I decided to go ahead and take the leap into higher end gear since I now have a headphone amp. My question is which one of these cans will be best suited for rock/techno? I don't know if anyone has heard the sound signature (tapered off highs and highly present mids) of the HD 448s, but I loved them for rock and techno, I just wish they had a little more defined bass. I am afraid that if I go with the 600s they will be to bright or if I go with the HD 650's they will be too dark for rock. Can anyone give me any advice?