I'm also surprised there hasn't been a fix to this (yet).
Another interesting anomaly (at least on my systems): If you load Windows Media Player on the XP virtual machine (doesn't have to be playing anything) the sound is suddently perfect !!
For example, if I go to Yahoo in IE and play a video, the sound is garbled/scratchy.
If I then load Windows Media Player; then go back to Yahoo and stream the same video, it will play perfectly 
Note that the exact same XP virtual machine running under the same version of VMWare installed on Windows 7 will work perfectly -- it's only when the host is Windows 8 that this problem surfaces. Also, Windows 7 and Vista virtual machines work perfectly ... the issue is only with XP VM's.