| 摘要 |
PURPOSE:To reproduce a rich and low temperature area with a simple circuit by including a means enlarging the gain of an amplifying circuit as the interrupting frequency of a low pass filter is lowered while constantly maintaining an output sound pressure level in the cross over frequency of the output sound pressure level of the speakers of right and left channels and the output sound pressure level of a woofer. CONSTITUTION:An acoustic signal from the acoustic signal sources 4, 6 of both right and left channels is added in an adder 8 and applied to the amplifying circuit 9. A gain changing means 10 is disposed in connection with this amplifying circuit 9. The acoustic signal amplified in the amplifying circuit 9 is filtered in the low pass filter 11, amplified in an amplifying circuit 12 and made the acoustic by the woofer 3. In relation to the low pass filter 11, an interrupting frequency changing means 13 is disposed. The gain changing means 10 and the interrupting frequency changing means 13 are interlockingly constituted, and accordingly, the gain of the amplifying circuit 9 is changed, thereby the interrupting frequency of the low pass filter 11 is changed. |
