and you believe in that graph ? or your ear? I don't. I think that if you pull 10 people off the street and ask them to listen to the HD800 and HE500, all will say HD is bass light compared to HE500.
I am not debating bass quality/extension here or which bass one would prefer. Graphs, especially the one in the link, is extremely misleading to me. I do find bass on HD800 satisfying as well for certain genres but not all. That's where the HE500 comes in. Maybe, it's just a personal taste/preference matter. Just my 2c.
Fyi I'm a bit drunk at the moment.