OK, I see it now. I apologize for being in a hurry and not looking more carefully at all 8 pages of that PDF document. Apparently I had a major brain fart. :dontknow: It certainly does couple the driver to the box via the magnet brace.
Interesting concept. I don't think that it would be trivial to implement, though, because you'd have to be pretty much "spot on" (as the British say) with the dimensions to ensure a snug fit into the magnet.
Progress report: all 24 panels (to make both boxes) have been cut! Time to fire up the router.
P.S. If this box design turns out to be a flop, I can always order up some 24" or 30" sonotube.