Q: Simply speaking, what do 5.1, 6.1 and 7.1 surround mean?
A: 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 difference is in the number of surround speakers (or the speakers that are typically behind and/or to the left and right of the listening position): two in a 5.1 system, three in a 6.1 system, and four in a 7.1 system. The .1 refers to the subwoofer. Obviously, a 5.1-channel soundtrack can be played on a 5.1-speaker system, but many people don’t know that it can also be played on a 6.1- or a 7.1-speaker system. To do this, the two surround signals in the 5.1 audio are spread across the three or four surround speakers. This distribution can be accomplished by a Dolby Digital EX decoder or a THX Surround EX decoder.