So... it turned out there are 2 major versions of the HD650.
The older ones had a black acoustic-silk screen, while the newer HD6XX share a metal sound-screen.
The older ones sound dark and some call the veiled, while the new ones sound more forward and ballanced.
I got a brand new pair but I expected them to sound dark as night. Naturally I was surprised, but now it all makes sense.
I guess I don't wanna have another expensive HD600... Don't get me wrong, they are great cans but I wanted something really warm for a change.
The Denons (AH-D2000 mainly) look decent warm and fun... strangely their price recently exploded from 220€ to 439€...