Logic bounce sounds 'dull' after bouncing (the top end dissapears)

I have had an issue for some time now where whenever I bounce a track (I have tried every bounce setting under the sun) I listen back to it through iTunes, quicktime player and other software and it looses some of the 'crisp' top end sound, making the mix sou dull; like I've said i've tried all different file formats, offline/realtime, dithering, normalisation on and off, nothing changes it. This is not a mixing issue either. I can take an wav/mp3 of a professionally mixed sound and simply bounce it with no changes being made and the same thing happens. This isn't on my mac either as it happens when I share it to other devices. I am stumped and have spent hours trying to fix the issue including reinstalling logic.

The only thing I can think of is I downloaded 'EQMAC' once but that has now been installed. I can't find ant left over files that are changing the quality either.

Hope someone can help!