Do you have a filter? I didnt see one mentioned, that kills alot of noise, i use accoustic blankets and wrapp the fan and the ducting up until my duct muffler, its kills 90% of the noise. I staple the blankets against the wall behind my fan also to soak up and extra noise. If for some reason your not using a filter, which i hope you are, a ductmuffler works stuck on the end of a fan also. I dont mount mine on the ceiling or walls either i think its to unbalanced and vibrates. i just stand a 14in mountain air filter up, put a 14inch to 12 inch reducer, then the 12 vortex, 12 inch elbow out the room, and my room floor is covered in gym to absord any other sounds from floor fans to air pumps ect, also great for crawling around easy on the knees. My room is ultra quiet ,that was my biggest paranoia as well