I've been searching for someone who has tackled this project but it doesn't seem to have happened. I really enjoy the idea of this sub, it seems to be a bit of a legend. I thought about building something similar with some Dayton Ultimax 12's or 15's.
From what I've gathered from my research, there is two drivers on either side of the outside that fire outwards and two drivers within a sealed box that fire into the larger box. The drivers are apparently in a push/pull arrangement, but I have no clue what the phase alignment is on them. The problem is I've never seen a picture of the inside of the large box, only under the removable driver cover. This leads me to believe the sealed section is basically as big as you see it, but it could extend further into the box.
The major issue is how on earth do you model this? Sealed section within a ported box. I don't think it would work to model a 4 driver vented, nor would it work to model just a 2 driver vented.
Anybody got any ideas?