Visualizing the performance of large-aperture microphone arrays

The use of arrays of microphones having a large number of elements (hundreds) is now in place in research laboratories, and will soon be practical for real applications. In rooms of auditorium or conference size, a large number of microphones will virtually always imply that the aperture will be large compared to the focal distance. This requires understanding the volume selectivity of irregular, widely-distributed sets of microphones. In this paper, several pictures of the beamforming performance of large-aperture distributions of microphones are presented. The purpose is to illustrate some of the pitfalls in large-aperture microphone-array design