You can also try to describe these sounds like @PiecesOfKate did with her cat. But I would think that recording the noise would be easier in this case?
I should replace the fans on my case one of these days. It’s from '07. The stupid thing is that my wife’s more recent case is nicer in many ways even though it’s quite a bit cheaper.
But anyway, one of my fans occasionally makes annoying broom broom noises instead of being quiet, or even locks up on occasion.
On the flipside, except for presumably my GPU my computer can pretty much run fanless. I’ve got a nice Be Quiet! Shadow on top of my CPU. The motherboard refuses to boot if the fan isn’t running, but in a moment of brain damage I short circuited it to make it think the fan was connected and it didn’t go much over 50° even under full load. Normal operating temperatures (with fan) are from ~30 on the cold end to ~40 on the hot end. Fanless that changes to something like 40 to 55.
I mean, I still run with fans because less temperature keeps disks (and probably other components) alive for longer but the motherboard is built on the assumption of the stock cooler.
I used to have an online friend from england who, when I made a bad joke, used to say “You hear that? That is the sound of me angrily grinding my teeth so loudly that even you can hear it over there!”