Subwoofer - thoughts on Rythmic F12

One thing to be aware of is that the F12 is available with your choice of an aluminum coned-woofer (the F12), and with a paper coned one (the F12G, the "G" to signify GR Research, whose Danny Richie collaborates with Rythmik Audio’s Brian Ding).

Choosing between the aluminum and paper cone may be dependent upon whether you want to prioritize music, or movies. Rythmik Audio’s Brian Ding prefers aluminum cones for their greater stiffness (compared with paper)---less cone "flexing", Danny Richie the paper cone for it’s more "natural" (he feels) sound when reproducing music, especially that played on acoustic instruments.

Either one will be a worthwhile upgrade from the SVS SB-12.

I'll echo the comments from @bdp24 but with a little more enthusiasm because my upgrade was actually from an SVS SB-2000 to a Rythmik F12G. The lighter weight paper cone with the servo motor tech is extremely fast and articulate, all the way down into the teens hz range. It can reveal sub bass textures like a very high end floorstanding speaker. It's faster than the aluminum cone version, and that's why I went with it. It moves less air, but I greatly prioritize music quality over movie soundtrack quality. I use a large gauge solid OCC silver power cable with it, and OCC copper interconnects.

Also, read up on or watch the video of Danny describing the numerous options beyond the ordinary on the PEQ amp. You may not think you'll want them until you realize you do.

2 thumbs way up for the Rythmik servo subs!

@gladmo makes a great point about the lower moving mass of the paper cone version of the F12, and the resulting reproduction of low frequency fine detail.

I have a pair of the Rythmik Audio/GR Research OB/Dipole Subs, each of which employs a pair of the paper cone woofer that has been optimized for open baffle use. Imagine the "speed" (settling time) of the F12 servo-feedback woofer, with no enclosure! It's the only woofer/sub I've ever heard that blends well with dipole planar loudspeakers (including a pair of KEF B139 woofers in transmissionline enclosures I own). If you've heard the Magnepan bass panels of the big Tympani and MG30.7 models you have an idea of the sound of the OB/Dipole Sub, but with reproduction of even the bottom octave (20-40Hz). But an OB/Dipole sub is not for everyone, or every application. For those there is the Rythmik Audio F12. I have no doubt a lot of REL and JL Audio owners would be very surprised if they ever heard a Rythmik sub.

I can attest that the F12 is pretty hard to beat, particularly if your emphasis is on music---it's tight, controlled, and has unlimited adjustability. Also, here's a tip---the instructions point out that the volume control does not dictate how loud the bass plays, but it IS an adjustment for how much bass you FEEL. Initially, I thought the bass from the F12 was on the lean side, but once I started experimenting with the volume control, I got all the bass I needed, and more.