The Organ Body

By Pascale LeBlanc Lavigne

Some words that frequently come up when we delve into the world of the pipe organ.

Stops

Console

Flues

Stop knobs

Manuals

Wind system

Flue pipes

Reed pipes

Ranks

Some terms that the artists and Avatar team often pronounced as they explored the creative possibilities of a MIDIfied pipe organ.

CoMIDI

Arduino

Patch

MIDIfied

Max/MSP

Controllers

Cables

It’s buggy!!!

Come on, it worked yesterday!

In working as project manager on the collaborative project Plein Jeu, I really wanted to understand (at least minimally) how a MIDIfied pipe organ functions. Usually, when I’m at the beginning of a learning process, I need to start trying things out right away. However, absorbed by the responsibilities related to my role in the project, I didn’t have the time required to learn how to play the organ through a computer interface, so I adapted my learning process to the context. To understand the functioning of this complex instrument equipped with a digital interface, I intuitively drew a parallel between the components of the pipe organ and parts of the human body. Inevitably, such a transpositional process has certain shortcomings and cannot in any way lead to an in-depth understanding of the subject. Nevertheless, this nebulous analogy helped me to better appreciate the beauty of the works created with this ancient instrument, re-envisioned here. In the hopes of revealing how MIDIfied organs function, I will share with you what I have learned.

The Organ Body

If we were to think of the organ’s various tones as its voice and the pipes blowing the air out as its throat and lips, then the organ’s console—the place where the organist sits—would be its brain: the control centre.

The console is complex and composed of several manuals (keyboards for the hands) and pedals (a keyboard for the feet). Each one offers different divisions of the organ. On either side of the console are small mechanical knobs, called stop knobs. Each knob bears the name of an instrument, from wind to percussion to string instruments.

 

This system reinforces the idea that the organist is both musician and conductor.

 

Activating the stop knobs admits pressurized air to one or multiple ranks of pipes. These sets of pipes and the sounds they make are called stops, though sometimes they are also referred to as registers: the register of the trumpet, the register of the cello, etc. The combination of different stops used to play a piece, according to the tones the organist or artist seeks to produce, is called registration.

 

The structure and function of this mechanical process suggest that the pipe organ could be the ancestor of the synthesiser.

 

Air is constantly being produced by the organ’s wind system, its lungs. A variety of mechanisms direct and modulate the air being blown into the different pipes in order to produce various tones, as gentle as a lullaby, as cheery as the song of the common chaffinch, as solemn as a funeral march.

But even if you pulled out all the stops, there would be one proviso: the many components of the console are both too numerous and too spread apart for an organist to physically explore the instrument’s full potential on their own. In other words, unless you have eight arms and can move as fast as the Flash, it is humanly impossible to activate more than a certain number of keys and stops at one time, in any given moment. Fortunately, the language of the digital interface allows us to overcome these limitations.

Broca’s Area: Language Production

Although the pipe organ tends to be associated with a certain conservatism in our collective imagination, this age-old instrument has gone through many minor and major transformations throughout its history. The most recent technological advances have sought mainly to facilitate the upkeep and adaptation of these immense wind instruments. It is now possible to control these powerful architectural instruments not only through the console, the place from which the organist usually operates the organ, but also through a digital interface: the MIDI language. The keys and stops of the console (metaphorically associated with the organ’s brain) can thus be activated without an organist actually touching them.

Broca’s area is a region in the human brain associated with the production of words. Like our brain, the MIDI interface doesn’t produce any sounds directly. It is however used in the production of tones.

Musical

Instrument

Digital

Interface

Generally speaking, the MIDI language allows the transfer of data between several electronic musical instruments, the computer being one of them. Some sound artists see MIDI as an additional tool that allows them to play an instrument in another way and explore its limitations.

The same applies to the organ. Thanks to the MIDI interface, the organ’s lungs send air through the pipes when an electromechanical valve receives an electrical signal. Usually, this electrical signal is sent when an organist activates the keys and stops of the console. Yet this electrical signal can also be sent from a computer keyboard or from sensors, and can even be programmed, and it is in this that the artist’s creative scope is transformed.

In addition, several computers can be interconnected! This means that several people can play this architectural instrument at the same time, a relatively unexplored avenue in the history of the pipe organ up to now. Without the MIDI interface, this possibility would have been unthinkable, as the space behind the console is rather limited.

A computer can then be connected to all kinds of sensors, such as light, motion, sound, and pressure sensors. These sensors collect and send data to the computer, which assures its translation through the MIDI language, that is its transfer to the mechanical parts of the organ. Any physical element (everyday objects, light, sound, human bodies, etc.) can now become an electronic device, interact with the organ, make it vibrate and produce tones.

 

For example, a pressure sensor carefully attached to a seat will produce electrical signals when someone sits down. These signals are then transmitted to a software program installed on a computer, which transforms them into MIDI data and connects them to the mechanical, electronic, and electromechanical components of the pipe organ.

 

Combined with the MIDI interface, computer programming is essential in order to make the translation of the electrical signals collected by the sensors and redirected to the mechanical parts of the organ possible. As the word programmer indicates, programming allows one to anticipate and organize production. In short, the MIDI interface, sensors, and programming allow the artists to broaden their intentions and experiments both individually and collectively.

Wernicke’s Area: Language Comprehension

The fact of combining signal capture, MIDI language, and programming to act on the organ’s mechanical elements is quite the feat and also liable to give many people a huge headache! Fortunately, Avatar’s technical team accompanied the artists in addressing several challenges. In addition to assuring the communication between all the digital languages, the team modified the MIDI interface typically associated with pipe organs and adapted it to the research-creation of sound artists breaking down barriers.

Starting from the premise that the limits of one’s language also mean the limits of one’s world, the Plein Jeu team has waged that the development of the pipe organ’s language will open up new creative spaces and reimagine the sound universe of this instrument’s powerful body.