Next cabinet I build is going to have the woofer and horn glued and bolted to the baffle. I stumbled across some adhesive that is sold with an undermount sink kit at Home Depot. Supposed to be aerospace type stuff. Or epoxy would do.

Then I would let in a door through the back panel with a wide rabbet to maximise contact surface, like watertight doors.Apply a gasket material and use bolts in t-nuts. Then have access without disturbing drivers and establishing even higher "Q".

This is great fun, isn't it? Enjoy!