MIDI is an acronym for Musical Instrument Digital Interface. It’s a series of digital messages used to transmit notes or alter the sounds of instruments. A Virtual Instrument Track in Mixcraft contains Virtual Instrument Clips, which in turn contain MIDI data. MIDI messages contain no actual audio - a good analogy is to think of MIDI as a sort of high-end player piano that tells virtual or hardware instruments what note to play, how long, and other details, such as pitch bend, mod amount, etc.
When middle C is played on a music keyboard, it sends a short message that translates to “play middle C.” When you let go of the key, a message is sent that translates to “stop playing middle c.” In addition, the message contains other information, such as the MIDI channel and key velocity. There are 16 MIDI channels which allow you to route MIDI messages. The key velocity is a number from 1 to 127 which describes how fast the key was depressed. A velocity of 1 would hardly be heard and a velocity of 127 would be full volume.
Each MIDI Note message contains the following information: note value (C0 - G10), key velocity (1-127), and MIDI channel (1-16).
This is the pitch value of the note. There are 128 possible MIDI notes, ranging from a low of C-1 to a high of G9.
This is how fast, i.e. hard, the key was pressed. Faster velocities usually correspond to louder sounds or may trigger extra sounds, depending on the instrument and how it’s programmed.
MIDI channels can be thought of like lanes on a freeway, with each of its 16 channels containing an independent MIDI data stream. In reality, MIDI messages are sent down the cable one after the other (i.e. serially), but because the data is moving very quickly, it’s fuctionally equivalent to multiple channels sent simultaneously (i.e. in parallel).
MIDI channels allow routing of specific channels to specific instruments or tracks.
A controller is a type of MIDI message that controls other parameters. The most commonly used controllers are the pitch and modulation wheels (or possibly a joystick, ribbon, or other fancy controller).
• Pitch Wheel (Pitch Bend)
This controller usually bends the pitch up or down. Though most MIDI controls have a range of 0-127, MIDI pitch bend has range of -8191 to 8192. This much finer scale is used our because our ears are extremely sensitive to tiny pitch changes, and it prevents audible “stepping” during pitch bends.
Modulation is most often used to control vibrato. You’ll see it abbreviated as “mod wheel,” or just, “mod.” Mod isn’t limited to vibrato - like most MIDI controllers,
it can be assigned to control almost any MIDI parameter. Like most other MIDI controllers, it uses the standard 0-127 range.
• Other Controllers
There are many other controllers allowing real-time control of instrument and plug- in parameters. Many are standardized. For example, MIDI controller #7 always controls volume.