A MIDI message that tells the receiver to change to another patch. The message contains a number in the range of 0-127 telling the receiver which patch to select. (On many synths, the unit’s panel display which shows the selected patch numbers the patches differently than the numbering convention that the program change message uses; the user must consult the manual to see how the program change message numbers are mapped to displayed patch numbers.) Most synths with patch memory will send a program change message when a patch is selected. See also bank select.