[blueshift]

Such softwares can't get the work done. Its just fake that they remove the voice or bgmusic. They just limit certain frequencies and the results are not even fair.
Theres vocal remove option in Adobe Audition too. Like rajasekharan said, all tracks are merged together i.e theres just a single audio waveform present.
You can remove a constant noise signal satisfactorily...but not vocals coz it is a varying signal.