An iterative microphone removal method for acoustic beamforming array design

Arcondoulis, E. and Liu, Y. (2019) An iterative microphone removal method for acoustic beamforming array design. Journal of Sound and Vibration, 442, 552-571. (doi:10.1016/j.jsv.2018.11.005).

Abstract

This paper presents a beamforming array design method that uses a large array of microphones and systematically reduces it to a predetermined number of microphones. The microphone, while included in the array, that results in the smallest (defined as Φ in this paper) product of frequency-averaged Main Lobe Width (MLW) and Maximum Sidelobe Level (MSL) of the point spread function using the cross-spectral beamforming algorithm is identified and removed. The reduction method is implemented in two ways: one-by-one microphone removal and an accelerated procedure that removes several microphones per iteration, where the removed number of microphones decreases in an exponential manner with increasing iterations. Multi-frequency array reductions, using 841 and 961-channel equi-and-non-equispaced grid initial arrays, are conducted over the frequency range of 2000 Hz–8000 Hz to replicate typical conditions in a small scale anechoic facility. These reduced arrays are compared against several logarithmic spiral and randomised pattern arrays and in most cases, reveal superior values of MSL, MLW and Φ. Single-frequency array reductions, using both 961 and 169-channel initial arrays, at the best-case frequencies for the logarithmic spirals, also display superior performance. Both the multi-and-single-frequency arrays can be used practically: the multi-frequency arrays possess an even performance across the simulated frequency range, whereas the single-frequency arrays possess excellent performance over narrowband frequency ranges and can be modified within an array stencil for each acoustic experiment.

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Contributors

Author: E. Arcondoulis

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