The Performance of Rotating Dual-Microphone System and its Application

The rotating dual-microphone system is designed to measure the spatial acoustical parameters of sound field in the room. It is mainly composed of a repeatable inspiriting sound source associated with two microphone fixed on slowly rotating platform. In this paper, a comprehensive investigation of performance of the test system by means of computer simulation and the experiment in anechoic chamber is presented, as well as the main affecting factors are also discussed. The spatial resolution of the system varies not only with the radius of the rotating microphone, but also with the direction of arriving sound wave. The study indicates that the system is provided with enough spatial resolution and can be applied to the room acoustic measurement conveniently. When the radius of the rotating microphone is more than 0.2m the measured beam width is less than 10 degrees. By using this system the directional impulse response of room can be analyzed in detail, and various objective spatial parameters of sound field can be obtained. Some practical applications in the auditorium are also described in this paper.