I've noticed this a few years ago, after reading some psychophysics papers, I was generating some pattern images based on what I read, when my monitor started e

I've noticed this a few years ago, after reading some psychophysics papers, I was generating some pattern images based on what I read, when my monitor started emitting tunes (not by radio emissions), I suspect piezo effect in some capacitor. I instantly realized my monitor could be intercepted accoustically...