The Preliminary construction

The plywood baffle reinforcement, glued and screwed to the MDF front baffle pieces.
The baffles and reinforcing plywood.

Driver mounting holes drilled through, and threaded inserts in place.

Filleting gets glued and screwed to all pieces.
3 layers of 30# roofing felt glued and stapled to the interior walls.

The small cutouts are for the cross bracing glue.