A five-channel microphone system for detecting 3-D acoustic image sources
Chulmin Choi, Lai-Hoon Kim, Se-Jin Doo, Yang-Ki Oh, Dae-Up Jeong, Koeng-Mo Sung · The Journal of the Acoustical Society of America · 2001
Measuring three-dimensional behavior of early reflections in a sound field has been an important issue in auditorium acoustics, since they are found to be strongly correlated with the subjective experience of spatial impression in rooms. A conventional way of detecting the direction and relative amplitude of reflections is to utilize a four-channel microphone system. This system, however, has the inherent possibility of missing some important reflections while exploring the early part of reflections. A new measurement system, which has five microphones on the apex of a tetrahedron and at the center of gravity, is proposed in the present work. The proposed system enables us to find more early reflections accurately, which previous four-channel microphone systems might miss. A peak detecting pair matching algorithm, which gives dominant peaks of impulse response automatically by typical iteration, was adopted, since we should find exact peak positions of measured impulse response in order to calculate source positions accurately. In the present paper, the theoretical backgrounds and features of the five-channel microphone system are presented. Also, some results from experiments using the system are discussed. Experimental results clearly show the advantage of the five-channel microphone system over the conventional four-channel microphone system. [Work supported by Korean Research Foundation Grant KRF-1999-1-310-004-3.]