Effects of grill patterns on fan performance/noise (2011)
Interesting that "no grill" is always the most quiet, is there no configuration possible (or has never been explored) where the air flows in such a way that sound waves cancel each other out? I.e., even holes emit noise 1/2 phase changed from the uneven ones? Would be a nice area of research. Perhaps it exists, I'm lazy (some 5 mins of searching gave me nothing).