This refers to specifying a new Patch on any given Track, for any given Channel.

A special MIDI message used to select different sounds over specific MIDI channels.

Most instruments and other items of MIDI equipment make use of 'programs'. In an instrument, for example, these are a series of preset control settings that give a range of different sounds. Program change messages therefore permit the required sounds to be selected at the appropriate times. Other items of MIDI equipment such as mixers and effects units are often controlled via program change messages.

A MIDI message that causes a synthesizer or other device to switch to a new program (also called preset, patch) contained in its memory.