Introduction to MIDI

Musical Instrument Digital Interface

At the beginning of the digital music age, musicians wanted a standard that could be useful in controlling any electronic musical device, without tying them to one particular manufacturer's product. In 1983, in order to satisfy this need, a few music manufacturers got together and created MIDI, which allowed everyone, rather than academic musicians and composers with access to very expensive equipment, to create electronic music.

MIDI (acronym for Musical Instrument Digital Interface) is a standard specification for networking two or more digital music devices together. This communications protocol allows devices which play, produce, record or mix sounds to 'talk' with one another.

Some kinds of digital devices which communicates through MIDI:

Drum Machine

Sampler

Sound Module

Synthesizer

Electric Piano

Midi controller

The meaning is that two musical devices can communicate with each other through MIDI. One (we'll call it "Master") can then control the other (which will be the "Slave").

We use special cables to transmit the MIDI data (optimal distance between the two musical devices should not exceed 10 feet) and 5-pin DIN jack connectors.

There are separate jacks for incoming MIDI signals (Midi-in), and outgoing MIDI signals (midi-out).

The basic messages of MIDI

While pressing a key on a digital music instrument, it transmits a "Note-On" message. The connected MIDI device knows that a new note has begun and it has to produce it.

While releasing the key the instrument sends a "Note-Off" message.

But the Note messages will include more information:

Pitch - The pitch of the certain note is included as a numeric value which is part of the MIDI protocol. The middle C key on a keyboard, for example, will produce the Note-On message with the numeric value of 60.

Velocity (volume) - If a key is pushed with great force, the resulting note will be louder than if it was gently pressed. That is the function of the velocity message which reflects how hard the note was played.

More MIDI messages

Here are a few of the many other messages in the MIDI command set:

Program change - a message that tells the instrument to change its patch (guitar, grand piano, flute etc.)

Sustain - a message that tells the instrument to press or release its sustain pedal.

Volume - tells the instrument to change its volume and by how much.

Pitch wheel - when the player moves the pitch wheel, a pitch wheel MIDI message is sent out.

Computers & MIDI

The system of standards to which most MIDI manufacturers subscribe, allows MIDI devices from different manufacturer to talk to one another. But with computer software it is easy to connect digital devices into a digital computer-based recording studio:

Software products use MIDI for variety of needs:

Translation of what is played into notation (Notation programs)
Recording studio with 16 tracks and more (Sequencers)
Ear development and theory practice (Educational programs)
Controlling of complicated setups of digital equipment (Utilities)

New MIDI instruments

The growth in popularity of MIDI recording, brought players to want to be able to use MIDI with the instruments they play best.

Manufacturers such as Yamaha developed MIDI guitars, Wind MIDI controllers, MIDI drum pads sets and even electronic cello and bass:

Wind MIDI controller

Electric Drum pad

Electric Bass

Midi more...

You may find more information on MIDI technical standards in the MIDI Manufacturers Association (MMA) web site at