If you are getting crackling noise on HDA audio cards in Ubuntu 9.10.If yes,it is very easy to fix this issue all you have to do is remove the new power-save option in the new audio drivers.
Procedure to follow
Open terminal and enter the following comamnd
gksudo gedit /etc/modprobe.d/alsa-base.conf
This will prompt for password
Now you have to delete last two lines where you see power-save option
Save and exit the file.
If you want you can take backup of the above file before doing any changes
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