I'm truly terrible at comparisons like this but I'll try.
HD-650 is a great sounding HP. Clear, accurate, nice bass and clear mids crisp natural highs (to me not veiled at all, I think this is source/dac/amp related) but not sharp, fatiguing or harsh in any way, you can listen to them for hours easily. They sound 'good' and I thought for the price were a great all rounder. They really are.
Then I tried the D7000's for the first time today. Instantly I was smiling, nodding my head and really loving the music. They're more exciting and engaging, gorgeous liquid mids, crisp highs and more detail in the upper mid/treble region that the 650's - not as bright as the 650's though, for example the sizzle on high hats is more prominent on the 650's than the D7000's to my ear. On the denons there is no sibilance, kick, toms, snare, cymbals, female vocals, guitars etc sound very accurate to my ear (I play music so I know what instruments sound like to me live). There's a weight and warmth the denons have the 650's don't but I wouldn't call them coloured. I can't handle Audiotechnias for that reason and these are nothing like the 3000ANV's for example.
650's - how studio monitors sound (accurate, somewhat clinical)
D7000 - how I EQ my guitar amp and how well engineered gigs sound (fun, enjoyable)
Really just a nice overall sound to me, and the level of comfort for me is far better than the 650's. I do want to persue the MarkL mod to reduce the bass flabbiness though, to tighten it up a little, I think that'd be beneficial. Some bass sounds are just too prominent for my liking.
Edited by phonyx - 4/4/13 at 5:21am