Volume 133, Issue 4, April 2013
- jasa express letters
- letters to the editor
- general linear acoustics 
- nonlinear acoustics 
- aeroacoustics, atmospheric sound 
- underwater sound 
- ultrasonics, quantum acoustics, and physical effects of sound 
- transduction 
- structural acoustics and vibration 
- noise: its effects and control 
- architectural acoustics 
- acoustic signal processing 
- physiological acoustics 
- psychological acoustics 
- speech production 
- speech perception 
- speech processing and communication systems 
- music and musical instruments 
- bioacoustics 
- acoustical news
- book reviews
- reviews of acoustical patents
Index of content:
- JASA EXPRESS LETTERS
133(2013); http://dx.doi.org/10.1121/1.4793566View Description Hide Description
A massless acoustic source is proposed for scale model work. This source is generated by focusing a pulsed laser beam to rapidly heat the air at the focal point. This produces an expanding small plasma ball which generates a sonic impulse that may be used as an acoustic point source. Repeatability, frequency response, and directivity of the source were measured to show that it can serve as a massless point source. The impulse response of a rectangular space was determined using this type of source. A good match was found between the predicted and the measured impulse responses of the space.
Using Fisher information to quantify uncertainty in environmental parameters estimated from correlated ambient noise133(2013); http://dx.doi.org/10.1121/1.4792836View Description Hide Description
Efforts to characterize environmental parameters from ambient noise must contend with uncertainty introduced by stochastic fluctuations of the noise itself. This Letter calculates the Fisher information and Cramer-Rao bound of an unbiased correlated ambient noise parameter estimate. As an illustration, lower bounds on the error covariance of medium speed and attenuation parameters are obtained for a two-dimensional isotropic ambient noise scenario. The results demonstrate that an optimal sensor separation exists for obtaining the minimum error and the predictions are validated using simulated parameter inversions. The influences of record length, bandwidth, signal-to-noise, and spatial resolution are discussed.
133(2013); http://dx.doi.org/10.1121/1.4793767View Description Hide Description
Early reflections are not always strong and sparse enough on the timeline to be easily identified when reviewing the impulse response diagram. This paper presents a method for the detection of early reflection in the room impulse response using multifractals. The proposed method uses the distribution of Hölder's exponent calculated for the acoustic impulse response for early reflection detection. The obtained results confirm the assumption that impulse response signals exhibit self-similarity, and that fractal theory can be used for the detection of early reflections.
133(2013); http://dx.doi.org/10.1121/1.4793579View Description Hide Description
It is hypothesized that room-acoustical quality correlates with the information-transfer rate. Auditoria are considered as multiple-input multiple-output communication channels and a theory of information-transfer is outlined that accounts for time-variant multipath, spatial hearing, and distributed directional sources. Source diversity and spatial hearing are shown to be the mechanisms through which multipath increases the information-transfer rate by overcoming finite spatial resolution. In addition to predictions that are confirmed by recent and historical findings, the theory provides explanations for the influence of factors such as musical repertoire and ensemble size on subjective preference and the influence of multisource, multichannel auralization on perceived realism.
Anticipatory lip gestures: A validation of the Movement Expansion Model in congenitally blind speakers133(2013); http://dx.doi.org/10.1121/1.4793436View Description Hide Description
In this paper, anticipatory co-articulation of the lip protrusion and constriction gestures is investigated in speakers with visual deprivation. Audio-visual recordings of 11 congenitally blind French speakers producing [V −round C −round V +round] sequences were measured with a lip shape tracking system. Lip protrusion and constriction values and their relative timings were analyzed. Results show that despite the reduced magnitude of lip protrusion and constriction area in blind speakers, the timing of the anticipatory gestures can be appropriately modeled by the Movement Expansion Model [from Abry and Lallouache (1995a). Bul. de la Comm. Parlée 3, 85–99; (1995b). Proceedings of ICPHS, pp. 152–155; Noiray et al. (2011). J. Acoust. Soc. Am. 129, 340–349], which predicts lawful anticipatory behavior expanding linearly as the intervocalic consonant interval increases.
133(2013); http://dx.doi.org/10.1121/1.4793584View Description Hide Description
Sensitivity of nonlinear acoustic methods to the presence and the evolution of micro-damage has been proven in various studies on a wide range of materials. In this contribution, a guided wave approach is proposed to characterize polymer based composite plates taken at intact as well as damaged states. The changes in the nonlinear hysteretic parameters are observed by changing the order of the excited flexural resonances. The analysis is based on the evolution of the velocity frequency dispersion of the generated guided waves, where flexural modes are considered separately and together as a function of the dynamic strain.
