im assuming yor plan is to feed the instrumental into the left channer and the original into the right channel at equal amp and then phase reverse one leaving the acapella?
hmmm
wavelab does it and so does pro tools. almost anything should. its a standard function
yeah. pretty much every wave editor has an invert function. the process to get the accapella works, but you have to line up the 2 waves perfectly. which can be difficult.