Wanna help me build a subwoofer?

New to this site! I want to consider building a portable PA system powered subwoofer. Will primarily be used for outdoor events. Somewhere in the 1200w continuous range, 136db spl@1m range. I think it could be fun and possibly cost efficient to a $1500 sub. Can you point me in the right direction? Maybe even an old thread on this. Thanks!
 
No worries.

The best price to performance ratio seems to be the large-format tapped horns. THs get more per driver than ported boxes. Something like a B&C 18SW115 in a Keystone cabinet, for example, would be a good start.

Best of luck on your journey. Do you have any equipment so far, or are you setting off from scratch?

Chris