In the Wind: Ringing through the night

John Bishop

Listen to the voices.

Alan Laufman, who founded the Organ Clearing House in 1961, was in his final illness during the summer of 2000 when he asked me to join the company to help its work continue when he was finished. During that summer and fall, I sat with him for countless hours as he passed on the company lore and history, warning me of potential pitfalls and hinting about tricks he had picked up over the years. Among many other things, he warned that I would be spending a lot of time typing stoplists. When the company was young, he was working with a manual typewriter, carbon paper, and Wite-Out. (Remember those little bottles with a brush in the cap?) He kept a typewritten list of available organs: builder, year, location, number of manuals, number of stops. If you sent him a letter with $3.45 in stamps, he would send you a copy of the list. Updating the list meant retyping it completely. There were dozens of organs.

Happily, many stoplists are now available online from the websites of organ companies, churches, and the brilliant, comprehensive Pipe Organ Database created under the auspices of the Organ Historical Society (pipeorgandatabase.org), and it is easy to publish a stoplist on our website by attaching a link to a file or web page. “Click here to download specifications.” Still, I sometimes need to type the stoplist while referring to a photograph of the stop jambs. It is easy enough for a modest organ, but once you get over fifty stops, it takes a lot of flicking back and forth between screens to get it all accurately.

I review a dozen or more stoplists every time I spend a day at my desk. They are open as tabs on web browsers. I refer to them when talking on the phone. I type them, edit them, file them, and publish them. And while there are almost infinite variations, there are also similarities that apply to many American organs. I am often speaking or corresponding with people who have purchased an old church building who are altogether unfamiliar with organs, telling them how to gather the information I need to assess the marketability of an instrument. I might be speaking with a real estate developer sitting on the organ bench, mobile phone camera at the ready. I ask how many keyboards? “Three.” “Are there banks of knobs on either side of the keyboards?” “Yes.” “Do you see a group of knobs marked ‘Great’ on the right side?” “Yes.” “From the bottom up, you might read 8′ Diapason, 8′ Dulciana, 8′ Melodia, 4′ Octave, and so on?” “Exactly right. How did you know?” I just knew. It goes on: 4′ Flute d’Amour, 2′ Fifteenth, Mixture IV, 8′ Trumpet.

Is there one pedal stop? It is either Bourdon or Subbass, some smart people label it using the German Subbaß. Are there two pedal stops? I will bet lunch that it is one of these two pairs, 16′ Bourdon and 8′ Violoncello or 16′ Open Wood Diapason and 16′ Bourdon. How many three-manual organs have a Choir division that reads 8′ Concert Flute, 8′ Dulciana, 8′ Unda Maris, 4′ Flute, 8′ Clarinet? A ten-stop Swell division would have 8′ Viola da Gamba, 8′ Viole Celeste, 8′ Stopped Diapason, 4′ Principal, 2′ Octavin, Plein Jeu III, 16′ Bassoon, 8′ Trompette, 8′ Hautbois, and 4′ Clarion, a list that is familiar to thousands of organists.

Of course I am oversimplifying. I notice that my imaginary organ has 8′ Dulciana on both Great and Choir, fair enough because those are both common places to find that stop. If the organ was a little larger, we might have a Geigen Diapason on the Choir, or we might change the Great Dulciana to an Erzähler. One organ I played a lot when I was young had an 8′ English Diapason on the Choir. If the organ was a little larger, there would be an 8′ Diapason on the Swell, a few more independent Pedal stops like 16′ Principal, 8′ Octave, 4′ Choralbass (or Choralbaß), and 16′ Trombone. As I throw more stops at my imaginary organ, I am still using names that are common to many, even most American organs. So I raise the question, if pipe organ stoplists are so predictable, what’s new under the sun?

Making a list

If you leaf through a stack of printed stoplists, you will notice a common form that connects them all. Stops are separated by division, they are listed from lowest to highest pitches, maybe there is a mixture or two after the usual flues, and the reeds are last. When there are several flue stops of the same pitch, they are listed in order, principal, string, flute. The biggest apparent variety is the number of stops and number of divisions. So why don’t all organs sound alike?

Just like regional accents in any language, there are countless ways an organ stop like Principal or Gedeckt can sound. When an organ is being planned, the person or people responsible for how it will sound make decisions about what materials to use to make pipes, what wind pressures should be to complement the acoustics of the room and placement of the instrument, what scales should be used (the ratio between length and diameter of a pipe), and how each stop should be balanced with all the others.

The choice of materials is a good place to start. Hard metal like tin produces a bright tone; soft metal like lead produces a darker tone; and lead and tin are mixed in alloys through the spectrum. It is rare to find pipes made of pure tin because that metal is too hard to work with when doing the meticulous finicky work of voicing. Adding ten or twenty percent lead softens the metal enough to allow the voicer to manipulate the metal more easily, but the tone still benefits from the hardness. It is also rare, even a mistake, to make pipes of pure lead because the metal is so soft and heavy that the pipes cannot support their own weight. As the revival of classic organ building got rolling in the last third of the twentieth century, some organ pipes were made with such high lead content that the pipes collapsed after only a few years. Builders realized that when duplicating the high lead content found in antique pipes, they failed to consider that modern metallurgy produces purer materials while ancient lead was full of impurities. Throw a handful of impurity into the melting pot, and the lead gets stronger. It is the opposite of skimming the floating stuff off the top of your chicken stock pot.

The same applies to making wood pipes. Softwoods like spruce or fir produce darker tones, while hardwoods like oak or maple produce brighter sounds. It is common to find neat little 2′ Principals made of oak in portable continuo organs that produce crystal clear tones, and in the Taylor & Boody organ at Grace Church in New York City, the beautiful Choir 8′ Principal Dolce that forms the façade just behind the organ bench is made of white oak.

Wind pressure is a critical choice because it determines what style of voicing is possible. Bright, transparent choruses in Classic-style organs require low pressures, while the broad, rich, and even powerful voices in a Romantic or symphonic organ are produced by high pressures. The symphonic style of pipe organs was made possible in the early-twentieth century by the introduction of the electric blower, allowing voicers to use great volumes of air at high pressures without worrying about the aches and pains of the people pumping the bellows. The fact that all the organ symphonies of Widor were written for a huge organ that was hand-pumped speaks volumes about the skill and resourcefulness of the organbuilder.

Like the choice of materials, scaling is an essential part of planning an organ. Middle C of an 8′ Principal could be 1-3⁄4 inches or 2-1⁄4 inches in diameter, depending on the tonal character desired. Varying the scale of wood pipes is a matter of changing the dimensions of the cross section. Low CCC of a 16′ Double Open Wood might be twice the width and depth of the same note in a wood 16′ Violone. The Double Open will produce a hefty, broad bass tone, while the Violone with keener tone will provide more clear definition of pitch with crisp speech.

Color my world.

Thirty years ago, when we chose a paint color, the person in the store looked up a formula and used a machine with a lot of tubes of basic colors to put the correct number of ounces of each color into the can of base paint, one tint at a time. The same action is done now with computerized machines that produce the accurate little squirts of color. Those color-blending machines in your neighborhood hardware store are just like choosing registrations for a piece of organ music. Draw a little blue (8′ Diapason) and red (8′ French Horn) and you get a lovely purple.

Some organists register their music in a formulaic way. “I always use flutes 8′, 4′, and 2′ in this passage” or strictly use registrations printed in a score. That approach misses the opportunity to create your own tone color. Consider Bach’s Fugue in E-flat Major, the “Saint Anne,” BWV 552ii. Start the elegant main subject on principals 8′ and 4′. Perfect. You might say that is the way I have always done it, but one organ I often played has a beautiful 8′ Oboe that I combined with the 8′ Principal to create a gorgeous sound that allowed the counterpoint to be heard clearly and gave harmonic richness to the soaring passages. I sometimes added the 4′ Octave midway before changing to something sparkling for the sprightly 6/8 section.

If you are preparing to play a particular piece on a particular organ for the first time, take a few minutes to play the first few measures on fifteen different combinations. If you were cooking, you would add some olive oil (rich and earthy), oregano (aromatic), garlic (bitter and spicy), butter (smooth and creamy), and diced tomato (flavorful and moist), and you get a wonderful sauce.

Start with an 8′ Trumpet (rich and earthy), add a 4′ Octave (a touch of brilliance), add the 2-2⁄3′ Quint (harmonic blend), and you have the start of a French Grand Jeu. Why is that such a satisfying sound? The pipes of the Trumpet have rich overtones at the first, second, third, and fourth overtones (4′, 2-2⁄3′, 2′, 1-3⁄5′). In our three-stop combination, the Quint is emphasizing the second overtone. Beautiful. Go ahead and add the 2′ and 1-3⁄5′ to complete the Cornet. Play around with those overtones. Draw the 8′ Oboe and 2-2⁄3′ Quint for a nice solo combination. If the 1-3⁄5′ is not too loud, it will sit delicately on top of the Oboe and Quint. If it is loud and spicy, it might be too much. Maybe emphasize 8′ pitch by adding a stopped flute, or better yet, a chimneyed flute because it also emphasizes the second overtone. Use your ears and listen.

Staying with the French tradition of overtones, start with an 8′ Gedeckt or Stopped Diapason, add 4′, 2-2⁄3′, 2′, and 1-3⁄5′. That is the classic Cornet. But do not leave it at that just because the score says so. Try all the possible combinations of those five stops, with and without the tremolo. There are lots of possibilities, and one of them is just right, or if it is not such a great organ, one of them is better than the others.

Here is some more ear training. Hold a single note on an Oboe or Cromorne and flick the 2-2⁄3′ on and off a few times. You can train your ears to hear the second overtone (Quint) in the solo voice of the reed. This trick works best in the tenor octave where the overtones are heard most clearly. Once you can easily identify that harmonic, try the same trick with 1-3⁄5′ until you are certain you can hear the fifth overtone in the solo reed voice. Now you can use your ears discriminately to choose the most luscious registration.

Mind your Zs and Qs.

A friend who is a brilliant organist associated primarily with a large symphonic organ once told me he had no use for organ stops with Zs or Qs in their names. Quintadena, Sesquialtera, Terz (Terzian), Zimbel, Prinzipal, and Dulzian are all stops you would find in a modern low-pressure organ, perhaps with open-toe voicing and high tin content—not your favorite sounds if the rolling, robust, even mysterious sounds of a symphonic organ are your thing. On the other hand, that somewhat snobby comment from my friend would be the reverse for many organists who love the brilliant instruments of Visser-Rowland, Holtkamp, or Zimmer where there are lots of Zs and Qs. There is something for everyone.

