Dolby Surround

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Dolby Surround is an analogue audio technology developed by Dolby Laboratories. Originally demonstrated in 1982, it is the consumer version of Dolby Stereo (which confusingly uses more than two speakers), typically used in theatrical films to give the illusion of "surround" sound.

Dolby Surround is a four-channel audio set-up, consisting of left and right speakers, a "centre" speaker typically placed behind a user, and a "surround" channel that is spread across the other three. While the technology has existed since at least 1976, when brought to the home the four signals would usually be combined into two to create stereo surround compatible with most television and Hi-Fi equipment of the day. With a Dolby Surround decoder, the stereo information is split back into four intended channels to simulate a cinematic experience.

Dolby Surround came into video games in the early 1990s, debuting on the Super Nintendo Entertainment System before being carried through to newer platforms. Today this variant of Dolby Surround is rarely used, as Dolby (and its rivals) have since produced more elaborate set-ups with significantly more sound channels (and speaker requirements).

In terms of Sega produce, Dolby Surround began to appear in Sega Saturn games during the mid-1990s, before being officially supported by the Sega Dreamcast in mid-2000. Few games make use of the technology, likely as most consumers were unable to reap the benefits, but also potentially expensive licensing costs.

This variant of four-channel Dolby Surround system is typically known just as "Dolby Surround", however in 1987 a slightly different form of four-channel system was released (which decodes a true centre channel rather than the rear-centre seen here), whose decoders are labeled "Dolby Pro Logic" (confusingly "Dolby Surround" continued to be a name used for analogue audio, which would be decoded by a Dolby Pro Logic system, even though the quality of the audio and amount of channels could vary). "Dolby Pro Logic II" was often seen in post-2000 video games, however it is variants of "Dolby Digital" (a digital system, as opposed to this analogue one) which are generally used in games today.