What is MIDI?
MIDI is a digital remote control interface for music systems, but has come to relate to a wide range of standards and specifications to ensure interoperability between electronic music systems.
MIDI-controlled equipment is normally based on microprocessor control, with the MIDI interface forming an I/O port. It is a measure of the popularity of MIDI as a means of control that it has now been adopted in many other audio and visual systems, including the automation of mixing consoles, the control of studio outboard equipment, lighting equipment and other machinery. Although many of its standard commands are music related, it is possible either to adapt music commands to non-musical purposes or to use command sequences designed especially for alternative methods of control.
The adoption of a serial communication standard for MIDI was dictated largely by economic and practical considerations, enabling it to be installed on relatively cheap items of equipment and available to as wide a range of users as possible. The simplicity and ease of installation of MIDI systems was largely responsible for its rapid proliferation as an international standard.
Unlike its analog predecessors, MIDI integrates timing and system control commands with pitch and note triggering commands, such that everything may be carried in the same format over the same piece of wire. MIDI makes it possible to control musical instruments polyphonically in pseudo real time: that is, the speed of transmission is such that delays in the transfer of performance commands are not audible in the majority of cases. It is also possible to address a number of separate receiving devices within a single MIDI data stream, and this allows a controlling device to determine the destination of a command.
Excerpt from Sound and Recording: Applications and Theory, 7th Edition by Francis Rumsey and Tim McCormick © 2014 Taylor & Francis Group. All Rights Reserved.
About the Authors
Francis Rumsey is Consultant Editor and Technical Writer for the Journal of the Audio Engineering Society, and runs his own consultancy company, Logophon Ltd. Until 2009 he was a Professor at the University of Surrey (UK), specialising in audio engineering and psychoacoustics. He is chair of the AES Technical Council, a Fellow of the AES, and a busy organist.
Tim McCormick is aformer Deputy Head of sound at the Royal Exchange Theatre in Manchester (UK), has extensive experience in design and manufacture of audio electronics, and has worked at Klark Teknik and with the RSC at Stratford (UK) where he plotted and operated the sound for many shows as well as designing and building audio equipment when the need arose. Also interested in medieval architecture, The Cathedrals, Abbeys and Priories of Wales was published on 2010.