抄録
In this paper, we deal with a newly developed spherical array microphone system in which approximately equal directional characteristics for octave band frequency ranges from 250 Hz to 2000 Hz can be realized in every direction and a response in arbitrary direction in the whole space can be computed out by one measurement by placing microphones on concentric spherical surfaces at random whose radii are in geometric progression. In this system : (1) Since average response method is exercised in consideration of time lag for the incidence of sound wave in arbitrary direction, the holding of directivity and improvemet of S/N ratio can be expected at the same time from the time average and space average. (2) Since sounds are kept successively at their measuring time at each sound receiving point as completely synchronized impulse response, if once measured, an impulse response in arbitrary direction in the whole space can be composed by post-treatment. (3) Since microphones are placed on spherical surfaces by regarding the whole space as equal value, more equalized space information for the whole space can be obtained.
