A
ak-51
My 10" fan is quieter than my 6" fan; same brand (sunleaves). If noise is a concern I would just get a variac and turn it down a bit. With either of my fans, cutting the voltage just a little bit makes a big difference in noise. Using insulated ducting, especially on either side of the fan, will cut down on noise as well. With insulated ducting, bungee cords suspending the fan itself and a variac to turn it down a bit I've managed my noise pretty well. It's to the point where you would notice other things before the noise, such as very bright lights or a slight odor or a bunch of plants.