How good can it sound?

Another important reason to use your ears when you are registering music at the organ is the condition of the tuning and pipe speech of your chosen organ. If Hauptwerk and Rückpositiv are not in tune with each other, do not couple them together, or you will get a nasty zinging of high-pitched pipes like a swarm of bees. If the Trumpet is flat against the rest of the organ because it is hot in the church, do not use it. Your listeners would rather hear a reduced registration than the fingernails-on-the-blackboard sensation that comes from bad tuning, and most of them would never know that you would have preferred to use the Trumpet just then if it sounded a little better.

For over thirty years I maintained an organ in Boston that had large tin pipes in the façades of Pedal, Great, and Rückpositiv cases. There was a long, thin window at the peak of the ceiling that ran the length of the building, and at a certain time of the year, sunlight beaming through that window would parade across the organ’s façade at 10:00 in the morning, just the time to be finishing your prelude and starting the opening hymn. Over the years there was a procession of organists, and I showed them all how to pay attention to that sunlight because for a brief time, the Principal pipes would be heated up by the sun and go sharp from the rest of the organ. Is it too fussy to pay attention to tuning to that kind of detail? I guess it depends on your ears, but the pitch of organ pipes changes with temperature. You can add that to your knowledge base. Science is a real thing.

If you are choosing a solo combination for the cantus firmus of a chorale prelude and your precious Oboe has a squawker on the second note of the melody, do not use it. There is sure to be another combination that sounds good enough, and your listeners will never know you did not get your first choice. A lot of wedding marches will be spoiled when the fourth F-sharp of the Trumpet is a lulu. Take it up a half step, or if transposition is not your strongest suit, you can go down a half step by imagining the key signature of D-flat and using the same notes. As you choose stops to combine, play chromatic scales up and down the keyboard on every stop you plan to use and listen for uneven voicing. Maybe a few notes are too soft or too loud. Maybe a few pipes are slow to speak, have too much unpleasant chiff, sound raspy, or cause some woodwork to vibrate and buzz. Choose a different stop or combination of stops. The point is to make the organ sound as good as it can. It is all about listening.

As you listen and experiment like this, write down issues you found that caused you to change your mind about what stop to use. That list becomes a guide for your service technician. If the console log book says that the third D-sharp of Swell Flute d’Amour is too soft, it will get corrected during the next service call. Conscientious organ technicians are pleased to find that list, because they know they can make the organ sound better for you.

A few months ago, during a nice restaurant dinner with a colleague who was voicing an important new organ, I asked what he hoped to achieve with the completed instrument. “I want to build something beautiful that will enrich the people who hear it.” It is your duty as organist to use each organ you play to its best advantage.

Michael McNeil

Michael McNeil has designed, constructed, and researched pipe organs since 1973. He was also a research engineer in the disk drive industry with twenty-seven patents. He has authored four hardbound books, among them The Sound of Pipe Organs, several e-publications, and many journal articles.

Editor’s note: The Diapason offers here a feature at our digital edition—two sound clips. Any subscriber can access this by logging into our website (www.thediapason.com), click on Current Issue, View Digital Edition, scroll to this page, and click on each <soundclip> in the text.

The Clicquot organ at Houdan

The community of Houdan with a current population of just over 3,000 is located about thirty-five miles due west of Paris, France. In 1739 the organbuilder Louis Alexandre Clicquot completed the organ at Houdan in the church of Saint James. He was the father of François-Henri Clicquot who built the organ at the cathedral of Poitiers, and he was also a member of the family who to this day produces the wonderful champagne of that name. 

The organ at Houdan is preserved in virtually every detail of its original construction. For this we have to thank that it was placed in a small community without the resources to “modernize” it—large and prosperous cities have a habit of “improving” the organs in their care and irretrievably losing their history. The organ was unmolested until it went silent in the 1870s.

Fortune struck in the 1960s when Jean-Albert Villard, the organist titulaire of the F.-H. Clicquot organ at the cathedral of Poitiers, intervened when plans were formulated to modernize the instrument and discard most of its heritage. Villard and the efforts of many other preservationists prevailed, and the work of restoring the organ in its original state was entrusted in 1969 to Robert and Jean-Loup Boisseau. This is the organ we hear today. If you ever wondered why French Baroque music sounds lackluster on modern organs tuned in equal temperament, wonder no longer and buy the download of a new recording of the organ at Houdan by Régis Allard.⁹ It is a revelation; at Houdan the music sounds as it did to its composers and their intent becomes clear.

The limited resources of the community of Houdan were also probably responsible for the incredible economy in the design of the Clicquot organ. It has twenty-one stops distributed on three manuals (the third manual is treble-only), the pedal has no stops and simply couples to the bottom two octaves of the Grand Orgue, and there are no 16′ stops. But what looks at first like a tonal design lacking in grandeur is in fact extremely versatile and very grand. The French Classical scaling and voicing is musical and exciting without being in the slightest overbearing—the grandeur derives from its meantone temperament.

Meantone was an invention of the Renaissance, and one of its earliest practitioners was Pietro Aaron, who described his scheme for tuning it in 1523. While earlier temperaments going back all the way to Pythagoras favored pure fifths, the new system favored pure thirds at the expense of the fifths. In Aaron’s version there were eight pure thirds, four very impure thirds, reasonable fifths that beat about twice as fast as equally tempered fifths, and a wolf fifth that took up the remaining error. Aaron placed that wolf fifth on G-sharp and E-flat. There is always an error to be accommodated with our twelve-tone octave, and in equal temperament we distribute that error equally with the result that no intervals are in tune without beats. 

The wisdom of François Bédos de Celles

Our equally tempered third is a dissonant monster to which we have simply become accustomed. Bédos was well aware of equal temperament and despised it. His thoughts are worth revisiting: 

Among these schemes, two are the most worthy of note. One is called the old system, whereby the fifths are unequally tempered [meantone]; and the other is the new, which diminishes all the fifths to a lesser degree, but equally [equal temperament]. The mathematicians and the music-theorists disagree here. The latter, judging only by instinct and ear, cannot accept the new temperament, which they find harsh and less harmonious than the old one. Indeed, the fifths are diminished by only one-twelfth of a comma . . ., and all equally, with the result that all major thirds sound blurred, which makes a harsh impression on the ear. According to the old temperament, about eleven fifths are diminished by one-fourth of a comma. This is a greater adjustment than one-twelfth of a comma, but it saves, or keeps perfect, eight major thirds. 

Since altering these fifths by one-fourth of a comma still does not lead to a perfect octave, one fifth is sacrificed by having all the rest added to it, making it quite jangled. However, it lies in a seldom-used key. Organ-builders call this fifth the ‘wolf.’ Despite the prestige of the scientists who devised the new system, it has nevertheless been abandoned, even though it is less imperfect than the other, in theory. Music theorists prefer the old system, alleging that fifths may be altered one-fourth of a comma and even more without becoming disagreeable, whereas imperfect thirds must of necessity offend the ear: thus their old system is not inferior to the new . . . .
Moreover, the composer makes use of the very defects of the scale, finding in it resources for emphasizing the character of his various compositions. Whether the tone be gay, mournful, sublime, majestic, etc., he selects a mode suited to the harmonies most expressive of his idea. The new temperament does not offer this resource. Since all the intervals are equal, they all have the same character, with nothing to offset the harshness of the thirds.¹  

The point of meantone is its harmonic purity, tension, and color. The heart of meantone is the pure third, which has a benefit not explicated, but intuited by Bédos. A pure fifth sounds the second and third harmonics of a tone an octave lower, e.g., the interval at middle C to G has an audible subtone that sounds tenor C. Equal temperament fifths come close to purity, and we make use of that subtone to create pedal resultants. But here is a key feature of meantone: its pure thirds sound a subtone two octaves lower, e.g., middle C to E sounds the fourth and fifth harmonics of a subtone that sounds low C. When a French Classic composer uses a pure major third in the tenor, that sound contains a very real and audible subtone at 16′ pitch. This is why the Houdan organ sounds grand without a single 16′ stop. Listen to this soundclip of the “Suite du premier ton,” from Livre d’orgue II, Fugue, by Nicolas Clérambault to get a sense of the 16′ subtones created by meantone’s pure thirds <soundclip1>.⁹  

If you take a deep dive into researching the temperament of the Houdan organ you may find different opinions. The notes in the PDF booklet accompanying the recording heard in the soundclips simply states it to be “mésotonique,” and American organbuilders who have visited this organ report that it is tuned in 1⁄4-comma meantone with the wolf on G-sharp and E-flat, which is Pietro Aaron’s version. But according to Timothy Tikker at least one source reports that the Houdan organ may be tuned in the temperament devised by the French Classic organbuilder Dom Bédos, a variant of Aaron’s version.²  

Are these two temperaments really different, and are the differences important? At first hearing, the recording of the Houdan organ abounds in pure thirds. Aaron’s version has eight pure thirds, and according to Bédos, his version has seven pure thirds and one “slightly diminished” third on B-flat.³ Tikker states that Bédos’s tuning gained widespread favor in late eighteenth century France with its sonority.²

Beat rates describe sonority

There are many ways to compare the two temperaments. We will use beat rates (beats per second) to determine the relative purity of intervals—and beats are what you actually hear when you play an impure interval.⁴ A pure interval is consonant and has no beats; an impure interval with many beats has dissonant tension. Beat rates depend on actual frequencies, so we must keep in mind that the beat rates we will see in this article are referenced to the specific pitch A = 440 Hz; if the relative pitch is A = 395 Hz, like the organ at Houdan, the beats will be slightly slower. Beats will double for each ascending octave, so if an interval has two beats in the bass, it will have four beats in the tenor, and so on. We use beat rates for this comparison because we want to compare the relative consonances and dissonances of these temperaments, i.e., we want to understand their sonorities. 

Pietro Aaron’s meantone

Beat rates can be calculated for all the common intervals, and a table of the beat rates for Pietro Aaron’s meantone is seen in Figure 1.⁵ The second column in Figure 1 lists the notes from A-sharp in the bass octave to F in the middle octave. The third column lists the frequencies of those notes. The next columns show the beat rates for the intervals of the minor third (m3), major third (M3), fourth (4), fifth (5), minor seventh (m7), major seventh (M7), and major ninth (M9). A quick glance at this table will show the eight pure major thirds (0 beats) for the notes C, D, D-sharp, E, F, G, A, A-sharp. The wolf fifth on G-sharp–D-sharp in the tenor has 12.⁹ howling beats per second; it will have twice as many beats in the middle octave. There are four very impure thirds on C-sharp, F-sharp, G-sharp, B—Bédos called these “wolf” thirds. From this table you can get a feel for the extreme variation from consonant purity to dissonant impurity in meantone intervals. Modern conventional wisdom has held that these dissonances are to be avoided, but as Bédos noted, classical composers consciously used these dissonances to enhance emotional effects. Listen to this soundclip of the “Suite du deuxième ton,” Livre d’orgue, I. Plein jeu, by Nicolas Clérambault <soundclip2>.⁹ This vibrant color is completely lacking in equal temperament.

