| 摘要 |
PROBLEM TO BE SOLVED: To provide an acoustic processing circuit that makes provision for the discrete digital multi-channel system without deteriorating sound quality and causes no noise sound against a sudden change in an input amplitude. SOLUTION: In this circuit, coefficient multipliers 2L-2RS multiply a coefficient (a) by digital audio signals of Lch-RSch and a coefficient multiplier 4 multiplies a coefficient (b) by a digital audio signal of an LFEch to reduce the amplitude. A synthesized audio signal added by an adder 3 is inputted to a limiting circuit 6, where the amplitude exceeding a prescribed threshold (c) is limited to the threshold (c), and a coefficient multiplier 11 multiplies a coefficient (d) by the signal to restore the amplitude into the original one. A low pass filter 12 extracts only the low frequency component, which is used as an output of a woofer channel SWch. The input to the low pass filter 12 has the original amplitude and then no frequency characteristic deterioration is caused due to insufficient amplitude and noise sound due to a sudden amplitude change of the input of the limiting circuit 6 is eliminated as a high frequency component. |
