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.
Yes. It’s not necessarily the size that makes the noise, but rather the rpm required of the smaller fans to move an equivalent amount of air. I have a fan in my phone, for instance. It is so small that it spins at 23,000 rpm to make just a small amount of air movement I can barely feel, but easily hear. My ceiling fan can’t be heard at all but still moves WAY more air while spinning at a couple hundred rpm. The air turbulence from blade speed is most of what you hear from a fan.
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?
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.
Yep, which is why those Dyson fans emit an annoying high-pitched shriek.
I just imagined someone turning on a fan and hearing an electric f1 car drive by
Yes. It’s not necessarily the size that makes the noise, but rather the rpm required of the smaller fans to move an equivalent amount of air. I have a fan in my phone, for instance. It is so small that it spins at 23,000 rpm to make just a small amount of air movement I can barely feel, but easily hear. My ceiling fan can’t be heard at all but still moves WAY more air while spinning at a couple hundred rpm. The air turbulence from blade speed is most of what you hear from a fan.