Key features of the Bédos temperament

So how does the Bédos temperament differ, and does it have any advantages? This question is not easily answered because Bédos left apparently conflicting instructions: these include tables of various types of commas and some specific instructions for tuning his temperament that do not correlate. There is less conflict when we understand that the tables of commas appear to describe conventional meantone; John Brombaugh has analyzed these commas and the author has used Brombaugh’s frequencies to produce a table of beat rates that are virtually identical to the Aaron meantone.⁶ Bédos’s comma tables and tuning instructions can be found in the Ferguson translation of Bédos’s monumental work, The Organ-Builder.⁸ Referring to Volume I, §§1142–1145, Bédos clearly states that for his temperament there are “three fifths [D-sharp to A-sharp, G to D, B to F-sharp] that are diminished more than the others [beat faster].” Bédos also clearly states in §1145 that the major third A-sharp to D “should be slightly diminished and beat slowly.” A major third tuned flatter than pure is very unusual! Something seems amiss here, but the beat rate program will shed some light. 

The construction of the Bédos beat rates

In the first column of Figure 1, the beat rate program shows the sequence of tuning the intervals used in the construction of the table. The analysis of the Bédos temperament uses the same sequence until we get to the A-sharp, and from that point it took a few iterations to get it to the point where the advantages of the Bédos temperament became obvious. Those not wanting to dive into the details may skip to the next section.

The use of a plus sign on a beat rate means that we tuned the new note sharp, and a minus sign means we tuned it flat.⁷ Starting with the A-sharp, instead of using the fourth F to A-sharp = +2.2 beats we will use +3.0 beats; Bédos mentions that the fifth B-flat to F beats faster, so the A-sharp will be tuned higher to make the major third on A-sharp to D diminished. We next tune the “diminished” major third so: A-sharp to D = -1.0, making the D diminished from pure by -1.0 beat (it is -2.0 beats an octave higher in the tenor).  

The major third D to F-sharp is tuned pure. Next, the fourth A-sharp to D-sharp is tuned +2.4 beats rather than the original +1.5 beats, and Bédos states that this interval will beat faster. It was determined by iteration that this preserves the original purity in the D-sharp major third. 

The rest is easy. All of the remaining major thirds, D-sharp to G, G to B, and E to G-sharp are tuned pure. It is very important to note that we have re-tuned G and B; both have new frequencies. Figure 2 shows the beat rates for the presumed Bédos temperament.

The sonority of the Bédos meantone

If the sound of pure major thirds in Aaron’s meantone is impressive, now try to imagine the sound of pure fifths, pure major thirds, and pure minor thirds. One result of Bédos’s instructions is that the keys of C and E now have completely pure major and minor triads. And the purity in the key of C extends to the interval of the major seventh. An inspection of the table in Figure 2 will show that we also achieved Bédos’s seven pure major thirds and one slightly diminished major third on B-flat with two beats in the tenor octave. 

Bédos did not make clear in his instructions that he significantly changed the beat rates of the fifths C to G and E to B when he diminished the third on B-flat and adjusted for its effects—those fifths are now pure! The pure fifths are part of the source of the confusion in his instructions. Bédos starts with instructions for a normal meantone and then modifies it. Perhaps he thought this would be obvious. The steps for tuning the normal meantone in Figure 1 are included at the end of this article.

A price is paid for this new sonority, which we can see in the worse wolf fifth with 15% more beats. The fifths on D-sharp, G, and B are all now degraded, as noted by Bédos. If this is indeed Bédos’s temperament, it has some very interesting sonorities.  

The pure triads are very unusual; only the Kirnberger I temperament has two major triads of such purity (not to be confused with the more common versions, Kirnberger II and III).⁴ 

Graphics read better than numbers

Tables of numbers are difficult to read, so we can get a better feel for the relative sonority of the Bédos meantone by using color graphics to represent the relative purity and tension between the twenty-four major and minor triads. In Figure 3 we see the Aaron and Bédos meantones represented by major triads in downward facing triangles and minor triads in upwards facing triangles. The lines between the notes are colored to represent purity (bright green), less purity (yellow-green), tension (yellow), and dissonant impurity (orange and red). The actual beat rates are indicated with the numbers placed next to the colored lines. The sonority of the Bédos meantone is now quite evident in the distribution of green.

Key features are satisfied

While we cannot be certain that Bédos’s temperament is represented in Figure 2, the temperament in that table does indeed have an improved sonority, and it follows Bédos’s instructions. The beat rate table in Figure 2 resulted from an attempt to incorporate the diminished third on B-flat with the least amount of adjustment to the Pietro Aaron meantone, and it also resulted in the faster beating fifths on D-sharp, G, and B. These are noted by Bédos as key features of his temperament. The pure major and minor triads on C and E were not a goal of this exercise; they were the surprising result when the adjustments caused by the diminished third were complete!

Unresolved issues

A survey of the literature will show that Bédos’s instructions have been interpreted in many different ways. Some of this confusion results from the conflicts between Bédos’s specific description of his tuning method and his tables of commas.⁸ Brombaugh has shown that the tables of commas describe normal meantone, but there is one other issue in Bédos’s specific instructions for tuning. He sets the tuning bearings for the third octave of the Prestant, i.e., 1′ to 1⁄2′ pitch, and he specifies that the interval G to D has five or six beats per second.³ While this beat rate is faster than the normal meantone fifth, it is much slower than the beats obtained for that interval in Figure 2: those beats will be faster in the octave of his tuning bearings.

Other interpretations of the Bédos tuning instructions may yield different results than those in Figure 2, but any new interpretation must also satisfy the constraints Bédos has described: a diminished third on B-flat and the faster beating fifths on D-sharp, G, and B. Many interpretations of the Bédos temperament exist, but only the interpretation in Figure 2 meets all of those constraints.

The Clicquot organ at Houdan

It is reasonably certain that the Houdan organ is tuned in 1⁄4-comma Pietro Aaron meantone. But the value of controversies is that they push us to re-explore our previous assumptions, and the exercise in this article may shed new light on the temperament of François Bédos de Celles. 

I hope you enjoy the remarkable meantone sonority of the Houdan organ as much as I do. Two recent recordings are well worth your money.^{9, 10}

Notes & References

1. François Bédos de Celles, O.S.B., The Organ-Builder, an English translation of the original L’Art du facteur d’orgues, 1766–1778, by Charles Ferguson, The Sunbury Press, 1977, pp. 230–231, §1135.

2. Personal communication, January 2019.

3. The Organ-Builder, p. 233, §§1140, 1142.

4. Michael McNeil, “Exploring the Sound of Keyboard Tunings,” The Diapason, April 2016, pp. 20–21. This article gives a description of the tradeoffs when comparing temperaments with cents or beat rates.

5. Detailed and accurate instructions for tuning the Pietro Aaron temperament that appears in this table may be found in Tuning the Historical Temperaments by Ear, by Owen Jorgensen, Northern Michigan University Press, Marquette, 1977, pp. 173–177. An abbreviated version is appended to this article.

6. Personal communication, April 2019.

7. This program and the instructions for its use are contained in a DVD with the author’s book, The Sound of Pipe Organs, CC&A, 2014, Amazon.com. The program is admittedly difficult to use. 

8. The Organ-Builder, pp. 230–234.

9. Régis Allard, Magnificat 1739, Editions Hortus, 2017. Available as a download from www.editionshortus.com. The tuning of the Houdan organ in this recording is spotless.

10. Michel Chapuis and Emmanuel Mandrin, Marc-Antoine Charpentier: Messe pour le Port-Royal, E 8598, Auvidis, France, 1997. This recording showcases the accompanimental balances of the Houdan organ with solo voices. The radiance of the meantone purity with the voices is remarkable.

Method for tuning the Aaron meantone:⁵

Inputs to the beat rate program are noted in [  ]

1. Tune middle C. [263.2] This will yield A = 440Hz. (McNeil)

2. Tune C below middle C pure to middle C. [C–C]

3. Tune E below middle C pure to C below middle C. [C–E]

4. Tune G-sharp below middle C pure to E below middle C. [E + G#]

5. Test all C, E, and G-sharp for purity.

6. Tune F below middle C pure to C below middle C and then raise F until it beats equally (1.6 beats) between the two Cs. [C + F + 1.6]

7. Tune A below middle C pure to F below middle C. Test that tenor C to A and tenor E to A beat equally (2.0 beats).   [F + A]

8. Tune C-sharp above middle C pure to A below middle C. Test that C-sharp above middle C beats equally with G-sharp and E below middle C (2.5 beats). [A + C#]

9. Tune the C-sharp below middle C pure to the C-sharp above middle C. Test that both C-sharps beat equally with the E below middle C (2.5 beats).   

10. Tune A-sharp below middle C pure to F below middle C, and then raise the A-sharp until it beats at the same rate as the small minor third A-sharp–C-sharp (2.2 beats). [F + A# + 2.2]

11. Tune the A-sharp an octave lower than middle C pure to the A-sharp below middle C. Again, test that A-sharp–F and A-sharp–C-sharp beats equally (1.1 beats), where A-sharp is an octave lower than middle C.   

12. Tune D below middle C pure to the lower A-sharp. Test that the interval D–A beats 1.4 compared to the interval F–middle C at 1.6 beats. [A# + D]

13. Tune F-sharp below middle C pure to D below middle C. Test that the C-sharps above and below the F-sharp beat equally (1.7 beats). [D + F#]

14. Tune D-sharp below middle C pure to the lower A-sharp and then raise the D-sharp until it beats equally between the lower and upper A-sharp (1.5 beats). [A# + D# + 1.5]

15. Tune G below middle C pure to D-sharp below middle C. [D# + G]

16. Tune B below middle C pure to G below middle C. [G + B]

17. Tune B an octave below middle C pure to B below middle C. Test that D-sharp–A-sharp beats equally with E–B in the octave below middle C (1.5 beats).

