Not many people post about HD800 and Asgard 2
So... Ill try to help since when i was looking I didn't find much.
First of all Asgard 2 is warm sounding the mids are pushed up a few db and the bass is a bit too, im 100% about this plz don't argue :p
Soo HD800's problem is that it has a 6k peak and the asgard 2 doesn't bring it down... Soooo if u don't like that then Asgard 2 isn't the best.
But If you like how the HD800 sounds then.... Yes the asgard 2 sounds really good. You get WAY more than enough volume dynamic is very good. and that's about all.
I have heard many set ups and to be honest Asgard 2 Bifrost + HD800 probably gets you 90-95% there (009=100%)
just a small note HD800 sounds nice but its not something you can use for 5 hours because of the treble peaks(your ears gets tired), for that you should get LCDs.