The Good, The Better, The Bass
Watching a movie without a subwoofer is like driving a bus on the autobahnyou can do it but it's not going to be as thrilling as you'd like. A great home theater does one thing wellit brings the magic and wonder of movies into your home and the subwoofer is a major player.
Do You Hear Thumping?
Most folks tend to turn subwoofer level too high because they're used to "boomy" bass. However bass should be more about clarity and detail, not thumps. Car stereo enthusiasts can "bass" a Big Gulp right out of the cup holder but it's still not accurate sound. Great bass shows itself as a seamless transition between the subwoofer's low notes and the high notes produced by the front/left/center/right speakers.
One Sub Is Great, Two Is Better
One sub is good but two can be better. There are a lot of complex acoustic explanations for this but we'll keep it simple. Adding a second sub cuts down on the first sub's workload and dramatically reduces dead spots in the room. Be sure to use identical subs!
Up Against the Wall!
To avoid boomy or unnatural sounding bass, try placing the subwoofer against the front wall a ½ room lengths. If you can pull off the grille cover of your sub, locate the dust cap at the center of the subwoofer speaker and use this as your center when moving your sub around.
Aim Low and Work Your Way Up
Finding the right spot is all about experimenting. Reset your surround controller subwoofer level to a low setting. Next play some music with a lot of clean, tight bass sounds. Jazz recordings with acoustic string bass or classical music work great. While listing to the music, adjust your surround processor sub level upward. You might be tempted to crank it high but if you've removed the boomy bass, you'll start hearing clarity and inner detail.