Photo: the keydesk of the Houdan organ. Photo credit: William T. Van Pelt

Michael McNeil

Michael McNeil has designed, constructed, and researched pipe organs since 1973. He was also a research engineer in the disk drive industry with twenty-seven patents. He has authored four hardbound books, among them The Sound of Pipe Organs, several e-publications, and many journal articles.

Very few organs survive the depredations of time. Some are the victims of wars and fires, but most are the victims of the good intentions and interventions driven by changing tastes in sound. Those few that have survived such calamities usually have something special about them in their sound or their visual impact. The 1750 Joseph Gabler organ at Weingarten, Germany, is special on both counts—its dramatic chorus makes music come alive, and the architecture of its casework and façade is a stunning tour de force.

The Gabler organ has been criticized since almost the time it was built for its lack of power, having almost a chamber instrument quality. But the Gabler organ has a dramatic flair and musicality that sets it apart from most pipe organs, perhaps teaching us some valuable lessons in tonal design.

Human sensory perception takes notice only of changes. The old joke about cooking a live frog has more than a grain of truth to it. Place a frog in hot water, and it jumps out; raise the temperature of the water slowly, and the frog will take no notice and become dinner. It is the same with sounds. If a sound does not change, we do not notice it or we lose interest. Gabler was a master of the control of change in sound, and this is the heart of the drama in his organ. By way of example, Johann Sebastian Bach’s early composition, the Toccata in E major, BWV 566, requires an organ with a dramatic sound to pull it off, not just a loud organ. Peter Stadtmüller’s 1975 recording of BWV 566 on the Gabler organ takes us to new emotional dimensions <soundclip1>.¹ The Gabler organ’s lessons go to the heart of musicality.

In 1986 Friedrich Jakob and the organbuilding firm of Kuhn published a wonderful book on the Gabler organ at Weingarten. Die Grosse Orgel der Basilika zu Weingarten is available from Orgelbau Kuhn AG, Männedorf, Switzerland.² We are very fortunate that Jakob and Orgelbau Kuhn took the time to write this book and publish it. In an effort to better understand the sound of this instrument, I translated some of its passages with Google Translate, edited the translation as an organbuilder would understand it, and then graphically analyzed the data from the appendix of this book. This is but a very small part of what this book has to offer, and those seriously interested in this organ should purchase this wonderful book.

The current basic specifications of the organ after the restoration by Kuhn are:

Manuals: compass C to c′′′, 49 notes; pitch a′ = 419 Hz at 15 degrees Celsius; wind pressure = 70 mm water column.

Pedal: compass C to d′, 27 notes (originally C to g); pitch a′ = 419 Hz at 15 degrees Celsius; wind pressure = 70 mm water column.

Orgelbau Kuhn restored the Gabler organ between 1981 and 1983. The work was carried out partly in Männedorf, partly in Weingarten, and was summarized as follows:  

A. Static remedial measures:

• Renovation of the gallery floor, partial replacement of supporting beams. 

• Improvement of the Kronpositiv position. 

• Improved support for the bracing of the Positive chest.

B. Removal of added features:

• Demolition of the additional works built in 1954.

• Rebuilding of the Barker machine and restoration of the continuous direct mechanics.

• Rebuilding of the electric trackers for the Kronpositiv, reconnection to the Oberwerk by means of the original conductor blocks.

• Rebuilding of the numerous bellows as well as the newer wind ducts and blower system.

• A reconstructed wind system with six wedge bellows.

C. Normal cleaning and restoration work.

• Make the whole organ wind-tight again.

• Treatment against wood pests. 

• Reworking of all mechanical parts, in particular the axle points. 

• Repair and reconstruction work on the pipework. 

• Tuning in an unequal temperament.³  

Pipework repair

Orgelbau Kuhn performed the normal repairs on pipes that would be expected from centuries of tuning damage. Split pipe seams and loose languids were resoldered, deformed pipe bodies were rounded, and new sections were added to the tops of damaged pipes. 

The effect of the wind system on sound dynamics

The dynamic response of the Gabler wind system is one of most important aspects of its dramatic sound. While measurement data of the wind system is lacking, Orgelbau Kuhn carefully described what they found and what they changed:

The Gabler wind supply in the north tower had already been replaced for the first time in the work of 1861/62. In place of the six original wedge bellows, there were ten box bellows of a new design. Probably in 1912 during the installation of an electric blower the wind system was again modernized by the construction of a large, so-called double-rise bellows.

In the course of the restoration, six wedge bellows were again set up, however, according to practical requirements, with motor operation. The old beams of the bellows chamber did not allow any definite conclusions as to the former position of these six bellows, so free assumptions had to be made.

The original wind duct system, in so far as this had not been done earlier, was practically completely expanded in 1954 and replaced by a new version with cardboard pipes. On the basis of a large number of traces (cut-outs on the casework, color traces on the walls, cut-outs on the beams and on the grids, as well as on the original windchest connections), the course as well as the dimensioning of the Gabler wind duct system could be known.

In three places, where it was obviously not possible to expand, some of the original ducts were preserved. On the one hand, these are the supply ducts to the two Rückpositives under the floor, on the other by a section of the connecting channel above the façade middle flat. This remainder was of particular importance. This is a double channel (57 x 17.5 cm outer dimensions) with a middle wall. The upper part of the duct is marked with “Manual” and the lower part with “Pedal” with a weakly readable red pencil. This was the proof of the actual execution of the wind separation for manual and pedal, which was already required in the contract.⁴

Data on the size of the bellows, ducts, and pallet boxes would allow a calculation of the capacitance (volume) and the inductance (mass, or weight on the bellows) of the wind system. From this data the resonant frequency could be calculated, giving insight into the slow, dramatic risetime of this wind system on full demand. What we do know from the elegant layout drawings of the Gabler organ by Orgelbau Kuhn is that the wind ducts were very long, and the cardboard ducting from 1954 (heard in the 1975 recording by Peter Stadtmüller) was apparently larger in cross section. (“In three places, where it was obviously not possible to expand, some of the original ducts were preserved.”⁴) This means that the internal volume of the wind ducts was larger in 1975, and the sheer length of the ducting indicates a very large internal volume for the entire wind system.

In the 1975 recording we hear a very long, slow surge in the sound of the full pleno driven by a very low resonant frequency in the wind system, and this is a large part of the dramatic sound of the instrument. Such a slow wind system obviously forces a slower tempo, and that is how Stadtmüller interpreted the Toccata in E Major in the glorious acoustics of the basilica. From this we see an essential component of dramatic change: a slow buildup of power when the full organ is played and the wind system is forced to work hard <soundclip2>.¹ The current sound of the organ post-restoration still retains a very dramatic sound, but it is slightly faster, and may be the consequence of the smaller ducting cross sections with less capacitance.¹⁵ When asked about the pipe organ, Igor Stravinsky is reported to have said, “The monster doesn’t breathe.” Although it may have been unintended, Gabler’s gift to us is that he makes the organ breathe.

To put this into perspective, the author took careful measurements in 1996 of the J.-E. & J. Isnard wind system on their organ at St. Maximin, France, and calculated its resonant frequency to be 1.2 cycles per second, a value that correlated very well with actual measurements of the slow, grand surge of this wind system.⁵ Although it is not as long a surge as what we hear in the Gabler organ, the J.-E. & J. Isnard organ at St. Maximin also features a dramatic buildup in power on full organ, the result of high capacitance and high mass in the wind system.

Famous organs with dramatic chorus effects, e.g., the Isnard at St. Maximin, tend to exhibit a purposeful starving of the wind supply where the total area of the toes that can be played in a full plenum are roughly equal to or even greater than the cross section of the wind duct that feeds them. Gabler’s reduction of ranks in the Kronpositiv to alleviate wind starvation, as noted by Orgelbau Kuhn, does indeed suggest that Gabler restricted the cross sections in his ducting. To more fully understand the wind flow of this organ we need measurements of the ducting, pallet openings, channels, and pipe toe diameters for each division.

The effect of the mixture designs on sound dynamics

Pipes are very effective sources of change in sound when they are out of tune (think of the richness of a celeste). We also hear complex dynamic changes in the sound when the speech transients of many pipes combine to form a complex onset of speech in the attack of a chord. The most obvious sources of tonal change are Gabler’s immense mixtures that contain as many as twelve ranks in a single stop. His Sequialters are also constructed of many ranks, and they are scaled exactly like the mixtures. The combination of the Hauptwerk Mixtur, Cymbalum, and Sesquialter contains a vast number of pipes that, as Jakob nicely phrased it, have the effect of a “string choir.”

Multiple ranks at the same pitch do not produce significantly more power (the power increase of doubling the pipes at a single pitch is the square root of 2, or 1.4 times the power). The significant effect is in the depth of the chorus, which is heard as subtle celesting (mistuning) in sustained chords, and which is also heard in the attack of a chord where many pipes speaking together have subtle differences in the speed of their speech and their harmonic content. To some degree these effects are mitigated by the “pulling” effect; pipes of the same pitch placed closely together on the same channel will tend to “pull” each other into tune. But the Gabler chorus has not only many duplicated pitches in a single mixture, it has three such mixtures on the Hauptwerk with limitless possibilities for subtle mistuning effects. The upper pitch ceiling in Gabler’s mixtures is a 1⁄8′ pipe. The preponderance of mixture tone resides in the region from 1⁄2′ to 1⁄8′ pitch, precisely the frequencies to which human ears are most sensitive.

Understanding the sound of the Gabler organ

The appendix of the book contains wonderful data on pipe diameters, mouth widths, and mouth heights (cutups). No data exists on the diameters of the toe openings or the depths of the pipe flueways. This data would allow us to understand the very high cutups of the pipework in this organ. Furthermore, the ratio of the areas of toes to flueways plays a large role in the speech of these pipes. We can only hope that this data will someday be made available. The very useful reed pipe scales in the appendix would benefit from additional data on shallot opening widths, tongue lengths from the tuning wire, tongue widths, and tongue thicknesses, all of which would help us to better understand the sound, especially the very effective Pedal 16′ Bombarde.

Orgelbau Kuhn addressed the low power of the Gabler organ in their description of its scaling and voicing.

The sound of the Gabler organ was already felt as comparatively weak, often as too weak. From the construction period, there were no complaints, because the deadlines and costs were too much in the foreground. Even so, the sound development must have been perceived as partially deficient. This is borne out by the various supplementary technical measures taken by Gabler to increase the sound: the lifting of the roofs by means of cable mechanics, the opening of the side walls of the Oberwerk and the Pedal. All these changes, however, did not benefit much. The reason lay deeper . . . .

