| 摘要 |
PURPOSE:To obtain a unique surround effect by using 1st and 2nd low frequency signals with a prescribed phase difference so as to amplitude-modulate input R and L channel signals and superimposing the modulated signal onto the input R-channel and L-channel signals so as to use the result to an input signal to R-channel and L-channel speakers. CONSTITUTION:R and L channel signals fed via input terminals 11, 12 are fed to variable gain amplifiers 13, 14, the gain of the variable gain amplifiers 13, 14 is controlled in response to the low frequency signal fed via the input terminal 15. The outputs of the variable gain amplifiers 13, 14 are superimposed on an adder 17 and the result is an amplitude modulation wave signal, which is one input to a subtractor 20 and an adder 21 respectively. The R and L channel signals are fed to other inputs of the subtractor 20 and the adder 21. The outputs of the subtractor 20 and the adder 21 are fed to speakers R, L, from which a reproducing sound is obtained. Thus, a unique surround effect is obtained. |
