I had same result as you , almost nothing happening at all in that range when I had my HD800 ( just sold them ), and I thought it was due to the 300 ohms impedance. I did not have this problem with my Denon AH-D7000 as they were 25 ohms, and I think 107 or 108 db sensitivity, so by 9 position, had plenty of loudness, and did not need to go higher. I just received yesterday my LCD3, and put them on burn in with my BP6 pre, as I did not want my BHA-1 to run very hot for a couple of days, can't comment on them yet in that range.