| 摘要 |
In a surround sound reproduction system the required number of power amplifiers is reduced by effecting at least part of the decoding operation by the manner in which the various loudspeakers are connected to the outputs of the power amplifiers while preserving linear independence of the signals fed to every set of three loudspeakers. In one embodiment, the loudspeakers are grouped in pairs such that the sum of signals fed to the loudspeakers of each pair is the same for all of the pairs, a first amplifier is arranged to receive said signal and a respective second amplifier for each pair of loudspeakers is arranged to receive the signal to be fed to one of the loudspeakers of such pair, the second loudspeaker of each pair being connected between the output of the corresponding second amplifier and the output of the first amplifier. In another embodiment, the number of loudspeakers is one greater than the number of power amplifiers, one loudspeaker is connected between earth and a common terminal and the other loudspeakers are connected between the common terminal and the output of a respective amplifier.
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