| 摘要 |
PURPOSE:To obtain a stereo wide effect or the zoom effect by providing two nondirectional microphone units in addition to two unidirectional microphone units arranged to the left and right and adding or subtracting a difference signal output between the two nondirectional microphone units to/from the output of the unidirectional microphone units. CONSTITUTION:A differential amplifier 18 extracts the output of a left channel nondirectional microphone 15 and the output of a right channel nondirectional microphone 16. A mixer circuit 21 uses a switch 31a to select the output of an amplifier 17 of a left channel unidirectional microphone 13 and the output of the differential amplifier 18 or the output of an inverting amplifier 20 and mixes them. A mixer circuit 22 uses a switch 31b to select the output of an amplifier 19 of a right channel unidirectional microphone 14 and the output of the differential amplifier 18 or the output of the inverting amplifier 20 and mixes them. In the case of the wide position, the stereo wide effect is obtained by adding sounds in the right (H) direction and the left (J) direction only, and in the case of the tele-position, the directivity is electrically controlled by subtracting the sounds above. |
