Same iPhone, same earphones but, since upgrading to 2.1 last week, when using the iPod the treble seems to be much, much higher and the bass not so prominent - so much so it's starting to really hurt my ears. The EQ is set to Off (as it always has been). Selecting treble boost makes the treble stupidly high and treble reducer just sounds muddy. So, is it my ears or have others noticed this? Also, is it possible to temporarily change back to an older firmware to compare?