Update.
I was at Marc's this last weekend, and got to listen to the corner horns. In short they sound fantastic. Such a full, weighty sound from a single 6 1/2" driver is a real surprise. They really throw a large soundstage too, and without a narrow sweetspot. I could be very happy with these just as they are, but Marc wants to fill in some of the lower octaves. Actually the bass is there, but not in large supply.
So we set out to assemble us some 'paint by number' subwoofers Friday evening. Within 45 minutes we had both subs glued and assembled, save the outer pieces and the drivers. This guy builds a beautiful kit, that the most inexperienced hobbyist can easily navigate. The next evening we finished them off in short order, and even took the opportunity to play some 50 Hz. and 20 Hz. test tones through them. These long throw 7'' subs move some serious air through the tapped horn enclosures. I was gobsmacked at the amount of low end, visceral bass. We did find a small leak in our glue joint on one sub, and it created a different frequency note when not plugged. The pressure really was unexpected for me, Marc of coarse was not at all surprised. I'm sure he'd already calculated how far they could throw a ping pong ball at X Hz.
I believe he delivered the corner horns and subs to the painter for prep and paint before he left today for the land of Crumpets and Crowns. Then we'll finish them off with some solid Wenge trim.
Stealing your thunder again Marc, but I had to talk up these brilliant speakers.