Argyris
Head-Fi's third most long-winded poster.
Aside from the nasty dips and peaks in the treble, the HD700 does have a little more sub bass. For me the treble is too volatile and would require more fiddling with the EQ than I'd be willing to diddle with.
Fair enough. Mind, I think you could get a similar increase in bass extension by going with the HD 650 (depending on which measurements and accounts you agree with), and without the additional signature issues.
I've always thought the HD 700 plot reminds me of a lot of V-shaped IEMs: midbass hump, a trough of some description in the upper mids, and a prominent spike in the low-to-mid treble. I've personally never liked this general signature shape very much, particularly the treble spike, which is smack in the middle of where I'm most sensitive.
I'd be interested in how somebody who has heard both the HD 600 and HD 700 would compare them, mainly to see if these plots line up with their experience. Sometimes I've felt like the plots match pretty closely to my initial expectations; other times they seem way off. Because of this I always place more weight on actual listening impressions when it comes to headphones, particularly if a specific issue (e.g. pronounced sibilance) keeps coming up. Sound is funny. And subjective. Which is annoying when trying to work out what to buy with limited funds.
EDIT: Closer reading of previous posts shows me that StanD has heard them both. Must read more carefully.