Subwoofers are speakers designed to reproduce very low bass frequencies. “Kickboxes” in cars that deliver that resounding “boom boom” are subwoofers. Subwoofers are also common in home theater applications. Subwoofers are larger than typical loudspeakers and require more power, which means they have different cabling requirements than standard loudspeakers.
There are two types of Subwoofers – passive and powered. A passive subwoofer is much like the other loudspeakers in your system albeit bigger! It is powered by your amplifier. Subwoofers require a lot more power for that driving bass than your other loudspeakers So you must be sure that you amp puts out enough power and you must use speaker cable of an appropriate gauge to carry the increased power required.
A powered subwoofer on the other hand solves both of those issues. A powered subwoofer is a self-contained stand-alone unit with its own built-in in amp. As such it only requires an interconnect cable from the line out of your amp. It also doe not draw any power from your amp so your amp can more easily power you mid-range and tweeters, delivering a great in home theater experience.
