Discover the MIDI standard and its future

Francis

Francis

Composer ⎜ Sound Engineer ⎜ Sound Designer


Maybe you’re from the generation that uses Ableton Live, Logic Pro X or Native Instruments’ Maschine?

Are you familiar with the standard MIDI acronym for Musical Instrument Digital Interface?

This communication protocol dedicated to music allows your synthesizer, master keyboard, drum machine… To communicate with your favorite sequencer, to allow you to compose your music.

The MIDI born in 1983, evolves slowly but surely.

At noon* a bit of history!

Interoperability became an important issue with the democratization of synthesizers in the 1980s.

Musicians are limited to playing only one or two synthesizers simultaneously. This requires several musicians to play several synthesizers.

Being able to control several synthesizers from a single keyboard became a necessity.

The midi
Jean Michel Jarre studio in the 70s

In this context the synthesizer designers Dave Smith, Ikutaro Kakehashi and Tom Oberheim met at the NAMM show in June 1981 (yes, the NAMM show already existed!).

From this meeting a reflection on the standardization of communications between synthesizers was going to be born…

3 years after this meeting, the first demonstration took place at the 1983 NAMM show between a Jupiter 6 from Roland and a Prophet 600 from Sequential Circuit by their two representatives and founders, Ikutaro Kakehashi and Dave Smith.

The ATARI ST computer was released in 1985 because of its integrated MIDI connectors and the quality of its sequencers. It popularized the MIDI standard among musicians and the general public.

It reminds me of a time when I was using my ATARI Mega STE with Notator from Emagic, the ancestor of Logic Pro X.

The IMA, which stands for International Midi Association, manages the MIDI standard, while the MMA MIDI manufacturers Association manages the manufacturers’ position.

At noon and a quarter actually

The physical connection is managed by 5-pin DIN connectors. A midi cable with a maximum length of 15 meters. A symmetrical serial type connection as shown in the diagram below.

official MIDI cable connection diagram
official MIDI cable connection diagram

For those who are familiar with the connection of a HIFI Din cable, the difference in cabling is noticeable.

HiFi Din cable connection diagram
HiFi Din cable connection diagram

Pins 1 and 3 are unused, pin 2 serves as ground and pins 4 and 5 carry a voltage of 5 volts with a current of 5 mA.

Unidirectional MIDI links require 2 connectors. One for the input named MIDI IN and one for the output named MIDI OUT.

Basic MIDI link
Basic MIDI link or synth 1 drives synth 2
Midi link IN / OUT
Midi link IN / OUT

Some devices equipped with these 2 sockets have a third socket called MIDI THRU. In practice, synths are often connected in cascade, forming a communication network.

There are two methods to achieve this kind of network:

  • Cascading as shown in diagram 1.
  • In parallel via a MIDI interface as shown in diagram 2.
Midi cascade link
Diagram 1 midi cascade link
Midi link with an interface
Diagram 2 Midi link with an interface

TRS and other connectors

Very important point to understand with the MIDI Standard !!!

This protocol does not transmit an audio signal. It only transmits messages to control a B device from an A device.

The list of possible messages:

  • Note on/off to start and stop each note. Each note has its own velocity to indicate how strongly the note is played.
  • Control change this protocol allows to control 128 playing parameters such as volume, panning, filters…
    • each control changes at an adjustment range of 0 to 127.
  • Program change, which allows you to select a patch (a tone) from a synthesizer sound bank.
    • The MIDI standard does not specify which program number changes (from 0 to 127) for which instrument sound.
    • To compensate for this, in September 1991 MMA adopted the General MIDI standard to provide a mapping between program changes and synth sounds.
      • The GM standard will evolve with Roland’s GS and Yamaha’s XG proprietary format.
      • Officially launched in 1999, version 2 of General MIDI was released. It remains compatible with version 1
  • The protocol allows the tempo of the devices, called slaves, to be synchronized to a master clock.

I haven’t yet talked about the number of MIDI channels that can be used on physical synths. The standard uses 16 channels.

Depending on your configuration when working with virtual instruments, in my opinion you only have the limit of your software.

Noon minus a quarter limitations and alternatives

The rise of computer sequencers, software instruments driven by dedicated control surfaces has pushed MIDI to these limits.

There is a standard specifically developed to drive pipe organs and digital organs taking into account the specificities of the organ (multiple stops on the same channel), it is the POMI standard for Pipe Organ Midi Interface.

MIDI POLYPHONIC EXPRESSION Revolution

MPE, which originally stood for Multidimensional Polyphonic Expression, was adopted by MMA in February 2018 and renamed MIDI Polyphonic Expression.

Present on instruments and controllers for several years now such as Roli keyboards.

Many softwares such as Reaktor, Kontakt, Cubase, the UVI Falcon, or Logic Pro X to name but a few support this particular MIDI protocol.

an example to better understand…

My Native Instruments Komplete Kontrol keyboard transmits all notes on the same MIDI channel.

Example: I play a chord on my keyboard and I move the pitch bend wheel, all the played notes are affected by the pitch bend.

Hence the term Polyphonic Expression.

The MPE Protocol uses a specific channel for each note, using a separate channel for each note, making it possible to transmit these controllers individually for each note without influencing the other notes played.

Here’s a video with Roli keyboards: Roli Block in action

MPE settings in Logic Pro X :

Open the Roli Dashboard application on your computer and make the settings as shown in the image below.

Roli Dashboard
Roli Dashboard on Mac

The MPE settings in Logic are found in each of the virtual instruments as explained in the image below.

Alchemy MPE setting
Alchemy MPE setting

List of virtual instruments Logic Pro X MPE compatible :

  • Alchemy
  • EXS24
  • ES2
  • Sculpture
  • Retro Synth
  • Vintage Clavinet
  • EFM1

To discover more about Logic Pro X don’t hesitate to click on this link.

we find as manufacturer Haken with the Continuum, Expressive E which is coming soon with the Osmose keyboard made in partnership with Haken.

For the moment the MPE standard is a young one in the world of computer-aided music . Since its adoption by the MMA the development will become interesting, to be watched closely, even if for the moment the prices of MPE keyboards remain high.

Some manufacturers are making efforts in this direction, Roli for example with the Blocks makes the MPE financially more accessible.

Maybe I’ll tell you more in a future article, stay tuned…

*midi in French means noon