The weak sound of the Gabler organ . . . finally led to the construction of auxiliary works, along with stylistic considerations as a result of the altered sound tastes of the time. This resulted in 1912 in the construction of the Seraphonwerk with seven high-pressure registers (150 mm water column) as well as the supplementation of the Kronpositiv by a Cymbal.

What is the source of the relatively weak sound, or rather the relatively low decibel performance of this organ? According to our findings, there are essentially four. The scales of the pipework by Gabler, the sometimes precarious wind conditions, the inhibited sound egress due to Gabler’s compact design, and finally the throttling by the narrowing of the toeholes of the pipes. The number of nicks is irrelevant in this context.

Orgelbau Kuhn pointed to the casework as a source for the low power of the organ.

A[nother] reason for the relative weakness of the sound is to be found in the comparatively small openings for egress of the sound . . . . The big façade pipes are very closely spaced. Apart from the triangle openings around the pipe feet only very narrow slots between the pipes are available for the egress of sound.

Interestingly, images of the façade show that Gabler added carved ornaments between the feet of the façade pipes, further blocking the egress of sound.

Massive, unperforated pipe shades also reduce the egress of sound. While the three problems of scaling, wind supply, and compact construction were already present, the fourth problem only arose as the organ aged: the narrowing of the toe holes due to the very steep angles of the toeboard bore chamfers on which they sat. Last but not least, it was also due to late maintenance. This secondary damage was discovered and corrected in the course of the restoration, while the other characteristics of the Gabler style, of course, remain untouched.⁶

Scaling

The scaling of the Gabler organ is unusually narrow for such a large acoustical space. And unlike the French who scaled their foundations wide but kept the upperwork stop scales narrow, Gabler uses a constant scale, which is narrow in both the foundations and upperwork. Why would Gabler do this? The answer may lie in the layout of his unusual principal chorus, which with its enormous mixtures looks more like an ancient Blockwerk than a typical chorus of his time. Here is Orgelbau Kuhn’s description of the problem:

We can only confirm: Gabler had difficulty with the scales. It is not only in the strings, but in general, that the composition of the scaling is quite narrow. Obviously, he looked at the size of the scales as an absolute one, whereas in reality they were dependent on space. For the giant room of the Weingartner Basilica, respectable distance considerations were appropriate. As a result of these under-nourishing scales, the principal is already near the strings, while the strings are already struggling against the frontier, where a clean, precise, and reliable approach to the fundamental tone is scarcely possible.

That is why Gabler also had to make extensive use of voicing aids, not only of nicking, but also of other voicing aids such as front and box beards. By making use of these aids, at least, all the pipes were able to speak in the fundamental, but a development of the power of the organ was not possible.

Gabler sought to compensate for this scaling deficit through numerous double-ranked and multiple-ranked voices. In the mixture voices, Gabler goes much further. In the Hauptwerk, for example, he built the Mixtur 2′ with ten ranks, the Cimbel 1′ with twelve ranks, and the Sesquialter with nine ranks. Through these chorus effects, Gabler sought to achieve sound power, a power that was not due to the too narrow scales. As we have seen in the Kronpostiv, but also in the Mixturbass, he had wanted to go further in this direction of multiple ranks, but he was, to a certain extent, overtaken by the second evil: he came to the limits of the wind supply. The long wind trunks made an inadequate supply, so that in the course of the work he was forced to cut back on the number of ranks (in the Kronpositiv, for example, a reduction from 18 to 2 ranks).

This struggle for sound and wind is clearly visible to the expert on the evidence in the construction. This desperate wrestling resulted in a great success. But it is clearly a struggle and not a virtuosic play with the principles of organbuilding. The result is a result of the struggle and not artistic design.⁶

The wonderful scaling data in this book was entered into a spreadsheet that normalized the measurements into Normal Scales for pipe diameters, mouth widths, and mouth heights (or “cutups” to a voicer). This graphical presentation allows a much easier interpretation of the data. A set of graphs of the Hauptwerk (Figures 7, 8, and 9) and Pedal (Figures 10, 11, and 12), with commentary, are presented at the end of this article.

The graphs of the pipe diameters (Figure 7) corroborate Orgelbau Kuhn’s assertion that much of the low power was due to narrow scaling. Mouth widths are usually a better indication of relative balances of power, but Gabler used mouth widths that were generally very close to the normalized mouth width scale (one fourth of the pipe circumference), and as such, the normalized mouth width scales (Figure 8) are very similar to the normalized pipe diameters.

The normalized mouth height (or cutup) scales (Figure 9) are remarkable. Gabler’s mouth heights are generally fairly low in the bass increasing to extremely high values in the trebles, so high in fact, that 1⁄8′ pipes are cut up roughly 40% of their mouth widths. The relatively high mouths would suggest pipes with very open toes and flueways, although this data is unfortunately not tabulated. 

Gabler knew how to use very wide scales, but he only used them in his flutes (see the graph of the Hauptwerk, Figure 7). Is Gabler showing us what a Gothic chorus would look like? The chorus effects of these multiple-ranked mixtures are astounding, unique, and very musical. Chorus dynamics, not power, may have been his objective. The subtle imperfections of tuning in these ranks produce subtle celesting on a grand scale. Subtle differences in voicing will produce a rich chorus effect resulting from random differences in the speech onset of the pipes in these mixtures. Gabler may have aimed at the grand sound of a Gothic Blockwerk, not loud, but rich in texture and chorus effects.

Few unmolested pipes remain from the Gothic period, much less complete organs, but one example stands out: the 1475 organ by da Prato in the Basilica of San Petronio, in Bologna, Italy. As recent research shows, this organ is largely original and serves as an elegant example of a Gothic chorus.⁷ The author graphed and combined the data for both the Gabler and da Prato organs. In Figure 1 we see data for normalized pipe diameters, and in Figure 2 we see normalized mouth widths. The data for the da Prato chorus extends to 24′ low F; the 32′ value is a straight-line extrapolation of the 16′ and 24′ da Prato data.8 The Gabler chorus includes the Hauptwerk and Pedal pipes, which extend to 32′.

Scaling data are intrinsically noisy; variations from the intended scale are produced both by the pipemaker and by the person who measures a pipe. Variations of +/- a halftone are normal. The data are remarkable because both sets of data converge on the same intended diameter and mouth scale. We do not know if Gabler imitated the da Prato scales or any other Gothic design, but the similarity of the Gabler and da Prato scales is unquestionable. The dotted black line represents the approximate intended scale, the red lines represent the actual Gabler pipes, and the blue lines represent the actual da Prato pipes.

Gothic pipework (Figure 3) from an organ by an unknown builder in Ostönnen, Germany, exhibits an unusual design characteristic also seen on the façade pipes of the Gabler organ (Figure 4). Figure 3 shows an extension of the upper lip at the sides of the mouth (red arrow), making the mouth width slightly narrower than the width of the flueway.⁹ We do not know if Gabler was taking his cue from a Gothic model, but the comparison is interesting.

Voicing

The minimum data set to understand the voicing of an organ includes the mouth height (“cutup”), toe diameters, flueway depths, treatment of the languids (bevel angles and types of nicking), and presence or absence of ears and other such devices. Like the da Prato organ of 1475, the Gabler organ exhibits no ears on the façade pipes and presumably none on the internal pipes of the principal chorus. Orgelbau Kuhn provides data on cutups, but not on toe diameters or flueway depths. Voicers adjust toe diameters and flueway depths to affect the flow of wind for more or less power. Voicers raise cutups to make the pipe tone smoother with less harmonic bite. More wind, from either the toe or flueway, will increase power and make the tone brighter with more harmonic bite. A more powerful and brighter timbre can be made smoother again with higher cutup. Hence, it is important that we know all three variables—cutups, toe diameters, and flueway depths—if we are to understand the voicing. We have only mouth height data. 

A common precept of neo-Baroque voicing was the rule that the mouth height should be 1⁄4 of the width of the mouth. There is, of course, no basis for this in historic work, nor is there any theoretical basis, and it produces a rather strident timbre in most pipework. The normalized mouth heights of the Gabler organ, seen in Figure 5, are remarkable. Only in the bass do they approach a value which produces a height 1⁄4 of the mouth width (this occurs when the normalized mouth height scale in halftones is the same as the normalized mouth width scale in halftones). But as the pitch ascends for the Gabler pipes, so do their normalized mouth heights, until at the highest 1⁄8′ pitches the mouths are very high, about 40% of their mouth widths. Also of note is that the treble mouth heights of the principal chorus are almost as large as the mouth heights of the very wide flutes in the Hauptwerk. The same trend is seen in Figure 6 of the da Prato mouth heights, but the typical da Prato values are lower, a reflection of that organ’s lower wind pressure. The highest mouths in the da Prato graph are also those of its flutes. Gabler’s treatment of mouth height looks very much like the Gothic work of da Prato, adjusted for higher wind pressure.

Reiner Janke sent the author photos of pipe mouths from the 1743 choir organ at Weingarten, also built by Gabler. These photos show very generous flueway depths and deep, fine nicking. Although we do not have toe diameters to confirm this, it may be reasonable to assume that Gabler’s high mouth heights in the treble reflect a desire for a more ascending treble.

Orgelbau Kuhn limited their analysis of the voicing to the presence of nicking and the method of tuning:

While ‘tuning’ means the mere regulation of the pitch, the ‘voicing’ includes the processing of all partial aspects of a musical tone, including the loudness, the tone color, the tone accent, or the transient response. This eminently artistic work is generally performed only when a new organ is being built, or when a major rebuilding is carried out.

A restoration, especially if it also includes changes or regressions in the wind supply system (bellows and wind duct system), also causes a new voicing of the pipework. It is necessary to think philosophically about the original Gabler voicing, and it would be wrong to assert that it had remained intact, for the intervening interventions were too great. Of course, we did studies on other Gabler organs, but also on instruments of other South German masters such as Holzhay and Höss, but there were no exact models for the voicing in the Weingarten types, one simply had to work with the existing pipe material. The technical procedure can be easily rewritten. First, the pipes were normalized and repaired where necessary (open solder seams and loose languids soldered). The languids were then carefully placed in the correct position for an optimal response to the pipe in the fundamental. In the rest, as little as possible was changed.

Gabler has made extensive use of nicking. This can be seen in the non-speaking but voiced façade pipes c′–d′ of the Kronpositiv, which are completely unchanged. In addition to the original nicking of Gabler, the main body of the pipes also contains nicking of other handwork. It turned out to be impossible to assign only the newer nicking, but to leave the Gabler nicking unmarked. So it was decided not to work the languids; the insertion of new languids was not considered at all . . . .

