Theoretical comparisons of dual microphone systems

We compare and evaluate the various noise cancellation schemes available in what we term ´dual microphone systems´ (DMS). A DMS is a directional audio-capturing device consisting of two microphones with possibly different directional characteristics: omnidirectional; bidirectional; cardioid. A general structure is proposed to represent coherently the different schemes for the DMS. This is followed by a theoretical derivation of the performance of various DMS configurations under incoherent, coherent and diffuse noise fields. The relationships between the different configurations and some guidelines for designing DMS are also presented.