[Semiregular]

Which music are you listening to?

Which artists, genre?

Everything else comes in second place to this. If it's popular music, x-factor stuff, popular rock then you should hear that bump in the 8k range as that's where the vocals are. For playback on radios, car steroes, TV's, standard HI-FI's and ipods, that's how it should be just so that the vocals can be heard properly amongst the mess of everything else.   

I listen to artists like: Kikou Sound Works, AVtechNO!, L75-3, S.C.X and Powerless Decision. They are all either jpop, electonic or something in between.

It's weird though, as when i first got these they seemed to sound quite balanced. They have gotten louder and more harsh during the week i've had them.
I admit that some of the songs were brighter out of the box than with my previous phones (Sennheiser CX 150) but now everything is so bright that it make my ears hurt. Not fun

 

[SennHI808]

ie80

 

[CantScareMe]

Oh right. I haven't heard them tracks, but they must be okay- they weren't harsh at the start. Somethings at fault. They shouldn't really change like that on you. It could be that the cable connection is disturbed by some dust or sweat (happened on my shure se315 for a bit). It could be a problem with the nozzel or the iem body. It could be that the tips are not ideal or in proper position.
 
Or it could be yourself that has changed- your ear/physical health, state of listening, time of listening, way of wearing the earphones, deepness of fit.........
These may seem far-fetched, but I have come across every single one of them factors, amongst many others, responsible for effects that you mentioned- an earphone suddenly sounding much more brighter and harsher.