Amazon.com: BESTISAN Powered Subwoofer, 6.5" Active Home Audio Subwoofer in Compact Design,LFE & Stereo Line Inputs & Audio Output, Built-in Amplifier for Home Theater/Receiver/TV/Speakers, Black, SW65D : Everything Else
Aperion Audio Blog – Tagged "best subwoofer design"
Pyle 8'' Active Down Firing Subwoofer - Home Theater Surround Sound Black, Magnetic Design (BLACK) - Walmart.com