133(2013); http://dx.doi.org/10.1121/1.4794934View Description Hide Description
This paper presents the empirical probability density of the power spectral density as a tool to assess the field performance of passive acoustic monitoring systems and the statistical distribution of underwater noise levels across the frequency spectrum. Using example datasets, it is shown that this method can reveal limitations such as persistent tonal components and insufficient dynamic range, which may be undetected by conventional techniques. The method is then combined with spectral averages and percentiles, which illustrates how the underlying noise level distributions influence these metrics. This combined approach is proposed as a standard, integrative presentation of ambient noise spectra.
Computationally efficient parabolic equation solutions to seismo-acoustic problems involving thin or low-shear elastic layers133(2013); http://dx.doi.org/10.1121/1.4794348View Description Hide Description
Shallow-water environments typically include sediments containing thin or low-shear layers. Numerical treatments of these types of layers require finer depth grid spacing than is needed elsewhere in the domain. Thin layers require finer grids to fully sample effects due to elasticity within the layer. As shear wave speeds approach zero, the governing system becomes singular and fine-grid spacing becomes necessary to obtain converged solutions. In this paper, a seismo-acoustic parabolic equation solution is derived utilizing modified difference formulas using Galerkin's method to allow for variable-grid spacing in depth. Propagation results are shown for environments containing thin layers and low-shear layers.
133(2013); http://dx.doi.org/10.1121/1.4794931View Description Hide Description
This letter develops a Bayesian approach to matched-field tracking of multiple acoustic sources in a poorly-known environment. Markov-chain Monte Carlo methods explicitly sample the posterior probability density over source locations and environmental parameters, while analytic maximum-likelihood solutions for complex source strengths and noise variance in terms of the explicit parameters allow these parameters to be sampled efficiently. This produces a time-ordered sequence of joint marginal probability distributions over source range and depth, from which optimal track estimates and uncertainties are extracted. Synthetic examples consider tracking a submerged source in the presence of a louder shallow interferer in an unknown environment.
133(2013); http://dx.doi.org/10.1121/1.4794933View Description Hide Description
Listeners can use temporally pre-presented content cues and concurrently presented lipreading cues to improve speech recognition under masking conditions. This study investigated whether temporally pre-presented lipreading cues also unmask speech. In a test trial, before the target sentence was co-presented with the masker, either target-matched (priming) lipreading video or static face (priming-control) video was presented in quiet. Participants’ target-recognition performance was improved by a shift from the priming-control condition to the priming condition when the masker was speech but not noise. This release from informational masking suggests a combined effect of working memory and cross-modal integration on selective attention to target speech.
133(2013); http://dx.doi.org/10.1121/1.4794932View Description Hide Description
Talking silently to ourselves occupies much of our mental lives, yet the mechanisms underlying this experience remain unclear. The following experiments provide behavioral evidence that the auditory content of inner speech is provided by corollary discharge. Corollary discharge is the motor system's prediction of the sensory consequences of its actions. This prediction can bias perception of other sensations, pushing percepts to match with prediction. The two experiments below show this bias induced by inner speech, demonstrating that inner speech causes external sounds to be heard as similar to the imagined speech, and that this bias operates on subphonemic content.
133(2013); http://dx.doi.org/10.1121/1.4795215View Description Hide Description
A mathematical model for approximating the contributions of identification and recall errors on the ability to repeat a list of N items is developed. In memory recall tasks where the items are independent and unrelated to each other, the probability of correctly repeating a list of items can be approximated as the product of the probability of correctly recalling all the items and the probability of correctly identifying an isolated item raised to the power of N. This relationship suggests that unaccounted for reductions in identification performance can severely affect estimates of memory.
133(2013); http://dx.doi.org/10.1121/1.4795219View Description Hide Description
In November 2012, an experiment demonstrating biological mimicry method for covert underwater acoustic communication (UAC) was conducted at Lianhua Lake in Heilongjiang China. Dolphin whistles were used for synchronization while dolphin clicks were used as information carrier. The time interval between dolphin clicks conveys the information bits. Channel estimates were obtained with matching pursuit (MP) algorithm, which is useful for sparse channel estimation. Adaptive RAKE Equalization was employed at the receiver. Bit error rates were less than 10−4 with 37 bits per second data rate in the lake trial.
