Yep, I heard them at a meet:
Honestly, they were just ok for a closed back. They are as close to a closed back HD800(S) as you will get. But I couldn’t find 1 thing that they did as well or better than the original HD800(S). Maybe a little more bass quantity, but I use EQ for that anyways. So sonically it is a compromise in every way. Though I will admit the build felt even more premium and nice than the open backs as well as the glass being a really cool feature. But the price just doesn’t seem justified. If it were around HD800(S) prices like $1500 I think that would be fair. But at $2400 you have to really specifically need a closed back version of HD800(S) to justify it. Besides isolation, there’s no reason I would go for HD820 over HD800(S), especially when you can pick up used HD800’s for ~$650 these days. If I were to get a more neutral/reference closed back I would grab an Eikon at half the price of HD820.