It would be great to be able to custom mix the accompaniment track. For example, If I want to show the ensemble how the tenor sax, trombone, timpani, and tuba part sounds like together I can select just those parts to play back. Another example would be to be able to isolate the instruments that have the counter melody and just have that as the play back. Since Smartmusic already has individual instrument tracks under the "My Part" feature, I feel this would be the next step. Thanks!