Gonna start the build log for this customer i'm building a box for. Here's the specs we are going for in this box. Internal Volume: 13.006 ft^3 Port Area: 232.5 in^2 Port Tune: 31.23 hertz With the max dimensions the customer wants to use, we're looking at 2.16ft^3/sub before actuall speaker displacement. This should work out right around spec to these subs. Sub up, Port back design, pretty straight forward. It's gonna be big. lol Currently the customer had a local shop (audio express, home of the $1 dollar wire fire) build him a box. They gave him three seperate boxes, two per box, with some really nasty tuning and build quality was horrible. I'm trying to remedy this. I'll post pics up as soon as I get a few. Stay tuned.