OTHER TECH

The paper assumes you have a typical rectangular room and are trying to locate one, two, and finally, four subwoofers. (Avoid using a square room. Modes have a big effect on bass distribution in spaces of less than 30 x 30 feet, and that problem is only exacerbated if your home theater is square.)

To accurately position a single sub, you have to eliminate any self-respect you might have and crawl around on the floor. Move your chair, couch, or beanbag, and place your sub in the key listening position. Then go around on your hands and knees, listening for the location with the best sound. That doesn't necessarily mean the loudest spot - you're looking for clear and even bass. (Use a DVD or CD that really gives your low-frequency driver a workout.)

There's no hard-and-fast rule for subwoofer placement, so it's best to start in one of the room's corners and then move in and out and several feet up and down the wall from where you're thinking of putting the sub. (For more setup tips, see "Subwoofer Setup Secrets.") As you look for the optimal spot, you'll find some locations where the bass is boomy and too loud, and others where it almost disappears. Once you've found the best location, move the sub there and return to your listening position.

Making slight changes to your listening spot can also improve the sound. Avoid sitting in the exact center of the room or right against a wall. If your couch is near a wall, bring it out a little. And if your chair is in the center of the room, move it back or forward or a bit to the side.