should the box for my subwoofer be completly air tight. the is a small hole in the back of it and i was wondering if i should seal the hole.

 

seal it up the tighter the better

 

Yeah, seal the hole, particularly if it's a small box. It builds more preasure behind the sub giving it more "bump". In a small box even a little hole can cause a lot of preasure loss. The only holes that should be in a sub box are the ports if it's designed that way.

 

Small box = Sealed "air tight"
Medium throu large box = Sealed or ported
Ported must be equal per side and porportional to air displacement at desired level.