Not to overrun the DIY section or anything but I still have this driver.
UM12-22 12" Ultimax
Ended up mothballing it in exchange for two sealed RSS315HF-4 in a music only system. This was before I really spent any time at all tuning my system. I see now that the suggested ported cabinet by PE is 2 cu ft. It must have changed because I ended up with roughly the same size sealed and the ported version at the time was considerably larger or I would have went with the vented.
My question is, if someone just had this barely used driver on hand, what would you build with it. I don't need anything below 30 hz, really, or not if the compromises towards better overall sound mean sacrificing the lowest capabilities. Would this work in a car system, perhaps?