Hello Houdini...

I had a 2000 CFM fan running with 16 inch ducting ...20 feet... The five OH came to the house one day.. NO problem.. no noise.. nothing...

I mounted the EXHAUST using a bicycle tire and spray foam,.. this reduced the vibration and noise!!!

NOW.. there are other prioblems using such a big fan.. it will fOOk the air flow up in your entire HOUSE.. no more fires in the fire place.. and many doors will get bent over several months of intense suction..

If you use a speed regulator on your fan.. it will probably make more noise at slower speeds..

iloveyou