It was designed to allow different musical equipment to talk to other equipment and the basic idea is actually quite simple. MIDI stands for Musical Instrument Digital Interface, and it was invented (in a cross collaboration by a small group of top synth makers) in the early 1980’s. The target channel determines whether a MIDI note is interpreted as a percussion note or a pitched note.There a lot of talk about midi on various forums, but theres also lots of threads which suggest that theres still quite a bit of misunderstanding about what actually is, so I thought I’d have a quick look at it this time. To turn a message into a percussion note-on message, just play the note over the percussion channel (channel 9 in General MIDI).īass Drum 1 with a velocity of 79: 1001 1001-0010 0100-0100 1111 (bin) => 99-24-4F (hex). In both cases, the note-on messages are assigned to one of the non-percussion channels. As I'll discuss is a future article, there are ways of modifying the channel-volume, but there is no way of changing the volume of an individual note. Notice the primary limitation! Once a note is played, there is no way of chaning the velocity. In my experience, only the most feature-rich computer-based MIDI synthesizers/sound-drivers will vary the timbre with the velocity. More expensive MIDI synthesizers will change the timbre of the played note as the velocity in the note-on message changes. Additionally, the timbre or instrument quality will change along with the velocity. The faster that one strikes a piano keys, the louder the note will sound.