QUOTE(Martinchris23 @ Jul 21 2008, 08:43 AM)

Voice cancel software relies on the vocals to be at a certain frequency (usually higher than most other sounds in a song), then cuts anything at that level out of the song. Sometimes it works well, but most of the time the song itself sounds wrong as they'll be other things in that frequency which give it depth.
The tech is a bit more mature these days.
It has an algorithm that looks at a multitude of things. One is that for many songs vocals tend to be equally in both channels whereas instruments do not., (this allows you to do phase change cancellation, leaving the instruments untouched), advanced software uses ffts and wavelet analysis to work out what is vocal and what is not and cancel it out.
The stuff that happens 'on the fly' isn't as good as the process offline code, I m hopeful that they use a good algorithm and you rip your songs to the hard-drive to be processed offline more thoroughly.