| 摘要 |
PURPOSE:To provide an acoustic zoom effect by arranging four omnidirectional microphones at the right apex of a cube and respectively performing electric signal processing while setting M microphones at both the terminals of one diagonal and setting S microphones at both the terminals of the other diagonal. CONSTITUTION:Microphone units 9, 10, 11 and 12 are entirely omnidirectional and arranged at the respective apexes of the cube in any suitable size. The output of the unit 10 is inputted to a delay unit 13. When a distance between the units 9 and 10 is defined as (d) and acoustic velocity is defined as (c), delay time tau of the delay unit 13 is applied by tau=d/c. The output of the delay unit 13 is subtracted from the output of the unit 9 by an adder 14. The output of the added 14 is corresponding to the output of the unidirectional M microphone. An adder 15 outputs the output of the unit 11 and the differential signal of the unit 12, and the signal is corresponding to the output of the bidirectional S microphone and amplified by an amplifier 16. Adders 17 and 18 output the sum signal and differential signal of the amplifier 16 and the adder 14. Thus, satisfactory characteristics are provided as an MS system stereo microphone. |
