Andy,
Are you using a Mac? If so, try going to the "Appearance" Control Panel, and under the Sound tab, set the sound track to None. Restart your computer - and your problems should be gone!!!
I also used to have this static / popping noise whenever playing DVD's. It is a Mac OS / Apple DVD Player problem and not related in any way to your speakers.
If you are using a PC, I have no idea how to help you...
Hope this helps.