After a couple of weeks with the new HE400 with new driver revision, I have to say it has way to much treble compared to the older version (which I returned due to a driver defect).
Please give this feedback to Dr Bian and the Hifiman engineering team, as it's really important that they don't tune this headphone into something worse than how it was before and ruin its building reputation. ALL current reviews of HE400s describe it as dark with slight treble sparkle, but the new revision of HE400s are clearly not that, and are just plain hot in the treble.
Makes me wish that I hadn't sold my r2 version!! I will wait until HFM retunes this driver before I'd consider buying another pair.