My measurements look rather different. I'll post them later or tomorrow with some accompanying discussion. I'll show frequency response and THD measurements to start, compared to HD800, HD800S and MDR-Z1R. That video above is interesting (the one with Lachlan and his colleague). In that video are impressions from two gents prior to having seen any measurements. Brian (@AxelCloris) is working on editing Axel Grell's HD820 presentation from CanJam New York now. We hope to be able to post that in the coming days. My long story short: The HD800S has the edge in overall resolution -- that should be no big surprise. The HD800S is open-back, free-breathing, unencumbered by some of the issues of acoustics/physics that must be dealt with for this class of closed-back headphone. That said, for tonal balance, the HD820 is my personal favorite of the three HD8XX models. (For reference, I have a pretty strong preference for the HD800S versus the HD800.) Let's talk more later.