Select item 320070199.
J Acoust Soc Am. 2020 Jan;147(1):671. doi: 10.1121/10.0000555.
Phonetic convergence to Southern American English: Acoustics and perception.
Clopper CG1, Dossey E1.
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Abstract
Phonetic convergence is linguistically and socially selective. The current study examined the constraints on this selectivity in convergence to Southern American English by non-Southern Americans in a word shadowing task. Participants were asked either to repeat the words after the model talker, to repeat the words after the model talker from Louisville, KY, or to imitate the way the model talker from Louisville, KY, said the words, in a between-subject design. Acoustic analysis of the participants' productions revealed significant phonetic convergence on word duration and back vowel fronting, but not on /aɪ/ monophthongization, across all three instruction conditions. These findings suggest social selectivity such that convergence on stereotyped variants is avoided, but convergence to a talker with a non-prestigious variety is not. A perceptual assessment of convergence confirmed the acoustic results, but also revealed significantly more convergence in the explicit imitation condition than in the two repetition conditions. These findings suggest that explicit instructions to imitate lead to greater convergence overall, but do not completely override social selectivity. A comparison of the acoustic and perceptual assessments of convergence indicates that they provide complementary insights into specific features and holistic patterns of convergence, respectively.
PMID: 32007019 DOI: 10.1121/10.0000555
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Select item 3200701810.
J Acoust Soc Am. 2020 Jan;147(1):325. doi: 10.1121/10.0000585.
Prediction of the aerodynamic sound generated due to flow over a cylinder performing combined steady rotation and rotary oscillations.
Ganta N1, Mahato B1, Bhumkar YG1.
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Abstract
Analysis of sound generated due to a laminar flow past a circular cylinder subjected to the mean rotation along with the rotary oscillating motion has been performed for the Reynolds number Re = 150 and the Mach number M = 0.2. The direct numerical simulation approach has been used to study modifications in the generated sound field over a range of forcing parameters using disturbance pressure field information. Flow and sound fields are accurately resolved over a nondimensional radial distance r≤100 from the center of the cylinder. Frequencies, as well as wavelengths of generated sound waves, have been effectively altered by varying the forcing frequency-ratio, whereas the directivity nature of the radiated sound field has been modified by varying the forcing amplitude-ratio. Doak's decomposition technique has been used to understand the reasons behind changes in the radiated sound fields as the forcing parameters are varied.
PMID: 32007018 DOI: 10.1121/10.0000585
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Select item 3200701711.
J Acoust Soc Am. 2020 Jan;147(1):616. doi: 10.1121/10.0000576.
Inter- and intra-regional variation in intonation: An analysis of rising pitch accents and rootedness.
Reed PE1.
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Abstract
Regional linguistic variation is a widely known characteristic of American English, with the American South as one of the many foci. However, in much of this literature, Appalachia is lumped together with other Southern varieties. Further, the vast sociolinguistic literature has documented intra-regional variation along socio-indexical lines. However, most variation studies have focused on vocalic variation at the expense of other sources of variation, which may have different patterns and meanings. The present study was designed to explore intonational variation in conversational speech in two varieties of American English: Appalachian and Southern. Additionally, the intra-regional variation in intonation present in Appalachian English was explored considering the rootedness (local place-based attachment) of speakers. The results revealed significant effects of regional dialect on both the quantitative and qualitative realization of pitch accent. Further, intra-regional variation was significantly impacted by socio-indexical aspects, including rootedness, of individual speakers. The findings from this study demonstrate that both region and socio-indexical features are expressed intonationally and also provide motivation for additional exploration of intonational variation across and within the regional varieties of American English.
PMID: 32007017 DOI: 10.1121/10.0000576
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Select item 3200701612.
J Acoust Soc Am. 2020 Jan;147(1):137. doi: 10.1121/10.0000494.
A comparison of four vowel overlap measures.
Kelley MC1, Tucker BV1.
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Abstract
Multiple measures of vowel overlap have been proposed that use F1, F2, and duration to calculate the degree of overlap between vowel categories. The present study assesses four of these measures: the spectral overlap assessment metric [SOAM; Wassink (2006). J. Acoust. Soc. Am. 119(4), 2334-2350], the a posteriori probability (APP)-based metric [Morrison (2008). J. Acoust. Soc. Am. 123(1), 37-40], the vowel overlap analysis with convex hulls method [VOACH; Haynes and Taylor, (2014). J. Acoust. Soc. Am. 136(2), 883-891], and the Pillai score as first used for vowel overlap by Hay, Warren, and Drager [(2006). J. Phonetics 34(4), 458-484]. Summaries of the measures are presented, and theoretical critiques of them are performed, concluding that the APP-based metric and Pillai score are theoretically preferable to SOAM and VOACH. The measures are empirically assessed using accuracy and precision criteria with Monte Carlo simulations. The Pillai score demonstrates the best overall performance in these tests. The potential applications of vowel overlap measures to research scenarios are discussed, including comparisons of vowel productions between different social groups, as well as acoustic investigations into vowel formant trajectories.
PMID: 32007016 DOI: 10.1121/10.0000494
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Select item 3200701513.
J Acoust Soc Am. 2020 Jan;147(1):579. doi: 10.1121/10.0000549.
Modeling dynamic trajectories of front vowels in the American South.
Renwick MEL1, Stanley JA1.
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Abstract
Regional variation in American English speech is often described in terms of shifts, indicating which vowel sounds are converging or diverging. In the U.S. South, the Southern vowel shift (SVS) and African American vowel shift (AAVS) affect not only vowels' relative positions but also their formant dynamics. Static characterizations of shifting, with a single pair of first and second formant values taken near vowels' midpoint, fail to capture this vowel-inherent spectral change, which can indicate dialect-specific diphthongization or monophthongization. Vowel-inherent spectral change is directly modeled to investigate how trajectories of front vowels /i eɪ ɪ ɛ/ differ across social groups in the 64-speaker Digital Archive of Southern Speech. Generalized additive mixed models are used to test the effects of two social factors, sex and ethnicity, on trajectory shape. All vowels studied show significant differences between men, women, African American and European American speakers. Results show strong overlap between the trajectories of /eɪ, ɛ/ particularly among European American women, consistent with the SVS, and greater vowel-inherent raising of /ɪ/ among African American speakers, indicating how that lax vowel is affected by the AAVS. Model predictions of duration additionally indicate that across groups, trajectories become more peripheral as vowel duration increases.
PMID: 32007015 DOI: 10.1121/10.0000549
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Select item 3200701414.
J Acoust Soc Am. 2020 Jan;147(1):606. doi: 10.1121/10.0000552.
Voiced stops in the command performance of Southern US English.
Walker A1.
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Abstract
Four self-identified code-switchers from Southwest Virginia and six actors who did not identify as having Southern accents each recorded two sets of stimuli in which they aimed to produce a more Southern and a more Standardized US accent. An analysis of the Voice Onset Time (VOT) of phrase and word initial voiced stops revealed that both groups of speakers produced more tokens with prevoicing (lead or negative lag voicing) when speaking in the Southern versus the Standard guise, and that in the Standard guise, the Southern speakers produced more prevoiced tokens than the actors. These findings support fairly recent descriptions of lead voicing as a feature of Southern US English. They additionally show that despite the lack of overt commentary about this feature, speakers have an awareness of the association between lead voicing and Southern US English because they manipulate the feature in a socially meaningful way; in Labov's [(1972). Sociolinguistic Patterns (Blackwell, Oxford)] terminology, negative lag voicing is a marker of Southern US English.
PMID: 32007014 DOI: 10.1121/10.0000552
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Select item 3200701315.
J Acoust Soc Am. 2020 Jan;147(1):EL32. doi: 10.1121/10.0000500.
Reflection of an ultrasonic wave on the bone-implant interface: Comparison of two-dimensional and three-dimensional numerical models.
Hériveaux Y1, Haïat G1, Nguyen VH2.
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Abstract
Quantitative ultrasound is used to characterize osseointegration at the bone-implant interface (BII). However, the interaction between an ultrasonic wave and the implant remains poorly understood. Hériveaux, Nguyen, and Haiat [(2018). J. Acoust. Soc. Am. 144, 488-499] recently employed a two-dimensional (2D) model of a rough BII to investigate the sensitivity of the ultrasonic response to osseointegration. The present letter aimed at assessing the validity of the 2D assumption. The values of the reflection coefficient of the BII obtained with two and three-dimensional models were found not to be significantly different for implant roughness lower than 20 μm. 2D modeling is sufficient to describe the interaction between ultrasound and the BII.
PMID: 32007013 DOI: 10.1121/10.0000500
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Select item 3200701216.
J Acoust Soc Am. 2020 Jan;147(1):74. doi: 10.1121/10.0000490.
Approximate impedance models for point-to-point sound propagation over acoustically-hard ground containing rectangular grooves.
Mellish S1, Taherzadeh S1, Attenborough K1.
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Abstract
A modal model for diffraction by a contiguous array of rectangular grooves in an acoustically-hard plane is extended to predict the free space acoustic field from a point source above such a structure. Subsequently, an approximate effective impedance model for grooved surfaces is presented. Measurements have shown that these ground surfaces can be used for outdoor noise reduction but accurate modelling has required the use of computationally expensive numerical methods. The extended modal model and approximate impedance model inspired by it yield equivalent results in a fraction of the time taken by the boundary element method, for example, and could be used when designing grooved surfaces to reduce noise from road traffic.
