My wife’s monitor generates a high-pitched squeal while displaying mostly-white images (Google & many other webpages). The brighter the image, the more intense the tone. The pitch is very high, similar to the almost inaudible buzz that a television generates when it’s on, but muted. The problem is severe at 1024x768, 32bits, 85Hz, but persists at any refresh rate from 60-85Hz. Changing the resolution eliminates the problem – going to 1152x864 makes the noise go away.
What on earth causes a monitor to squeal like that? The problem is pronounced at such a common / popular resolution that I’m surprised the manufacturer (MAG Innovision) hasn’t been deluged with complaints.
You might try fiddling with the brightness or contrast of the monitor. I vaguely recall from my television days that the program monitor would get rather noisy if fed a signal that was “too white” (i.e., brighter than the whitest white that can be legally broadcast). Or maybe the chroma level (we may have had the same problem with oversaturated yellows - I just can’t remember, now that I don’t have to deal with it).
It could also be something to do with the kind of things you’re asking it to display - if you have your desktop set to a high-contrast scheme, or one with lots of primary colours.
I’ve heard that it is actually possible to control the tone that the monitor produces so as to generate (something like) music - by displaying a sequence of images consisting of vertical black and white bars - the width and spacing of the bars affects the note produced. Probably quite a swift way to destroy to flyback transformer in a CRT though (and just won’t work at all in the case of (most) flat screens).
Sometimes the whine can be selective, in that only one person in the household can hear it. I’m sure people have been driven mad by less. Sometimes electronic equipment can emit ultrasonic noise which is above the frequency range of human hearing, but if someone suffers from a particular type of tinnitus, the intermodulation product produced by mixing the tinnitus noise with the ultrasonic noise is within the range of normal hearing, and manifests itself as an annoying tone that no-one else can hear.
A transformer that is delaminating will squell. In this case it could be the high voltage one for the screen. You could try setting the display control to use a different syncing format to send the monitor signal or set it to a different frequency output.