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For the HI listeners, inter-listener variability in most estimated SII parameters was larger than intra-listener variability of the qBIF procedure.To examine difficulties experienced by cochlear implant (CI) users when perceiving non-native speech, intelligibility of non-native speech was compared in conditions with single and multiple alternating talkers. Compared to listeners with normal hearing, no rapid talker-dependent adaptation was observed and performance was approximately 40% lower for CI users following increased exposure in both talker conditions. Results suggest that lower performance for CI users may stem from combined effects of limited spectral resolution, which diminishes perceptible differences across accents, and limited access to talker-specific acoustic features of speech, which reduces the ability to adapt to non-native speech in a talker-dependent manner.The exact expression for the difference between the acoustic field in an attenuating Pekeris waveguide and the corresponding truncated waveguide is presented. The derivation replaces an earlier version [Evans, J. Acoust. Soc. Am. 74, 193-194 (1983)] that yielded only an approximate estimate of the same difference. The theoretical simplification resulting from the finite truncation is stressed, in contrast to the infinite half-space.The first-order steerable differential arrays (FOSDAs), which have found a variety of applications in speech and audio processing, are usually designed by construction of two orthogonal dipoles using four microphones. Actually, however, three microphones are enough to construct a FOSDA by forming two dipoles with a shared microphone, which is the scheme with the minimum number of microphones and, hence, the most cost-effective. This paper studies the design and analysis of such three-element FOSDAs by using a least-squares method. In particular, the effect of the array configuration on the three-element FOSDA is studied, and optimum array configurations under different steering angle ranges are derived in terms of both beampattern fitting quality and white noise gain. It also reveals that care should be taken to avoid a conservative setting of the steering angle range in order to achieve superior design of the three-element FOSDA.When investigating the wave propagation and mode conversions in a thin aluminum plate partially immersed in water, a kind of wave packet interaction was observed. It was found that the transmitted ultrasonic signal consists of different wave packets, which contain essential information of different wave types. When the incident angle is very small, the signals can be identified as the major wave packet followed by its tail. The major packet includes the information of the incident wave while the tail is related to the mode conversion and propagation in the plate. When the incident angle increased, the major packet was literally engulfed by its tail, indicating that the directly transmitted incident ultrasound disappeared and more energy was coupled into the plate. The interactions between different wave packets found here reveal the excitation and propagation mechanisms of Lamb waves in plates, which would benefit applications in ultrasonic imaging, signal recognition, underwater acoustic communication, and so on.A method for estimating acoustic absorption in porous materials is presented in which the thermal and viscous boundary layers are modeled through boundary conditions to the Helmholtz equation for the acoustic pressure. The method is proposed for rigid-framed porous materials in which vibration of the frame is negligible compared to pressure fluctuations in air. Pepstatin A in vivo The method reduces computation times by 2 orders of magnitude compared to a full thermoviscous acoustic solver. Furthermore, the method is shown to be highly accurate over geometrical features and frequencies of interest as long as thermal and viscous boundary layers do not overlap and the effects of the sharp changes in curvature are negligible. The method is demonstrated for a periodic sound absorber from the literature as well as a sound absorber with a randomly graded microstructure.This study compares prosodic structural effects on nasal (N) duration and coarticulatory vowel (V) nasalization in NV (Nasal-Vowel) and CVN (Consonant-Vowel-Nasal) sequences in Mandarin Chinese with those found in English and Korean. Focus-induced prominence effects show cross-linguistically applicable coarticulatory resistance that enhances the vowel’s phonological features. Boundary effects on the initial NV reduced N’s nasality without having a robust effect on V-nasalization, whose direction is comparable to that in English and Korean. Boundary effects on the final CVN showed language specificity of V-nasalization, which could be partly attributable to the ongoing sound change of coda nasal lenition in Mandarin.Zero index metamaterials have shown the ability to achieve total transmission or reflection by embedding particular defects with various effective parameters. Here, we present that tunable sound transmission can be realized by configuring a subwavelength-sized dopant inside zero index acoustic metamaterials. Despite its small spatial signature, the dopant is able to strongly interact with the acoustic waves inside the whole zero index metamaterials. It is due to the essence of the zero effective index that can homogenize the pressure field within the metamaterials. Sound transmission can thus be fully switched on and off by adjusting the dopant’s surface impedance. A simple rectangular cavity with varied lengths is proposed to provide the required impedance boundary. Our model of correlating the dopant design with sound transmission performance is validated theoretically and numerically. We further demonstrate the utilization of the proposed design to effectively modulate the sound focusing effect. Such a dopant-modulated sound transmission scheme, with its simplicity and capability, has potential applications in fields like noise control and ultrasonography.A class of active nonreciprocal metamaterials is developed to control the flow and distribution of energy along periodic dynamical systems. Such a development constitutes a radical departure from the currently available approaches where the non-reciprocities are generated either by utilizing various physical sources of passive nonlinearities, gyroscopic circulators, spatiotemporal modulation, or active control of nonlinear systems. The proposed active Nonreciprocal Gyroscopic Meta-Material (NGMM) cell consists of a one-dimensional acoustic duct provided with linear dynamic control capabilities that virtually synthesize a gyroscopic control action that generates non-reciprocal characteristics of tunable magnitude and direction. The controller is designed in order to enable the spatial control and redistribution of the wave propagation energy flow along the acoustic duct. During this entire process, the system behaves in a linear fashion. Numerical examples are presented to demonstrate the basic features, non-reciprocal behavior, as well as the energy flow characteristics.