Thanks, but I think the transition might be too abrupt. I know you're Dubstep Girl, but I'm definitely not Dubstep Boy.
This probably doesn't add much, but I remember moving from the 650 to the LCD 2 R1 and feeling it was in a different class altogether (though it still took me two weeks to wean myself off the 650's homogenous and seductive mids). However, I never liked the sound of the HE-500 and found it inferior to the DT880 Pro. I'd like to compare the HE-500 and 650, but I strongly suspect I'd prefer the 650. Jerg's mods? Well, the HE-500 sounded bad enough to me that I couldn't believe mods could rescue it, just as the Fostex T50RP sounded so bad I couldn't believe that could be rescued either. I'm happy to be proved wrong, but frankly, unless I develop a sudden and inexplicable aversion to the 880, I'm not that interested.
BTW, I'm not suggesting the HE-500 sounds anything like as bad as the T50RP. To my ears that baby is an absolute disaster unmodded.
The earpad modification I devised was specifically targeting issues with HE500's sound, mainly the midrange ringing and the poor mids->treble transition which, believe me, bugged me a lot. It's not some holistic crap branded as mods hoping to do something to a headphone's sound, and hoping it's more positive than negative.
Yes, I realize you put a lot of work into that mod and the results were much lauded--no doubt justifiably. As I say, always happy to be proved wrong. And of course the HE-500 has only relatively minor problems compared to the Fostex, which to my ears is all over the place. HE-500 even unmodded is clearly a quality product.