PMID: 32007012 DOI: 10.1121/10.0000490
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Select item 3200701117.
J Acoust Soc Am. 2020 Jan;147(1):152. doi: 10.1121/10.0000568.
Numerical modeling of submicron particles for acoustic concentration in gaseous flow.
Liu J1, Li X1, Hu FQ2.
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Abstract
This paper intends to explore the rationality and feasibility of modeling dispersed submicron particles in air by a kinetic-based method called the unified gas-kinetic scheme (UGKS) and apply it to the simulation of particle concentration under a transverse standing wave. A gas-particle coupling scheme is proposed where the gas phase is modeled by the two-dimensional linearized Euler equations (LEE) and, through the analogous behavior between the rarefied gas molecules and the air-suspended particles, a modified UGKS is adopted to estimate the particle dynamics. The Stokes' drag force and the acoustic radiation force applied on particles are accounted for by introducing a velocity-dependent acceleration term in the UGKS formulation. To validate this methodology, the computed concentration patterns are compared with experimental results in the literature. The comparison shows that the adopted LEE-UGKS coupling scheme could well capture the concentration pattern of suspended submicron particles in a channel. In addition, numerical simulations with varying standing wave amplitudes, different acoustic radiation force to drag force ratios, and mean flow velocities are conducted. Their respective influences on the particle concentration pattern and efficiency are analyzed.
PMID: 32007011 DOI: 10.1121/10.0000568
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Select item 3200701018.
J Acoust Soc Am. 2020 Jan;147(1):459. doi: 10.1121/10.0000618.
Acoustic spatial patterns recognition based on convolutional neural network and acoustic visualization.
Wu H1, Wei X1, Zha Y1, Jiang W1.
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Abstract
In this work, a convolutional neural network (CNN) is applied to recognize acoustic spatial patterns with the aid of acoustic visualization. The acoustic spatial patterns are obtained by the singular value decomposition of an acoustic radiation operator built with the boundary integral equation. It is to explore the powerful capability of the CNN in the image processing by analogously rendering the measured acoustic spatial patterns into images. Due to practical limitations, a higher resolution of an acoustic image is achieved by interpolating the pressure on a coarse grid. Steady-state analysis of acoustic problems is a complex domain problem. The acoustic fields are then supplied into a CNN scheme as two-channel data which are real and imaginary components of the pressure. Random noises and incident waves with varying energy are added to the measured data to simulate influences from uncorrelated and correlated noises, respectively. It is demonstrated that once the CNN scheme is built and trained with adequate data, which is numerically synthesized, the patterns can be more accurately and robustly recognized by comparing it with the cross-correlation based methods. The hierarchical feature representative as well as nonlinear perception makes the proposed method a promising approach for fault diagnosis and condition monitoring based on spatial acoustic measurements.
PMID: 32007010 DOI: 10.1121/10.0000618
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Select item 3200700919.
J Acoust Soc Am. 2020 Jan;147(1):643. doi: 10.1121/10.0000550.
Perceiving Southernness: Vowel categories and acoustic cues in Southernness ratings.
Gunter KM1, Vaughn CR1, Kendall TS1.
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Abstract
Southern U.S. speech has been the focus of much sociophonetic work. In terms of vowel patterns, Southern speech is often characterized by the Southern Vowel Shift (SVS, involving shifts in /e/, /ɛ/, and /aɪ/), back vowel fronting, and changes in glide dynamics. The SVS, in particular, is said to play a primary role in distinguishing the South as a unique dialect region. However, there have been few investigations of the role of various vowel quality differences in perceptions of Southern accent, particularly across the vowel space beyond /e/, /ɛ/, and /aɪ/, or that ask whether any aggregate speaker-level acoustic measures align with listeners' perceptions, despite some suggestions in the literature to this effect. The current study examines what acoustic cues contribute to non-Southern listeners' evaluations of words spoken by Southerners as sounding more or less Southern accented, looking at a range of vowels from across the vowel space. Results indicate that listeners rate the speakers' productions of /u/ and /ɔ/ as most Southern and that vowel dynamics and speaker-level measures were the acoustic factors most predictive of Southernness ratings. These results together call for further work examining vowel dynamics and a more complete set of vowel categories in perception studies of Southern speech.
PMID: 32007009 DOI: 10.1121/10.0000550
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Select item 3200700820.
J Acoust Soc Am. 2020 Jan;147(1):383. doi: 10.1121/10.0000554.
Acoustical News.
Moran E1.
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Abstract
Editor's Note: Readers of this journal are encouraged to submit news items on awards, appointments, and other activities about themselves or their colleagues. Deadline dates for news and notices are 2 months prior to publication.
PMID: 32007008 DOI: 10.1121/10.0000554
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Select item 3200700721.
J Acoust Soc Am. 2020 Jan;147(1):161. doi: 10.1121/10.0000474.
A comparison between two modal domain methods for personal audio reproduction.
Zhu Q1, Qiu X1, Coleman P2, Burnett I1.
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Abstract
Personal audio provides private and personalized listening experiences by generating sound zones in a shared space with minimal interference between zones. One challenge of the design is to achieve the best performance with a limited number of microphones and loudspeakers. In this paper, two modal domain methods for personal audio reproduction are compared. One is the spatial harmonic decomposition (SHD) based method and the other is the singular value decomposition (SVD) based method. It is demonstrated that the SVD based method provides a more efficient modal domain decomposition than the SHD method for 2.5 dimensional personal audio design. Simulation results show that the SVD based method outperforms the SHD one by up to 10 dB in terms of acoustic contrast and up to 17 dB in terms of reproduction error for a compact arc array with five loudspeakers, while requiring fewer microphones around the zone boundaries. The SVD based method retains the inherent efficiency of optimizing in a modal domain while avoiding the inherent geometric limitations of using SHD basis functions. Thus, this approach is advantageous for applications with flexible system geometries and a small number of loudspeakers and microphones.
PMID: 32007007 DOI: 10.1121/10.0000474
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Select item 3200700622.
J Acoust Soc Am. 2020 Jan;147(1):500. doi: 10.1121/10.0000607.
A theoretical investigation of the nonlinear acoustic response of abrupt area contractions.
Kawell ST1, Humphreys LH1, Stubbs DC1, Scarborough DE1.
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Abstract
Acoustic instabilities are frequently the culprit for engine failure. To mitigate these instabilities, an accurate model of the nonlinear acoustic pressure profile of the system is necessary. This study develops a nonlinear model for the acoustic response of an area-contraction. The derivation begins with the unsteady Bernoulli equation which is formed into the pressure drop across the area-contraction. Each acoustic variable is assumed to be time-harmonic and is written as the sum of a steady and fundamental term. Using a Fourier transformation, nonlinear expressions for the pressure drop and impedance are derived as functions of the steady and acoustic velocity. These expressions capture the nonlinearity of the acoustic response when the flow can reverse out of the orifice, i.e., the amplitude of the mean velocity is less than the amplitude of the oscillating acoustic velocity. This impedance model is verified by archive quality acoustic response data from a previous study.
PMID: 32007006 DOI: 10.1121/10.0000607
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Select item 3200700523.
J Acoust Soc Am. 2020 Jan;147(1):428. doi: 10.1121/10.0000580.
Two-dimensional finite-difference time-domain formulation for sound propagation in a temperature-dependent elastomer-fluid medium.
Huang Y1, Hou H1, Oterkus S2, Wei Z1, Gao N1.
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Abstract
This study focuses on the two-dimensional (2-D) finite-difference time-domain (FDTD) formulations to investigate the acoustic wave propagation in elastomers contained in a fluid region under different thermal conditions. The developed FDTD formulation is based on a direct solution of the time-domain wave equation and the Havriliak-Negami (H-N) dynamic mechanical response of the elastomers. The H-N representation, including double fractional derivative operators, can be accurately transferred from the frequency-domain to the time-domain by using Riemann-Liouville theory and the Grunwald-Letnikov operator for fractional derivative approximations. Since the Williams-Landel-Ferry shift function is related to the relaxation time for different thermal conditions, the proposed scheme represents a simple and accurate prediction of acoustic wave propagation for varying thermal conditions. The pulse-wave propagation in a viscous fluid field is simulated by investigating the Navier-Stokes equations. The acoustic properties of different elastomers in a variety of temperatures are obtained by means of the proposed FDTD formulation and validated by a good agreement with the experimental data over a wide frequency range. Additionally, the 2-D examples relevant to wave propagation in different elastomers contained in a fluid field are implemented. The proposed FDTD formulation can be used to predict 2-D acoustic wave propagation in different thermal conditions accurately.
PMID: 32007005 DOI: 10.1121/10.0000580
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Select item 3200700424.
J Acoust Soc Am. 2020 Jan;147(1):218. doi: 10.1121/10.0000569.
Analytic error control methods for efficient rotation in dynamic binaural rendering of Ambisonics.
Magariyachi T1, Mitsufuji Y1.
