Eddie, do you use a vocalizer? If so you can do some neat improv stuff with that, particularly when singing In The Still of The Night by the Five Satins. Its just a matter of kicking it in and out with the foot switch when harmony is needed. It also works grea with some of the Beach Boy songs.

The only drawback with the pre-recorded back-up vocals is timing and the inability to be able to extend the length of the song. I tried this once and could never quite make it work the way I wanted.

Good Luck,

Gary