Some Apple Studio Display owners have taken to online forums to complain that their monitors make a high-pitched buzzing sound that appears to be emanating from the top of the screen or behind it, and may be being caused by electrical interference.
There are complaints on Twitter, Reddit and the Apple Support Community dating back to June, and more recently on the MacRumors forums, about the issue, which is variously described as an “electrical buzzing” and “constant ringing” that is “loud,” “high-pitched,” and “very annoying.”
Several owners have found that the sound is not fan-related and only happens when a MacBook Pro or iPad is plugged into the Studio Display. Some have also noted that the noise can vary in intensity and pitch depending on the time of day, suggesting an electrical shielding issue may be the cause of the fault.
Read more at MacRumors.com