I am looking for a real good closed back headphone in addition to my HD800. The closed back I would use out and about and to listen to certain music that doesn't sound good on the HD800. Some bands I like but don't listen to too often, for example Boston and the Red Hot Chili Peppers don't sound good on the HD800. Also genres like hiphop and rap don't sound good at all on the HD800, I don't really listen to hiphop but I like to be able to. The headphones may have some punch but I'd like them to be at least fairly neutral and not too overbassed. A headphone I am thinking about is the Audeze EL-8 closed back, this because I have owned a EL-8 open back before and I like the sound signature. Another headphone I might be interested in is the MrSpeakers Aeon Flow closed back, although it is slightly more than I want to spend. My budget is about 600USD and I want to buy a pair second hand. Another option might be another open back headphone next to my HD 800 that fulfills my wishes and something like an Audio Technica M50x for out and about. My question is if there are any other headphones that I should consider. Thanks!