plz explain this....

[tushar uniyal]

Hey...just a few moments back I heard(*lolz...not for the first time)the sound produced by the fan when its rotating..so anybody who could explain me the reason of the vibration sort of sound....? Thx in advance

I wrote the query in a wrong manner....dont reply and sry:(

[studiot]

The frequency of the sounds you hear are a multiple of the number of blades of the fan.

Sound is, of course, generated by moving air, which is what a fan does.