I'll second the VMPS, bargain bass that is tuneable. Just big boxes. Get a Pair for movies and use the adcom! I use to use a Hafler DH-500 with a pair of the VMPS standard subs and it was amazing for movies, they just take space (Wish I got a pair of largers!) Put them together(Screw the drivers in and cable it) and save some money too.
If you need a smaller sub and less bass, older NHT subs are passive and cheap, but are better at music versus Movies.
If you need a smaller sub and less bass, older NHT subs are passive and cheap, but are better at music versus Movies.