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Abstract
Dynamic binaural rendering of Ambisonics considering head movements gives a highly realistic sensation to listeners owing to the precise localization and the presence of dynamic cues. Dealing with a head movement is often achieved in the spherical harmonic domain by multiplying Ambisonic signals by a Wigner D-matrix (WDM) with the aim of rotating signals in the opposite direction to the head movement. However, for a vertical rotation, the system requires an enormous computational cost owing to the structure of the WDM, whose number of block diagonal elements increases with the spherical harmonic order of Ambisonics. In this paper, a method is introduced to reduce the computational cost related to the vertical rotation by approximating a WDM with a banded WDM generated from the truncated sum of a power series expression of the WDM. By using an analytically derived upper bound of the approximation error, two methods are devised to determine the minimum bandwidth which archives the maximum computational cost reduction under the user-preferred threshold. The experimental results show that there is a trade-off between the approximation error and the computational cost and that these methods are applicable to the use case of interest, i.e., dynamic binaural rendering of Ambisonics.
PMID: 32007004 DOI: 10.1121/10.0000569
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Select item 3200700325.
J Acoust Soc Am. 2020 Jan;147(1):242. doi: 10.1121/10.0000623.
ACOUSTICAL STANDARDS NEWS.
Blair-DeLeon NA1, Struck CJ2.
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Abstract
American National Standards (ANSI Standards) developed by Accredited Standards Committees S1, S2, S3, S3/SC 1, and S12 in the areas of acoustics, mechanical vibration and shock, bioacoustics, animal bioacoustics, and noise, respectively, are published by the Acoustical Society of America (ASA). In addition to these standards, ASA publishes a catalog of Acoustical American National Standards. To browse the latest copy of our catalog, visit our website at https://acousticalsociety.org/download-catalog/.Comments are welcomed on all material in Acoustical Standards News.This Acoustical Standards News section in JASA, as well as the national catalog of Acoustical Standards and other information on the Standards Program of the Acoustical Society of America, are also available via the ASA Standards home page: https://acousticalsociety.org/acoustical-society-standards/.
PMID: 32007003 DOI: 10.1121/10.0000623
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Select item 3200700226.
J Acoust Soc Am. 2020 Jan;147(1):205. doi: 10.1121/10.0000561.
Erratum: Asymptotic limits of some models for sound propagation in porous media and the assignment of the pore characteristic lengths [J. Acoust. Soc. Am. 139(5), 2463-2474 (2016)].
Horoshenkov KV1, Groby JP2, Dazel O2.
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PMID: 32007002 DOI: 10.1121/10.0000561
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Select item 3200700127.
J Acoust Soc Am. 2020 Jan;147(1):49. doi: 10.1121/10.0000514.
Classification of odontocete echolocation clicks using convolutional neural network.
Yang W1, Luo W1, Zhang Y1.
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Abstract
A method based on a convolutional neural network for the automatic classification of odontocete echolocation clicks is presented. The proposed convolutional neural network comprises six layers: three one-dimensional convolutional layers, two fully connected layers, and a softmax classification layer. Rectified linear units were chosen as the activation function for each convolutional layer. The input to the first convolutional layer is the raw time signal of an echolocation click. Species prediction was performed for groups of m clicks, and two strategies for species label prediction were explored: the majority vote and maximum posterior. Two datasets were used to evaluate the classification performance of the proposed algorithm. Experiments showed that the convolutional neural network can model odontocete species from the raw time signal of echolocation clicks. With the increase in m, the classification accuracy of the proposed method improved. The proposed method can be employed in passive acoustic monitoring to classify different delphinid species and facilitate future studies on odontocetes.
PMID: 32007001 DOI: 10.1121/10.0000514
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Select item 3200700028.
J Acoust Soc Am. 2020 Jan;147(1):EL43. doi: 10.1121/10.0000592.
A note on wind velocity and pressure spectra inside compact spherical porous microphone windscreens.
Niu F1, Zhao S2, Qiu X2, Zhang D1.
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Abstract
Simultaneous measurements of wind velocity and pressure fluctuations were conducted in a wind tunnel to investigate the wind noise source inside compact spherical open celled porous windscreens. The existing outdoor wind noise models are found to be inadequate to predict the wind noise inside a wind tunnel. This paper proposes a model to predict the interior stagnation pressure, which agrees with the wind noise measured inside the windscreen within a bandwidth, where the exterior turbulence-turbulence interaction pressure overestimates the wind noise level. The limitations of the proposed model and other potential sources for wind noise inside porous windscreens are discussed.
PMID: 32007000 DOI: 10.1121/10.0000592
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Select item 3200699929.
J Acoust Soc Am. 2020 Jan;147(1):516. doi: 10.1121/10.0000603.
Analysis of acoustic radiation force on a rigid sphere in a fluid-filled cylindrical cavity with an abruptly changed cross-section.
Shi J1, Li S1, Deng Y1, Zhang X1, Zhang G1.
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Abstract
This paper studies the acoustic radiation force of a rigid sphere positioned in a fluid-filled cylindrical cavity with an abruptly changed cross-section. This cavity consists of a semi-infinite front tube and a coaxially connected semi-infinite rear tube with different cross-sectional area through a transverse planar junction. Considering a plane wave propagates along the cavity, the exact expression of the acoustic radiation force exerted on the sphere in the front tube is deduced. The effects of the distance between the sphere and the planar junction and the radius ratio of the front tube to the rear tube on acoustic radiation force are analyzed. Numerical results show that the distance influences the acoustic radiation force periodically. Both the distance and the radius ratio of the tubes affect the magnitude and the direction of acoustic radiation force. A finite element model about the calculation for the acoustic radiation force on the sphere in the fluid-filled cylindrical cavity with suddenly changed cross-section is built to validate the theoretical results. The comparison results between the theoretical computation and the finite element simulation are in good agreement with each other. This work can support future studies for the predictive control of a particle in the cavity which has an abruptly changed cross-section.
PMID: 32006999 DOI: 10.1121/10.0000603
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Select item 3200699830.
J Acoust Soc Am. 2020 Jan;147(1):285. doi: 10.1121/10.0000605.
Geoacoustic inversion using ray-based blind deconvolution of shipping sources.
Zhang X1, Durofchalk NC2, Niu H1, Wu L1, Zhang R1, Sabra KG2.
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Abstract
The ray-based blind deconvolution algorithm can provide an estimate of the channel impulse responses (CIRs) between a shipping source of opportunity and the elements of a receiving array by estimating the unknown phase of this random source through wideband beamforming along a well-resolved ray path. However, due to the shallow effective depth (typically <10 m) and low frequency content (typically less than a few kHz) associated with shipping sources, the interfering direct and surface arriving pair and subsequent bottom and surface-bottom arrival pair cannot always be resolved in the CIR arrival-time structure. Nevertheless, this study demonstrates that the bottom reflection loss can be inferred from the ratio of the magnitude spectra of these two arrival pairs if a frequency-dependent correction (which can be purely data based) is applied to correct for the dipole source effect. The feasibility of the proposed approach is demonstrated to invert for the geoacoustic parameters of a soft-layer covering the ocean floor using a nonlinear least-square algorithm.
PMID: 32006998 DOI: 10.1121/10.0000605
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Select item 3200699731.
J Acoust Soc Am. 2020 Jan;147(1):147. doi: 10.1121/10.0000564.
REVIEWS OF ACOUSTICAL PATENTS.
Fulop SA1.
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Abstract
The purpose of these acoustical patent reviews is to provide enough information for a Journal reader to decide whether to seek more information from the patent itself. Any opinions expressed here are those of the reviewers as individuals and are not legal opinions. Patents are available via the internet at the USPTO website, and also using Google Patents.
PMID: 32006997 DOI: 10.1121/10.0000564
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Select item 3200699632.
J Acoust Soc Am. 2020 Jan;147(1):411. doi: 10.1121/10.0000594.
Exploring the promise of broadband fisheries echosounders for species discrimination with quantitative assessment of data processing effects.
Benoit-Bird KJ1, Waluk CM1.
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Abstract
It remains an open question how well the increased bandwidth afforded by broadband echosounders can improve species discrimination in fisheries acoustics. Here, an objective statistical approach was used to determine if there is information available in dual channel broadband data (45-170 kHz) to allow discrimination between in situ echoes obtained from monospecific aggregations of three species (hake, Merluccius productus: anchovy, Engraulis mordax; and krill, Euphausiia pacifica) using a remotely operated vehicle. These data were used to explore the effects of processing choices on the ability to statistically classify the broadband spectra to species. This ability was affected by processing choices including the Fourier transform analysis window size, available bandwidth, and the method and scale of data averaging. The approach to normalizing the spectra and the position of individual targets in the beam, however, had little effect. Broadband volume backscatter and single target spectra were both used to successfully classify acoustic data from these species with ∼6% greater success using volume backscatter data. Broadband data were effectively classified to species while simulated multi-frequency narrowband data were categorized at rates near chance, supporting the presumption that greater bandwidth increases the information available for the characterization and classification of biological targets.
PMID: 32006996 DOI: 10.1121/10.0000594
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Select item 3200699533.
J Acoust Soc Am. 2020 Jan;147(1):541. doi: 10.1121/10.0000505.
Vowel acoustic characteristics of Southern American English variation in Louisiana.
Chung H1.
