So I played around with my setup, dropped in some stands and 5.1 speaker setup, ran some calibrations, did some adjustments, then threw a lot of heavy LFE blurays to see what would happen. While the SB12 supplied bass, it just didn't quite slam as much as I wanted. For music, the SB12 is excellent, fast and responsive, runs circles around my old STF-2, very musical, but if you want slam for movies, there's only so much as a sealed sub can do apparently, unless you opt for the more expensive SB13 Plus or something like the HSU ULS-15, which I hear can really pull some deep output, according the numbers.
I suppose it was my fault that I'm in a position to return it, I really wanted to believe that a sealed sub would be enough in my room for my tastes, for some people the SB12 will be fine. After having a HSU STF-2 in my room and feeling pretty satisfied for over a year, I'm hoping a PB12 will take things up to a higher level with deeper output and even more slam with movies. I am at least glad that I had a chance to try out a sealed sub, and a fine sub at that.
So I decided for sure to get the PB12-NSD, I don't give a hoot if the box is big and unsightly, I just want my movies to slam and rattle the walls. I'm going to talk to SVS tomorrow about doing a return for my SB12 so I can order the PB12 instead.
BTW, one weird thing I noticed was that there is a subwoofer thump when a bluray switches into encoded surround playback. This sometimes happens 2 or 3 times during title intro. I never noticed this problem on my other Pioneer receiver, I don't know if its this new receiver(Pioneer 1121-K) or the sub, I checked the sub cable(Premium one from monoprice) its seems to be plugged in fine. What gives???