@bdp24, this has been an interesting and timely thread. I’m encouraged to read that ESL speakers respond so well with Rythmik subs.
My dedicated music room is pretty much finished sans subwoofer support. I use JansZen’s hybrid Valentina ESL speakers driven by Linear Tube Audio’s ZOTL40 amp and MZ2 preamp, both license David Berning designs. I’m also a vinyl junkie just recently adding the new Technics SL-1200G turntable.
This mix provides a very well balanced and revealing system. Bass with the JansZens is flat to about 30Hz, but I know something is missing and I would classify my bass as super clean, accurate, but polite. I’m not a bass freak, but even David Janszen has told a few of us customers that bass has a ton of ambient information that lives well below what the speakers can produce that only good subwoofers will bring forward. He uses explanations that clip my understand, but in the end he puts it that bass can be great with the right support. A few of us do use subs and I think I’m next. Everyone says use 2 subs. My room is modest size.
My independent research has somewhat narrowed the search to JL Audio and SVS sealed subs and to the servo controlled Rythmik F12G. I have had a 15" Velodyne servo sub in my HT for years and I like what the servo approach does for control. I really like reading what the Rythmik approach does. I also like that the F12G is more affordable than the JL Audio e-series subs. All the other sub brands I’ve researched seem like me-too designs. SVS has stood out simply due to great pricing and amazing customer support. I do know of one friend who uses Vandersteen subs but I know those are priced higher than I care to spend, given that I’m already sold on the idea that I’ll want two.
One nice feature of my LTA amp is it has a pre-amp pass through ability for single ended connections. My amp is between my speakers on a floor rack so bridging interconnects to a couple of subs placed by each speaker should be an easy setup.