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Abstract
This study examined acoustic characteristics of vowels produced by speakers from Louisiana, one of the states in the Southern English dialect region. First, how Louisiana vowels differ from or are similar to the reported patterns of Southern dialect were examined. Then, within-dialect differences across regions in Louisiana were examined. Thirty-four female adult monolingual speakers of American English from Louisiana, ranging in age from 18 to 23, produced English monosyllabic words containing 11 vowels /i, ɪ, e, ɛ, æ, ʌ, u, ʊ, o, ɔ, ɑ/. The first two formant frequencies at the midpoint of the vowel nucleus, direction, and amount of formant changes across three different time points (20, 50, and 80%), and vowel duration were compared to previously reported data on Southern vowels. Overall, Louisiana vowels showed patterns consistent with previously reported characteristics of Southern vowels that reflect ongoing changes in the Southern dialect (no evidence of acoustic reversal of tense-lax pairs, more specifically no peripheralization of front vowels). Some dialect-specific patterns were also observed (a relatively lesser degree of formant changes and slightly shorter vowel duration). These patterns were consistent across different regions within Louisiana.
PMID: 32006995 DOI: 10.1121/10.0000505
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Select item 3200699434.
J Acoust Soc Am. 2020 Jan;147(1):EL7. doi: 10.1121/10.0000496.
An array pairing method for localizing distributed sources by acoustic beamforming.
Arcondoulis EJG1, Liu Y1, Xu P1, Chen N2.
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Abstract
An acoustic beamforming concept is presented that alleviates some misrepresentation caused by deconvolution algorithms that can oversimplify distributed sources as a series of point sources. In the Array Pairing Method (APM) an initial array beamforms the acoustic source, then an iterative randomized array is calculated whereby the square-rooted product of the beamformer output possesses a minimum product of Maximum Sidelobe Level (MSL) and Main Lobe Width (MLW). A single and distributed source simulation and a single and dual speaker experiment using the APM reveal significant improvements in MSL and MLW and resolution in the distributed source region.
PMID: 32006994 DOI: 10.1121/10.0000496
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Select item 3200699335.
J Acoust Soc Am. 2020 Jan;147(1):146. doi: 10.1121/10.0000560.
Erratum: A three-parameter analytical model for the acoustical properties of porous media [J. Acoust. Soc. Am. 145(4), 2512-2517 (2019)].
Horoshenkov KV1, Hurrell A1, Groby JP2.
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PMID: 32006993 DOI: 10.1121/10.0000560
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Select item 3200699236.
J Acoust Soc Am. 2020 Jan;147(1):554. doi: 10.1121/10.0000553.
The rise of Canadian raising of /au/ in New Orleans English.
Carmichael K1.
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Abstract
New Orleans English (NOE) has always stood out amongst Southern Englishes, since NOE speakers do not participate in the Southern vowel shift, and instead display features more commonly associated with New York City English. While these traditional features of NOE are on the decline, this study establishes the adoption of a new feature in the dialect that is similarly distinctive within the Gulf South: the pre-voiceless raising of the nucleus of /au/. Based on statistical analyses and consideration of the social context in post-Katrina New Orleans, this paper argues that this feature is a change in progress which appears to pre-date the demographic shifts following Hurricane Katrina, and which arose independently rather than due to contact with /au/-raising speakers. The social and phonetic findings in this paper converge to support arguments for the naturalness of raising in pre-voiceless environments, and for the likelihood of this feature being more widely adopted within the region. Moreover, the presence of Canadian raising of /au/ in NOE represents an additional way that the local dialect continues to diverge from patterns in the vowel systems found in nearby Southern dialects, and retain its uniqueness within the American South.
PMID: 32006992 DOI: 10.1121/10.0000553
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Select item 3200699137.
J Acoust Soc Am. 2020 Jan;147(1):245. doi: 10.1121/10.0000556.
Longer vowel duration correlates with greater tongue root advancement at vowel offset: Acoustic and articulatory data from Italian and Polish.
Coretta S1.
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Abstract
Voiced stops tend to be preceded by longer vowels and produced with a more advanced tongue root than voiceless stops. The duration of a vowel is affected by the voicing of the stop that follows, and in many languages vowels are longer when followed by voiced stops. Tongue root advancement is known to be an articulatory mechanism, which ensures the right pressure conditions for the maintenance of voicing during closure as dictated by the aerodynamic voicing constraint. In this paper, it is argued that vowel duration and tongue root advancement have a direct statistical relationship. Drawing from acoustic and ultrasound tongue imaging data from 17 speakers of Italian and Polish in total, it is proposed that the comparatively later closure onset of voiced stops is responsible for both greater root advancement and shorter closure durations of voiced stops. It is further shown that tongue root advancement is initiated during the vowel, and vowel duration and tongue root position at vowel offset are positively correlated so that longer vowel durations correspond to greater tongue root advancement.
PMID: 32006991 DOI: 10.1121/10.0000556
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Select item 3200699038.
J Acoust Soc Am. 2020 Jan;147(1):337. doi: 10.1121/10.0000583.
Best sensitivity of temporal modulation transfer functions in laboratory mice matches the amplitude modulation embedded in vocalizations.
Cai H1, Dent ML1.
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Abstract
The perception of spectrotemporal changes is crucial for distinguishing between acoustic signals, including vocalizations. Temporal modulation transfer functions (TMTFs) have been measured in many species and reveal that the discrimination of amplitude modulation suffers at rapid modulation frequencies. TMTFs were measured in six CBA/CaJ mice in an operant conditioning procedure, where mice were trained to discriminate an 800 ms amplitude modulated white noise target from a continuous noise background. TMTFs of mice show a bandpass characteristic, with an upper limit cutoff frequency of around 567 Hz. Within the measured modulation frequencies ranging from 5 Hz to 1280 Hz, the mice show a best sensitivity for amplitude modulation at around 160 Hz. To look for a possible parallel evolution between sound perception and production in living organisms, we also analyzed the components of amplitude modulations embedded in natural ultrasonic vocalizations (USVs) emitted by this strain. We found that the cutoff frequency of amplitude modulation in most of the individual USVs is around their most sensitive range obtained from the psychoacoustic experiments. Further analyses of the duration and modulation frequency ranges of USVs indicated that the broader the frequency ranges of amplitude modulation in natural USVs, the shorter the durations of the USVs.
PMID: 32006990 DOI: 10.1121/10.0000583
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Select item 3200698939.
J Acoust Soc Am. 2020 Jan;147(1):85. doi: 10.1121/10.0000509.
Acoustic feedback path modeling for hearing aids: Comparison of physical position based and position independent models.
Sankowsky-Rothe T1, Schepker H2, Doclo S2, Blau M3.
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Abstract
Acoustic feedback in hearing aids occurs due to the coupling between the hearing aid loudspeaker and microphones. In order to reduce acoustic feedback, adaptive filters are often used to estimate the feedback path. To increase the convergence speed and decrease the computational complexity of the adaptive algorithms, it has been proposed to split the acoustic feedback path into a time-invariant fixed part and a time-varying variable part. A key question of this approach is how to determine the fixed part. In this paper, two approaches are investigated: (1) a digital filter design approach that makes use of the signals of at least two hearing aid microphones and (2) a defined physical location approach using an electro-acoustic model and the signals of one hearing aid microphone and an additional ear canal microphone. An experimental comparison using measured acoustic feedback paths showed that both approaches enable one to reduce the number of variable part coefficients. It is shown that individualization of the fixed part increases the performance. Furthermore, the two approaches offer solutions for different requirements on the effort to a specific hearing aid design on the one hand and the effort during the hearing aid fitting on the other hand.
PMID: 32006989 DOI: 10.1121/10.0000509
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Select item 3200698840.
J Acoust Soc Am. 2020 Jan;147(1):399. doi: 10.1121/10.0000510.
Theoretical analysis on structure of sound energy field decay of acoustical radiosity model with finite initial excitation.
Honghu Z1.
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Abstract
The acoustical radiosity model (ARM) is a typical algorithm in geometrical acoustics to simulate the sound field in a room of ideally diffusely reflecting boundary. Even in such a room, the sound field decay is a complex process, as the relaxation of the sound field observed in simulations has shown. Based on the Laplace transform of the acoustical radiosity equation, this paper gives a set of properties of the ARM. It shows the system has a series of real or complex conjugate L-eigenvalues and corresponding L-eigenfunctions. Under the relaxation condition, the sound energy decay on the room boundary, generated by finite initial excitation, can be expanded as a summation of decay components, which are composed of real and/or complex conjugate decay modes. Each decay mode is a decaying and oscillating L-eigenfunction corresponding to an L-eigenvalue. The real part of the L-eigenvalue is the exponential decay rate, and the image part is the angular frequency of the oscillation. The reverberant sound field inside the room space has a similar decay structure to the boundary. As an example, the decay structure in a sphere is analyzed. The relaxation of the sound field is explained by the geometrical significance of the sound field decay.
PMID: 32006988 DOI: 10.1121/10.0000510
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Select item 3200698741.
J Acoust Soc Am. 2020 Jan;147(1):657. doi: 10.1121/10.0000551.
Acoustic cues and linguistic experience as factors in regional dialect classification.
Alcorn S1, Meemann K2, Clopper CG3, Smiljanic R2.
