It’s also possible to reduce perceived noise with some blade spacing tricks. I remember reading about how Apple designed the MacBook fan blades to seem really quiet under normal load. It was pretty interesting to read. I’m too lazy to find a link, but it should be easy to find with a quick search, if interested.
Fans are usually loud in proportion to their speed. Quiet ceiling fans have a big diameter and many blades. Doesn’t a small fan cause a lot of noise?
Yep, which is why those Dyson fans emit an annoying high-pitched shriek.
Honestly depends on speed, quality of bearings and motor, blade geometry and thickness as well as any possible enclosures.
The biggest source of noise with fans is air cavitation.
It’s also possible to reduce perceived noise with some blade spacing tricks. I remember reading about how Apple designed the MacBook fan blades to seem really quiet under normal load. It was pretty interesting to read. I’m too lazy to find a link, but it should be easy to find with a quick search, if interested.
I just imagined someone turning on a fan and hearing an electric f1 car drive by