Originally Posted by TMRaven
HE-400 is definitely more laid-back. The HD600's mids are borderline aggressive. If the type of rock you listen to has lots of electric guitar, you might pick the HD600. I tend to like the HE-400 more for prog rock.
Maybe you're using the wrong deffinition of aggressive here, if one exists that is.
I find the HD600s really laid back, not quite to the extent of the HD650s which are laid-back to the point they're referred too as veiled. THe HD600s are, for me, a good neutral headphone to relax with; classical, classic rock, smooth jazz that sort of thing... If I want a more up-beat sound while remaining neutral I'd consider a DT880; acoustic, rock, indie etc. A more aggressive sound from here would be a SA5000 or perhaps a HD800.