those vortex fans work really good, but I have 2 squirel cages that I suspended with twine, and taped to my flex hose and they run quieter than the vortex. I think its because they don't pull as much as that "turboprop" in my vortex. the intake sounds like itll pull yer face off. haha... Seriously, if yu have to get a squirel cage, hanging it reduces a lot of the humm.