More from Amazon.com : http://www.amazon.com/gp/product/B007E9JG2S?tag=thefatkidin06-20

Atlantic Technology SB-900DF-BLK 8 Down-Firing Powered Subwoofer 125-Watt (Single Black)

125-watt powered subwoofer
8 long-throw woofer cone
Oversized surround for extended excursion with low distortion
Adjustable crossover and distortion-detection circuitry
Achieves a low end of 32 Hz the lowest in the audible spectrum