it is a registration. midi and front panel setup saved to a location. I play along with the midi. At the end of the midi the front panel voice 1 and voice 2 definitely and visibly change volumes. This affects me because sometimes a create a small midi, like the violin solo in dust in the wind. I play the solo guitar, and when the violin comes in I start the midi. Therefore I continue to play the song after the midi finishes, and the volume jumps. If I played the midi to the end of the song it wouldnt really matter.