RD-500: Duplicate program changes transmitted from the RD-500
The RD-500 transmits program change messages on the Upper and Lower zones when
a Patch is selected. In addition to these messages, the RD-500 also transmits a
program change message on it's Control Channel which is set to MIDI Channel 16.
While the Upper and Lower transmit zones can be edited to NOT transmit program
changes, the Control Channel always transmits.