Proper setup for best sound stage, HT experience, and music decoded in 5.1 is to have the tweeters of your left/right mains and center at ear level, or as close as possible. Many times this is not possible due to room/furniture limitations, but for best results this is important. Also, your left/right/center speakers should be the same distance from the primary listening position. This forms a slight arc around the listening position.
What will it do for you? Give you a proper setup, that is if you want that.
