MIDI
MIDI (/ˈmɪdi/; Musical Instrument Digital Interface) is a technical standard that describes a communication protocol, digital interface, and electrical connectors that connect a wide variety of electronic musical instruments, computers, and related audio devices for playing, editing, and recording music.[1]
For other uses, see MIDI (disambiguation).
A single MIDI cable can carry up to sixteen channels of MIDI data, each of which can be routed to a separate device. Each interaction with a key, button, knob or slider is converted into a MIDI event, which specifies musical instructions, such as a note's pitch, timing and loudness. One common MIDI application is to play a MIDI keyboard or other controller and use it to trigger a digital sound module (which contains synthesized musical sounds) to generate sounds, which the audience hears produced by a keyboard amplifier. MIDI data can be transferred via MIDI or USB cable, or recorded to a sequencer or digital audio workstation to be edited or played back.[2]
MIDI also defines a file format that stores and exchanges the data. Advantages of MIDI include small file size, ease of modification and manipulation and a wide choice of electronic instruments and synthesizer or digitally sampled sounds.[3]: 4 A MIDI recording of a performance on a keyboard could sound like a piano or other keyboard instrument; however, since MIDI records the messages and information about their notes and not the specific sounds, this recording could be changed to many other sounds, ranging from synthesized or sampled guitar or flute to full orchestra.
Before the development of MIDI, electronic musical instruments from different manufacturers could generally not communicate with each other. This meant that a musician could not, for example, plug a Roland keyboard into a Yamaha synthesizer module. With MIDI, any MIDI-compatible keyboard (or other controller device) can be connected to any other MIDI-compatible sequencer, sound module, drum machine, synthesizer, or computer, even if they are made by different manufacturers.
MIDI technology was standardized in 1983 by a panel of music industry representatives, and is maintained by the MIDI Manufacturers Association (MMA). All official MIDI standards are jointly developed and published by the MMA in Los Angeles, and the MIDI Committee of the Association of Musical Electronics Industry (AMEI) in Tokyo. In 2016, the MMA established The MIDI Association (TMA) to support a global community of people who work, play, or create with MIDI.[4]
Applications[edit]
Instrument control[edit]
MIDI was invented so that electronic or digital musical instruments could communicate with each other and so that one instrument can control another. For example, a MIDI-compatible sequencer can trigger beats produced by a drum sound module. Analog synthesizers that have no digital component and were built prior to MIDI's development can be retrofitted with kits that convert MIDI messages into analog control voltages.[14]: 277 When a note is played on a MIDI instrument, it generates a digital MIDI message that can be used to trigger a note on another instrument.[2]: 20 The capability for remote control allows full-sized instruments to be replaced with smaller sound modules, and allows musicians to combine instruments to achieve a fuller sound, or to create combinations of synthesized instrument sounds, such as acoustic piano and strings.[30] MIDI also enables other instrument parameters (volume, effects, etc.) to be controlled remotely.
Synthesizers and samplers contain various tools for shaping an electronic or digital sound. Filters adjust timbre, and envelopes automate the way a sound evolves over time after a note is triggered.[31] The frequency of a filter and the envelope attack (the time it takes for a sound to reach its maximum level), are examples of synthesizer parameters, and can be controlled remotely through MIDI. Effects devices have different parameters, such as delay feedback or reverb time. When a MIDI continuous controller number (CCN) is assigned to one of these parameters, the device responds to any messages it receives that are identified by that number. Controls such as knobs, switches, and pedals can be used to send these messages. A set of adjusted parameters can be saved to a device's internal memory as a patch, and these patches can be remotely selected by MIDI program changes.[a][32]
Composition[edit]
MIDI events can be sequenced with computer software, or in specialized hardware music workstations. Many digital audio workstations (DAWs) are specifically designed to work with MIDI as an integral component. MIDI piano rolls have been developed in many DAWs so that the recorded MIDI messages can be easily modified.[33] These tools allow composers to audition and edit their work much more quickly and efficiently than did older solutions, such as multitrack recording. Compositions can be programmed for MIDI that are impossible for human performers to play.[34]
Because a MIDI performance is a sequence of commands that create sound, MIDI recordings can be manipulated in ways that audio recordings cannot. It is possible to change the key, instrumentation or tempo of a MIDI arrangement,[35]: 227 and to reorder its individual sections,[36] or even edit individual notes. The ability to compose ideas and quickly hear them played back enables composers to experiment.[37]: 175
Algorithmic composition programs provide computer-generated performances that can be used as song ideas or accompaniment.[2]: 122
Some composers may take advantage of standard, portable set of commands and parameters in MIDI 1.0 and General MIDI (GM) to share musical data files among various electronic instruments. The data composed via the sequenced MIDI recordings can be saved as a standard MIDI file (SMF), digitally distributed, and reproduced by any computer or electronic instrument that also adheres to the same MIDI, GM, and SMF standards. MIDI data files are much smaller than corresponding recorded audio files.