Experimental study of dual microphone systems

We compare and evaluate the various noise cancellation schemes available in what we term a dual microphone system. A dual microphone system (DMS) is a composite directional audio-capturing device which consists of two microphones, each microphone having possibly different directional characteristics, e.g., omnidirectional, bidirectional or cardioid. By recasting the various combinations of two microphones for a DMS into a coherent and familiar framework of generalized sidelobe canceller (GSC), we subsequently derive the expected noise reduction of various structures under incoherent, coherent and diffuse noise fields, followed by a series of experiments in a typical office environment. These results are indicative of the achievable reduction of noise in real applications. The relationship and differences between the various methods are also discussed.