Turning notes into sounds - Channels

• We’ve seen that a sound is specified in terms of a bank number and a program number, which together identify a patch. ( Sometimes ‘program’ and ‘patch’ are used to mean the same thing, but that’s not really true unless you only have one bank ).
• When a note message arrives on a MIDI channel, then if the MIDI instrument is listening on that channel it must know the bank number and program number that it will use to identify the patch that will make the sound for that note.
• In other words, the MIDI controller does not specify the sound that the instrument should make – only the note.
• So the MIDI instrument stores bank and program number for each MIDI channel as part of it’s configuration. If this info is not specified for a channel, then a note received on that channel will not make a sound.
• Note that this ‘mapping’ of channel to patch can be different for every MIDI instrument that is listening.