I had been using a Polk PSW 404 for a 2 channel set up in my recording studio / listening room. Had the opportunity to upgrade to a Rythmik F12SE and it made a huge difference.
The Polk took a lot of fussing to get "right" but never really worked well in my set up. Too loud, too soft, too boomy, etc.
I'm still playing with the Rythmik's tuning and placement, but so far I like what I hear. It adds authoritative bass without being overbearing or boomy. I'm hearing bass notes I've never heard before on tracks I thought I knew well.
My only issue at this point is my mains now need replacement. Looking to stop in to Ascend and have a listen to the Sierra 2's.