As an organist I sometimes feel a little neglected when it comes to new music being written for my instrument, and I get it, the pipe organ is weird and locationally restrictive. Nonetheless, I think the pipe organ offers composers a unique set of sonic capabilities, and with this post I hope to shed some light on what those are.

Sustain: As long as the bellows motors keep running, you can sustain a note or notes indefinitely on the pipe organ. You can achieve this with hands or with heavy objects placed on the manuals (keyboards) or pedalboard (played with the feet). Depending on which stops are pulled, this sustain can result in some nice overtone-interplay in the air. And while you have sounds sustaining you can also have other things going on depending on how many of the performer’s hands or feet are engaged in the sustained portion.

Footwork: Most organists are as versatile playing with their feet as they are with their hands. This means that you have another line to play around with besides the hands, and it’s also possible to play chordal/cluster structures in the pedals (e.g., by having the right foot depress two adjacent keys and the left foot press two other adjacent keys; see the ending of hell und dunkel by Gubaidulina).

Timbral variety: Depending on the size of the organ, you usually have several different types of stops to choose from. Here’s a good guide to the classification of stops. In addition to 8′ stops (which are essentially “at-pitch” with the piano), 4′ stops (one octave higher than 8′) and 2′ stops (two octaves higher then 8′), many organs will have 16′ stops (one octave lower than 8′), and “mutations” like 2 2/3′ (a twelfth above 8′) and 1 3/5′, and “mixtures” (which play multiple ranks usually including 5ths and/or thirds). This Encyclopedia of Organ Stops is pretty handy. The variety of stops means that there is a lot of flexibility with register and complexity of tone. Want a certain line to be played very high? Indicate that part should be played on a 2′ stop. Want the sound to be a little more colorful overtone-wise? Indicate that a mutation stop should be pulled.

I will keep adding to this post as I think of more info that might be useful to composers. In the meantime, just as you—a composer—would (I hope) consult with a pianist, or bassoonist, or cellist about what is and isn’t possible to do with the instrument, how certain things sound, etc., please consider consulting with an organist about the organ’s capabilities. Feel free to comment here with thoughts or suggestions.

A good way to start with any organ is to ask the organist (or office admin) for the “organ specification”, which will tell you which stops that particular organ contains and also other details. Sometimes the organ specification will be available on the organization’s website. Here’s a good guide to understanding organ specification lists. (Thanks to Melita Lara for her comment which led to this addendum.)