My rpi has been really loud with its fan for the last long while. I could still hear it behind a cupboard and a door. While diagnosing a usb thumb drive’s i/o issue, I decided to dampen the sound.
Using 6 roofing screws, I pulled the rubber and metal washers off and put on the fan mounts to the case. It has had the effect of increasing the mass of the case and reduced the sound in pitch and volume, I expect the lower pitch will be easier to muffle.
It is much less annoying.
The washers were a bit larger than the fan mount plastic sockets. I did not try to force it to sandwich between the fan and the case.
So I looked into it:
I have a 2 prong connected power source, A 1 prong needs to be in ground, and the only pins with power and adjacent to ground is 5v.
There are some options with getting a mofset and control by gpio or splitting the sockets but I didnt want to add scope creep
The two 3v3 pins are not consecutive to Ground pins. You need another connector for your fan, or plug extensions cables. https://pinout.xyz/pinout/pin1_3v3_power/