I sent my M5 back. Maybe they have been defective?
I already wrote this in another thread:
Somehow I don't like the highs. I don't know how to describe it as I'm noob in this stuff. If I would describe it exaggerated, they sound a bit tinny and sometimes I get the feeling like there is a kind of a slightly echo.
My LG in-ears which came with my smartphone aren't very good and only have much bass which seems to swallow the higher area and they have a much worse resolution but they are more comfortable to hear somehow. I guess I prefer weak highs to very present and higher resoluted but kind of weird highs? In general for me the M5 are to bright/high. I don't have a problem with highs in general as my Superlux HD681 do have a lot of them and I love those headphones. It's just how it sounds with the M5. Even the room and where the instruments appeared in it sometimes sounded wrong.