Side note. The HD650 have been burning in around the clock for the past few days to put the finishing touch on the break in. Since I have 3 headphone amps at the moment, with a few of them connected to the Schiit Gungnir DAC at a time, I will usually listen to one pair and the other is burning in its box. The HD650 make me smile every time I put them on. Very good set for extended listening sessions. Tighter and deeper bass than the HD600 and a slightly more extended top end. Mids are just as smooth and slightly laid back just like the HD600.
Do I hear the "Sennheiser veil" that is often discussed and beaten to death on other forums? Well by comparison to Focal Utopia and Elear, yes...
Definitely. It is still a resolving enough set where you are not missing anything, it is just presented in a more laid back, non-fatiguing and forgiving way. It is a great headphone that will take you across hours of various genres of music and recording quality. I don't get tired of them, makes me want to keep listening, way past my bed time.
One little gripe I have with it is that the tension of the headband is just a bit too much. The earpads are a bit stiffer than the HD600 and I feel the pressure on my head more so than the HD600. When I wear the HD600, I often forget they are on my head at all and try to walk away from the computer with the cord still attached.