The labial bass pipes are provided with cleanly inscribed tuning slots proportioned to the pipe diameter up to the 2′ position. Attempts have shown that stops without these tuning slots could not be tuned over the entire range of octaves. These tuning slots are therefore to be regarded as original. In contrast to later practices, however, these tuning slots are only scribed and not fully enrolled.

Tuning 

The absolute pitch is A = 419 Hz at 15 degrees Celsius. The original temperament was very similar to Gottfried Silbermann’s meantone. It was characterized by eight not pure, but good, major thirds, eleven tempered fifths, and one large Wolf fifth on D-sharp to G-sharp. It had an equal temperament fifth at C, extending to -12 cents at G-sharp and extending to +5 cents at D-sharp.

The current milder tuning deviates from the original meantone and has an equal temperament fifth at C, extending to -9 cents at G-sharp and extending to +1 cent at D-sharp.10 It is not known if the Musical Heritage Society recording of 1975 reflects Gabler’s original tuning or something closer to the present tuning.1 Like Gottfried Silbermann, Gabler uses high cutups in his voicing for a less strident timbre, and this works well with meantone temperaments, mitigating the harshness of the more dissonant intervals.

Reflections

Friedrich Jakob reflected on the sound of the Gabler organ:

How is the sound of the Gabler organ to be characterized? We are confronted with the general problem of describing sound with words. With features such as warm, round, pointed, sonorous, bright, and so on, no exact statements are possible. Still, be tempted.

The Gabler organ is certainly not a forceful organ. Power and brilliance are missing in comparison to the normal large organ. The sound is somewhat reserved, veiled, poetic, and pastel colored. The tremendous multiple ranks of the mixtures give the effect of a string orchestra. Minimal deviations of the individual voices do not result in any false tone, but a larger range of the right one. It was very important to leave the organ intimate in character with the chamber music and not to have a wrong symphonic influence. But since everything is wind-tight again, and every pipe is speaking the fundamental, the organ sounds a little more powerful than before.¹¹

The claim has been made that Gabler did not understand the principles of scaling as they relate to larger rooms, and Jakob describes very convincing evidence that Gabler struggled with the power. But the inflection point of Gabler’s constant scale at 1⁄2′ demonstrates that Gabler had a good grasp on the effect of distance on the sound absorption of higher frequencies. Tones extending from the deep bass up to the pitch of a 1⁄2′ pipe will carry very effectively over long distances, but pitches above that point will lose energy in their interaction with the atmosphere, so much so that the sound of a 1⁄8′ pipe will lose 5 dB in power at 500 feet.¹² One halftone of scaling is equivalent to 0.5 dB of power, so this means that 10 halftones of wider scaling must be used at 1⁄8′ to compensate for the atmospheric losses at 500 feet. Gabler widened his mixture pipes by 8 halftones from 1⁄2′ pitch to 1⁄8′ pitch. The length of the Basilica of Saint Martin and Saint Oswald at Weingarten is 102 meters, or 335 feet. Gabler has compensated very well for the distance losses. The absolute values of these scales are indeed much narrower than what we would typically find in rooms of this size, but the mathematics show that Gabler was cognizant of the effects of large distances. But Jakob also convincingly demonstrates that Gabler was not satisfied with the power, went to some trouble to correct it, and ultimately failed in the effort.

Figures 7 and 8 show the diameter and mouth width scales of the Hauptwerk. Note how much wider Gabler scales his flutes relative to the principal chorus. These flutes are quite powerful and provide an extremely effective contrast to the mixture plenum. A wonderful example of this contrast can be heard in Ton Koopman’s interpretation of the Bach Concerto in A Minor after Vivaldi, “Allegro,” BWV 593 <soundclip3>.¹⁵ Here Koopman demonstrates that Gabler’s flutes can cut through the principal chorus. While typical interpretations of this concerto use contrasting principal choruses, Koopman’s performance gives a clarity and beauty to this concerto that can only be heard with Gabler’s tonal balances. Gabler’s organ, if it is not powerful, is extremely musical, and we can learn much from his example, all of it applicable to organs with more power.

To summarize, some of Gabler’s musicality derives from the intense chorus effects of the mixtures with their many ranks, the many duplicated pitches, and the subtle depth created by the mistuning of those multiple ranks. Multiple ranks do not significantly increase power, but they do increase the sense of chorus.

Another aspect of the musicality of the organ resides in its very slow wind response, which takes the form of a dramatic surge to full power when the organ is playing a full pleno. Another effect that produces a slower wind is a high resistance in the wind system, and Jakob mentions this in his description of the Kronpositiv ducting, which was so restrictive that Gabler was forced to remove a large number of ranks on that chest. Many classical organs feature wind trunks that were purposely designed with smaller cross sections to barely flow the required wind, or even starved the wind to a degree.¹³  

Finally, Gabler employed very large scales in the deep bass of the Pedal. Along with the robust Bombarde 16′, the Pedal produces a tactile effect underpinning the modest power of the manual pleno. The overall effect of the Gabler organ is intensely dramatic without being at all overbearing. To reduce this to a basic philosophy, Gabler was a master of designing for a sense of change in the sound, both aural and tactile. The acoustician R. Murray Schafer observed that “. . . a sound initiated before our birth, continued unabated and unchanging throughout our lifetime and extended beyond our death, would be perceived by us as—silence.”¹⁴ His point was that for a sound to have drama, to grab our attention, it must change: change in pitch with the subtle mis-tunings of his multiple-ranked mixtures, and change in power with the slow rise in the pressure of the wind. The organ at Weingarten is the singular achievement of a master, and even if by today’s standards the overall power seems modest, we can use Gabler’s lessons to great advantage.

 

Excellent recordings exist of the restored Gabler organ.¹⁵ See also Youtube for a cut from this CD: Präludium & Fuga C Moll, BWV 549: www.youtube.com/watch?v=hWWtpS-yvKI.

 

The following normalized graphical data for the Hauptwerk and Pedal were constructed from Jakob’s data. Email the author for a copy of the original Excel file with the data and normalizations, which also includes the Oberwerk: [email protected]. Readers interested in the theory behind these normalizations may refer to The Sound of Pipe Organs.¹²

Hauptwerk data (see Figures 7–9)

Jakob’s claim that narrow scaling is responsible for much of the low power of this organ is amply supported by the normalized pipe diameter data. Gabler is using a “constant scale,” where all pipes speaking the same pitch are the same scale, regardless in which stop they appear or in which part of the keyboard compass they appear. This constant scale averages -7 halftones from 16′ to 1⁄2′ pitches, then increases rather linearly to +1 halftone at 1⁄8′ pitch. The normalized mouth widths seen in the next graph follow a similar trend because Gabler scaled his mouth widths very close to 1⁄4 of the pipe’s circumference, the basis of the normal mouth width scale.

Gabler’s normalized mouth heights are remarkable in their deviation from the pipe diameter and mouth width Normal Scales, and they tell us something about Gabler’s intentions in power balance from the bass to treble. High mouths are a tool of the voicer to achieve a smoother, less bright tone, or alternatively, a more powerful tone when the pipe is winded with larger toes or larger flueways. Gabler uses the mouth height as an independent variable, perhaps to achieve an ascending treble power in the plenum. Data on the toe diameters and flueway depths would give us a deeper understanding.

The diameter and mouth scales of the Hauptwerk 8′ and 2′ flutes are very wide. The Gabler flutes are very smooth and liquid in tone and have very high mouths when plotted on the Normal Scale, but those mouth cutups would appear low when looking at the actual pipes because the diameter and mouth scales are very wide. Gabler knew how to use very wide scales, but he only applied such scales to the flutes, perhaps suggesting that his narrow principal chorus scales were an intended result, even in this large acoustic.

Pedal data (see Figures 10–12)

In Gabler’s Pedal we also see a constant scale, but it has a different shape, averaging about +3 halftones at 32′ pitch, descending linearly to about -7 halftones at 2′ pitch, and thereafter remaining roughly flat at that scale up to 1⁄2′ pitch. These wide scales in the deep bass are the source of the tactile effect in Gabler’s sound. Human hearing becomes dramatically less efficient in the bass; at about 20 Hz we hear and feel a sound at about the same level. Below that frequency we tend to only feel the sound. The frequency of a 32′ pipe is 16 Hz and is much more felt than heard. Note the very wide scales of the 16′ Octavbass. It is powerful enough to achieve a strong tactile effect; also note its very high cutups, which imply full wind at the toes and flueways. 

Like the Hauptwerk, the Pedal mouth widths are similar in normalized scaling to the pipe diameters and tell a similar story. Also like the Hauptwerk, the Pedal mouth heights dramatically ascend with higher pitch. 

The Pedal Bombarde is full length with rectangular wooden resonators. The effective scale of a wooden resonator is its diagonal measurement, i.e., the width of its standing wave, and this reed measures a very generous 240 mm at low C. Combined with the tactile character of the deep bass flue pipes, the Bombarde is a very strong component of the drama achieved by the Gabler chorus.

Notes:

1. Peter Stadtmüller, Toccata in E major, BWV 566, J. S. Bach, Musical Heritage Society MHS 3195, Gabler organ, Basilica of Saint Martin and Saint Oswald at Weingarten.

2. Friedrich Jakob, Die Grosse Orgel der Basilika zu Weingarten, Geschichte und Restaurierung der Gabler-Orgel, Verlag Orgelbau Kuhn, Männedorf, Switzerland, 1986, 146 pages. The book and shipping totaled 73.00 Swiss Francs. At this time Kuhn is only able to receive funds wired to their account, which makes the book rather expensive to those of us who live across the Atlantic Ocean. Email Orgelbau Kuhn AG: [email protected]. Website: www.orgelbau.ch.

3. Ibid., pp. 40–43.

4. Ibid., pp. 55–56.

5. My statement of the “. . .motions of the bellows plates. . . to be ≈ 1.25 Hz” for the Isnard wind system in The Sound of Pipe Organs, page 108, has errors that I missed as a result of the closeness of the calculated resonance in Hz and the measured period of the response in seconds. My measurement of the bellows response at 1.25 seconds represented three motions of the bellows, down-up-down, which is 1.5 times the period of the wind surge. Therefore, the correct period, one cycle of two motions, down-up, is 1.25 / 1.5 = 0.83 seconds. Inverting that (1 / 0.83 seconds) gives us 1.20 Hz, or cycles per second, which perfectly correlates to the correctly calculated resonant frequency of the system.

6. Die Grosse Orgel der Basilika zu Weingarten, pp. 72–79.

7. Oscar Mischiati and Luigi Ferdinando Tagliavini, Gli Organi della Basilica di San Petronio in Bologna, Pàtron Editore, Bologna, 2013, 577 pp.

