Optimum near-field response for microphone arrays

Abstract

This paper describes the effects of optimizing the weights of an arbitrary microphone array for near-field target locations. Optimum near-field weights are shown to provide increased gain for near-field sources when compared to a uniformly weighted delay-and-sum beamformer. Practical improvements in array gain due to constrained optimization are shown to be greatest at locations close to the array and for microphone spacing which is small in relation to the operating wavelength.