| 摘要 |
An expandable multi-dimensional sound system has two modes of operation. Prior to the detection of a 20 kHz tone, the system is configured such that input audio panned hard to the left or right will result in the center and surround channels steering down so that the signal is only passed through the left front and right front channels, respectively. Mono information is fed only through the center channel, as the left and right front channels cancel any center channel or mono information. Material panned hard to the surround position steers down the front left and right channels and is only fed to the rear surround channels. No information is fed to the front center channel due to the fact that the signal contains only difference information. Directional steering to the rear channels is still provided in the absence of any hard broadband left or right panning. Upon the detection of a 20 kHz tone, the system is re-configured such that the left and right front channels and the center channel become disabled. The overhead channel becomes enabled, and the surround channels are not attenuated under hard broadband left or right panning conditions. Center information is fed through the overhead channel, while hard left information appears at the left rear channel and hard right information appears at the right rear channel. Upon the detection of a second 20 kHz tone, the system reverts back to its original operating configuration.
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