Think about this logically for a second. How many ears do you have? Hopefully you counted two. Now if you haven't damaged these ears, you can likely hear clearly out of each of them. Notice that there are not five ears like these immense muli-million dollar systems insist that you use.
The 5.1 system is only a way for large Zaibatsus to take your money.
The first argument of the other half is that you can obviously hear things that are behind you and therefore you need a speaker to re-create this effect. Oh how wrong you are. Yes you can hear things coming from behind you, but this is not because of the positioning of a speaker, it is because of the way your brain interprets certain sound signals coming in from the outside. A normal speaker if powered by the correct
amplifier can easily reproduce this setup.
NAD Electronics produces fabulous products that can easily do this.
The second argument usually comes from companies like
Bose. It's the same deal, they say you get a more realistic representation of the sound. Well here's something for you, perhaps you've heard of it, it's called
physics.
Destructive interference occurs quite often when two speakers are pointed at eachother which actually cancells out the sound altogether.
Sure, the
price may lead you believe their equipment is superior, however the top theater products cost way more than they do, and they are all designed around digital
stereo sound. Next time you are at a
movie theater look around a bit. You will only not see rear-channel or center-channel speakers. You may see speakers lining the walls, but those are designed to reproduce the imaging from the front two. Plus those speakers only really transmit
high-frequency sounds since the bass and
lowends are easily transmitted across the theater from the front. When you are in a big theater and you hear a sound come from behind you, it is not from a certain speaker. All the speakers are playing it, but it is the
sound processor that the theater has stored away somewhere that recreates that effect.