A multichannel sound technology that produces five channels
of sound in the left, right, center, left surround and right surround positions.
5.1 systems also have 1 channel for LFE (low frequency effects) which is usually
sent to a subwoofer.
5.1 Channel Setup This was the first true surround sound setup. There was a four-point surround system but the lack of centre speaker prevented the true cinematic sound experience.
7.1 Channel Setup Again the introduction of another satellite speaker is required when using the 7.1 speaker. This system gets rid of the centre rear speaker and replaces it with two rear surround speakers.
Surround Sound Past, Present, and Future (PDF) A history of multichannel audio from mag stripe to Dolby Digital. The first commercially successful multichannel sound formats were developed in the early 1950s for the cinema. At the time, stereophonic sound, a concept new to the public, was heavily promoted along with new wide-screen formats by a film industry feeling threatened by the rapid growth of television.
