MP3 and surround systems

I was just wondering if any of you had any problem playing MP3s (or audio in general) using all 5/7 speakers + subwoofer?

So far, I've only managed to get 2.1 audio on my NForce2 Soundstorm for music. Movies and games like Doom 3 works perfectly fine.

I've found a couple of plug-ins for Winamp thats supposed to allow playback on all channels (or at least 5)..

eg.
http://www.winamp.com/plugins/details.php?id=129453
http://www.winamp.com/plugins/details.php?id=122003
http://www.winamp.com/plugins/details.php?id=136942

Have any tried any of them? The reviews for them seems mixed (some claims loss of quality.. I don't get it, I don't expect some complex upmixing.. just a duplicate of the front stero channel on the other speakers will do).

look here for more information - http://www.nforcershq.com the forums are most usefull.
To get 5.1 in winamp try checking under options,preferences, output, directsound output and make sure allow hardware acceleration is checked. The best plugin i've found is dfx for winamp and you can get it from www.fxsound.com

Set the Nforce Control Panel speaker config to "Clone". It'll mirror the front to the rear, doing exactly the same as those plugins. For whatever reason you may want to do this.

I use media player classic and theres a plugin for this that allows you to choose which speakers play which channels. Sounds better than winamp and even stereo mp3's and divX files sound better when on the front & rear.

Ah, so thats what clone does. Thanks!
Now any way of cloning the side speakers too? :D

Edit: Sorted, thanks!