I'd advise you do the following to update the Nvidia drivers and fix the LPCM sound mapping issue (may fix your crackling too).
Code:sudo add-apt-repository ppa:ubuntu-x-swat/x-updates sudo apt-get update sudo apt-get install nvidia-current nvidia-current-modaliases nvidia-settings sudo wget http://pastebin.com/download.php?i=f5f9654bb -O /etc/asound.conf sudo wget http://pastebin.com/download.php?i=f2e38265 -O /usr/share/alsa/cards/HDA-Intel.conf
Been running XBMC on my Revo for over a year and would NEVER want to use anything else.
Slap the Aeon Skin on there and its a thing of beauty.
If you need further help I'm more than happy to oblige.
Thanks for your help - it is greatly appreciated.
