Surround sound

Surround sound is the concept of expanding the spatial imaging of audio playback from 1 dimension (mono/Left-Right) to two or three dimensions.

Specifications

5.1 uses:

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• Five discrete audio channels:
• Three for speakers at the front (stereo left and right, plus centre mono)
• Two for surround speakers at the side or rear (stereo left and right)
• A sixth, low-frequency effects (LFE) channel carries supporting deep bass sound effects, ranging from 10 Hz to 120 Hz, which can for example be used by a subwoofer.

5.1 EX includes a third surround channel that can be decoded at the listener's option for playback over additional surround speakers placed behind the viewers (rear speakers). The additional center rear information is split between the left and right back surround channels.

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7.1 would use two additional speakers, although no consumer home cinema applications currently exist for it. Some computers and video game systems are capable of outputting a discrete 7.1 signal, and a number of mid-to-high end receivers support it if it is available.

Related Topics:
Consumer - Home cinema - Discrete - Receiver

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Note:

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A distinction is made between the number of discrete channels encoded in the original signal, and the number of channels that are reproduced for playback; these can be added using matrix decoding. A distinction is also made between the number of channels reproduced for playback, and the number of speakers over which these channels are played.

Related Topics:
Discrete - Matrix decoding

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A 5.1 EX signal, for example, contains 5.1 discrete channels of information. Parts of the signal are then passed through a matrix decoder to create a 6.1 channel playback signal. The 6.1 channels are then properly played over 7.1 channels (i.e. 7 speakers and a subwoofer).

Related Topics:
Discrete - Matrix decoder

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