Ok, M9 did not like my Silver Streak Kimber cable. (tried with some other interconnects) Indeed, with LCD-X on balanced there is no competition between soloist and m9 in any department, transparency, attack, details, etc. Must get a balanced cable for HD800 and fast
All my headphones are cabled for balanced operation. The M9 should be used balanced whenever possible. I have a couple of single ended adapters in case I ever need to plug any of my headphones into a single ended amp.