MIDI and YOU

1. MIDI and YOU Orchestra in a Box

2. What is MIDI? • Musical Instrument Digital Interface • MIDI is a protocol - a standard by which two electronic instruments (as well as other things) can communicate • MIDI defines both a physical (wires, plugs and voltages) and a logical (how the information is organized) component.

3. Uses for MIDI • MIDI only contains the instructions necessary to “reconstruct” a song. (e.g. sheet music for electronic instruments) • A MIDI command basically contains note numbers, note velocities, and note-on messages - THAT’S ALL! Okay there’s a little more to it…but as a result: • File sizes are extremely small, so a large amount of information takes up a small amount of space (or bandwidth) • MIDI does not care what type of instrument is receiving the message (i.e. what it is triggering - the same messages could trigger a drum sound or a piano) • In addition to the recording studio, MIDI is used for web-based applications, for mobile devices, even to control lighting and effects at shows

4. MIDI Specs • First defined in 1983 - not much has changed • 31.25 kbaud - serial communication • Allows for 16 separate channels of information on a single cable (i.e. it can send information for up to 16 different “instruments” simultaneously) • Any parameter can have up to 128 different values

5. Anatomy of a MIDI message • A MIDI message is built up of two or three bytes, each of which is 10 bits long • MIDI channel voice messages contain channel number the message is intended for (1 thru 16), command (e.g. note on), and velocity information (how hard a key is played). <channel 1><note 64><velocity 85><note on>

6. A little music theory • There are 7 primary pitches which are given letter names A through G; • On the 8th pitch, the pattern is repeated, giving us the octave. • Western music recognizes 12 distinct pitches per octave • Time is divided in bars or measures • Each bar is defined as having a specific number of beats • Each beat is defined as the length of a specific note (e.g. quarter-note or eighth note)

7. Octave numbers • MIDI has 128 notes. On a piano sound, middle C is note 60 • Some design schemes number the octaves (e.g. -1, through 9 • The octaves are numbered from lowest to highest with C being the start of the octave. • Each note is named with its letter and octave (e.g. C4, E4, G4) • The octave numbers are not standard which can be confusing. (e.g. Middle C could be called C3 or C4, but it is still note 60)

8. MIDI Signal Chain • MIDI flows in one direction • MIDI devices have three ports: IN, OUT, and THRU - MIDI OUT carries MIDI messages that a device generates, MIDI IN receives the MIDI messages, and MIDI THRU simply copies any messages that appear at the MIDI IN port and passes them down the chain. • Up to three MIDI devices can be daisy-chained without any noticeable latency in the chain

9. Common MIDI devices • A controller sends MIDI messages OUT to other MIDI devices - typically sequencers, sound modules, and synthesizers • A sound module has a number of pre-recorded sounds stored in its memory. MIDI messages tell the module which sound/note to play • A sequencer stores MIDI events in the order in which they happen. It is a multi-track recorder for MIDI data. It sends this data OUT to other devices • A synthesizer generates sound “artificially” by electronic means. MIDI can be used to control a number of synthesizer parameters

10. General MIDI • General MIDI was an attempt to standardize MIDI instruments so that it would be easier to use for long distance collaborations, computer music, and web-based applications. • General MIDI devices have specific instruments assigned to specific numbers so that a device or computer playing back a MIDI file will use the proper instrumentation. • Channel 10 is reserved for drums • Not all MIDI devices are meant to be General MIDI compatible

11. Working with MIDI in the box In most DAW programs (such as ProTools) you will need two types of tracks to work with a MIDI instrument (whether it is in or out of the box): • MIDI Track (duh) - this acts as a MIDI sequencer for a single MIDI channel. It will enable you to record notes and control the MIDI instrument • Aux Input/Track - this will enable sound from the MIDI instrument to be heard in the mix with other recorded tracks in the DAW • Some DAW’s may also have specific tracks for using software instruments

12. Software Synthesizers • A software synthesizer is a virtual instrument • Virtual - “existing…in effect though not in actual fact” - Webster’s II New Riverside Dictionary • A software synth generally exists as a plug-in in a DAW • Plug-in: “A computer program…that interacts with another [program] to add a specific function…” - en.wiktionary.org/wiki/plug-in • A software synth is basically a MIDI instrument that exists in software instead of the real world • It needs all the same things that an external MIDI instrument (such as a sound module) would need (except cables).

13. MUY IMPORTANTE • MIDI does not generate or transmit any sound or audio signal whatsoever • You cannot hear MIDI • MIDI is only a protocol - a language which computers and electronic instruments use to communicate. Humans cannot hear MIDI. • You can only hear the result of a properly routed MIDI message, provided it is sent to a device capable of making sound • MIDI is NOT digital audio in any way, shape, or form