Design of broadband beamformers robust against microphone position errors

Fixed broadband beamformers using small-sized microphone arrays are known to be highly sensitive to errors in the microphone array characteristics. This paper describes a procedure for designing broadband beamformers with an arbitrary spatial directivity pattern, which are robust against errors in the microphone positions. The presented design procedure optimises the mean performance of the broadband beamformer and hence requires knowledge of the probability density function of the microphone position errors. Simulations with a small-sized microphone array show the performance improvement that can be obtained by using a robust broadband beamformer design procedure.