What would be the best sounding 12″ sub for a q-logic bandpass box?
It is going to be very hard to pick a sub to go in your box. You usually make a box after you already have the sub. Especially if the enclosure is a bandpass one. Bandpass enclosures require a lot of careful design to fit correctly with your sub. Putting the a sub in the wrong enclosure will sound horrible and can possibly even damage you sub. You will need to do a LOT of research to pick a sub that will work. If you want to keep that enclosure and pick a sub for it then you should start by contacting subwoofer manufacturers. You should give them the specifications of the enclosure and ask if they have any subs that will work in that enclosure. You will need to include the enclosures front volume, rear volume, and tuning frequency of the ported part of the enclosure. Good Luck!!!