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Abstract
Listeners are able to classify talkers by regional dialect of their native language when provided with even short speech samples. However, the way in which American English listeners use segmental and prosodic information to make such decisions is largely unknown. This study used a free classification task to assess native American English listeners' ability to group together talkers from six major dialect regions of American English. Listeners residing in Ohio and Texas were provided with a sentence-long (experiment 1) or paragraph-long (experiment 2) speech sample produced by talkers from each of the six regions presented in one of three conditions: unmodified, monotonized (i.e., flattened F0), and low-pass filtered (i.e., spectral information above 400 Hz removed). In both experiments, listeners in the unmodified and monotonized conditions made more accurate groupings, reflecting their reliance on segmental properties for classifying regional variation. Accuracy was highest for Northern and Western talkers (experiment 1) and Mid-Atlantic talkers (experiment 2). Listeners with experience with multiple dialects as a result of geographic mobility did not show increased accuracy, suggesting a complex relationship between linguistic experience and the perception of available acoustic cues to socioindexical variation.
PMID: 32006987 DOI: 10.1121/10.0000551
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Select item 3200698642.
J Acoust Soc Am. 2020 Jan;147(1):174. doi: 10.1121/10.0000566.
Accommodation of gender-related phonetic differences by listeners with cochlear implants and in a variety of vocoder simulations.
Winn MB1.
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Abstract
Speech perception requires accommodation of a wide range of acoustic variability across talkers. A classic example is the perception of "sh" and "s" fricative sounds, which are categorized according to spectral details of the consonant itself, and also by the context of the voice producing it. Because women's and men's voices occupy different frequency ranges, a listener is required to make a corresponding adjustment of acoustic-phonetic category space for these phonemes when hearing different talkers. This pattern is commonplace in everyday speech communication, and yet might not be captured in accuracy scores for whole words, especially when word lists are spoken by a single talker. Phonetic accommodation for fricatives "s" and "sh" was measured in 20 cochlear implant (CI) users and in a variety of vocoder simulations, including those with noise carriers with and without peak picking, simulated spread of excitation, and pulsatile carriers. CI listeners showed strong phonetic accommodation as a group. Each vocoder produced phonetic accommodation except the 8-channel noise vocoder, despite its historically good match with CI users in word intelligibility. Phonetic accommodation is largely independent of linguistic factors and thus might offer information complementary to speech intelligibility tests which are partially affected by language processing.
PMID: 32006986 DOI: 10.1121/10.0000566
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Select item 3200698543.
J Acoust Soc Am. 2020 Jan;147(1):25. doi: 10.1121/10.0000493.
A model of auditory brainstem response wave I morphology.
Kamerer AM1, Neely ST1, Rasetshwane DM1.
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Abstract
Use of the auditory brainstem response (ABR) in research has increased in the search for physiological correlates of noise-induced damage to the cochlea. The extraction of data from the ABR has traditionally relied on visual determination of peaks and troughs to calculate metrics such as wave amplitude. Visual determination can be reliable when evaluated by trained, experienced personnel, but noisy waveforms and overlapping waves produce uncertain data. The present study proposes and validates a method of fitting summed Gaussian functions to the summating potential and wave I of the ABR. This method could be useful to the research community studying these potentials by providing more accurate measures of wave amplitude than by visual determination.
PMID: 32006985 DOI: 10.1121/10.0000493
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Select item 3200698444.
J Acoust Soc Am. 2020 Jan;147(1):364. doi: 10.1121/10.0000597.
Measurement and empirical evaluation of acoustic loss in tube with abrupt area change.
Ueda Y1, Yonemitsu S1, Ohashi K1, Okamoto T1.
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Abstract
This study measures the acoustic power loss that occurs when an acoustic wave passes through a tube with an abrupt change in area. It is determined that the power loss is proportional to the third power of the velocity amplitude, and that the proportionality coefficient depends upon the area change ratio of the tube. On the other hand, the proportionality coefficient is almost independent of the acoustic impedance and frequency in the 80-250 Hz range. Furthermore, the effect of a tapered tube in reducing the coefficient is experimentally investigated. Based on these experimental results, an empirical estimation method for the acoustic power loss is proposed and validated using a high-pressure-helium-filled tube.
PMID: 32006984 DOI: 10.1121/10.0000597
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Select item 3200698345.
J Acoust Soc Am. 2020 Jan;147(1):627. doi: 10.1121/10.0000542.
Perception of local and non-local vowels by adults and children in the South.
Jacewicz E1, Fox RA1.
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Abstract
This study assessed the ability of Southern listeners to accommodate extensive talker variability in identifying vowels in their local Appalachian community in the context of sound change. Building on prior work, the current experiment targeted a subset of spectrally overlapping vowels in local and two non-local varieties to establish whether adult and child listeners will demonstrate the local dialect advantage. Listeners responded to isolated target words, which minimized the interaction of multiple linguistic and dialect-specific features. For most vowel categories, the local dialect advantage was not demonstrated. However, adult listeners showed sensitivity to generational changes, indicating their familiarity with the local norms. A differential response pattern in children suggests that children perceived the vowels through the lens of their own experience with vowel production, representing a sound change in the community. Compared with the adults, children also relied more on stress cues, with increased confusions when the vowels were unstressed. The study provides evidence that identification accuracy is dependent upon the robustness of cues in individual vowel categories-whether local or non-local-and suggests that the bottom-up processes underlying phonetic vowel categorization in isolated monosyllables can interact with the top-down processing of dialect- and talker-specific information.
PMID: 32006983 DOI: 10.1121/10.0000542
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Select item 3200698246.
J Acoust Soc Am. 2020 Jan;147(1):EL1. doi: 10.1121/10.0000497.
The effects of speech intelligibility on English scientific literature reading in Chinese open-plan offices.
Lou H1, Ou D1.
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Abstract
A laboratory experiment was conducted to study the effects of speech intelligibility on English scientific literature reading performance in Chinese open-plan offices (both the occupants' native language and ambient speech noise were Chinese). The objective performance and subject perceptions of 20 participants were tested under different speech intelligibility conditions. The results highlight the significant negative impact of speech noise on occupants' performance. Moreover, a comparison of these results and those of previous studies implies Chinese occupants engaged in English scientific literature reading tasks are more sensitive to the changes of speech intelligibility and have higher requirements for acoustic environment.
PMID: 32006982 DOI: 10.1121/10.0000497
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Select item 3200698147.
J Acoust Soc Am. 2020 Jan;147(1):EL55. doi: 10.1121/10.0000559.
Development of a French version of the Modified Rhyme Test.
Zimpfer V1, Andéol G2, Blanck G3, Suied C2, Fux T2.
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Abstract
A reproducible method to measure the intelligibility of communication systems is required to assess their efficiency. The current study seeks to develop a French version of the Modified Rhyme Test (MRT) [(House, Williams, Heker, and Kryter (1965). J. Acoust. Soc. Am. 37, 158-66], an intelligibility test composed of 50 six-word lists, originally developed for military applications and now widely used. An evaluation of the authors' French MRT was carried out, reproducing the original experimental conditions used by House and colleagues. Very similar results were found between the original MRT and the French MRT, validating the latter for further use and dissemination.
PMID: 32006981 DOI: 10.1121/10.0000559
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Select item 3200698048.
J Acoust Soc Am. 2020 Jan;147(1):260. doi: 10.1121/10.0000609.
A performance comparison of tonal detectors for low-frequency vocalizations of Antarctic blue whales.
Bouffaut L1, Madhusudhana S2, Labat V1, Boudraa AO1, Klinck H2.
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Abstract
Extraction of tonal signals embedded in background noise is a crucial step before classification and separation of low-frequency sounds of baleen whales. This work reports results of comparing five tonal detectors, namely the instantaneous frequency estimator, YIN estimator, harmonic product spectrum, cost-function-based detector, and ridge detector. Comparisons, based on a low-frequency adaptation of the Silbido scoring feature, employ five metrics, which quantify the effectiveness of these detectors to retrieve tonal signals that have a wide range of signal to noise ratios (SNRs) and the quality of the detection results. Ground-truth data were generated by embedding 20 synthetic Antarctic blue whale (Balaenoptera musculus intermedia) calls in randomly extracted 30-min noise segments from a 79 h-library recorded by an Ocean Bottom Seismometer in the Indian Ocean during 2012-2013. Monte-Carlo simulations were performed using 20 trials per SNR, ranging from 0 dB to 15 dB. Overall, the tonal detection results show the superiority of the cost-function-based and the ridge detectors, over the other detectors, for all SNR values. More particularly, for lower SNRs (⩽3 dB), these two methods outperformed the other three with high recall, low fragmentation, and high coverage scores. For SNRs ⩾7 dB, the five methods performed similarly.
PMID: 32006980 DOI: 10.1121/10.0000609
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Select item 3200697949.
J Acoust Soc Am. 2020 Jan;147(1):273. doi: 10.1121/10.0000563.
Sentence perception in noise by hearing-aid users predicted by syllable-constituent perception and the use of context.
Miller JD1, Watson CS1, Leek MR2, Wark DJ3, Souza PE4, Gordon-Salant S5, Ahlstrom JB6, Dubno JR6.
