I didn't really compare them head to head but I enjoyed how the X1's seemed to fully engage you in music, they're quite forgiving too.. To me the he-400s sound more veiled.. the soundstage isn't as curved (X1's have angled drivers), he-400s bass is tighter/more defined.. but X1's bass hits HARD. he-400 sound more metallic overall, more sibilant. I think i like X1's vocals better, but i enjoy he-400s superior separation and detail more, not a fan of non-replaceable earpads either. I'm not sure if the superior separation gives the illusion of a more deep soundstage, but that's another thing I noticed.
Edited by Jabse - 1/19/13 at 12:29pm