TIP: Knowing the MIDI messages that are available to us when sequencing for acoustic instruments – Part 1
By Andrea Pejrolo
While we all know the importance of having the best sounds, libraries and gears when it come to writing, sequencing and producing for hybrid ensembles, one aspect that it is often forgotten is the importance of the MIDI messages that are available to use to control and manipulate our electronic orchestras. I can’t stress enough how crucial it is to know, in detail, all the MIDI messages and in particular all the CC messages that we can use to take direct control of our performances and virtual instrumentalists. In this article I wil discuss the categories of the MIDI messages and their functions. In part 2 of this article I will talk about the MIDI CC messages.
In order to exploit fully the creative power offered by the MIDI standard, it is crucial to precisely know and identify the MIDI messages that are available to us. While you may be familiar with some of the most common messages (e.g., Note On, Note Off), there are many others (CC# 11, CC# 73, CC# 74, etc.) that are essential if you are trying to bring your MIDI productions to the next level. Let’s take a look first at the main categories of the MIDI standard.
MIDI MESSAGES AND THEIR PRACTICAL APPLICATIONS
The messages of the MIDI standard are divided into two main categories: channel messages and system messages. Channel messages are further subdivided into channel voice and channel mode messages, while system messages are subdivided into real-time, common, and exclusive messages.
Channel voice messages
Channel voice messages carry information about the performance; for example, which notes we played and how hard we pressed the trigger on the controller. Let’s take a look at each message in this category in detail.
Note On message: This message is sent every time you press a key on a MIDI controller. As soon as you press it, a MIDI message (in the form of binary code) is sent to the MIDI out of the transmitting device. The Note On message includes information about the note you pressed (the note number ranges from 0 to 127 or C-2 to G8), the MIDI channel on which the note was sent (1–16), and the velocity-on, which describes how hard you press the key and ranges from 0 to 127 (with a value of zero resulting in a silence).
Note Off message: This message is sent when you release the key of the controller. Its function is to terminate the note that was triggered with a Note On message. The same result can be achieved by sending a Note On message with its velocity set to 0, a technique that can help to reduce the stream of MIDI data. It contains the velocity-off parameter, which registers how hard you released the key (note that this particular information is not used by most MIDI controllers at the moment).
Aftertouch (pressure): This is a specific MIDI message that is sent after the Note On message. When you press a key of a controller, a Note On message is generated and sent to the MIDI OUT port. This is the message that triggers the sound on the receiving device. If you push a little bit harder on the key after hitting it, an extra message, called Aftertouch, is sent to the MIDI OUT of the controller. The Aftertouch message is usually assigned to control the vibrato effect of a sound, but, depending on the patch that is receiving it, it can also affect other parameters, such as volume, pan, and more.
There are two types of aftertouch: polyphonic and monophonic. Monophonic aftertouch affects the entire range of the keyboard no matter which key or keys triggered it. This is the most common type of aftertouch, and it is implemented on most (but not all) controllers and MIDI synthesizers available on the market. Polyphonic aftertouch allows you to send an independent message for each key. It is more flexible as only the intended notes will be affected.
Pitch bend: This message is controlled by the pitch-bend wheel on a keyboard controller. It allows you to raise or lower the pitch of the notes being played. It is one of the few MIDI data that do not have a range of 128 steps. In order to allow a more detailed and accurate tracking of the transposition, the range of this MIDI message extends from 0 to 16,383. Usually, a sequencer would display 0 as the center position (non-transposed.)
For more articles on MIDI, visit Andrea Pejrolo’s blog – www.acousticmidiorchestration.com
Andrea Pejrolo is the Assistant Chair of the Contemporary Writing and Production department at Berklee College of Music in Boston.
Andrea is a composer, producer, audio engineer and bassist. He is the author of Creative Sequencing Techniques for Music Production(1st edition 2005, and 2nd edition 2011) and Acoustic and MIDI Orchestration for the Contemporary Composer(2007) and has written several articles for music magazines, including Sound On Sound, Bass World Magazine (USA), Muralann and Boheme Press (Canada), and Il Capitello Publisher (Italy). Andrea has extensive and active professional experience as a sound designer, audio engineer/producer, MIDI programmer and composer for film, TV, theater and multimedia. Some of his recent collaborations and projects include iAcoustica Studio drum library, iDrum Rock Edition for iPhone/iPad in collaboration with Izotope, arrangements and recording with the City of Prague Philharmonic Orchestra, Kevin Bacon’s “Lover Boy”, Harry Davis’ “MVP”, Don Sebesky, ABC, CBS, Cy Coleman, Burning Petals Music Production (U.K.), the Broadway Show “Swing” (St. James Theater, NY), and the Grand Canyon Music Festival.
Andrea holds a Ph.D. in jazz composition/performance from New York University, a Master in Composition for Film, TV, Theater and Multimedia from the University of Bristol (U.K.) and a Music Diploma in Jazz Performance from Manhattan School of Music in New York City.