You find the HD650 too smooth?
What does 'smooth' mean in regards to frequency response and transients?
When I hear electric guitars on the HD650 the 'grain' on their sound is much more apparent than with my DT880 which has a very soft attack and tends to smooth over the grain. In this way I'd call the DT880 smoother. The peaky treble response with the DT880 on cymbals and other high frequencies, however, definitely makes the HD650 smoother than the DT880 in that regard.
If I had to describe the HD650 I would say that it sounds like a GRADO (my SR60) with a lot less treble and more mid bass. The mids are almost equally forward. To put it another way, the HD650 and SR60 seem from the same family, but tuned differently and the DT880 seems like a different beast altogether.
Again, that impression seems weird... Is it?