Besides the box Jmac is designing for me, I'm also going to modifiy the sealed box my 15s are in. I am making plans to port it. Very, very low. Jmac's will be 34 hz with shared chamberspace; this one is going to be 24hz, seperated chamberspace. I thought about a small port tuned to 5 or 10hz, but if you look at how ported boxes work, it's very impractical.
Now, naturally I don't know the first thing about port length, so I use a calculator.
After doing some math, if I do a roundabout (Contours with the side walls, as opposed to labyrinth style) slot on the bottom instead of the side, I can get away with a 1"x15"(15 sq inches for those not wanting to think) port 30 inches long for that kind of tuning.
2.18 cubes, 1x15x30 inch port, 24hz. How do you think this would sound?