I think some creative labs drivers for their soundcards let you do funky stuff like that, if you have such a nice soundcard. For me though, if I come across such media, I just use Media Player Classic, since it's built-in audio filter lets you do channel-mapping on the fly, so you could just map the single left/right channel over both speakers temporarily Unless anything's changed in later versions though, you can only remap whole channels, not mix like 50% left to right or something