What is a subwoofer?
What is a subwoofer exactly? The common notion is that it is a large square box with a large driver in the middle. And it’s big. Very big (did I just mention that again?).
The sole purpose of a subwoofer is to reproduce the deepest of bass and to take over the reproduction of this part of the sound stage. Your speakers are not supposed to play the deepest tones, as this makes it more than difficult to place them correctly.
For home use there's typically two types of subwoofers available. Sealed and ported subwoofers. Sealed subwoofers consist, as their name suggests, of a sealed cabinet and a the bass reflex subwoofer is very similar in looks, but it's usually a little large and has one or more holes (ports). As a general rule the sealed subwoofers are a little smaller than their ported brother, but can't play as loud. The bass reflex subwoofers are a little larger and can typically play a little louder.
Very often a subwoofer is a square box with a build in amplifier and a large loudspeaker (the driver). The bigger the box, amplifier and driver, the louder the subwoofer can play – in general.
In order to reproduce the deepest bass a lot of power is required from the amplifier, or a large membrane area is needed (a big speaker driver). If both is present it is just great.
Why do I need a subwoofer?
Everybody needs a subwoofer. Eventhougth you bought the biggest speakers available (nothing wrong with that by-the-way) you still need a subwoofer.
If you want deep and clean bass in abundance – and who doesn’t? – then you need to get yourself a subwoofer.