Studio Display "Buzzing" sound

It sounds like an earthing issue with the power socket. Have you tried different power point in your home or office location?

If the above doesn't resolve then if its within the warranty and apple care period then you could ask for a return and get new units.

It had happened to my Apple Studio Display, and I had exchanged it 3 times at my local store. Finally, I had to return the 3rd unit and get the money back.

Please see the video included below. I was experiencing high-pitched intermittent buzzing like crickets... however, it was not loud. It was very annoying and I was getting headaches from it! I couldn't tolerate it given that I paid a premium price for it, so had to just return it.

https://www.youtube.com/shorts/QDXrO8SAm0k

If you find a fix then please share here. I would like to buy it again in future.

I would like to recommend you consider a UPS unit to protect your wonderful and expensive devices. So the one with Sine Wave would be a bit more expensive roughly $500 Australian dollars or higher, but still worth it. If there is a thunderstorm or power issue, it will protect your set-up. At the same time you will get regulated power for all devices. Anyway, good luck :)