Polk Audio PSW505 12-Inch Powered Subwoofer (Single, Black)

Real wood veneer finish, Slot Load Venting improves bass response. If you have any electrical (50/60Hz) hum in your system you’re going to hear it clearly as soon as you hook up your subwoofer. Most hum problems are caused by “ground loops.” That is, the electrical grounds of the components in your system are not at the same electrical potent.
Polk subs sound better because they’re built better. Rock-solid MDF construction (including a 1 inch thick front baffle) suppresses enclosure panel resonance for distortion-free, accurate response, big 12 inch long throw driver for longer excursion and better linearity.
Huge Hi-Roll Surrounds that support their longer excursion, Most powered subwoofers are good for just gut-rumble and boom. Polk understands that you listen to music too so our subs are tight, precise and accurate. The wide, long Slot Load Vent dramatically lessens turbulence, noise and distortion, pouring out a tidal wave of precise, thunderous bass!
High current 300 Watt Continuous (460 Watt Dynamic) power amplifier, Adjustable low pass crossover, phase switch and volume control allows perfect blending with any main speaker. Compatible Devices-TV,Video Monitors
Auto on/off circuit that automatically turns your subwoofer on when it senses a program signal. When no signal is present, the amplifier turns off within 15 minutes, Unfiltered LFE input for use with low pass filtered subwoofer output jacks.