How are you creating your mp3's? Because a properly ripped 320 kbps mp3 should be virtually indistinguishable from a FLAC. I mean, I can't tell a difference between a 24/192 hi-res file and a 320 mp3 made out of that 24 bit file on Beyerdynamic T1's plugged into a 2000 dollar DAC/amp. I'm talking about ABX testing in Foobar...in 99% of cases can't even notice the slightest difference. Only with some extreme examples there might be tiiiiiiiiiiiiiiiiny differences in smoothness and dynamics, but that might be placebo, because I've never actually managed to score well in a ABX test, and I have extremely good hearing, I hear channel imbalances down to a difference of 1 db, had several pieces of equipment replace because of that, but only after the manufacturer tested them, trough hearing alone they didn't hear problems, I did in like 5 seconds after trying it. I think what you mean by K612's not being good for compressed recordings is that they're not good for badly mastered and badly recorded stuff, or badly ripped files. There are big differences between two mp3 files if one is well done and other badly done. Format plays much less of a role in the whole story, as long as it's a properly ripped 320 kbps mp3 of highest quality, or any kind of FLAC.
