Acoustically Coupled Microphone Arrays

An analysis is presented of the performance benefits that can be achieved by introducing acoustic coupling between the diaphragms in an array of miniature microphones. The introduction of this coupling is analogous to the principles employed in the ears of small animals that are able to localize sound sources. Measured results are shown, which indicate a dramatic improvement in acoustic sensitivity, and noise performance can be achieved by packaging a pair of small microphones so that their diaphragms share a common back volume of air. This is also shown to reduce the adverse effects on directional response of mismatches in the mechanical properties of the microphones.