[LIVE] Static garbled buzzing on Flash video (with video example)

i wonder if anybody can offer me any support on this, when i watch most flash videos (SportsDevil plugin all the time and sometimes YouTube) the picture is fine but the audio is a garbled static buzzing noise, where all the voices come out really high pitched. Click here to see a video of what i mean (806Kb)

i've run sudo apt-get install adobe-flashplugin assuming that would solve it but it hasn't. I'm running 10.1 Git:Unknown (Compiled Mar 9 2011) on an Acer Revo R3600 with audio over HDMI. Cheers

still struggling with this if anyone has any pointers