Add QSC to the Doc's suggestions above, they too may/may not need a quieter fan mod. Keep in mind, you'd likely void your warranty once you open up the unit. the GX5 was used by a member who used to frequent the boards not too long ago(with a combo of PSB/Axiom speakers).

You may want to contact QSC directly and ask them about such a mod. I'm sure I read somewhere on another forum that they did this for someone who wanted a quieter fan for HT use.

Half of communication is listening. You can't listen with your mouth.