The more I think about it, I'm almost certain that there is a bug in the vocal harmonizer.
There should be a way to take out the original voice when you're using the harmonizer. Otherwise there would be no reason to include voices such as Karaoke Girl and Squeeky Mouse (or whatever they call it). The have no use unless you can use them only as a novelty.
Or maybe I'm missing something. You wouldn't want a mouse singing harmony with you would you?
DonM