Yeah what I heard corresponds with the graph, the 580 while has a similar tone to the 600 (so it's not nearly as laid back as the 650) the 580 has a bit more bass.
Not laid back, dark and boring like the 650 but not too bass lite like the 600. So yeah just perfect. The 600 is a tad more airy tho and the 650 has that warm euphonic lushness.
Excellent summation. Reflects why I rate my "tweaked" HD580s a hair ahead of my HD600s. Too bad more folks haven't had the chance to audition the HD580s, especially "version 2" (as discussed in this thread) which I have.