If you just followed the QR code to this site and are standing in Duke Chapel, you are probably hearing the tuning of the Kathleen Upton Byrns McClendon Pipe Organ (Aeolian Organ Company, 1932) located in the chancel. What follows are answers to questions you may have about the tuning process you are hearing.
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I am John Santoianni and I am the Ethel Sieck Carrabina Curator of Organs and Harpsichords. I take care of the instruments here at the Chapel as well as in the Music Department and the Divinity School. When I am tuning, I need the Chapel to be as quiet as possible so I can better hear the pitches and overtones of the pipes I am tuning. Even quiet talking is distracting and gets in the way of my work. Yes, I can hear you! Other distractions I encounter are vacuum cleaners, planes, trains, helicopters, lawn mowers, heavy rain and wind, someone on a cell phone, slamming doors, and all the cheering from Cameron Indoor Stadium (a slight exaggeration for the last one). Whether the pipes are very loud or very soft, they all require very attentive listening to get the tuning just right.

Every acoustic instrument needs to be tuned from time to time. For pipe organs, the changing seasonal temperatures affects the internal temperature of the Chapel which causes the overall pitch of the organ to change—but not evenly, so the pipes become out of tune with one another. I will be tuning this one organ for at least a week.

There are approximately 6,700 pipes in the Aeolian organ, and my goal is to tune just about all of them.

If you are standing in front of the steps to the chancel, you can see 117 pipes in the four sections of the façade cases. There are two main cases facing each other in the chancel, and two “lancets” that face into the crossing. Of these 117 pipes, only 24 actually speak—the rest are there just for decoration (called “dummies”). You are only seeing less than .4% of all the speaking pipes of this organ.

Behind the beautifully carved oak facades are three large rooms called chambers. The largest chamber is about 25’ square.

Pipes inside the Aeolian Organ

All the pipes sit on windchests that hold pressurized air as well as the mechanism that allows the wind into the pipes. The photo above shows a view of two of the windchests for the “Great” manual (the Aeolian has four manuals and a pedalboard; each manual controls a different collection of pipes). The smallest pipes in this photo are thinner than a pencil, and the largest pipe on the right has a diameter of about 9” and is about 10’ tall. There are 15 main windchests and many more “offset windchests” that hold the very tallest pipes. The longest pipe in the organ is about 34’ long and 14” across at the top.

Pipes inside the Aeolian Organ

This photo is a view of the “Choir” division that has approximately 1,600 pipes. If you see some pipes that look bent over, that is called mitering and it allows the tallest pipes to fit under the ceiling.

I begin by setting the temperament on one “rank”. (A rank is a complete set of pipes making one particular quality of sound.) This means getting the placement of the pitches for each of the 12 notes in an octave just right—not too sharp or flat. I then tune the rest of the pipes for this rank to that octave. I then tune another rank to the first rank. And another. And another. There are about 100 ranks.

Pipes inside the Aeolian Organ

This photo shows two different ways I can change the pitch. I am pointing to a tuning sleeve. If I tap it up with my tuning iron, the pitch will become flat (the longer the pipe, the lower the pitch). If I tap it down, the pitch becomes sharp. The wooden pipes behind have a metal flap. If I push the flap down, the pitch goes flat; if I push it up, the pitch goes sharp. Depending on how the pipe is constructed, there are at least five other ways that pipes can be tuned. Most of the tuning requires very small adjustments.

I may be giving my ears a rest, or adjusting a pipe that is too loud or too soft, a process called “voicing.” I may be going from one chamber to another, and that can take several minutes and requires several ladders. There is also some “housekeeping” to do inside the organ chambers, such as cleaning up the dust that accumulates, and removing the occasional dead bugs.

Temperature changes! As I tune, the temperature of the Chapel will change throughout the day. It will be cooler in the morning, and become warmer as the day progresses—even with an amazing HVAC system. The building soaks up the heat of the day, and the heat is transferred through the walls and ceilings. As the chambers heat up, the pitch rises as well, but not evenly; the smaller the pipe, the more it will go sharp and for larger pipes less so. As the Chapel cools in the evening, the pitch will drop. I am constantly having to listen carefully and make adjustments as I go.

For each degree Fahrenheit the temperature rises, the pitch will go up .5 Hz. (One hertz (Hz) equals one cycle per second.)  If I tune a rank of pipes to “modern” pitch (where a=440 Hz.) at 9:00 a.m. when the chambers are at 68°, but the temperature rises to 70° by noon, the pitch will now be 441 Hz.—but not evenly. This is the battle every organ tuner faces. We have to calculate where to set the pitch at the beginning of a tuning session to get it at the right place at the correct temperature for when the organ will be used the most. Typically, this would be between 11:00 a.m. and 12-noon for Sunday services.

Here is a link to a video my colleague James Todd made that shows another of the Chapel’s pipe organs, the Benjamin Newton Duke Memorial Organ (Flentrop, 1976) and how it works. But don’t watch it in the Chapel. Remember---I can hear you!