I convinced a buddy of mine to build a Keystone sub for a PA he's putting together. It needs some bracing and the casters rattle, so they will have to go. He wanted me to rough in his DSP and we got it sounding pretty decent for a mostly empty garage. I would say this Keystone is probably a step up from my 2x18 subs I built a few years ago, despite being smaller, lighter, and cheaper to build.
JBL SRX812p on top -
B&C 18TBW100-4 inside -