sound problems in a video

I am also having this problem.  I am running Win 7 pro (64bit), IE9, with latest updates of all system and flash software.  The music on videos plays at the normal volume but I can only get voices when I go to full volume, and then it's just quiet static.  This happens when I'm watching a video either directly on Youtube or a link from another site to a Youtube video.  I followed the Adobe flash player troubleshooting steps up through disabling hardware acceleration, but no luck.  A few things on my settings confuse me.  In my control panel flash player shows as 32 bit, is there a 64 bit version I should be running?  The ActiveX version is 14.0.0.125, but the plug in version is 13.0.0.214.  Finally,I have been into the Youtube website since I deleted my cache and browsing data, but it doesn't show up in the list when I try to increase the storage limit.  I'd greatly appreciate any hints as to what I should try next, maybe uninstall/reinstall flash player?

Thanks

ETA:  This does not occur on all videos, only some.  It's more likely to occur during a link to youtube, but does sometimes happen if I go directly in.  Any ideas on what else to look at would be appreciated.