You can adjust this with the brightness on the remote control. I can practically no longer hear the projector from about 30-40% brightness.

I also only know the option of controlling the fan indirectly via the brightness. At low brightness, the fan also runs slowly and somewhat less loudly. Whether you find it loud depends on the film, the ambient noise and your own perception. Personally, I'm a little disappointed, it's a little too loud for me during quiet films. (Otherwise, however, everything is fine with this device).