Wednesday, February 21, 2007

Apple #226: Pipe Organs

Earlier this week, I went to a pipe organ concert. A cathedral near where I live just got a new, enormous organ, and they hosted four organists from the area. The music they played was challenging -- even I, who knows nothing about this instrument, could tell that -- but it was also fantastic, mainly because of the instrument itself. It sounded like I was listening to an entire orchestra, there were so many different sounds, but they were all coming out of one instrument.

I don't know how many pipes this thing has, but I'd guess easily over 50. Some of the pipes in the middle of the whole array are tremendously tall; I'd say somewhere in the neighborhood of 15 feet high. Then there are little clusters of shorter pipes, flanked by cupids -- yes, actual cupids. The pipes are shiny and the wood encasing them is rosewood or some other bright red wood, and the whole thing gleams and looks as if it knew exactly what it is capable of.

Pipe organ at St. Matthew's Cathedral in Washington, DC. Note how small the organist and console are relative to the pipes behind them.
(Photo by Keith Stanley)

When those organists got the lower registers working, I tell you, the sound just permeated everything -- the cathedral, the inside of my body, my mind -- in an entirely, complete, and good way. It was magnificent.

The program they handed out before the concert was quite lengthy, and it included some kind of chart about the organ's construction. The chart is divided into four groups, each one labeled Great (middle of case), Positive (above keydesk), Swell (oberwerk position), and Pedal. I don't know what these terms mean, but I'd guess they refer to each bank of keyboards available, and also to the pedals you'd play with your feet while your hands went like mad.

Beneath each one of these headings is a list of various terms, some in Latin, some in German, with numbers next to them, such as "Principal 16" and "Qvintadeen 16." I want to find out what this chart means, and I also want to learn more about these instruments in general.

The console of the pipe organ at Christchurch Priory, in Christchurch, England. Several different keydesks are present in this organ. The knobs flanking the keyboards also correspond to divisions of pipes.
(Photo from Christchurch Priory)

  • The organ I heard is a pipe organ. The pipes are like whistles, sticking up out of a box. Air is pumped into the box and then travels into the pipes that are opened or closed by the organist working the stops.
  • It used to be, the wind necessary to blow through the organ was provided by some poor sap pumping in the air with a bellows. Now, however, most organs have electronic blowers, which look sort of like generators, and which have lots of high-powered fans.
  • Every pipe organ is different. The pipes might be made of different materials, there might be tons of ranks of pipes and several corresponding keyboards, or there may only be one or two ranks of pipes. Also, the organ-maker might choose to make the pipes of varying varying heights and tones, which taken together, results in a completely different instrument.
  • Regardless of how large or small it is, every pipe organ is a miracle of organization. I'll break it down into its components to help you get an idea of the size and complexity these things can reach. Before I begin, it's important to remember that the pipes you see behind the organ are only a fraction of the pipes in total. Most of the pipes get stacked in descending order of size behind the pipes you can see.

Pipe organ at the Terrell Heritage Society Museum, in Texas. Some of the behind-the-scenes pipes are just visible behind that first array of pipes in front.
(Photo from the Terrell Heritage Society)

  • Each pipe in an organ is different. Each pipe is of a particular height and circumference and made of a particular material and may or may not have something capping it on top, etc. The upshot is, each pipe produces its own particular sound.
  • But each pipe is part of various ever-larger groups, in the same way that a bluebird is a single bird, but it is part of a species, then a genus, then a family, and so on.

