Volume 119, Issue 6, June 2006
- jasa express letters
- acoustical news—usa
- acoustical news—international
- book reviews
- reviews of acoustical patents
- letters to the editor
- general linear acoustics 
- nonlinear acoustics 
- aeroacoustics, atmospheric sound 
- underwater sound 
- ultrasonics, quantum acoustics, and physical effects of sound 
- structural acoustics and vibration 
- noise: its effects and control 
- applied acoustics paper: acoustical measurements and instrumentation 
- acoustical measurements and instrumentation 
- acoustic signal processing 
- physiological acoustics 
- psychological acoustics 
- speech production 
- speech perception 
- bioacoustics 
Index of content:
- JASA EXPRESS LETTERS
119(2006); http://dx.doi.org/10.1121/1.2198947View Description Hide Description
High-frequency functors are arguably among the earliest perceived word forms and may assist extraction of initial vocabulary items. Canadian 11- and -olds were familiarized to pseudo-nouns following either a high-frequency functor the or a low-frequency functor her versus phonetically similar mispronunciations of each, kuh and ler, and then tested for recognition of the pseudo-nouns. A preceding the (but not kuh, her, ler) facilitated extraction of the pseudo-nouns for -olds; the is thus well-specified in form for these infants. However, both the and kuh (but not her-ler) facilitated segmentation for -olds, suggesting an initial underspecified representation of high-frequency functors.
119(2006); http://dx.doi.org/10.1121/1.2198567View Description Hide Description
Motivated by the active process of the outer hair cell (OHC) in the mammalian inner ear, a real time decomposition of speech into modulated components is presented. A generalized phase lock loop (GPLL) was applied to decompose the speech signal into its envelope and positive instantaneous frequency (PIF) parts, which can be further processed and represented by timing information alone. A log-derivative operator is applied to the bandpass signal. Analytic and antianalytic components occupying non overlapping frequency bands are separated by filtering. The proposed algorithms are used to represent speech signals processed through a bandpass filter bank.
- BOOK REVIEWS
- REVIEWS OF ACOUSTICAL PATENTS
119(2006); http://dx.doi.org/10.1121/1.4798251View Description Hide Description
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. Printed copies of United States Patents may be ordered at $3.00 each from the Commissioner of Patents and Trademarks, Washington, DC 20231. Patents are available via the Internet at http://www.uspto.gov.
- LETTERS TO THE EDITOR
Comments on “Intraspecific and geographic variation of West Indian manatee (Trichechus manatus spp.) vocalizations” [J. Acoust. Soc. Am.114, 66–69 (2003)]119(2006); http://dx.doi.org/10.1121/1.2195047View Description Hide Description
This letter concerns the paper “Intraspecific and geographic variation of West Indian manatee (Trichechus manatus spp.) vocalizations” [Nowacek et al., J. Acoust. Soc. Am.114, 66–69 (2003)]. The purpose here is to correct the fundamental frequency range and information on intraindividual variation in the vocalizations of Amazonian manatees reported by Nowacek et al. (2003) in citing the paper “Signature information and individual recognition in the isolation calls of Amazonian manatees,Trichechus inunguis (Mammalia: Sirenia)” [Sousa-Lima et al., Anim. Behav.63, 301–310 (2002)].
Comparison of Levitt- and Zwislocki-type adaptive procedures for stimulus placement in human listenersa)119(2006); http://dx.doi.org/10.1121/1.2195088View Description Hide Description
The “3-down, 1-up” adaptive stimulus placement rules attributed to Levitt and Zwislocki were compared in the context of human interaural time difference discrimination, employing otherwise commonly used procedures (e.g., averaging reversals to estimate threshold). The Zwislocki rule typically accumulated over three more reversals than the Levitt rule but the rules were approximately equally efficient. This may be because the additional reversals did not provide additional information or that any additional information was countered by other factors, such as the lower theoretical asymptotic response probability (0.75 vs 0.794). Relative bias between rules was also explored with the aid of a simulation.
