Some Duo-Arts play notes 1, 2, 3 and 4: the ones with transposing
tracker-bars (of course), and the 88-note ones.  It's easy to get
down and under and switch all the tubes over 2, 3 or 4 notes between
the bleeds and the stack, and bingo, you've added feet onto the
length your piano.  Try it, its fun!

Bruce Grimes