What if the vibration is on the recording and the headphone is not able to produce it ie. is not fast enough? What is ideal exactly? I don't think a headphone should stay "ringing" for a sense of false realism.
These are very detailed and I find the tone with many instruments is spot on. They don't sugarcoat anything, but notes are easy to follow and they lack coloration that would make a headphone boring in the long term. Musicality in its finest. By that I mean, that it's accurate enough but not harsh, like many studio gear that's meant to pinpoint flaws in recordings. That said, the treble is still a bit too hot.
Not sure if it's my head or not, but I've been listening to the 8400 for two or three hours today and I think the bass response is much more articulate than what it used to be. I go back to recordings I tried when it wasn't quite spot on and more stuff is not distinguishable. Could this be burn-in or that my listening habits have just adjusted? Maybe should take this particular piece of conversation to the 8400 thread
Edit: I have to add that I can't go back to the K272HD anymore. A triumph