Clarkvan

And the computer send the sound through the sound card to the receiver via a standard stereo analog 3.5mm jack. (the green one) and then directly to the sub through a different jack (only using one side because it is mono)

Thanks for the quick reply. No, unfortunately it only has subwoofer input. Low level, low-pass signal.

I have an external receiver and subwoofer. The receiver is old or else it would have a subwoofer out and solve this problem. I am trying to find a computer program with minimal distortion that will allow me to use my subwoofer and speakers in a 2.1 setup from my sound card. It works while watching some movies (if the file is 2.1 or 5.1 native etc...) But most mp3 and FLAC files seem to be in stereo. When I test the speakers in windows the speakers make a high noise and sub makes a low noise like it should to show they are working. The program that came with the card does not like Vista (Creative Control Panel) and will not open. I have had it working before on my other computer with same card and program but it had problems there to and needed to be opened 10 times before it would run. I have also got it working with this setup and a Dolby plugin for Winamp but the plugin makes it sound terrible (very distorted) Any programs to try? or better add-ons for winamp? Thanks