So how many watts are actually necessary to thump a movie? I know a lot has to do with design of the sub and size of the room, but can I get people to list how many watts they are running to their subs (specifically DIY subs) and their perceived "thump" factor?
Do you just want high SPLs or sound quality? For just raw SPL, get Kicker Solo-baric 15" or 18" driver, put a least 1000 clean watts to it, put it in a large slot ported cabinet tuned to around 20Hz and tear the walls down. For sound quality with high SPL, you will need a higher grade driver oriented towards low distortion.
As for power, pretty much any direct radiator system needs lots of power. A horn sub can make do with little power in exchange for making a MONSTROUS sized cabinet to effect horn loading into the 20's cycle range needed for HT. Though personally, I will still take very high grade direct radiator set up(TC Sounds drivers, JL W7, etc.) to a horn loading set up using lesser drivers.
-Chris