To the OP
One overlooked problem with trying to remove vocals is it is based on assuming that the vocalist is dead center in the mix. Today that is not necessarily true. The other problem is that most vocalist have stereo reverb added and you cannot get the voice out of the mix completely. There use to be a device advertised in the back of Popular Science that guaranteed it could remove most vocals but I doubt that it worked as advertised for all vocal removal chores.
There is a new piece of software from Sony Creative which I have not tried that maybe able to do what you are seeking. It is somewhat expensive but there is a trial version available. Here is a link to the information
SpectraLayers Pro Overview. It is available for the PC and the Mac. It does have some fairly specific hardware and software requirements.
Best of luck!
__________________
-TOM-
Thomas W. Bethel
Managing Director
Acoustik Musik, Ltd.
Room with a View Productions
Oberlin, OH 44074
www.acoustikmusik.com
Doing what you love is freedom.
Loving what you do is happiness.
Celebrating 18 years in the mastering business in 2013