Hello All:
I have the current version of Avast! Internet Security and run Google Chrome in the sandbox - however, when I go to watch youtube video’s etc., there is no sound. I have added C:\Windows\System32\audiodg.exe to the exclusions but still no luck??
Tony 
Reboot, it should work. If not, remove the default from Chrome (if you set it to open auto with sandbox) and open it up only once with the sandbox. That should fix it.
If that didn’t work, you’d need to do an avast! repair. Control Panel>Uninstall Programs>Avast>Change>Repair>Follow instructions and reboot (Important.)
I had this same problem a while back when I had avast pro. I think my solution was to use a wildcard for exclusion
*\audiodg.exe as when I tried to use the path it never worked.
Edit: link to my own post http://forum.avast.com/index.php?topic=97658.msg779076#msg779076