Why not just play your part on the keyboard against the midi file or MP3 backing track as if you were just in a band as another player while they do all the singing....
Real bands don.t want to do that...You have a drummer, sax, and guitar players.. They don't want to go the karaoke way..

I don't understand why no one gets my concept... if all I mentioned can be done it is a perfect performance set..
It would be as easy as play live... play a style... or play a SMF... all would reside in the same performance,,, and the music score with lyrics will be on the monitor (for live play and style play..
Why would I want to use backing tracks with a band,,, I left the last band after 13 years of this...