8. Michael McNeil, A Comparative Analysis of the Scaling and Voicing of Gothic and Baroque Organs from Bologna and St. Maximin, e-publication, PDF, Mead, Colorado, 2016. Email the author for free copy:
[email protected].

9. See Youtube video of the organ at Ostönnen: www.youtube.com/watch?v=YxmsZ5ksaVY. Also see the Youtube panoramic video of the Gabler organ in which you can zoom in to see the same treatment of the façade pipe mouths: www.panorama-rundblick.de/gabler-orgel-weingarten. Click on the red arrow to move to the front of the console to see the 32′ façade.

10. Die Grosse Orgel der Basilika zu Weingarten, p. 78.

11. Ibid., p. 79.

12. The Sound of Pipe Organs, pp. 13–14.

13. Ibid., pp. 119–127. See the example of the wind flow calculations for the Isnard organ at St. Maximin.

14. R. Murray Schafer, The Tuning of the World, Alfred A. Knopf, New York, 1977, p. 262.

15. Ton Koopman, J. S. Bach Orgelwerke II, Gabler-Orgel, Basilika Weingarten, Novalis CD, 150 020-2, 1988.

 

Photo: The 1750 Joseph Gabler organ, Basilica of Saint Martin and Saint Oswald, Weingarten, Germany (photo credit: Thomas Keller; see the source in Note 9)

John Bishop

The life of π

If you have maintained bird feeders, you know what squirrels can do. They are powerful, lithe acrobats, and they can outsmart almost any attempt to deter them. I recognize several individual male gray squirrels in our yard that are strong and agile enough to leap three or four feet from the ground on to the cone-shaped baffles. They shinny up the steel poles, over the tops of the feeders, hang upside down, and gorge themselves.

Some days I think it is okay to feed the squirrels as well as the birds, letting them take turns, but one day last week as I watched them dominate, it occurred to me that I could make a new baffle of different design, a two- or three-foot disc of plywood with flashing around the edge. If they jumped on it, it would surely flip and dump them off. I took a quick measurement and set off to the lumber yard for a sheet of half-inch exterior plywood and some flashing. How much flashing? It comes in ten-, twenty-, and thirty-foot rolls. I told the kid behind the sales desk (he’s younger than my kids) that I planned either a twenty-four- or thirty-inch circle. Let’s see. Twenty-four inches is two feet. Two times π is about six-and-a-quarter feet. Thirty inches times π is a little less than eight feet. Easy. Ten feet will do it.

The kid asked, “What’s π?” I told him it is a number discovered by a Greek mathematician named Archimedes who lived around 250 B.C. that defines all the properties of a circle. Π = roughly 3.14. Multiply π by the diameter of a circle and you get the circumference (c = πd), or multiply π by the radius squared to calculate the area of the circle (a = πr²). I added that Archimedes came up with other really useful ideas like the continuous inclined plane (the thread of a screw), and the properties of levers. “So a carpenter can use math,” he observed. I told him he could also use π to figure out the difference between a twelve- and sixteen-inch pizza. 3.14 x 12 = 37.68 square inches. 3.14 x 16 = 50.24 square inches. (I used the calculator in my iPhone.) Adding four inches to the diameter makes the pizza a lot bigger. If a bite of pizza is two square inches, the bigger pie has twenty-five more bites.

I took the ten-foot roll of flashing, drove into Building 3 to pick up the plywood, and went home to cut my circle. I decided on thirty inches and tied a Sharpie and an awl to a piece of string fifteen inches apart to make a rough compass. I marked and cut the circle, used little screws to attach the flashing to the sombrero-like gizmo, and mounted it on the pole under the bird feeder. It took the squirrels less than two days to get to the feeder.

Simple Simon met a π-man . . .

Carpenters work automatically with increments of sixteen inches, the standard distance between studs, joists, and rafters. To make things easy, most metal tape measures have clear markings every sixteen inches. A good carpenter knows sixteen inches perfectly. A baker makes a twenty- or thirty-pound batch of bread dough and cuts it into one-pound pieces. Maybe he checks each one with a scale, but he develops a knack for the heft of a pound. Our butcher does the same. I ask for a pound of ground beef, he grabs at the bowl, and puts 15.77 ounces on the scale. “You’ve done this before.” Experienced organ tuners develop a similar knack for the length of a pipe relative to the pitch. You hear the pitch and reach for the pipe of the correct length.

I worked in an organ shop that used twenty millimeters as the standard thickness for milling lumber for organ cases. We bought 4/4 (one-inch thick) rough-sawn wood from a lumber yard. Planing it flat and then to thickness, we could reliably get twenty millimeters from it. I had twenty-millimeter wood in my hands so much that I could tell if a stick was nineteen or twenty-one millimeters. Likewise, we set the “key-dip” on a keyboard, the distance of travel for the natural keys. It is usually something like ten or twelve millimeters. If you have spent three or four days leveling keyboards and adjusting key-dip, you can tell a millimeter difference in a heartbeat.

∏ is special. It is approximately 3.14, more accurately 3.14159265359 . . . . There is apparently no limit to the number of digits—as of now, it has been calculated to 31.4 trillion digits and counting. I have no concept of how those digits are calculated, so I accept 3.14. That is a lot fussier than sixteen-inch studs, and it is a great example of a concept that is all around us that we do not necessarily think about. When I was a kid on school field trips, I was interested in an exhibit at the Museum of Science in Boston that showed a perfect sphere and a perfect cone on a scale. Each shape had the same radius, and radius and height were equal. They balanced. My old-guy memory of my young-guy thinking had me wondering, “Who figured that out?” You can prove it by using π to calculate the volume of each shape.

The simple circle equations, a = πr² and c = πd, are pretty familiar. I will take it a step further. The volume of a cylinder is πr² (the area of the circle) times the height (v = πr²h). The volume of a cone is v = πr²h/3. The volume of a cone is one-third the volume of a cylinder of the same dimensions. The volume of a sphere is v = 4/3πr³. I suppose you can guess I was pleased with myself for the little math lesson I gave the kid in the lumber yard. But what do bird feeders have to do with pipe organs?

The organ pipe maker is the π-man. People who make organ pipes live and breathe π. To make an organ pipe, you cut out three pieces of metal, a pie-shape (no relation to π) for the foot, a rectangle for the resonator, and a little circle for the languid (the horizontal piece at the joint between the foot and the resonator). The width of the rectangle and the length of the curved top of the cone both equal the circumference of the pipe. The circumference of the languid equals the width of the rectangle.

I wish that every organist could witness the making of organ pipes, the soul of our instrument. The metal is blended in a melting pot (just the right amount of lead, tin, eye of newt, and toe of frog) and cast into sheets on a long table. A few seconds after the sheet is cast, there is a magic moment when the liquid metal becomes solid. You can see it happen. The metal is planed to exact thickness, and some organ builders hammer softer metals (those with higher lead content) to make the metal denser.

Thick and strong metal sheets are cast for larger pipes. Low C of an 8′ Diapason is typically about ten feet long, including the foot and sometimes some extra length for tuning. (The speaking length of any organ pipe is measured from the lower lip of the mouth to the tuning point.) The highest note of that Diapason is a couple inches long from mouth to tuner, but take a look at some little mixture pipes, or the top octave of 1-1⁄3′ or 1-3⁄5′ ranks. The speaking length is a half inch or quarter inch and the diameter is a quarter inch or less. I will play with π a little to estimate that the rectangle of metal is 78/100 by 25/100 (1⁄4) of an inch, smaller than a chiclet. That’s a fussy little piece of metal to cut, much different from the carpenters’ sixteen-inch centers. The pipe maker forms that chiclet into a cylinder around a steel mandril, then solders the seams. Careful not to burn your fingers.

The pipe maker cuts sixty-one pieces of pie (toes), sixty-one rectangles (resonators), and sixty-one circles (languids), one of each for every note on the keyboard. Each is a different size. While the length of the pipes halve at every octave, the diameters of the pipes halve every seventeen notes or so. It is that halving that keeps scales (diameters) of the treble pipes large enough to speak, and it is that halving at seventeen that forms the beautiful parabola of the tops of the pipes as they sit on a windchest. When all those pieces are laid out in order on a table, they show the image of a rank of pipes. As I can tell the difference between eighteen and twenty millimeters in my fingers, so the pipe maker can pick up one of those rectangles and know what the diameter of the pipe will be.

I wonder how Archimedes came across π. What induced him to think so intently about a circle? Did the formula appear to him in a dream? Did he use trial and error? How did he check himself? Did he draw a grid on a circle and count the squares?

Radical radii

I spent a couple weeks in Germany in September of 2019. I wrote about organs I visited on that trip in the December 2019 issue of The Diapason, pages 14–15. I spent about a week in Überlingen, on the shore of the Bodensee, visiting my friend and colleague Stefan Stürzer, director of the respected organ building firm Glatter-Götz in nearby Pfullendorf, perhaps best known in the United States as builders, with Manuel Rosales, of the iconic “Disney Organ.” I sat one afternoon with Heinz Kremnitzer, the designer and engineer for the company, who told me about the process of designing and making the huge, curved pipes that have given the organ the sobriquet, “A Large Order of Fries.” Frank Gehry, architect of Walt Disney Concert Hall and creator of the organ’s visual design, called for the curves.

The first question was whether such an organ pipe would speak, so Glatter-Götz built low DDDD of the 32′ Violon as a prototype. The curves were marked on the huge boards that would be the sides of the pipes and cut using a hand-held circular saw. Big deal. We all have “Skilsaws” in our shops. But remember, that pipe was almost twenty-eight feet long, the length of an average living room. To assemble the pipe, the flat board that would be the back of the pipe was placed on sawhorses spaced far enough apart that the board sagged to approximate the correct curve. Glue was applied, the pipe assembled, and as anyone who has heard the Disney organ knows, the pipe spoke. Stefan told me that they borrowed dozens of extra clamps from neighboring organ companies to accomplish that complex job.

Each curve is a segment of a circle with a huge radius. Twenty-seven pipes of the 32′ Violon and ten pipes of the 32′ Basson are curved. Four different radii were used: 51.545 meters, 32.102 meters, 20.586 meters, and 13.027 meters. How much is 51.454 meters in feet? 169.11 feet. Double the radius to picture a 338.22-foot circle. That is more than the length of a football field, including both end zones. The length of the segments of those circles would be the speaking length of each pipe. With today’s sophisticated Computer Aided Design (CAD), that would be simple enough to draw. But turning that digital arc into a pencil line on a board is quite a process.

