Sound field reproduction system using narrow directivity microphones and boundary surface control principle

Acoustical science and technology

Akira Omoto¹  Hiroshi Kashiwazaki² 

[1] Faculty of Design, Kyushu University;Graduate School of Design, Kyushu University

关键词: Sound field reproduction;    Boundary surface control principle;    Inverse filter matrix;    Narrow directivity microphone;    Digital audio workstation;   

DOI  :  10.1250/ast.39.295

学科分类：声学和超声波

来源: Acoustical Society of Japan

【 摘 要 】

Boundary surface control (BoSC) is a useful method of reproducing the sound field physically. However, it is challenging in the case of real-time operation. This is mainly due to the calculation cost of a lot of inverse filter convolutions to obtain reproduction signals. This paper proposes a method for reducing of number of inverse filters and implements it in 24-channel narrow directivity (shotgun) microphone array and 24-channel circularly arranged loudspeaker array. Moreover, it provides an experimental evaluation of the reproduction accuracy according to measurement of reproduced wavefront. The accuracy of the reproduced wavefront by the filters, whose number was reduced to less than 1/5 by proposed method, was comparable with the case of full number of filters. Finally, a system aiming at sound field reproduction in a wide frequency range was constructed by a hybrid method of reproducing with an inverse filter in the low range and directly outputting from the speaker in the direction corresponding to the microphone in the high frequency range. We confirmed that real-time processing is possible for this hybrid method by using a convolution plug-in of digital audio workstation software.

【 授权许可】

Unknown