Does anyone know how the SVS SB13 Ultra compare with a PB12-NSD or the new PB2000 for low level movie performance (like -25)? Small size is kinda important because it is in a small room of about 1200 cu ft.
in the most general terms, the SB13 has a more capable driver and more power so it will have more output in the mid-upper bass range 50Hz and up. It will generally keep up with the PB12-Plus in the upper bass. But as you near 20Hz, the SB13 will lose out to the PBs near their tuning point.
So it does very well, but for movies where you also want lots of impact in the 20-40Hz range, the PBs are preferable. But *if* you have a small sized room, then your natural room gain will probably complement the sealed rolloff characteristics of the SB13 better and the SB will work very well for movies.
I like the fact that the SVS avoided too much signal manipulation to get strong 20Hz performance, they designed it to play strong and clean and integrate well into smaller home theatre installations, which is great for people that actually need smaller subs
edit: I also meant to add the SB should be pretty impressive for movies given the size of the room. If your room can be closed off (all doors sealed), then you will likely get a bit of pressurization (the impact in your chest) as well
Warpdrive has great information here. Based on the size of your room I would think the SB would work well in your situation.