This chart lists a few organ stops and the type and shape of their corresponding pipes.
(Image from The World's Largest Organs site)

Organ Stops
  • The first group to which a pipe belongs is the organ stop. Each stop produces a different timbre, or tonal color. The timbre, or tonal sound is often meant to sound like another instrument, typically a wind instrument such as a flute or an oboe -- which makes sense because the pipes are making noise because wind is being blown into them.
  • An organ stop includes 61 pipes, each pipe voiced to belong to that same timbre. If the pipes are controlled by foot pedals rather than by a manual keyboard, the organ stop includes 32 pipes.
  • I've listed some examples of the organ stops that are part of the organ I heard this week. The links will take you to a sound file that plays a sample of that one particular stop. The sound files play arpeggios of notes to give you an idea of what the organ stop sounds like across its full range of available notes.
    • The Gedackt stop is supposed to sound like a "covered flute."
    • The Hautbois is supposed to sound like a type of oboe.
    • The Nachthorn or "night horn" is a cross between a flute and a horn.
    • The Posaune is sort of a cross among the trombone, a trumpet, and a reed instrument.
  • The number after each organ stop name refers to the height of longest pipe in that stop. In the case of the stop noted as "Principal 16", the tallest pipe in that organ stop is 16' high.

The St. Peter Chapel Organ at Grace Lutheran Church in Lancaster, PA. This organ is relatively small, with very few of the pipes visible in the case.
(Photo from Grace Lutheran Church)

  • As far as I can tell, the terms "rank" and "organ stop" mean roughly the same thing. The phrase "organ stop" refers to the type of sound produced by the pipes in that given sound family. "Rank" refers to the physical pipes themselves, as they are arranged behind the keyboard. In other words, the pipes in a particular organ stop are ranked together. So, the same set of 61 pipes is a full rank for manually-operated stops, while 32 pipes is a full rank for stops operated by pedals.
  • Some ranks have a ton more pitches available than the typical rank. These are called Mutation, or sometimes Mixed stops. A Roman numeral after the organ stop name means that the organ stop has not one rank of corresponding pipes but that multiple of ranks of pipes. For example, Rauschpfeife III means the Rauschpfeife organ stop has three ranks' worth of pipes (183 pipes) for that particular organ stop, while the Cornet V has five ranks' worth (305 pipes).

This relatively new pipe organ at the First Presbyterian Church in Savannah, Georgia has forty-six ranks of pipes.
(Photo from the A.E. Schlueter Pipe Organ Company)

Divisions and Keyboards
  • Several ranks together are referred to as a "division." Each of the pipes in that division are controlled by a single, entire keyboard ("keydesk" in organ parlance). That division and its corresponding keydesk is given a name, such as Great, or Positive, or Choir.
  • Divisions operated by pedals are called, simply, Pedal. These are typically longer pipes, which produce the bass or lower notes, but that is not always the case.
  • Organs can also have a division referred to as the Swell. These pipes are encased behind wooden shutters, which the organist can open and close in order to make the sound emitting from the pipes "swell" forth.

This is just one division's worth of pipes (the Choir division) that are part of the organ at St. Raphael's Cathedral in Dubuque, Iowa
(Photo from Wikipedia)

The Organ I Heard

Based on what I've learned about stops and ranks and divisions, I'm going to do some calculations to figure how many pipes are in this organ that I heard.
  • 4 Divisions
  • 66 Organ stops in all (some of which are multiples)
  • Tallest pipes in the lot: 32 feet tall.
  • Total number of pipes (estimated): 5,085. Pretty much eclipses my original guess of "easily over 50."
  • This number of pipes explains why I felt like I was hearing an entire orchestra. Imagine hearing an orchestra of 5,000 people playing specific flutes and reed instruments and trumpets and trombones and anything else you could blow air into to make noise.

The organ at St. Patrick's Cathedral in New York has over 9,000 pipes.
(Photo from the New York City chapter of the American Guild of Organists)

So when people say, "pull out all the stops," if you did this in reality to a pipe organ this size, you would probably blow your eardrums or something. It would be serious business.

American Public Media, Pipedreams
Lawrence Phelps, Pipe Organs 101
Ross King Company, How an Organ Works
Concert Artist, Organ History, The Organ and How it Works
Wikipedia, Pipe Organ
Organ stop sound files from the Encyclopedia of Organ Stops

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