lol @ the very idea of a grow room being too noisy...
Its like saying "I wish I could flush my toilet after I take a shit, but when guests are over, I don't want them hearing the flushing sound, it's just so offensive"
Need to get real picky, get a nice long section (pref. straight) of 6 or 8" duct, and put the fan into the attic/roof area, bolted to the structure, w/ rubber washers, and connect it to the top of ur grow box...
If smell is a worry, get a filter on the tent end too.
Bottom line, if a fan or 2 in the room upstairs is "too much noise" consider donating your eardrums to someone who will put them to a more useful life....
My grow pulls in air from UNDER my home for fresh cool CO2 rich air... this makes the incoming air 10-30 degrees cooler than outside, as its a constantly shaded concrete slab under us, helps maintain cool