not "up" on 1/4 wave... but +1 on the large ported box with low fs sub.Man screw all this crap. Dude just make a large ported box with a lot of port and a long port. So it will be tuned to below 30hz. Find a sub with a low fs and call it a day. All this bandpass box it a not a small task and if done wrong is worthless.
If u want a real box look up 1/4 wave enclosures...........
Just stick with a ported box tuned low man....... damn..........