Not germain to your question, but just an interesting historical footnote for the "nothing new under the sun" department. The Hartley Concertmaster used the Hartley-Luth 24" woofer in a cute little 41"x29"x18" box that was, other than bracing, totally open in the back. Not quite true open baffle, but in the 70's that was quite different than anything else out there.
Someday I'll have to drag out my H-L 24" which is in a too-small bass reflex, open the back, plug the port, and see what that sounds like.
Ken