I've tried almost every Sennheiser headphone. This is the most open sounding closed Sennheiser. More open sounding than any closed Beyerdynamic, Audeze, MrSpeakers, Foster family (Fostex, Denon, EMU), Phillips, Bose, Beats, Audio Technica, closed headphone. Only the Sony MDR-Z1 is close to as open sounding. The Meze 99 Neo has a very 3D sound for a small cupped closed back, but the thick low mids and rolled off highs keep it behind as well. The HD820 has a more stereophonic spatial sound than their HD580, HD598, HD600, HD650, HD660, HD700. Only the HD800 and HD800s had that stereo placement height and depth, with some extra spaciousness as to be expected. Should you want the sound of the HD800s with smoother highs, better sub bass extension but no boominess and don't mind slightly less spatial airiness, these are your cans. There is something to be said about sub bass extension without added boom. They'd done that with the HD58X apparently, which has very slightly less lower mid, similar mid bass, but extended less rolled off subs. I've not heard that (they're on their way now) but their graphs tell me they are getting good at tighter, cleaner, yet more extended lows.