Time reversal microphone array systems for targeting sound sources in complex sound fields

A microphone array system based on the time reversal technique for targeting sound sources in complex sound fields is investigated in this paper. The feasibility and mechanism of the microphone array system are studied and the performance and basic rules are given. It is found that in free sound field, its performance is relevant to frequency, the shape and radius of the array. The higher frequency and the larger radius of the array, the better the array performance will be. In a common room, the array gain of a circle array at a predefined focus point can be more than 5dB larger than that at other places about 25cm far from the predefined focus point in the speech frequency range. The experiment in a common room and a reverberant room verified the above conclusions.