I had opportunity to try 560 this evening also at AC Gears (Thanks for the event guys!!). I guess guys already know how comfortable it is so skipping that part.
I do not own HE-500 So I can't really get into detailed comparison between HE500 and HE560, but from my memory, I can say one thing that this one definitely has more bass.
To my ears it sounds like it doesn't sacrifice anything to get better. For example, IMO the new Audeze LCD-X lost LCD-2 and 3's syrupy lush sound a little bit to get more balanced clear sound which makes people like either LCD-X or LCD-3(I like both though).
He-560 still have ortho's lush, emotional sound with decent amount of detail. I got lush female vocal with strings behind pretty clearly.
I didn't listen to any music with strong treble(I am not really a treble lover anyway) so can't really describe it's treble.
Mid: it could be the differences caused by using different set-up there but HE-560's mid sounds more lively and up close compare to LCD-X. I actually like HE-560's mid better than LCD-X's mid
Bass: pretty strong has tight impactful sound little less quantity compare to LCDs but tighter.
overall, to my ears it sounds like very lively detailed dynamic headphone sound + Ortho mid. Maybe it is weight that made me feels like I was wearing ortho headphone;;
I wish I had my own gear with HE-560 so I can get better comparison but M9 was too heavy for NYC subway
BTW when I said Dr. Fang that I am thinking about buying HE-6, he told me to wait for HE-560. Also I really like HM-820
Nice impression! Considering I recently got to hear the LCD-X (still prefer the LCD-2/LCD-3 personally) this kind of helps put it in to perspective a little more...also, good news on the mids. I can only imagine refinement getting better from these prototypes. ::my wallet gently weeps::