Design of inverse filters for multi-channel directivity reproduction of a sound source -Application to telecommunication system using sound casks

We developed a 96-ch immersive sound reproduction system based on the boundary surface control and are working on implementing it into an acoustical-space-sharing telecommunication system. In this paper, we propose a sound directivity reproduction method for a telecommunication system based on the boundary surface control. We estimate the radiation from a sound source by solving an inverse problem between the microphone array and the secondary sources. Then, the estimated radiation is reproduced by the secondary sources at the location of a virtual speaker or musical player in the shared acoustical space. Because the sound field of the virtual listener's position can be reproduced on the basis of boundary surface control, a distant listener can listen the speaker's sound involving changes which occurs as the result of the speaker's body movements as if they were in the same room or hall. We verify the effectiveness of this method by evaluating the directivity of the secondary sound sources in a free-field simulation and an experiment in an anechoic chamber.