Just as it’s important to check the polarity for your main speakers, you should check the polarity of the subwoofer relative to the main speakers. Some subwoofers have a phase adjustment that is either infinitely variable, or has several fixed settings. If the subwoofer is out of phase with the main speakers, you’ll get less bass at the crossover point. You want to adjust the phase to create the greatest output. This is difficult to do, though, without some test signals and an SPL meter. Using the 5.1 Audio Toolkit or another test disc, play test tones at the system’s subwoofer crossover frequency and measure the output with the SPL meter. Adjust the phase control on the subwoofer through its range. The setting that creates the loudest output, or the highest reading on the SPL meter at the crossover point is the correct phase adjustment.

6.       Perform a rattle test. When the movie action gets going, it’s not uncommon for intense bass to start vibrating various objects in your room especially if your house is a full of Tiki souvenirs from Hawaiian vacations. The sound of these rattling trinkets make the system seem louder than it really is and can be distracting. Whip out your test disc yet again for another useful tweak.

Set the volume at a normal level then play low frequency tones from the disc. Some discs have sweeps that start at really low bass frequencies and work their way up to higher frequencies. Others just have individual tones that you’ll need to step through. In either case, walk around the room and try to find those items that rattle. Different things will rattle at different frequencies. Use felt, rubber furniture protection pads, museum wax or cut up an old computer mouse pad to try to isolate the items as much as possible. Fill hollow objects with sand and tighten lighting fixtures. Once the room is rattle free, your system will sound cleaner and clearer.