Since it is tough for small-sized loudspeakers to reproduce frequencies under 40 Hz, and really tough for under 100 dB, people often choose to use a loudspeaker just for this purpose. Hence the subwoofer, a kind of loudspeaker that reproduces bass frequencies ranging most generally from roughly 20 Hz to around 200 Hz. DO you need one? Depends upon how well you want to hear, if your sound is reproduced under 40 Hz.

Subwoofers’ drivers, known as woofers, average between 8″ and 15″, and can run 34″ even. And drivers begin at 4;” those under 8″ generally don’t reproduce lower frequencies with good quality.

Since it is tough for small-sized loudspeakers to reproduce frequencies under 40 Hz, and really tough for under 100 dB, people often choose to use a loudspeaker just for this purpose. Hence the subwoofer, a kind of loudspeaker that reproduces bass frequencies ranging most generally from roughly 20 Hz to around 200 Hz. DO you need one? Depends upon how well you want to hear, if your sound is reproduced under 40 Hz.

Subwoofers’ drivers, known as woofers, average between 8″ and 15″, and can run 34″ even. And drivers begin at 4;” those under 8″ generally don’t reproduce lower frequencies with good quality.

My trip athena subwoofer powered by a Denon AVR-688 (sub in 300-watt amplifier built in) very powerful for an 8-inch subwoofer. … Cerwin Vega Bass athena subwoofer home theater surround sound Denon stereo speakers basso tronics sub

http://www.youtube.com/watch?v=XlV6mmcDWVY&hl=en