Weirdest sound problem: Static buzz, but only if mainly light screen colors

[Leiden]

Okay here's an interesting one. There's this low monotone electronic buzz coming out of my speakers. But only if the greater part of my screen is using lighter colors! Meaning, if for instance I have the terminal (black) full-screen there is no buzz. If I have it sized over the half of my screen there's a medium buzz. And if I am on the Google Search home page with the browser full screen (most of the screen white) there's a loud buzz. :S

And it's only if I run the sound through my amplifier. It's not audible if I just use the laptopspeakers.

Really, I have no idea even in what direction to start looking.

[towheedm]

This sounds like a ground loop between the amp and the sound card. Is your amp using a power cord with a ground pin? You could also check the cables between the amp and the soundcard. Could be that the connection on the shirld is broken. You may also want to try it with some desktop speakers and see if the noise is still there.

[idi0tf0wl]

Furthermore, see if the problem persists in headphones. If it is not your amplifier, you will (read: should) be able to hear the noise through headphones as well. If you do not, then you can be almost certain that the problem exists beyond your computer's internals.

EDIT: Though this won't necessarily explain the apparent phenomenon concerning the color ratios of your screen, it is important to approach these things empirically.