Subwoofer hunt

Rythmik's are very musical and integrate well with the mains but depending on your room size, may not have enough weight/ punch. I had the E15hp.
I currently use seaton Submersive hp+ master and slave sub. It's every bit as good as Rythmik sealed subs but a lot more potent in output, specially mid bass.

For more output than the E15HP (and F15HP, with a slightly larger enclosure) provides via it’s single 15" driver and 600w amp, Rythmik currently also offers the F25, with twin 15" drivers each driven by it’s own 400w amp. The E15, F15, and F25 are all sealed designs. There is also the FV15HP, with a single 15 and 600w amp in a ported enclosure.

In development now and available later in the year are two new models featuring the new Rythmik 18" driver, one with a single driver the other with two, both in ported enclosures. A sub with two ported 18" woofers---can you imagine the output capability?! And with Rythmik’s famed Direct Servo-Feedback sound quality. A game changer no doubt.

But Rythmik (in conjunction with GR Research) already offers a game-changing sub---the OB/Dipole Sub. Not as much output as a "normal" sub, but with a sound quality totally unlike any normal sub, regardless of price. Two (or three) 12" woofers mounted in an Open Baffle H-frame and operated in dipole fashion. This sub redefines the term "stops on a dime". THE sub for any planar loudspeaker (ESL. magnetic-planar, ribbon), or other high-resolution design. Absolutely without a trace of overhang/overshoot/resonance, and exciting fewer room modes (the front-to-back but not side-to-side room dimension), a major contributor to the "room boom" often experienced when a sub or two are added to a high-performance system. The only OB/Dipole Servo-Feedback Subwoofer in the world!

M&k subs are quite good,  they have adjustable high pass filters,  the new x line has two bass driver's, these compete well if not better jl audio subs. 

JL subs are bulletproof and easy to integrate because of the adjustments available including continuous phase.  They also have flat frequency responses which also makes them music worthy because the avoid frequency peaks- one note wonder syndrome  
I have used their mobile subs and amplifiers for years and just recently tuned a JL D110 sub to perfection in my home system.  
My room response is flat from 20Hz through the crossover.   They also tend to be equipped with generous amplifiers with lots of headroom.  Reliability and quality is top notch.