I don't thing that the HD800 is a bright headphone at all. I would rather say that Audeze is airless with to much bass.
Yesterday the LCD-X arrived and after 1 minute listening it is cleaer that it is an Audeze with the typical Audeze house sound. Okay it is not as dark and veiled as a LCD-2 but the bass quantity is to much (most the time) and voices are a little bit to dark as well and sounds not neutral as it should. The bass is to terse (I don't know if it the correct word) and push the rest of the frequencies one step to the background.
I use silver cables with the LCD-Xs and I've had no problem of the sort. The LCD-Xs, HD-800s, and T1s and my favorite headphones for classical music. I love the LCD-Xs because they sound li,e balm to the ears (a dark mahogany sound) while retaining the extended treble necessary for classical music. True, the soundstage is not as big as the HD800s or T1s, but it's not bad either...The Xs are one pair of euphonious cans!