OPTION Drive10UA actieve subwoofer, 25 cm, 120 watt RMS (2 x 60 watt RMS), bass boost & high-level ingang met autosense : Amazon.nl: Elektronica
Hertz DBA 200 actieve subwoofer
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
DIY Active Subwoofer : 15 Steps (with Pictures) - Instructables