Q. What should the speaker distance be between the two front speakers in a stereo or home theater system, as well as between the two surround speakers? I also want to know at what height I should mount my surrounds? Thanks. — Adi N.
A. Start by separating your front left and right speakers by about half the distance that you sit from the speakers. If you sit 12 feet back, separate the front left and right speakers by about 6 feet. You can vary this formula quite a bit. At 12 feet, I'd try anything between 5 and 8 feet.
Use enough separation between the two speakers so you can easily perceive the stereo effect and directional cues without getting the sense that the sound is emanating from two separate boxes at the front of the room. You want a smooth, seamless, stereo soundstage.
In home theater systems, this is much easier to achieve with a center-channel speaker (except when you are listening in 2-channel stereo, with no center running), because the center-channel speaker nicely fills in the middle. But even here, aim for an unbroken soundstage.
If you get a hole-in-the middle effect in stereo, then move the two mains closer together or toe them in slightly towards your listening position until you get a seamless soundstage in front of you.
There are no cast-in-stone rules about speaker distance placement other than avoiding corners (except for a subwoofer). Experimentation is the key. You can see some suggestions in our Audio/Video Tips section.
As for surround speakers, just remember the way surrounds are positioned in any Dolby Digital cinema--on the side walls, to each side of the listening area, approximately opposite each other and well above the level of your ears. Dolby Labs says that you can also move them slightly to the rear (up to 20 degrees) or a bit forward of an imaginary line drawn across the listening area. Axiom's multidirectional QS8 or QS4 surrounds are very flexible in this regard, and needn't be at the same height or speaker distance from the listeners.
If you are running a 6.1-channel or 7.1-channel system, the additional rear surrounds should be on the rear wall, not the sides, at about the same height as the side surrounds. Do not aim or angle any of the surrounds down toward the listening area. The purpose is to create an enveloping surround soundfield.