Originally Posted by tanveers
It really depends on how detailed you want your Surround Sound setup to be. The 5.1 Speaker setup was the Dolby Original Standard, but as professionals and consumers alike have pushed for "Bigger and Better" sound. You see the difference between the number of speakers depends on how define you want your Sound image to be. The more speakers added, the more space will be filled in giving you a more defined layout of the sound. As you know 5.1 configures a Left, Center, Right, Back Left, Back Right, and a sub. the 7.1 configuration has the same speakers but now includes side left and side right speakers which helps define the space even more than the 5.1 and so on. So the higher you speaker count (when placed correctly) the more defined your sound will be in that room. My suggestion to you is that you decide on how much definition you need for your area and setup what sounds good for the application that you need it for.
Lead Tech, AA Rental
Rear surrounds don't come into the mix until you get to 7.1 - the surrounds in 5.1 are side
speakers, regardless of what equipment manuals show in their diagrams.
Look at the pairs of surrounds marching down the side walls in movie theaters - that's
classic 5.1, and what most movies are mixed for.
Personally, given how the pinnae of the ears (the forward-pointing fleshy ear trumpets that focus our hearing) filter out sound from the rear, I don't see the purpose in 7.1. When I set my 5.1 system up, with speakers in the back - following the diagrams in the manuals, and levels calibrated with a sound pressure level meter - I found myself constantly walking over to the rear speakers to see if they were even on!
Only after a more experienced commenter at this site pointed out that the surrounds in 5.1 are supposed to be to the sides, not in the back, and I moved mine, did I get the benefit of surround sound.
Don't waste your money on rear channels, unless money means nothing to you.
If you do, you'll also want to ignore the level meter and turn the rears up to where you can actually hear them.
As far as sonic accuracy goes, "That's glory for you!" [as Humpty Dumpty would say]