Surround Sound
Standards
Placement
Center Channel
Level with your ears, close to the screen, directly at listener.
Front Right and Left Speakers
Equal distance from screen, equal distance from primary listening position. Between 22 and 30 degrees off center, and slightly in front. Tweeters at ear height (44"-ish)/ Center channel height when seated. 22 degrees is better for movies, 30 degrees is better for music.
Rear Right and Left Speakers (Surround Sound Speakers)
Speaker placement should 110-120 degrees off center, or 20-30 degrees to the rear of the listener. Slightly higher than front speakers (1-2 ft, or 6'ish). Don't aim at listener, aim at other wall, since surround sound is usually used for ambient noise.
Subwoofer
On the floor, typically a corner, or near the center channel.