Sound replaced with hideous noise sometimes when multiple sources produce sound

[Collin Stocks]

I have not been able to reproduce this consistently, but it happens often enough to test possible theories.

Sometimes when I have switched songs in a music player several times in a row (it does not matter which music player -- affects Rhythmbox, mplayer, flash, ...), or if multiple sources are trying to play audio at once, the audio system replaces all the audio with high pitch beeps.

This affects every audio application, including the window manager bell, applications which use PyAudio, Audacity, totem, mplayer, flash, gstreamer, ...

This seems to be some sort of glitch state, because it can be fixed by turning off all the audio sources and then turning them back on (they must all be off at the same time for the state to reset).

I have done a search online, but I can't find anything useful. Most of the search results either have to do with particular applications, or with the pc system beep, which has nothing to do with this problem.

Does anyone have any idea what might cause this? Or what I might do to go about reproducing the bug consistently?

System information:
Ubuntu 11.04
Kernel Linux 2.6.38-13-generic
GNOME 2.32.1

I can't recall at the moment what commands I should issue to give more system information and I have to go write an essay, so please ask me for more information.

[Collin Stocks (collinstocks)]

This is what the noise sounds like.