Thanks for all that! Good stuff. As I posted earlier, I'm going to get the 600 to compare to my long term 650 and hear for myself.
No problem. I owned both for a while, sold both, regret selling the HD 600 as I never got a real replacement/upgrade for it as I did with the HD 650. You should like the HD 600 quite a bit, curious which you will prefer long term. I also found the two to react a more differently on different amps and gear more than I expected.