Down 4 Sound - Quad 6.5" or 8" Custom Sub Boxes with Kerf
Custom Subwoofer Box. Had the Kicker Comp RT 6.75with passive radiator but it didn't have enough bass. How did I do for my first box? : r/FordMaverickTruck
Custom Subwoofer or Speaker Box Kit Enclosure Unfinished - Etsy
DIY Transmission line subwoofer box - first attempt
Custom Made Subwoofer Box - Bakersfield Car Audio & Stereo