I have a regular cab ranger and i built a sealed box as big as i could go with the space i have. I built it for 2 shallow mount 10s, but the box only has ~.85cuft for the 2 to share and minimum recommended is .75cubes a piece. I just went along and built the box, not quite sure what they would sound like. Well the outcome was they are really punchy and play nice on quick kick drum beats, but anything below about 45Hz they sound like crap unless you crank the volume way down.
I was thinking about taking one out and just running the one, but was wondering if there are other options to get the box to play lower. How much of a difference does poly-fill make? What about unhooking the other one and using it as a (can't think of what its called right now, like a dummy sub usually without a motor structure). How terrible do way undersized ported boxes sound?