GarageBand Frequency (Maybe iTunes)?

I've been working on some music in GarageBand and I've been listening to the music in iTunes with a Graphic EQ and noticed that the highest frequencies are all but missing. I'm one of those people who can hear when a tube tv is whining, even though I am getting to the stage in life where I won't be able to do that for too much longer.

I believe it to be Garageband because the missing frequencies are very obvious compared to a file downloaded from iTunes. Anyone else seen this issue?