The design and construction of a circular microphone array (CMA) that has a wide frequency range suitable for human hearing is presented. The design of the CMA was achieved using a technique based on simulated directivity index (DI) curves. The simulated DI curves encapsulate the critical microphone array performance limitations: spatial aliasing, measurement noise, and microphone placement errors. This paper demonstrates how the non-regularized DI curves for a given beamforming order clearly define the bandwidth of operation, in other words, the frequency band for which the beamformer has relatively constant and maximum directivity. Detailed and comprehensive experimental data that characterizes the CMA beamformer are also presented.
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http://dx.doi.org/10.1121/1.3658443 | DOI Listing |
Anal Chem
January 2025
International Joint Laboratory for Integrated Circuits Design and Application, Ministry of Education, School of Physics, Zhengzhou University, Zhengzhou 450001, China.
The photoacoustic spectroscopy (PAS) system commonly enhances the efficiency of optical-acoustic-electrical energy conversion by increasing the laser power, optimizing the resonance characteristics of the photoacoustic cell (PAC), and improving the sensitivity of acoustic sensors. However, conventional systems using a single-microphone or a dual-microphone differential setup for point sampling of the photoacoustic signal fail to account for its spatial distribution, leading to a loss of spatial gain. Drawing on microphone array theory derived from sonar technology, this study, for the first time, presents a PAS sensing system based on a four-microphone array, which is applied to detect chloroform gas.
View Article and Find Full Text PDFJ Acoust Soc Am
January 2025
Acoustic Technology, Department of Electrical & Photonics Engineering, Technical University of Denmark, Kongens Lyngby, Denmark.
Characterising acoustic fields in rooms is challenging due to the complexity of data acquisition. Sound field reconstruction methods aim at predicting the acoustic quantities at positions where no data are available, incorporating generalisable physical priors of the sound in a room. This study introduces a model that exploits the general time structure of the room impulse response, where a wave-based expansion addresses the direct sound and early reflections, localising their apparent origin, and kernel methods are applied to the late part.
View Article and Find Full Text PDFEar Hear
January 2025
Department of Otorhinolaryngology and Head and Neck Surgery, Radboud University Medical Centre, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands.
Objectives: Real-time monitoring of cochlear function to predict the loss of residual hearing after cochlear implantation is now possible. Current approaches monitor the cochlear microphonic (CM) during implantation from the electrode at the tip of the implant. A drop in CM response of >30% is associated with poorer hearing outcomes.
View Article and Find Full Text PDFSensors (Basel)
November 2024
Department of Computer and Electrical Engineering, Mid Sweden University, 851 70 Sundsvall, Sweden.
Traditional spherical sector microphone arrays using omnidirectional microphones face limitations in modal strength and spatial resolution, especially within spherical sector configurations. This study aims to enhance array performance by developing a spherical sector array employing first-order cardioid microphones. A model based on spherical sector harmonic (SSH) functions is introduced to extend the benefits of spherical harmonics to sector arrays.
View Article and Find Full Text PDFSensors (Basel)
November 2024
Key Laboratory for Key Technologies of IoT Terminals, Harbin Institute of Technology, Shenzhen 518055, China.
Multi-channel speech enhancement has become an active area of research, demonstrating excellent performance in recovering desired speech signals from noisy environments. Recent approaches have increasingly focused on leveraging spectral information from multi-channel inputs, yielding promising results. In this study, we propose a novel feature integration network that not only captures spectral information but also refines it through shifted-window-based self-attention, enhancing the quality and precision of the feature extraction.
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