How can I set up 4.1 speakers?

I have two pairs of speakers. One pair has a subwoofer. They are not made by the same company. The subwoofer does not have a place to hook in extra speakers. The pair without the sub is pretty bad quality; not sure if that's relevent for speaker placement.

I want to have quadraphonic sound. Is it possible to set it up? What sound card "line in"s do I need?

Thanks, /comp/. All help appreciated.

ps. I have an nVidia nforce (sound card) if you are wondering.

You'll need to tell the computer that you have a 4.0 system (as the sub will be handled by the front speakers not by the computer).  Simply plug the set with the sub into the front speaker output of your soundcard and the shitty pair into the surround output (if your card is 7.1 make sure you connect it to the 'side surround' not 'back surround' outputs).

As for speaker placement the fronts should be 30 degrees from front-centre and the rears should be between 90 and 110 degrees from front centre (so not way behind you like some people think).  You can then balance levels using the computer.

I know nothing about that soundcard so obviously it'll need to support at least 4.0 to do what you want.