| 摘要 |
PURPOSE:To reproduce sounds faithful to their original sounds even if the sound source distance is changed by disposing two directional microphone units on the same straight line and correcting an amplitude degree of an amplifier of the microphone closer to the sound source from the difference of frequency characteristics of the microphone unit further from the sound source. CONSTITUTION:Outputs of the 1st and 2nd microphone units 1 and 2 are inputted to a differential amplifier 3 and their outputs are obtained through a low-pass filter 4. Its output can be obtained as a level difference between both microphones 1 and 2 in a low frequency, and the result shows that the larger the output, the closer the microphones to the sound source. The output of the low-pass filter 4 is amplified by an amplifier 5, and gains of a variable gain amplifier 7 are controlled. On the other hand, the output of the 1st microphone unit 1 is amplified by a pre-amplifier 6, and its gains are controlled by the variable amplifier 7, thereby obtaining said output from an output terminal 8. |
