One Svs or two Paradigm????

I might try that. Although it might bog for loud, deep movie watching.
I was thinking of maybe a Paradigm Sub 1 or 2 used or demos. Both reviewed extremely well in both movies and music. If money is good then maybe two(lol)....

Regards Bacardi

Before I bought my Velodyne DD18+ I seriously considered two SVS SB13 Pluses, as two subs do supposedly make getting a smooth deep bass response easier, and I prefer the frequency response curve of a sealed box to a ported one. The SB13 Plus is just the right size for a pair in my room.

I like the SB13+ over the Paradigms due to design differences. Those 13.5" drivers are monsters, and the Paradigms use wimpy-by-comparison 10s. How could the output and distortion compare. You might even find that twin SB13+s make your Ultra unnecessary. I ended up not choosing SVS just because I couldn't audition them first, and I have a rule about that with speakers. But since you've made that leap already, the SB13+ is probably the best solution for twin subs I'm aware of.

I use a single Velodyne DD18+, which suffers from the same huge size as your Ultra, so I'm lucky I get away with only one in my room. I suppose the DD18+ is another alternative, though Velodyne's pricing may turn you off.

Have you tried the Ultra in sealed mode to see how it sounds?

Irvrobinson; nothing's wrong with it. I think it would blow the doors off the Seismic 110's. Won't have the speed of the two. My initial plan was to buy a SVS SB16 when it came out but haven't heard any news on its release date or final specs. I would actually keep the 13Ultra and run both. The 16 is a sealed enclosure with a 1000watts RMS digital DSP amp. For music the 16 would eat a lot out there(if comparable or beefier than the 13Ultra). The 13Ultra would handle the movies with low end crunch and headroom, and the 16 for gripping speed, dynamics, and authoritative snap and punch. I actually had a custom Hifi Pyon platform made for my 13Ultra because it only had little rubber feet that sat the sub too close to the carpet which made too much vibration. The platform was definitely a godsend to the issue and overall is visually stunning and utterly the most astonishing bass I've ever heard.
I am waiting for the SB16 but if it not released I might try two subs of the Paradigms. I think two PBS 13 Ultras are just overkill for my room and visually too big. I don't see how the small Seismic 110 goes down to 18HZ with its small footprint but two would be better than one. I run a full Paradigm Signature S1v2 fronts, C1 center and Adp1 rears. The two 110's would mate extremely well with my Sig setup.

Would you suggest anything else to me?

What's the problem with the PB13? Audioholics.com just tested it, and found that it was one of the best performing subs they've ever tested, and it won their "extreme" room size rating. In 15Hz mode that thing is apparently capable of some serious low-distortion output. (I"ve never seen one before, so I can't comment on how it actually sounds.) Based on specs alone, I'm guessing the SVS would blow the doors off of the Paradigms. Even two of them.

Conventional wisdom on this site seems to favor two subs even of lesser quality over one bigger or better sub-especially for music but tends to hold true for HT as well I've heard. This has a lot to do with room interaction and better integration rather than more ultimate volume output.