Sub problems

[firebirdman225]

I put my brand new audiobahn aw1251t dvc sub in a q logic box and the thing wasn't hitting hard at all,it seemed to rattle and stuff a little too, could this be because i wired it wrong or that the box is leaking air(my friend told me it was, i dunno) or that the sub box is .85 cu and my sub reccommends .88 cu?? I just dont want it to be the sub i dont want to have to return it.