119(2006); http://dx.doi.org/10.1121/1.2200696View Description Hide Description
The present study shows that on average, exposure to a , tone modulated sinusoidally in amplitude at with a 100% depth does not affect significantly amplitude modulation (AM) detection thresholds measured between 4 and when listeners are extensively trained to the AM detection task, with and without adaptor before data collection. These results are compatible with previous work given that a clear adaptation effect was observed during the first pilot trials. However, the results reveal that adaptation effects are not robust, and suggest that the mechanisms underlying adaptation to AM must be reevaluated.
119(2006); http://dx.doi.org/10.1121/1.2200047View Description Hide Description
Quadratic residue diffuser (QRD) groups are used to form a large diffusionsurface and extra sound absorption is introduced. In this paper we discuss how the installation pattern of QRD groups affects the sound absorption. The absorption coefficients of QRD in groups with different shapes and combinations were measured in a reverberation room. Notable variations in absorption were observed when the shapes of QRD groups change, especially at the low frequency range below the design frequency of QRD. Two peaks of absorption are observed. When a certain shape is chosen, the detailed combinations of QRDs cause little change in absorption.
119(2006); http://dx.doi.org/10.1121/1.2200049View Description Hide Description
Waveforms obtained by correlation of diffuse fields are now widely used to estimate times of flight and ballistic Green's functions. Theory, however, predicts that such passively obtained waveforms should equal the full Green function of a medium, and thereby convey information on the details of a structure and the presence of isolated scatterers. Here we investigate diffuse field correlations in a reverberant elastic body and demonstrate that their shear and Rayleigh waves allow us to image internal and surface features. Resolution in the resulting images is comparable to standard medical and seismic images.
- GENERAL LINEAR ACOUSTICS 
Expressions for direct evaluation of wave number in cylindrical shell vibration studies using the Flügge equations of motion119(2006); http://dx.doi.org/10.1121/1.2193814View Description Hide Description
Algebraic expressions for direct evaluation of structural wave number in cylindrical shells are presented for vibration described by the Flügge equations of motion. Applications of the expressions presented here include the evaluation of nondimensional correlation ratios for the estimation of dynamic stress from vibration velocity, and the development of more accurate transmission loss calculations.
119(2006); http://dx.doi.org/10.1121/1.2190165View Description Hide Description
Thin rubber layers with air-filled cavities can be used as anechoic submarine coatings. Normally incident sonar energy is redistributed in the lateral direction and absorbed. In this paper, the anechoic effect is studied theoretically and numerically by adapting techniques used in electron scattering and band-gap computations for photonic and phononic crystals. Reflection and transmission matrices are computed recursively, from basic ones for layers containing periodic arrays of spherical cavities. A method to locate zeroes of analytical functions is applied to prove the existence of, and to specify, thin coatings with vanishing reflectance at isolated frequencies. Coatings much thinner than quarter-wavelength ones are found. Most of the absorption loss takes place close to the cavities and scattering of compressional spherically symmetric waves is important. The viscoelastic shear-wave properties of the rubber are crucial for generating this loss. The requirements for vanishing reflectance are specified using a simplified model with normal plane waves and spherically symmetric waves, that includes effects of multiple scattering among the cavities. An energy relation is derived, relating the anelastic loss in the rubber coating to loss by monopole resonance scattering from isolated cavities. The noticeable effects of multiple scattering are incorporated by a modulating factor.
Approximations for the scattered field potential from higher mode transmission in rectangular apertures119(2006); http://dx.doi.org/10.1121/1.2197792View Description Hide Description
This paper considers the wave fields that result when a plane wave impinges at an arbitrary angle on a rectangular aperture in a rigid, thick wall. A nondimensional form of a prior Fourier transformsolution of this problem is derived, from which it is more easy to appreciate the relationship between the physical attributes of the aperture and incoming wave and the resultant acoustic fields. The scattered field from the aperture is examined in detail, in particular the modal contributions to the driving function for the amplitude of the velocity potential. Although the full scattered field contains both modal sum and modal coupling effects, it is shown that neglect of the modal coupling effects introduces minimal error to the solution in certain situations. An approximate analytical solution to the uncoupled analysis is then developed, which is accurate provided that the aperture is acoustically large, such that there are several cut-on modes within the aperture. The full nature of the scattered field can be easily interpreted from the nondimensional, analytical solution. In particular, an error analysis is given from which one can determine the required number of modes in a solution for given accuracy.
