Well, I did this test just last week.
I own 2 HPR122i's and I bought a K12 from Guitar Center.
I did side by side tests for hours.
Here's my opinion (and I would love to hear other people's opinions on this too):
I went back and forth on what I liked better....it was a very tough decision. They're both great FRFR solutions.
In the end, I returned the K12 (and now have a boat load of GC store credit that I wish I didn't have).
My reason for sticking with the HPR....it sounds bigger. And yes it is a bigger box...so some would say that it should sound bigger...but to me it was the difference between it sounding like a 1x12 guitar cab vs. a 2x12 guitar cab. And while that may not be important to some, to me it is.
I play hard rock music (not metal) and I love a heavy, chunky guitar tone (Zakk, Dimebag, Nuno). The difference (for my tone) between the speakers is that the K12 had a nice top end...very clear, cut very well. I really liked that, and it was something that I wasn't loving about the HPR, so it was part of what I was looking for (and found) in the K12. BUT...for palm muting and chunky tones....the HPR can handle a lot more bass. The HPR moves more air than the K12. My really chunky patches flopped out on the low end when I pushed them on the K12 (and yes, I re-eq'd my Output to the K12 to try and dial it properly...but it just doesn't respond as low as the HPR).
I went back and forth on this decision quite a bit, because although the HPR put out some really nice chunky low end....I kept thinking - "do I really need it?...And is the nicer top end on the K12 worth sacrificing some of the low end chunk?" Well in the end, I decided the HPR was the best fit for me. The decision came when I decided to try my clean patch. My favorite (Mark Day) clean patch sounded nicer on the HPR...it just had a bigger image. So not just my chunky patches...but also my clean patch sounded more pleasing.
BUT if I had never tried the HPR, I would have been VERY happy with what was coming out of the K12.
When I played had both the HPR and the K12 on together.....it sounded amazing....but I don't have room on most stages for 2 monitors, so the K12 went back.
My next step is to try the Atomics and (hopefully) find a FBT Verve 12 to try...
I would really love a speaker that combined the best features of the HPR (low end chunk) and the K12 (clear top end).
But in the mean time, I'm sticking with my HPR's.
On a side note....I would love to do a FRFR shootout in New England (Boston, New Hampshire area) if anyone is interested in getting together and bringing their speakers? I have QSC HPR's, JBL SRX (unpowered), RCF ART200a's.
