12-inch Home Theater Subwoofer DIY S013 200W Passive Subwoofer TV Computer Speakers Enthusiast HiFi Audio Amplifier 30Hz-120KHz - AliExpress
One unit (not pair) |12 Inch Woofer for Bass Compensation of Open Baffle or Cabinet | W-12 - Lii Song (Lii Audio), unique speaker, amplfier, quality and cost-saving parts for HiFi DIY
DIY 12 Inch Sealed Active Subwoofer - YouTube
THOR - subwoofer
DIY subwoofer I built. 12-in Dayton UM subwoofer and a 500 watt bash amplifier. Flat port design tuned to 20 hz. : r/hometheater