Engine Driven Fixed Fan?

Have any of you encountered fan noise at certain engine rpms when driving with a fixed 6 bladed fan? Thanks
Slip the belt off, and make sure it's coming from the fan area, and not the pump bearing.

I can't hear my fan over 2000, cuz the headers are starting to scream and the tires are already wailing. But I have a clutch on my 7-blader. lol.