So, I'm planning on building a custom box for a RockfordFostgate P1S410. It needs .50-.85 for a sealed enclosure, and 1.40 for a vented. My problem is my regular cab pickup. I have about a foot at the widest point, between seats and the cab-wall. My question is, with a 5 1/2" mounting depth, how much space should I have between the bottom of the sub and the inside of the box? I want to get decent sound out of it, but space is my main concern, I can make sacrifices if need be. Any opinions or ideas for an enclosure would be greatly appreciated.

 

flat subs in foot wells (kickpods )

 

2" min and even then it can cause defection from the pole of the sub(kinda like putting a 4" port 1-2" from the back of the sub or box)I would stay about 4-5" or more

If you don`t want to do something like a T shape box(sub between the seats and box extends behind) then you are left with side firing 8",A bass tube,Heavy mods,a bunch less foot room(you don`t want the sub damaged from smacking the seat back) or shallow mount subs.Anything can be done just depends on how far you are willing to go