The only way that I have been able to do this is, if it is in stereo, with vocals o
one side and music on the other (dual track). You can shut down one side an
make monaural (monophonic) tracks. To delete the vocals when they are dubbe
over or with the sound track you'll need some really sophisticated equipment.
There is a program called YoGen Vocal Remover, you could try. I don'
know if or how it works, but it is supposed to be a file splitter.
YoGen Vocal Remover 1.0 http://www.bajandodescargas.com/query/YoGen Vocal Remover 1.07.html
