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Chapter 2 Contents

MIDI Basics


MIDI is an acronym for Musical instrument digital interface.  The concept of and protocols for MIDI were established and consolidated at the National Association of Music Merchants (NAMM) conference in 1980.  Then in 1983, version 1.0 general MIDI I was developed and implemented by the MIDI Manufactures Association (MMA).  The standard configurations include

• A sound bank of 128 timbres.

• Responds to 16 discrete MIDI channels.

• Percussion sounds dedicated to channel 10

• Originally a 24-note polyphonic protocol was established but in 1999 it 

    changed to 32 polyphony, general MIDI version 2.0.

• 16 part multi-timbral.

• Are responsive to key velocity and respond to pitch bend, modulation, after 

    touch, breath controller and others 7 (channel volume), 10 (pan), 11 

    (expression controller), 41 (portamento on or off), 64 (sustain on or off), 121 

    (reset all controllers) and 123 (all notes off).  There are numbers undefined 

    data numbers that could be exploited for other data that one wanted to 



General MIDI 2 is the industry standard today and is compatible with General MIDI 1.

The one safeguard in the MIDI protocol to sound patents of proprietary data based, which were based on investments in research and development, was system exclusive messages.  System exclusive messages allow for the transmission of data form one synth to another synth from the same manufacturer (Korg to Korg, Roland to Roland, Yamaha to Yamaha, etc.).  This ensures that other product lines could not harvest proprietary information and by doing so could maintain competitive differences.

Serial Transmission

MIDI data is transmitted in series–that is one byte at a time.  There are two types of bytes that are transmitted via a shielded MIDI cable.  The connector at each end has 5 pins.  Pins 4 and 5 are the + and – data, pin 2 is the shield, and pins 1 and 3 were included in consideration for future developments.  Today they are still not used.


Illustration 2.1  MIDI Connection

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