Rythmik F 12 vs. SVS SB12-NSD vs. ?

Can't really answer your question directly, but when I asked Rythmik about a purely audio only sub they recommended the F12G over the aluminum coned F12.

I did a TON of research a few years back for a pair of subs for a high end, music-only system. That involved auditions of REL, Velodyne, JL, Martin Logan and a few others. It also involved a lot of test bench data review. Based exclusively on the latter, I narrowed it down to Rythmik and SVS (both sold direct, neither available for local audition). In both cases, I was looking at sealed box 12" subs.

These two test off the charts. The SVS had somewhat greater clean output below 40hz and the Rythmik has better group delay in the same band. I chose the Rythmik and have been very happy with the choice. However, I can't offer a comparison as (other than Velodyne SPLs - not in the same league as the Rythmiks), I never did a proper A-B in my listening room.

As to x-over point: That is a controversial subject that is complicated by room, set-up, and electronics.. My own take is:

If your electronics include full-range room correction (i.e. Audyssey, et al), cross as low as you like. If not, but your set-up includes multiple subs, cross higher so that the smooth response from multiple subs provides as much benefit as possible. For a single, non-corrected sub, higher is usually better, but trial and error is required.

Just MHO.

Marty

Personally I'd try to run dual subs since you have a good-sized room, and the dual subs can help even out bass frequencies and be run in stereo if that's something you might want. SVS offers a special where you can get two SB12s for $1150, which seems like a whole lotta quality bass for the money. Best of luck.