On Linux Mint Debian Edition (LMDE, 64bit) I lately experienced disturbing audio distortion when Adobe's flash player was rendering stuff. Nearly any flash application was affected except of a few like the youtube and vimeo video player.

Not sure about what to search for I finally found a workaround in the German Linux Mint community.
Simply create a start script for your browser containing the following lines:

#!/bin/sh
LD_PRELOAD=/usr/lib/x86_64-linux-gnu/libc/memcpy-preload.so firefox

Replace firefox with the binary of your browser.

Seems like some things changed in eglibc (2.13-3) concerning the memcpy() function for the 64bit architecture so you need set the LD_PRELOAD environment variable with that wrapper mentioned above.

This affects all 64bit debian testing/unstable based systems, of course.