I don't know, at least three hours-half a day for me to realize how good they truly were. It's kinda subtle how much detail they present to you, and being not quite as "easy" to get into and direct as the 650's it's almost simple to dismiss the 400. Someone mentioned gaming, these are more than perfect for it because of the soundstage/seperation, though it won't give you a very direct sound like some may want, I think it's the presentation is best for gaming IMO.
As for tracks for the 400, I'm going to have a really hard time with that one, it just does everything pretty good, but it is fast so really dynamic music is just great on it, feel free to try these out with some eq!
(Japanese Turntableism) Hifana - Tnaglang http://mp3juices.com/download/4806/135030153/01efa5f45a52/Hifana%20-%20Tnaglang%20(%D0%96.%20%D0%9A%D0%B0%D0%BD%D0%B4%D1%8B%D0%B1%D0%B0)
My taste is getting obvious here.
Edited by RushNerd - 10/2/12 at 6:20pm