I just designed my box and came and up with 12.37 sq inches of port per cube is that a little low? What does more sq inches of port per cube do? I also came up with about 4.03 cubes per sub before displacment I want to do a little larger what does everyone I think? My dimensions I used are 23width x 34height x 49 length. they will be in an 05 f150 with two kicker zx1500. 1 amps powering them for now will upgrade power. I know they give generall recomendations of 3-5 cubes per sub and 12-16 sq inches of port per cube. What is everyone else running? and what should I tune to? I did 27 hz my amps lowest is 25 hz and the way I understood what fi said was 2 above your amps lowest.