need help with box 2 l7 12s/ ported. dimensions, port size, etc

could anyone put a sktch together or tell me if im doing this right? i want it tuned to about 37 hz. = loud? my usable area is 48w20h14d
subs i guess can use anywhere from
1.75 ft3 + port displacement                                          3.25ft3 + port displacement
2.5x13.25 port 22.5 long                                               3x13.25''port 14.5 long
 
so if im building a box for loudness what would you recommend? and how long does port have to be etc? a simple sketch would help out alot. so thanks in advance to anyone willing to help.
im thinking of doing a boxx that is 2.5 ft3