Beyers QC is actually a bit off.

Did…did you just use the phrase "youthful ears"? Also, the DT line is super sibilant compared to these. The COP has no sibilance to speak of. What sort of volume must you be listening to that it starts to distort? At the level you should be more concerned about your hearing not the supposedly too thin membrane.

I completely agree with this review.  I too, was very excited about these headphones - purchased at $169.99, and I have been a big fan of mechanical items made in Germany.  Upon opening the packaging, physically the headphones are of rugged, very good quality.  They look great, they feel great, very comfortable on head.  Looked great on girlfriend, so I really wanted to keep them...

But then I tried them myself, was extremely disappointed with the sound which reminded me more of my Plantronics Gamecon 780's (Great deal for $50 to $60 bucks), and not close to my Ultimate Ears super FI Pro 5's.  Seeing as the sound was similar to a headset I paid $50 to $60 bucks for, I just couldn't justify them to myself.  The bass was OK, but high frequency sounds, was not good.

Therefore, I returned them and bought some Westone 2 Dual-driver's @ $179.99 on sale at Amazon.

Uh... you REALLY need to take your listening down dude. If the HE-400 sounded too sibilant you are listening WAY too loud. 

I just hope nobody will make buying decisions based on your review.