[bobgpsr]

And quite a few of those of use who use a pro amp for home theater (especially for driving DIY subwoofers) modify the fan's electrical drive. Take the covers off and insert a in-series dropping resistor of just the right ohm-mage and wattage to still let the fan turn but be much quieter. The value for this resistor will vary according to the fan voltage and current draw.

I also included a switch to bypass the dropping resistor when I know I'm going to be pushing the amp.