119(2006); http://dx.doi.org/10.1121/1.2200149View Description Hide Description
A novel approach is presented for the probabilistic characterization of the solution in inverse acoustic scattering problems. The approach consists of representing the unknown parameters of the scatterer as stochastic processes with spatially random fluctuations. The stochastic processes are represented by their polynomialchaos decomposition. The deterministic coefficients in this parametrization are then computed by solving a deterministic optimization algorithm with an appropriate objective function that captures the probabilistic significance of these coefficients. The general procedure is demonstrated by its application to a two-dimensional problem with the hidden object, a hard obstacle, being immersed in a heterogeneous medium. The formulation provides, as well, a measure of validity of a particular predictive model at matching experimental evidence.
Natural resonance frequencies, wave blocking, and energy localization in an elastic half-space and waveguide with a crack119(2006); http://dx.doi.org/10.1121/1.2195269View Description Hide Description
Sharp stopping of time-harmonic wave transmission in elastic structures with defects is considered as a manifestation of the well-known trapped mode effect. It is associated with natural resonance poles lying close to the real axis in the complex frequency plane. Nonresonant wave blocking may also occur due to antiphase combination of the incident and scattered waves. The present paper is aimed to give an insight into such phenomena using an analytically based computer model which strictly takes into account all wave interactions in a cracked structure. Numerical examples are restricted to the case of a line horizontal crack in a half-plane or in a layer (2D in-plane motion), that is, nevertheless, quite enough to demonstrate two kinds of the Rayleigh wave stopping mechanisms (resonant and nonresonant) as well as a possibility of pure real natural resonance frequencies and of a full blocking effect with energy localization.
Analysis and design of composite/folded variable area perforated tube resonators for low frequency attenuationa)119(2006); http://dx.doi.org/10.1121/1.2197791View Description Hide Description
Variable area concentric-tube-resonator mufflers may be used effectively for attenuating the odd harmonics. This ensures a broad-band transmission loss (TL) spectrum. In this paper, configurations that consist of variable area resonators within a uniform area muffler shell for enhancing the low-frequency noiseattenuation are investigated. The variable area resonator elements within a muffler allow multiple elements, where the sum of their acoustic lengths is more than the geometric length of the muffler. This shifts the overall TL spectrum toward lower frequency. The underlying idea of incorporating the extended inlets and outlets in these resonators, is to reproduce the broadband attenuation. It has the effectiveness of dissipative ducts without the use of any absorptive materials. The results have been validated by means of three-dimensional finite element analysis.
- NONLINEAR ACOUSTICS 
119(2006); http://dx.doi.org/10.1121/1.2197804View Description Hide Description
Nonlinear acousticproperties of a composite medium, consisting of hollow microspheres suspended in Castor Oil, at elevated hydrostaticpressure are experimentally investigated. The acoustic nonlinear parameter of the medium is found to be highly dependent upon hydrostaticpressure. varies from a small negative value near ambient pressure to a very large negative value (around ) in the vicinity of Pascals, above ambient pressure. With a further increase in hydrostaticpressure the magnitude of decreases passing through zero and finally becomes positive. Finite amplitude wave propagation in this medium at low hydrostaticpressures is characterized by waveform steepening in the backward direction leading to rarefactive shockwaves and, at high hydrostaticpressures, by steepening in the forward direction leading to compressive shockwaves. Estimates of are obtained from both the measurement of thermodynamic properties and from waveform distortion during propagation.