displaces more space than that sub you have.
You're absolutely right. Never dawned on me at the time. That'll be something to compensate for.
Jalat might. JoeF - but he's not a very frequent user of the forum. Just hi-jack a thread, or start yourself another one asking someone if they'd build you one. Most might suggest a slot ported box, instead of the square mess I've designed. Since it accomplished the same thing, and is easier to build.
The only reason I elected to go with the square port was since I read its the next best thing after a round port.