Is there some way to send a duplicate pre-volume-control version of the main signal to a different output device? This would be like the preview on a regular mixing board. It would let you listen to the song on headphones before bringing up the volume control for the main speakers. Among other things, this would let you treat two instances of foobar like two turntables. You could preview the next song on the phones and then fade between the two main signals. I'd only be running two-channel sound, if that makes a difference.

Thanks,
Drew

FooBar2000 is not a DJ tool, and I advise you to get software which is made for DJ use. Altough making a set of plugins for FooBar2000 would make this possible It would not run as smooth as a solution which has DJ use in mind from the beginning of.