Here is a great subwoofer to consider adding to your home theater setup, especially if you are sorely lacking in audio quality. A great addition to ante up the perk up your home entertainment system, the Klipsch Synergy Sub10 Powered Subwoofer is not just a powerful subwoofer. The Sub 10 also delivers a clarity, tightness, and undistorted deep bass response that you find on more expensive subs.
The Klipsch Sub10 is a large, heavy, unit with a powerful built-in low frequency amplifier. The driver is downfiring, so the driver cone faces downward. There is also a rear firing port. Below the rear port are the connections and controls.
The Klipsch Sub10 has adjustments for Phase (which matches the in/out subwoofer driver motion to the satellite speakers), Gain (subwoofer volume level), and Crossover (sets the point at which you want the subwoofer to produce low frequency sounds, against the ability of the the satellite speakers to reproduce low frequency sounds).