I recently spoke with an audio engineer (my Dad, who has worked in radio for many years) about something that's been bugging me for many years: Why do almost all computer speakers have some sort of annoying buzz or hum?
I know it has to do with voltage differences, power, RF emissions, etc... but I wanted to know more about what I could try to do to reduce the level of the noise. I've tried things like plugging everything into one outlet/power strip, using a filtered power adapter, using a ground loop reduction magnet, etc., with varying degrees of success.
60hz buzz in a speaker is typically induced in the power lead. If that is the case, the buzz will be in the speakers even if the audio connections are removed.
If the buzz is there with audio input to speakers is disconnected, the problem is the AC adapter, the actual power supply (from your mains), or the amplifier for the speakers (usually, for computer speakers, these are in one of the speakers or inside the subwoofer).