What is meant by 5.1, 6.1, and 7.1?
With respect to home playback, the terms 5.1, 6.1, and 7.1 mean that there are five, six, or seven main speakers, plus a subwoofer, in the playback system. (The subwoofer reproduces the LFE channel recorded on 5.1 soundtracks, plus any bass the main speakers cannot handle.) The difference is in the number of surround speakers: two in a 5.1 system, three in a 6.1 system, and four in a 7.1 system. Obviously, a 5.1-channel soundtrack can be played on a 5.1-speaker system. But it is not always understood is that it can also be played on a 6.1- or a 7.1-speaker system. To do this, the two surround signals on the 5.1 soundtrack are spread across the three or four surround speakers. This distribution can be accomplished by a Dolby Digital EX decoder, a THX Surround EX decoder, or other proprietary methods provided in home theater equipment by various manufacturers.
