I'll add that it is obvious when certain types of calculation start, too. It's neat to be able to point to this and say I wasn't crazy to a few friends who didn't believe me.
On an older computer an animated gif on a web page caused my speakers to feedback differently than playing video (and this worked even when the sound card was muted). And the signals never fully masked each other. I always suspected it was a grounding fault, but it was subtle and generally unobtrusive so I never tried to fix it (it's almost a feature, like a blinking hard drive light).
Notably it is far easier to hear through the amplifier that is the sound card, but even with no speakers, a quiet room will still show the same. As others noted above, CRT monitors are notoriously loud, and you can definitely hear different image patterns.
I can also get a good idea whether the CPU is idle or doing some particular task just by listening to the motherboard. This isn't any sort of paranormal effect, it's quite audible. I suspect most of it comes from the inductors on the CPU vcore DC-DC converter.
For me, the sounds I hear are somewhat like this:
Animated GIF = chuff-chuff-chuff, one chuff per frame transition
Scrolling terminal window = low hissing, like someone slowly breathing out
Dragging window around the screen = high-pitched whine
CPU stress test = very high-pitched whistling
Loading a big app = a more noisy hiss than scrolling the terminal window, interspersed with HDD sounds
I was tested at a young age to have above-average hearing range, so maybe that also has a factor in how well you can hear these things; I don't listen to loud music or subject myself to loud noises either.
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I'll add that it is obvious when certain types of calculation start, too. It's neat to be able to point to this and say I wasn't crazy to a few friends who didn't believe me.
On an older computer an animated gif on a web page caused my speakers to feedback differently than playing video (and this worked even when the sound card was muted). And the signals never fully masked each other. I always suspected it was a grounding fault, but it was subtle and generally unobtrusive so I never tried to fix it (it's almost a feature, like a blinking hard drive light).
Notably it is far easier to hear through the amplifier that is the sound card, but even with no speakers, a quiet room will still show the same. As others noted above, CRT monitors are notoriously loud, and you can definitely hear different image patterns.
I can also get a good idea whether the CPU is idle or doing some particular task just by listening to the motherboard. This isn't any sort of paranormal effect, it's quite audible. I suspect most of it comes from the inductors on the CPU vcore DC-DC converter.
For me, the sounds I hear are somewhat like this: Animated GIF = chuff-chuff-chuff, one chuff per frame transition Scrolling terminal window = low hissing, like someone slowly breathing out Dragging window around the screen = high-pitched whine CPU stress test = very high-pitched whistling Loading a big app = a more noisy hiss than scrolling the terminal window, interspersed with HDD sounds
I was tested at a young age to have above-average hearing range, so maybe that also has a factor in how well you can hear these things; I don't listen to loud music or subject myself to loud noises either.