Multi-channel seperate outputs with USB soundcard?

[dswalef]

It would be cool to DJ on a laptop where you could monitor one song while the other is playing and maybe also crossfade between the two. For this I imagine I would need a PC with a soundcard that has two seperate output channels. But it's not my PC, so I want something I can just plug in and it gives me an extra SEPERATE output channel.

I've been looking into if I can just hook up a USB (1.1) soundcard and use it together (simultanously) with an already installed PCI soundcard, and use some software that can make crossfades between the two.

But which USB soundcard and software will allow me to do that on a laptop?

[eviljohn2]

You could try this simply by running each source as mono. So the left stereo channel becomes source 1 and the right stereo channel becomes source 2.

I've seen people do live mixing on a laptop though and it wasn't pretty. Bad crossfading, drop-outs and on one occasion the Mac crashed mid-show!