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Abstract
Masked sentence perception by hearing-aid users is strongly correlated with three variables: (1) the ability to hear phonetic details as estimated by the identification of syllable constituents in quiet or in noise; (2) the ability to use situational context that is extrinsic to the speech signal; and (3) the ability to use inherent context provided by the speech signal itself. This approach is called "the syllable-constituent, contextual theory of speech perception" and is supported by the performance of 57 hearing-aid users in the identification of 109 syllable constituents presented in a background of 12-talker babble and the identification of words in naturally spoken sentences presented in the same babble. A simple mathematical model, inspired in large part by Boothroyd and Nittrouer [(1988). J. Acoust. Soc. Am. 84, 101-114] and Fletcher [Allen (1996) J. Acoust. Soc. Am. 99, 1825-1834], predicts sentence perception from listeners' abilities to recognize isolated syllable constituents and to benefit from context. When the identification accuracy of syllable constituents is greater than about 55%, individual differences in context utilization play a minor role in determining the sentence scores. As syllable-constituent scores fall below 55%, individual differences in context utilization play an increasingly greater role in determining sentence scores. Implications for hearing-aid design goals and fitting procedures are discussed.
PMID: 32006979 DOI: 10.1121/10.0000563
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Select item 3200697850.
J Acoust Soc Am. 2020 Jan;147(1):32. doi: 10.1121/10.0000515.
Feedforward multichannel virtual-sensing active control of noise through an aperture: Analysis on causality and sensor-actuator constraints.
Shi D1, Gan WS1, Lam B1, Hasegawa R2, Kajikawa Y2.
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Abstract
The multichannel implementation of the auxiliary-filter-based virtual-sensing (AF-VS) technique for active noise control applications is revisited and realized in the paper. Frequency-domain analysis based on random primary noise proves that the multichannel virtual-sensing active noise control (MVANC) technique can achieve optimal control at the desired virtual locations even if the signals at the physical and virtual microphones are not causally related. Further analysis on a number of sensor-actuator configurations shows that the MVANC technique achieves optimal control at the desired locations as long as the number of secondary sources does not exceed that of the physical error microphones. Furthermore, the simulations with measured transfer functions and real-time experiments conducted on a four-channel system validate the frequency domain analyses.
PMID: 32006978 DOI: 10.1121/10.0000515
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Select item 3200697751.
J Acoust Soc Am. 2020 Jan;147(1):11. doi: 10.1121/10.0000492.
Audio enhancement and intelligent classification of household sound events using a sparsely deployed array.
Bai MR1, Lan SS1, Huang JY1, Hsu YC1, So HC2.
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Abstract
A household sound event classification system consisting of an audio localization and enhancement front-end cascaded with an intelligent classification back-end is presented. The front-end is composed of a sparsely deployed microphone array and a preprocessing unit to localize the source and extract the associated signal. In the front-end, a two-stage method and a direct method are compared for localization. The two-stage method introduces a subspace algorithm to estimate the time difference of arrival, followed by a constrained least squares algorithm to determine the source location. The direct localization methods, the delay-and-sum beamformer, the minimum power distortionless response beamformer, and the multiple signal classification algorithm are compared in terms of localization performance for sparse array configuration. A modified particle swarm optimization algorithm enabled an efficient grid-search. A minimum variance distortionless response beamformer in conjunction with a minimum-mean-square-error postfilter is exploited to extract the source signals for sound event classification tasks that follow. The back-end of the system is a sound event classifier that is based on convolutional neural networks (CNNs), and convolutional long short-term memory networks Mel-spectrograms are used as the input features to the CNNs. Simulations and experiments conducted in a live room have demonstrated the strength and weakness of the direct and two-stage methods. Signal quality enhancement using the array-based front-end proves beneficial for improved classification accuracy over a single microphone.
PMID: 32006977 DOI: 10.1121/10.0000492
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Select item 3200697652.
J Acoust Soc Am. 2020 Jan;147(1):101. doi: 10.1121/1.5141370.
The impact of speaking style on speech recognition in quiet and multi-talker babble in adult cochlear implant users.
Rodman C1, Moberly AC1, Janse E2, Başkent D3, Tamati TN1.
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Abstract
The current study examined sentence recognition across speaking styles (conversational, neutral, and clear) in quiet and multi-talker babble (MTB) for cochlear implant (CI) users and normal-hearing listeners under CI simulations. Listeners demonstrated poorer recognition accuracy in MTB than in quiet, but were relatively more accurate with clear speech overall. Within CI users, higher-performing participants were also more accurate in MTB when listening to clear speech. Lower performing users' accuracy was not impacted by speaking style. Clear speech may facilitate recognition in MTB for high-performing users, who may be better able to take advantage of clear speech cues.
PMID: 32006976 DOI: 10.1121/1.5141370
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Select item 3200697553.
J Acoust Soc Am. 2020 Jan;147(1):525. doi: 10.1121/10.0000606.
Introduction to the special issue on English in the Southern United States: Social factors and language variation.
Shport I1, Herd W2.
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Abstract
The Southern United States have long been known for language diversity, yet linguistic research in this region has often focused on broad descriptions of characteristics of Southern American English as compared to other regional dialects of American English. Linguistic subregions in the South, however, are distinctly different from each other, and additional social variation also occurs within those subregions. Thus, the different English varieties spoken in the South cannot be collapsed under a single umbrella. Analyzing varieties of English in the Southern United States calls for a narrower approach, which will more accurately represent diverse Southern communities, their languages of practice, and the sound changes in process. Sociophonetic research on variation within English varieties in the Southern United States highlights theoretical and practical areas in speech acoustics that would otherwise remain under-documented and under-investigated, such as socially meaningful variation in vowel trajectories, nasalance of vowels, and temporal characteristics. The goal of this special issue is to bring together research that investigates the production and perception of Southern varieties of American English by documenting the segmental and prosodic patterns unique to these subregional varieties and by determining how these features are perceived by both Southerners and non-Southerners.
PMID: 32006975 DOI: 10.1121/10.0000606
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Select item 3200697454.
J Acoust Soc Am. 2020 Jan;147(1):480. doi: 10.1121/10.0000516.
Adaptive reweighting homotopy algorithm based compressive spherical beamforming with spherical microphone arrays.
Yin S1, Chu Z1, Zhang Y1, Liu Y1.
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Abstract
Compressive spherical beamforming (CSB) with spherical microphone arrays enjoys high spatial resolution and strong sidelobes suppression at medium to high frequencies. In this paper, the adaptive reweighting homotopy (ARH) algorithm is adapted to CSB, and the proposed method is abbreviated as ARH-CSB, which bypasses a priori signal-to-noise ratio (SNR) estimation. ARH-CSB iteratively solves the CSB model by determining the support set and adaptively searching for weights while estimating the source strength. Simulations and experiments demonstrate that ARH-CSB can effectively identify acoustic sources. Furthermore, compared to CSB solved by ℓ1-norm minimization algorithm and iterative reweighted ℓ1-norm minimization algorithm, ARH-CSB does not depend on a priori SNR and has better adaptability to low SNR, stronger robustness, higher weak sources quantification accuracy, and faster computation speed.
PMID: 32006974 DOI: 10.1121/10.0000516
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Select item 3200697355.
J Acoust Soc Am. 2020 Jan;147(1):EL50. doi: 10.1121/10.0000590.
A cluster-based direct source localization approach for large-aperture horizontal line arrays.
Wang L1, Yang Y1, Liu X1.
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Abstract
In this paper, the problem of source localization using one-step direct position determination (DPD) approaches with large-aperture horizontal line arrays is considered. In practice, it may be difficult to keep the array configuration and overlarge inter-element spacing may cause the split beam problem when decentralized DPD approaches are applied. A cluster-based coherent MUSIC DPD approach is proposed to handle the unfavourable array configuration. The large-aperture array is divided into several small-aperture arrays, which form a coherent cluster to keep the largest covariance lag unchanged. Experimental results with the SWellEx96 data demonstrate the performance gain achieved by cluster-based coherent processing.
PMID: 32006973 DOI: 10.1121/10.0000590
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Select item 3200697256.
J Acoust Soc Am. 2020 Jan;147(1):267. doi: 10.1121/10.0000599.
Erratum: Effect of evaporation and condensation on a thermoacoustic engine: A Lagrangian simulation approach [J. Acoust. Soc. Am. 141 (6), 4398-4407 (2017)].
Yasui K1, Izu N1.
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Abstract
In the original paper [Yasui and Izu, J. Acoust. Soc. Am. 141(6), 4398-4407 (2017)], the temperature gradient in Rott equations was assumed as zero by mistake as an author error, although temperature gradient was adequately taken into account in the numerical simulations of thermal conduction between a fluid parcel and the wall of a stack. In the present erratum, the results of the corrected numerical simulations are shown. The results show that the pV work done by a fluid parcel is larger in a wet stack compared to that in a dry stack not only in a traveling-wave thermoacoustic engine but also in a standing-wave thermoacoustic engine. The pV work is determined not only by the volume oscillation amplitude of a fluid parcel but also by the change in the mean volume of a fluid parcel.
PMID: 32006972 DOI: 10.1121/10.0000599
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Select item 3200697157.
J Acoust Soc Am. 2020 Jan;147(1):371. doi: 10.1121/10.0000584.
On the utility of perceptual anchors during pure-tone frequency discrimination.
Mathias SR1, Varghese L2, Micheyl C3, Shinn-Cunningham BG4.
