[R300]

I blowing dust off the drivers with straw, but stupidly touched one of the drivers by accident.  I've noticed a very small indenttion on one of the clear bubles covering the drivers.
 
I'm not 100% sure, but it just sounds the tiniest bit distorted compared to what I'm used too. I may be imagining it but want to fit a new capsule to make sure. Anyone know if this part can be easily replaced or is it a return to Sennheiser job?

 

[Nagasaki_Kid]

This is an easy repair. Just use some scotch tape and pop the dent out yourself. 
first stick tape to dent 
second pull gently ti unpop the dent from the driver.
 
driver replacement for the hd600 is easy diy no need to send in for repair.