DIY 5.1 surround sound for PC using various sets of speakers?

[moeburn]

So I'm wondering if this is possible - My motherboard's onboard soundcard is a Realtek, and it has plugs for Front Stereo, Rear Stereo, Side Stereo (7.1), and Center+Subwoofer. 

 

I've gotten DIY quadraphonic to work before, by using my giant KLH home theater tower speakers and a home theater amp for the front channel, and little harmon/kardon computer speakers for the rear channel.  But quadraphonic sound doesn't work very well, since almost every game and movie is either stereo or 5.1, and the dialogue usually ends up on the center channel - using quadraphonic on a 5.1 source means the dialogue gets really quiet.

 

So I'm wondering how I can use that center/subwoofer jack for a center speaker.  How does that type of jack usually work?  It's a 3.5mm jack, do they put the center speaker on the left channel and subwoofer on the right?  If I got a second set of computer speakers and plugged them into that jack, would the center channel come out on one of them, and then I can just unplug the other channel (I don't need a subwoofer)?  My realtek also has options for "swap center/subwoofer output" and "enable bass management", whatever that last one means.

 

Has anyone else ever done this kind of setup when they were on a tight budget?  Surround sound really helps give me an advantage in games, and it sounds awesome in movies and tv, but I can't really afford a whole new set of speakers or 5.1 headphones - plus I really like the sound of my massive (like the size of a large child) front tower speakers.  Thanks for any help!