subject: The Home Theater Subwoofer [print this page] Subwoofers are individual speaker units that are dedicated solely to reproducing low-frequency sounds, making them a very crucial part of your listening experience.
The typical frequency range of human hearing is between 20-20,000Hz. A good home theater system should be able to reproduce most of the frequencies within this range. Due to the fact that usually the center, fronts, and rear speakers in a surround sound system are usually not adequately equipped to produce those really low tones, most systems use a subwoofer. This speaker is only designed to reproduce the low bass tones and will not put out any other higher frequencies. Most really good subs are called powered subwoofers, due to the fact that they actually have their own amplifier and do not pull their power from the systems main amplifier that feeds the other speakers.
When looking for a good sub, there are 3 things to look for- size, power, and frequency range. If you have your system in a larger room then obviously there is a need to have a larger subwoofer, such as a 10", 12", or possibly even a 15". However, you have to be careful not to get a sub that is TOO large and powerful for the room that it is in. In such a case, it will be overpowering and drown out the other speakers.
Most powered subs have at least 75watts of their own power and can go up to 500 or 600+ watts. The amount of watts combined with the various available speaker sizes will all yield slightly different depths and tones. Lastly, any quality sub will come with multiple crossover frequency options.
By definition, crossover frequency is the frequency at which an audio device (receiver/amplifier) delivers equal power to the upper and lower frequency channels when both are terminated in specified loads. Basically, this setting on the subwoofer allows you to set how much bass you want the home theater system's receiver to put out to the sub. The lower frequency setting, the lower the amount of bass that is put out. Most subs will have a turn knob that adjusts from low to high, for example, 80-160. Every receiver is different in the frequency level that it is capable of putting out to the subwoofer. However, usually the best setting would be closer to the higher end of whatever the subs crossover is. That way between the receiver and the sub, you will get the best of what the two combined can put out. Typically, powered subwoofers also have a volume control to limit not the frequency, but simply the sound level.
Without the subwoofer in a home theater system, it would not be complete. They allow the listener to thoroughly enjoy and feel the sounds and effects, almost as if they were actually there in the movie themselves.
