Surround circuit and acoustic system using the surround circuit

摘要

PROBLEM TO BE SOLVED: To listen to matrix surround even with a digital amplifier without limiting the output. SOLUTION: A first speaker 21 and a second speaker 22 connected to output terminals 13 and 14 of a first digital amplifier 10 to which audio signals L and R of left and right channels are input from input terminals 11 and 12, and input terminals. The first surround speaker 41 and the second surround speaker 42, which are connected to the output terminals 33 and 34 of the second digital amplifier 30 to which the left and right channel audio signals L and R are input, respectively, and the second digital amplifier 30. Between the input terminals 31 and 32 and the left and right channel audio signals L and R, a difference signal extraction circuit 100 is provided which does not require an external power supply and generates a left and right channel difference signal S. The difference signal extraction circuit 100 is provided. Is composed of one isolation transformer 110 and two resistors 60 and 70. [Selection diagram]