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Abstract
Perceptual anchors are representations of stimulus features stored in long-term memory rather than short-term memory. The present study investigated whether listeners use perceptual anchors to improve pure-tone frequency discrimination. Ten amateur musicians performed a two-interval, two-alternative forced-choice frequency-discrimination experiment. In one half of the experiment, the frequency of the first tone was fixed across trials, and in the other half, the frequency of the first tone was roved widely across trials. The durations of the interstimulus intervals (ISIs) and the frequency differences between the tones on each trial were also manipulated. The data were analyzed with a Bayesian model that assumed that performance was limited by sensory noise (related to the initial encoding of the stimuli), memory noise (which increased proportionally to the ISI), fluctuations in attention, and response bias. It was hypothesized that memory-noise variance increased more rapidly during roved-frequency discrimination than fixed-frequency discrimination because listeners used perceptual anchors in the latter condition. The results supported this hypothesis. The results also suggested that listeners experienced more lapses in attention during roved-frequency discrimination.
PMID: 32006971 DOI: 10.1121/10.0000584
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Select item 3200697058.
J Acoust Soc Am. 2020 Jan;147(1):56. doi: 10.1121/10.0000470.
The small-slope approximation for layered, fluid seafloors.
Jackson D1, Olson DR2.
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Abstract
The small-slope approximation (SSA) for rough-interface scattering is most commonly applied to the upper boundary of either impenetrable media or uniform half-space media, but has been recently developed for layered media in the acoustic and electromagnetic cases. The present work gives an overview of three forms of the SSA for layered media. The first has been previously presented in the acoustics literature. The second is from the electromagnetics literature and in the present work is converted to the fluid-sediment problem. A missing proof is supplied of a key consistency condition demanded of the small-slope ansatz. As is usual, these small-slope results are expressed in k-space. A third SSA for layered seafloors follows from conversion of the usual half-space formulation from k-space to coordinate space. This form turns out to be useful for reverberation simulations. The three different approaches are compared with respect to scattering strength and the coherent reflection coefficient, but an assessment of their relative merits will require comparison with exact calculations.
PMID: 32006970 DOI: 10.1121/10.0000470
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Select item 3200696959.
J Acoust Soc Am. 2020 Jan;147(1):469. doi: 10.1121/10.0000582.
Variability in the rigid pinna motions of hipposiderid bats and their impact on sensory information encoding.
Qiu P1, Müller R1.
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Abstract
Many bat species, e.g., in the rhinolophid and hipposiderid families, have dynamic biosonar systems with highly mobile pinnae. Pinna motion patterns have been shown to fall into two distinct categories: rigid rotations and non-rigid motions (i.e., deformations). In the present work, two questions regarding the rigid rotations have been investigated: (i) what is the nature of the variability (e.g., discrete subgroups or continuous variation) within the rigid motions, (ii) what is its acoustic impact? To investigate the first question, rigid pinna motions in Pratt's leaf-nosed bats (Hipposideros pratti) have been tracked with stereo vision and a dense set of landmark points on the pinna surface. Axis-angle representations of the recorded rigid motions have shown a continuous variation in the rotation axes that covered a range of almost 180° in azimuth and elevation. To investigate the second question, the observed range of rigid pinna motions has been reproduced with a biomimetic pinna. Normalized mutual information between acoustic inputs associated with every pair of the rigid pinna motions showed that even small changes in the rotation axis resulted in more than 50% new sensory information encoding capacity (i.e., normalized mutual information less than 50%). This demonstrates a potential sensory benefit to the observed variability in the rigid pinna rotations.
PMID: 32006969 DOI: 10.1121/10.0000582
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Select item 3200696860.
J Acoust Soc Am. 2020 Jan;147(1):108. doi: 10.1121/10.0000487.
Investigating multidimensional characteristics of noise signals with tones from building mechanical systems and their effects on annoyance.
Lee J1, Wang LM1.
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Abstract
This paper investigates multidimensional characteristics of tonal noise from heating, ventilation, and air-conditioning systems, besides loudness and tonality, to improve prediction of annoyance. Two studies were conducted: multidimensional scaling (MDS) analysis to determine what other perceptual signal characteristics are important and perceptual weight analysis (PWA) to understand the impact of multiple tones in a signal. In the MDS study, paired comparison tasks were conducted to gather similarity and annoyance data. Results show that the latent perceptual dimensions are related to the signal's tonality, loudness, sharpness, and roughness. Including metrics for these perceptions, except roughness, improves the performance of earlier annoyance prediction models. Including both sharpness and tonal audibility does not further improve prediction performance, though. In the PWA study, noise stimuli with five-tone complexes between 125 Hz and 2 kHz were generated for subjective testing to obtain a perceptual weighting function. The levels of each tone were randomly adjusted for every trial, and both harmonic and inharmonic tone complexes were utilized. The PWA result was applied as a spectral weighting function to calculate a proposed weighted-sum tonal audibility metric. Utilizing the proposed metric instead of the traditional tonal audibility metric improves annoyance prediction to a similar degree as including sharpness.
PMID: 32006968 DOI: 10.1121/10.0000487
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Select item 3200696761.
J Acoust Soc Am. 2020 Jan;147(1):350. doi: 10.1121/10.0000577.
Electric-acoustic interaction measurements in cochlear-implant users with ipsilateral residual hearing using electrocochleography.
Krüger B1, Büchner A1, Lenarz T1, Nogueira W1.
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Abstract
Cochlear implantation is increasingly being used as a hearing-loss treatment for patients with residual hearing in the low acoustic frequencies. These patients obtain combined electric-acoustic stimulation (EAS). Substantial residual hearing and relatively long electrode arrays can lead to interactions between the electric and acoustic stimulation. This work investigated EAS interaction through psychophysical and electrophysiological measures. Moreover, cone-beam computed-tomography data was used to characterize the interaction along spatial cochlear locations. Psychophysical EAS interaction was estimated based on the threshold of audibility of an acoustic probe stimulus in the presence of a simultaneously presented electric masker stimulus. Intracochlear electrocochleography was used to estimate electrophysiological EAS interaction via the telemetry capability of the cochlear implant. EAS interaction was observed using psychophysical and electrophysiological measurements. While psychoacoustic EAS interaction was most pronounced close to the electrical stimulation site, electrophysiological EAS interaction was observed over a wider range of spatial cochlear locations. Psychophysical EAS interaction was significantly larger than electrophysiological EAS interaction for acoustic probes close to the electrode position.
PMID: 32006967 DOI: 10.1121/10.0000577
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Select item 3200696662.
J Acoust Soc Am. 2020 Jan;147(1):EL25. doi: 10.1121/10.0000473.
Evidence supporting synchrony between two active ears due to interaural coupling.
Bergevin C1, Mason A2, Mhatre N3.
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Abstract
Motivated by recent developments suggesting that interaural coupling in non-mammals allows for the two active ears to effectively synchronize, this report describes otoacoustic measurements made in the oral cavity of lizards. As expected from that model, spontaneous otoacoustic emissions (SOAEs) were readily measurable in the mouth, which is contiguous with the interaural airspace. Additionally, finite element model calculations were made to simulate the interaural acoustics based upon SOAE-related tympanic membrane vibrational data. Taken together, these data support the notion of two active ears synchronizing by virtue of acoustic coupling and have potential implications for sound localization at low-levels.
PMID: 32006966 DOI: 10.1121/10.0000473
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Select item 3200696563.
J Acoust Soc Am. 2020 Jan;147(1):381. doi: 10.1121/10.0000571.
The violin: A social history of the world's most versatile instrument.
Waltham C1.
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PMID: 32006965 DOI: 10.1121/10.0000571
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Select item 3200696464.
J Acoust Soc Am. 2020 Jan;147(1):388. doi: 10.1121/10.0000557.
Directional hearing sensitivity for 2-30 kHz sounds in the bottlenose dolphin (Tursiops truncatus).
Accomando AW1, Mulsow J1, Branstetter BK1, Schlundt CE2, Finneran JJ3.
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Abstract
Bottlenose dolphins (Tursiops truncatus) depend on sounds at frequencies lower than 30 kHz for social communication, but little information on the directional dependence of hearing thresholds for these frequencies exists. This study measured underwater behavioral hearing thresholds for 2, 10, 20, and 30 kHz sounds projected from eight different positions around dolphins in both the horizontal and vertical planes. The results showed that the sound source direction relative to the dolphin affected hearing threshold, and that directional characteristics of the receiving beam pattern were frequency dependent. Hearing thresholds obtained from two adult dolphins demonstrated a positive relationship between directivity of hearing and stimulus frequency, with asymmetric receiving beam patterns in both the horizontal and vertical planes. Projecting sound from directly behind the dolphin resulted in frequency-dependent increases in hearing threshold up to 18.5 dB compared to when sound was projected in front. When the projector was situated above the dolphin thresholds were approximately 8 dB higher as compared to below. This study demonstrates that directional hearing exists for lower frequencies than previously expected.
PMID: 32006964 DOI: 10.1121/10.0000557
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Select item 3200696365.
J Acoust Soc Am. 2020 Jan;147(1):EL62. doi: 10.1121/10.0000604.
Dong speakers outperform Mandarin speakers in behavioral pitch discrimination.
