Neumann NDH 20 body ?

hi i wonder if anyone can help me, i bought a pair of the ndh20 from some advice from a guy on youtube. I explained it was for listening to music and not for mixing. I read lots of reviews about how detailed these were.

when I put them on I felt the sound was “boxy” I’ve seen a few reviews like this. is this just how they sound or are these faulty ? I use ie600 iems and the edition XS for listening to music. so maybe I’m just used to there sounds ?

im using the qudelix 5k which seems to drive them with no issues. I’m just very disappointed. any advice would be much appreciated