A Patch Change is Ardour's description for a combination of MIDI program change and bank select messages, that typically instruct a synthesizer or sampler to select a sound to use on any given channel. Patch changes are shown within MIDI regions as small rectangles or flags, with a vertical line showing where in the region the patch change will occur.
A patch change is inserted by first ensuring that the mouse is in Grab Mode, then right-clicking on the MIDI region where the patch change is desired, then selecting <Region Name> > MIDI > Insert Patch Change.... The desired patch is then chosen from the dialog that appears.
Inserted patch changes always appear in the selected region at the Edit Point.
A patch change can be modified in Internal Edit Mode by right-clicking on it, then selecting the desired patch from the menu that appears. A patch change can also be modified by hovering the mouse pointer over the patch change to be modified and moving the mouse wheel until the desired program number is selected. The bank number can be modified similarly by holding down the key while moving the mouse wheel until the desired bank is selected.
A patch change can be moved, within the region in which it resides, by left-clicking it and dragging it to the desired location.
A patch change can be removed by holding down the key and then right-clicking on it.
MIDNAM files assign human-readable names to the "sound coordinates" (Program Change, Bank Select) of MIDI synthesizers and devices. A number of MIDNAM files come bundled with Ardour; if the MIDNAM for a device is not included with Ardour, a custom MIDNAM file can be created for device in question.
Selecting a MIDNAM is only possible if there is no MIDI synth on the track in question or the MIDI synth does not have a MIDNAM associated with it. In this case, it is possible to select the desired MIDNAM from a combobox in the MIDI track's header, usually directly below the track's fader. See MIDI Track Controls for more details.