I still am a fan of the HD650...Still one of the most tonally accurate cans to my ears.
All this talk of the treble being too muted is a load of crap in context to a reality based reference.
Of all the headphones I own the HD650 is exacto (the most correct) with treble levels when I reference the percussion and imaging test track....coming from a drumming background with lots of cymbal experience.
I can't stand how Senheisser turned its back on THE sound that MADE IT FAMOUS.
The HD600 has the EXACT same strengths and weaknesses as the HD650 in terms of articulation and they sound fundamentally the same to me with only a tiny variance...the difference is easily made up with the volume control or playing a different track. HD650 in the studio....believe it....very common.
HiFiman might have brought this sound over to us poor ass summit fi excluded...Hifiman are fast becoming legends...Robin Hood for us broke asses. I might check out a pair soon.