The RSL 10s mk2 is an excellent subwoofer, period. "Speedwoofer" is certainly an appropriate name, as this thing is quick, tight, dynamic, musical, and does everything I personally need for movies and for music. My mains are smooth silky great-imaging and moderately dynamic Q Acoustics Concept 50, but what the RSL does is open up and clarify the mids and highs of the Qs even further, and adds impact, kick, depth, and liveliness to the whole setup... it's the best of both worlds: awesome imaging and non-fatiguing clarity in mids and up top, and the liveliness and kick of Klipsch without the Klipsch drawbacks. No, the RSL doesn't really reach below 20, but I don't miss that at all, even having had it before... the RSL isn't "heavy" and ponderous: it adds life-like liveliness, and that's more important to me for all around enjoyment than making sure sure the "measurements" are flat to 20 or below. The RSL also easily disappears into the soundstage, and I cannot localize it at all (I cross at 60hz... which you might say of course you can't localize but the truth is I COULD localize a much more expensive sub crossed the same way even after dsp manipulation and various locations trials... I don't have localization problems at all with the RSL). I really enjoy the unconstrained live quality of the 10s mk 2. I'm curious about a ported Rhythmik, but it'd have to be the lv12-m in my circumstances which is fine, but I'm worried that although it might play deeper it won't have that same lively quality that the RSL brings.