Beamforming with small diameter microphone array

This article deals with beamforming in conjunction with 34mm diameter 7-element circular microphone array using MEMS microphones. The main possibilities provided by beamforming are reviewed with emphasis on speech sensing. Problems that are associated with the array's small physical size, requirements on microphones themselves and data acquisition are discussed. A general delay-and-sum and a chosen filter-and-sum beamformer are described. Performance of beamformers combined with purpose built microphone array is evaluated by means of measurements.