Just bought a new 650 and i can honestly say it is a big improvement over my 6xx with relatively new pads. The 650 is more alive with tighter bass better dynamics with more detail and surprisingly missing that slightly exaggerated mid bass of the 6xx. Also no Sennheiser veil. Seems to sound more like the hd600 but smoother and more balanced.I recommended to anyone who runs Roon to try some of the new headphone EQ presets for HD650. Never eq’ed my headphones in the past but the inner fidelity eq for HD650 in Roon is quite surprising. What was once occasionally muffled especially with vocals is now crystal clear without losing any of the 650 character.
Sounds fantastic on my Rebel Amp.