I have seen this facility on several mixers, and on a couple of arrangers. It never works great, because it doesn't take out the reverb of the vocal. I wouldn't expect it to be any different on this keyboard.
DonM
Correctomundo Don
.....I agree it just drops out the MID Frequencies leaving a pale vocal sound that you can still hear thru the mix
......on some songs work better then others....just another bad gimmicky feature this goes for many products that boast this magical scenario buyer beware IMO.