i have recently added he500 to my headphone collection of hd650 and d2000s. I have got to say that the treble and bass are so much better in the he500 compared to the hd650. But i just cannot for once think that the he500 are superior in the mid range. The mids on the senns are so damn special to my ears. Not saying that he500 are any slouch as they are not even properly burned in yet ....but i am so loving my headphone collection for the different sound signatures and also that i won't be able to afford anything higher for a long time to come.
Yup. The HE500 does have better highs and a touch better bass. But goshdarnit, the HD650 does mids so well that... well...damn. When I listened to the soundtrack for "Spacebattleship Yamato" film and the choir starts...the hd650 gives me shivers.