Hu A1, Wang M1, Li Y1, Tang Q2, Gu F3.
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Abstract
Tonal language speakers outperform non-tonal language speakers in behavioral pitch discrimination. Because the tone system differs in complexity across different tonal languages, it is unknown whether pitch discrimination differs across individuals speaking different tonal languages. There are nine tones in Dong but only four in Mandarin. This study investigates whether behavioral pitch discrimination is superior in Dong speakers compared to Mandarin speakers. Behavioral pitch discrimination was indexed by difference limens measured using pure tones and harmonic tones. The results indicate that Dong speakers outperformed Mandarin speakers in pitch discrimination tasks.
PMID: 32006963 DOI: 10.1121/10.0000604
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Select item 3200696266.
J Acoust Soc Am. 2020 Jan;147(1):191. doi: 10.1121/10.0000570.
Fast computation of time-domain scattering by an inhomogeneous stratified seafloor.
Olson DR1, Holland CW2.
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Abstract
Marine sediment properties exhibit fluctuations on a very wide range of scales in all three spatial dimensions. These fluctuations lead to scattering of acoustic waves. Seabed scattering models that treat such fluctuations are reasonably well developed under the plane-wave assumption. A recent model, called TDSS (time domain model for seafloor scattering), accurately treats the important point-source-point-receiver geometry for generally stratified fluid sediments-important because this is the geometry employed in many seabed scattering measurements. The computational cost associated with this model is very high and scales roughly with the product of mean source-receiver height above the basement to the fifth power and both bandwidth and wavenumber to the second power. Thus, modeling deep ocean scattering from a near sea surface source and receiver is prohibitive at frequencies above a few tens of hertz. A computational approach was developed based on Levin's method of oscillatory integration, which is orders of magnitude faster than standard numerical integration techniques and makes deep ocean seabed scattering computations practical up to many kilohertz. This approach was demonstrated to agree with the narrowband sonar equation in several simple environments in the limit of small bandwidths, but the TDSS model is expected to be valid for a much wider range of environments.
PMID: 32006962 DOI: 10.1121/10.0000570
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Select item 3200696167.
J Acoust Soc Am. 2020 Jan;147(1):1. doi: 10.1121/10.0000489.
Cross-correlation sensitivity kernels with respect to noise source distribution.
Skarsoulis EK1, Cornuelle BD2.
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Abstract
The cross correlation of the underwater noise field recorded at two receivers conveys information about the time-domain Green's function between the two locations, provided that sufficient energy is channeled into the acoustic paths connecting these. The efficiency of this procedure depends on the locations and characteristics of the receivers and noise sources, as well as on the refraction properties of the ocean sound channel. The sensitivity of the finite-frequency noise cross-correlation function with respect to the location and amplitude of the noise sources is studied here, taking into account the refractive features of the ocean environment. The sensitivity kernel describing changes in the cross-correlation envelope due to changes in the noise source distribution is used to highlight noise-source locations with maximum potential impact on the cross-correlation output.
PMID: 32006961 DOI: 10.1121/10.0000489
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Select item 3200696068.
J Acoust Soc Am. 2020 Jan;147(1):490. doi: 10.1121/10.0000586.
Transient solutions for the angular dependence of acoustical transmitters and receivers employing paraboloidal reflectors.
Cormack JM1, Hamilton MF1.
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Abstract
Time-domain solutions are presented for the angular dependence of waveforms in the far field of a point source at the focus of a rigid paraboloidal reflector, and also for waveforms at the focus as a function of the direction of a plane wave incident on the reflector. The main restriction is that the wavelength is small in relation to both the radius of the aperture and the minimum radius of curvature of the reflector, conditions which are satisfied for reflectors with appreciable gain. The solution in the far field due to a point source at the focus is related by the principle of reciprocity to the solution at the focus due to an incident plane wave. Both solutions are expressed as the convolution of an explicit expression for the unit step response with the time derivative of the pressure waveform incident on the reflector. Results are presented illustrating the angular dependence of the reflected pressure waveforms at the focus due to incident N waves and tone bursts.
PMID: 32006960 DOI: 10.1121/10.0000586
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Select item 3200695969.
J Acoust Soc Am. 2020 Jan;147(1):300. doi: 10.1121/10.0000588.
Causality-constrained measurements of aural acoustic reflectance and reflection functions.
Keefe DH1.
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Abstract
Causality-constrained procedures are described to measure acoustic pressure reflectance and reflection function (RF) in the ear canal or unknown waveguide, in which reflectance is the Fourier transform of the RF. Reflectance calibration is reformulated to generate causal outputs, with results described for a calibration based on a reflectance waveguide equation to calculate incident pressure and source reflectance in the frequency domain or source RF in the time domain. The viscothermal model RF of each tube is band-limited to the stimulus bandwidth. Results are described in which incident pressure is either known from long-tube measurements or calculated as a calibration output. Calibrations based on constrained nonlinear optimizations are simpler and more accurate when incident pressure is known. Outputs measured by causality-constrained procedures differ at higher frequencies from those using standard procedures with non-causal outputs. Evanescent-mode effects formulated in the time domain and incorporated into frequency-domain calibrations are negligible for long-tube calibrations. Causal reflectance and RFs are evaluated in an adult ear canal and time- and frequency-domain results are contrasted using forward and inverse Fourier transforms. These results contribute to the long-term goals of improving applications to calibrate sound stimuli in the ear canal at high frequencies and diagnose conductive hearing impairments.
PMID: 32006959 DOI: 10.1121/10.0000588
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Select item 3200695870.
J Acoust Soc Am. 2020 Jan;147(1):125. doi: 10.1121/10.0000491.
Dipole-based beamforming method for locating dipole sources with unknown orientations in three-dimensional domains.
Gao J1, Wu H1, Jiang W1.
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Abstract
In conventional delay-and-sum beamforming, the monopole source assumption may cause a dipole source to be misinterpreted, leading to incorrect mapping results. A dipole-based beamforming method is proposed that is an extension of monopole-based conventional beamforming. The dipole sources could be located with no prior knowledge of the source orientation, and the unknown orientation is arbitrary in a three-dimensional domain. The location of a dipole source is determined by calculating the beamforming results at predefined orientations and positions using a dipole-based propagation function, and the final beamforming result at each scanning point is determined by the maximum value at the predefined orientations. Numerical simulations and experiments are performed on rotating dipole sources, and satisfactory results for the location of these dipole sources are obtained with different orientations.
PMID: 32006958 DOI: 10.1121/10.0000491
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Select item 3200695771.
J Acoust Soc Am. 2020 Jan;147(1):596. doi: 10.1121/10.0000545.
Sociophonetic voice onset time variation in Mississippi English.
Herd W1.
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Abstract
Differences in the way voice onset time (VOT) is used across languages to maintain stop voicing contrasts have been well-documented, but less research has focused on VOT variation within voicing categories. For example, native English speakers are generally reported to produce word-initial voiced stops with short positive VOTs, but within category differences connected to self-reported gender and ethnicity have been reported in one preliminary study, with male speakers prevoicing more than female speakers and with African American speakers prevoicing more than Caucasian American speakers. For the current study, native speakers of English from Mississippi were recorded reading three repetitions of a pseudo-randomized list of words designed to investigate the connections between gender, ethnicity, and prevoicing of word-initial voiced stops. Participants self-identified their gender and ethnicity in an open-ended language background survey completed after recordings. Significant ethnicity, but not gender, differences were found, with African American speakers prevoicing voiced stops far more than their Caucasian American counterparts. Presumably, this difference is linked, not to ethnicity, but to dialect. These findings suggest that dialectal differences play a role in the VOT variation of word-initial voiced stops and that prevoicing may be a heretofore unidentified characteristic of African American English.
PMID: 32006957 DOI: 10.1121/10.0000545
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Select item 3200695672.
J Acoust Soc Am. 2020 Jan;147(1):446. doi: 10.1121/10.0000511.
Counting or discriminating the number of voices to assess binaural fusion with single-sided vocoders.
Wess JM1, Spencer NJ2, Bernstein JGW1.
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Abstract
For single-sided deafness cochlear-implant (SSD-CI) listeners, different peripheral representations for electric versus acoustic stimulation, combined with interaural frequency mismatch, might limit the ability to perceive bilaterally presented speech as a single voice. The assessment of binaural fusion often relies on subjective report, which requires listeners to have some understanding of the perceptual phenomenon of object formation. Two experiments explored whether binaural fusion could instead be assessed using judgments of the number of voices in a mixture. In an SSD-CI simulation, normal-hearing listeners were presented with one or two "diotic" voices (i.e., unprocessed in one ear and noise-vocoded in the other) in a mixture with additional monaural voices. In experiment 1, listeners reported how many voices they heard. Listeners generally counted the diotic speech as two separate voices, regardless of interaural frequency mismatch. In experiment 2, listeners identified which of two mixtures contained diotic speech. Listeners performed significantly better with interaurally frequency-matched than with frequency-mismatched stimuli. These contrasting results suggest that listeners experienced partial fusion: not enough to count the diotic speech as one voice, but enough to detect its presence. The diotic-speech detection task (experiment 2) might provide a tool to evaluate fusion and optimize frequency mapping for SSD-CI patients.
PMID: 32006956 DOI: 10.1121/10.0000511
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