133(2013); http://dx.doi.org/10.1121/1.4794350View Description Hide Description
Support vector machines (SVMs) have been proved to be an effective approach to speaker verification. An appropriate selection of the kernel function is a key issue in SVM-based classification. In this letter, a new SVM-based speaker verification method utilizing weighted kernels in the Gaussian mixture model supervector space is proposed. The weighted kernels are derived by using the discriminative training approach, which minimizes speaker verification errors. Experiments performed on the NIST 2008 speaker recognition evaluation task showed that the proposed approach provides substantially improved performance over the baseline kernel-based method.
133(2013); http://dx.doi.org/10.1121/1.4795217View Description Hide Description
Data are presented on the relation between loudness measured in categorical units (CUs) using a standardized loudness scaling method (ISO 16832, 2006) and loudness expressed as the classical standardized measures phon and sone. Based on loudness scaling of narrowband noise signals by 31 normal-hearing subjects, sound pressure levels eliciting the same categorical loudness were derived for various center frequencies. The results were comparable to the standardized equal-loudness level contours. A comparison between the loudness function in CUs at 1000 Hz and the standardized loudness function in sones indicates a cubic relation between the two loudness measures.
133(2013); http://dx.doi.org/10.1121/1.4795241View Description Hide Description
Deep vertical line arrays can exploit the reliable acoustic path (RAP), which provides low transmission loss (TL) for targets at moderate ranges, and increased TL for distant interferers. However, nearby surface interference also has favorable RAP propagation and cannot be separated from a submerged target without horizontal aperture. In this work, a physics-based Fourier transform variant is introduced, which achieves depth-based signal separation by exploiting the spatial structure resulting from the coherent addition of the direct and surface-reflected propagation paths present for submerged sources. Simulation results demonstrate depth-based signal separation without requiring knowledge of the ocean environment.
133(2013); http://dx.doi.org/10.1121/1.4795220View Description Hide Description
Personal watercraft (water scooters, jet skis) were recorded under water in Bramble Bay, Queensland, Australia. Underwater noise emissions consisted of broadband energy between 100 Hz and 10 kHz due to the vibrating bubble cloud generated by the jet stream, overlain with frequency-modulated tonals corresponding to impeller blade rates and harmonics. Broadband monopole source levels were 149, 137, and 122 dB re 1 μPa @ 1 m (5th, 50th, and 95th percentiles). Even though these are lower than those of small propeller-driven boats, it is not necessarily the broadband source level that correlates with the bioacoustic impact on marine fauna.
133(2013); http://dx.doi.org/10.1121/1.4795290View Description Hide Description
The purpose of this study was to quantify the change in distortion product otoacoustic emission (DPOAE) level upon ear canal pressurization. DPOAEs were measured on 12 normal-hearing human subjects for ear canal static pressures between −200 and +200 daPa in (50 ± 5) daPa steps. A clear dependence of DPOAE levels on the pressure was observed, with levels being highest at the maximum compliance of the middle ear, and decreasing on average by 2.3 dB per 50 daPa for lower and higher pressures. Ear canal pressurization can serve as a tool for improving the detectability of DPOAEs in the case of middle-ear dysfunction.
- LETTERS TO THE EDITOR
133(2013); http://dx.doi.org/10.1121/1.4792217View Description Hide Description
Auditory and visual digit span tests were administered to a group of absolute pitch (AP) possessors, and a group of AP nonpossessors matched for age, and for age of onset and duration of musical training. All subjects were speakers of English. The AP possessors substantially and significantly outperformed the nonpossessors on the auditory test, while the two groups did not differ significantly on the visual test. It is conjectured that a large auditory memory span, including memory for speech sounds, facilitates the development of associations between pitches and their verbal labels early in life, so promoting the acquisition of AP.
133(2013); http://dx.doi.org/10.1121/1.4794392View Description Hide Description
Voice quality features such as harmonic structure and spectral tilt are investigated in classifying vocalic segments into one of five boundary tones in the tones and break indices system. Static and nonstatic features are examined, and performance is compared with features related to duration, pitch, and amplitude, along with adjacent segment characteristics. From statistical tests, voice quality features are found to be significant for classifying prosodic boundary tones, and especially for distinguishing low-tone boundaries. Classification results using features selected from Kruskal–Wallis tests, Akaike information criterion values, and from sequential forward search show that using voice quality features leads to lower balanced error rates.