Setting up a surround sound system takes a little more work than most people realize, and correctly setting up the subwoofer crossover is one part of it that commonly causes confusion.
A surround sound system is designed to produce sound in such a way that the sound experience is nearly indistinguishable from actually being there, in the experience that is being portrayed. Achieving the right balance of sounds is critical. It is less about more sound than it is the correct combinations of sound.
What settings you choose, and the smoothest sound will largely be influenced by the size and shape of the room, thus the acoustics of the room in which you are setting up the sound system. Thoroughly read the manufacturer's directions for any additional settings that you will want to customize.
Once you can achieve the correct combination of sounds, you can turn it up as loud as you want.
Setting up the Crossover
The most common misconception in setting up the crossover is that most think that 2 adjustments need to be made; one in the receiver setup menu and one in the actual subwoofer. In almost all circumstances, the only adjustment needs to be made in the setup of the receiver.
When calling up the receiver's set up menu, there is frequently only one setting that needs to be addressed, which is to detect that there is a subwoofer present, and if that is the case, to make sure to turn the subwoofer to the "On" status.
Most will be preset to between 80 and 100 hertz, but it may also be necessary to set the hertz on the receiver setup menu. Set this to 8 hertz. You will want to set all other speakers (unless you have integrated two way speakers) to "Small", so that all of the deep tones are routed to the subwoofer via the "Subwoofer Out" jack in the back of the receiver.
Further Fine Tuning
The above instructions apply to systems that have a subwoofer and several small speakers to create the surround sound effect.
If your system has the subwoofer, large "Right" and "Left" speakers, as well as several small surround speakers, you will want to play a bit with the settings on all the speakers except the subwoofer. Again, the only settings that you will need to make sure you set are the "On" status and the hertz (set to 80).
You may want to try setting the right and left speakers to "Large" and the remaining speaker channels to "Small". Test this setting for the sound quality. If there is too much bass, change the settings on the right and left speakers to "Small" to reduce the amount of low tones that are sent to the large right and left speakers.