I wonder if it's the driver material? I think @tommytakis mentioned it being graphene at the show but it was very briefly in passing and I could be remembering wrong. ----- With regards to the measurements, I only listened briefly, but I didn't hear a severe dip in the 8k range that shows up on the measurements. Anecdotally, I've found that stuff like snares will sound off or cymbals won't quite have their "full color" with big dips in that region. Is this a measurement artifact or did I just not listen to enough music with these? Also, a completely different question @purr1n - have you used IEMs under ear muffs before? The few drummers I know all do this. The above provides a little more isolation once you find the particular muffs that you like and is more universal blah blah.