But wait, there is more. Remember there are ten curved reed pipes, the longest of which is over thirty-one feet and remember that reed pipes are tapered. How do you curve a tapered pipe? Easy, there are two different radii for each pipe.

Heinz spent weeks in the Los Angeles offices of Gehry Partners, LLP, designing the complicated supports for the curved pipes. The supports would have universal joints on each end to achieve the multiplicity of angles, and each pipe would have two supports to achieve rigidity. Heinz drew the supports into the CAD drawings, weaving each between the complex shapes and layout of the pipes. Take a look at a photo of the organ and imagine the task. Heinz’s last word on those big, curved pipes, “It was a challenge I really enjoyed.” Great thanks to Stefan Stürzer and Heinz Kremnitzer of Glatter-Götz for giving me permission to publish this fascinating information. I am not going to ask how Gehry arrived at a radius of 51.545 meters as the perfect curve.

A penny for your thoughts?

Our system of telling time has been derived from the movements of celestial bodies. The earth rotates in twenty-four hours. The moon orbits the earth in twenty-seven days. The earth orbits the sun in 365 days. There are anomalies in the way those cycles have been divided. Our months have different numbers of days, and there is a corrective “leap day” every four years allowing us to catch up. The exact measurement of time is a complex science, one that I do not have to worry about because my iPhone is the most accurate clock I have ever had. When I cross into a different time zone (which I will do “full-vax” in two weeks for the first time in almost fifteen months), Steve Jobs gives me a nudge with the exact local time.

Mechanical clocks are marvelous machines, and it takes meticulous attention to achieve really accurate timekeeping. Ian Westworth, the clock mechanic for the Houses of Parliament in Great Britain, is leading a team in the restoration of the Great Clock built in 1859 and installed in the Elizabeth Tower of the Palace of Westminster. While many people think “Big Ben” is the name of the clock, in fact, “Big Ben” is the name of the largest of the five bells, the solemn boom that tolls the hour.

On Tuesday, April 13, 2021, The New York Times published a story by Susanne Fowler under the headline, “What Does It Take to Hear Big Ben Again? 500 Workers and a Hiding Place.” The hiding place is the secret and secure location of the workshop where the clock is being restored. Many of the 500 workers are involved in the restoration of the tower and the four twenty-three-foot glass faces of the clock. An amazing 1,296 pieces of mouth-blown pot opal glass have been made, and the fourteen- and nine-foot hands of the clock are being restored to their original condition.

Mr. Westworth explained how they regulate the speed of the clock to keep accurate time. When the clock is operational, its speed varies by plus or minus two seconds in twenty-four hours. The weight of the pendulum controls the speed of the clock. They have calculated that adding or subtracting the weight of a penny (3.56 grams) changes the speed of the five-ton clock by two-fifths of a second over twenty-four hours. The clock is wound each Monday, Wednesday, and Friday. The clock mechanics keep careful track of the time of striking and adjust the speed at each winding by adding or subtracting a penny or two. That might be the only way you can actually buy time.

Sebastian M. Glück, Opus 24, New York, New York; Setauket Presbyterian Church, Setauket, New York

Sebastian M. Glück

Vice, virtue, and flexibility

Among the linguistic tics bandied about the organbuilding craft for the better part of a century is “judicious unification,” apologetically implying that the practice is quantifiably evil depending upon the extent of its use and the judgment of the builder. If we dislike the builder, it is dismissed as cheap expediency; if we adore the builder, it is the methodology of a thoughtful and clever artist. Both assessments can be, and have been, accurate. Duplexing (the ability to play a stop from more than one keyboard) and unification (the ability to play a particular stop at more than one pitch) have been in use for more than three hundred years. A century after the cinema organ flourished, many are granting “unit orchestras” absolution as we try to preserve the few that we have yet to destroy, with the expectation that accompanying silent films in church will reinvigorate appreciation for the organ, even if it is not used to play organ music.

In some circles, the conservative traditionalist falls from grace when employing a rank of pipes for more than one musical purpose, although a “pass” is granted if the duplexing or extending is achieved solely with wires, rods, and levers. Regardless of action type, compromise is inevitable when space is rationed. For the staunch purist, the compromise must take the form of a smaller instrument in which each stop serves a single function, eagerly sacrificing variety, color, and scope. The establishment may believe that such a design process is additive, but in truth, pressure is applied to exclude stops from the project. The builder who designs, scales, voices, and finishes a partially unified organ must weigh and assume responsibility for the musical consequences of each compromise.

At Setauket Presbyterian Church, I set out to design an organ that could be played, despite the unification or duplexing of nine of its twenty-five ranks, as a traditionally disposed instrument while avoiding some of the perceived pitfalls of the extension principle: lack of character distinction between the manual sections, “missing note syndrome,” divisional imbalance, and an ineffective Pedal department.

The assignment

The congregation owned a pipe organ built in 1968, to which artificial orchestral voices had been added. The ailing instrument had served adequately for hymnody and life cycle events, but the tonal design did not extend consideration to the performance of the established organ literature. When developing the specifications with consultant David Enlow, we agreed that if the organ could be used to perform the noble repertoire of the past, it would be a fine church organ. No instrument can be loyal to the music of every culture and era, but we were adamant that in addition to the features common to all schools of organbuilding, specific tone colors should be placed in the correct divisions at the proper pitches to enable an organist to bring a stack of scores to the console and honor as closely as possible the composers’ intentions.

Following a period of discussion, the decision was taken to build an organ entirely under the control of expression shutters. While this firm had not, until now, built a fully enclosed instrument, this uncommon practice is experiencing a centennial revival and showed merit in this situation. The existing organ had been completely enclosed, yet its two-rank mixture and narrowly scaled, fractional-length reeds were perceived as painfully harsh by the choir members who sat in front of the organ.

The intimate sanctuary lacks any desirable reverberation. Fortunately, its proportions produce no perceptible echo, and the new organ enjoys an elevated position, speaking down the length of the room, its tone blended and preserved by the barrel vault. Made entirely of timber, the flexible building absorbs lower frequencies, so the organ would need to provide ample harmonically complex tone at 16′ and 8′ pitch without succumbing to the lingering recycled fad for the deprecation of mixtures.

The key ingredients we established for the manual divisions were a pair of contrasting principal choruses, an 8′ harmonic flute for the Great, a string and its undulant, the components of a cornet, and the three primary colors of reed tone: trumpet, clarinet, and oboe. The structural forms of the flute ranks include open cylindrical, open tapered, open harmonic (overblowing), stoppered wood, and capped metal with internal chimneys. The different flutes are voiced and finished within a bounded range of amplitude for the sake of blend, although the harmonic flute is given its characteristic treble ascendancy.

The primary function principle

When utilizing a rank at more than one pitch, it is best to establish its primary function, treat it accordingly, and then identify its potential auxiliary uses and what must be modified to accommodate them. The following are a few examples from the Setauket organ:

The Great 8′ Principal is extended to provide the 2′ Fifteenth. The independent 4′ Octave permits the designer to recalibrate the Principal’s scale progression over the course of two octaves as the unit rank approaches the treble of the 2′ extension. Is it ideal? No. Is it better than extending the 4′ rank or having no 2′ Fifteenth at all? Certainly. The chorus becomes fully independent if the 2′ is retired when the Mixture is added because a 2′ rank enters at the first break of the Mixture.

The Great Flûte Harmonique is called for at 8′ pitch in the literature, so that is its primary function. It takes its bass from the 8′ Principal to continue open tone all the way to the bottom. The 4′ Flûte Octaviante, by extension, can be used as an independent voice, played with the 8′ Holzgedeckt or the 8′ Principal. Crime averted.

The Swell 8′ Chimney Flute also is made available beyond its primary function, playable at 2′ (and 1′) pitch to create oft-debated “gap” registrations in addition to completing the solo Cornet. The 4′ Night Horn stands on its own to alleviate missing notes in the flute choir. The 2-2⁄3′ Nazard is scaled and voiced for its primary function, but is also made available at 1-1⁄3′ rather than foregoing such a stop entirely. The Nazard and Tierce must be independent ranks for the sake of tuning and balance.

The Swell 4′ Principal is the pivot point and tuning reference for that division, one of two 4′ stops that can be selected to change the vowel of the full Cornet. Keying it at 8′ pitch gives the division an 8′ Geigen Diapason where none would fit, a boon to literature, service playing, and choral accompaniment. The 8′ octave is synthesized by playing the bass octaves of the 8′ flute and 8′ string together. This is by no means a confirmation of the 1960s falsehood that “a flute plus a string equals a diapason,” but the effect is quite satisfactory in that lowest octave and the pitch does not suddenly drop out. It lends body to the full ensemble when the organ is played with orchestra.

The reeds

If one is restricted to a single trumpet rank in a unit design, its treatment is unavoidably difficult because it cannot serve two masters. If it is powerful enough to stand as the Great 8′ Trumpet, it can be too forceful for its expected roles in the Swell. Conversely, if it is designed as a normal Swell stop, it may prove insufficient when drawn with the Great chorus, unsuitable for some solo functions, and too weak for the Pedal, even if its descent into the 16′ octave grows dramatically as it would in a French organ. Without a second trumpet, I chose to favor the Great and Pedal with a round and warm English quasi-Tromba that made the transition down to a rolling 16′ Trombone that sits majestically under the full organ. After a lengthy search, I located a heritage M. P. Möller rank of unusual construction, built and voiced on the needed pressure, that fit the bill. The resonators were restored and masterfully remitred by Organ Supply Industries to stand comfortably beneath the low ceiling of the chamber.

The Swell 8′ Oboe features English shallots with caps and scrolls, and is under no burden to act as anything else. If the Trumpet is too loud for a particular registration, the tone of the Oboe can be modified by one or more of the division’s flue stops, including the mutations.

The cylindrical half-length reed posed a mixed conundrum: where should it reside, what should it be, and what should it do? Any version of the American Krummhorn of a half a century ago was dismissed from the outset. A warm, round Clarinet with a bit of a bright “edge” would address anything from Clarinet soli in English choral anthems to dialogues in French Baroque suites. The extension down to a 16′ Basset Horn provides a rich reed timbre with a fully developed fundamental, giving the desirable growl and harmonic complexity of the “full Swell.” The sticking point is that it plays at 8′ pitch from the Great and 16′ from the Swell. Were the Great unenclosed, the 8′ Clarinet under expression would have been a forthright bonus, but since the Setauket organ is entirely enclosed, the Clarinet is seemingly in the “wrong” enclosure. It is assigned to the Great to chat with the Jeu de Tierce in the Swell, and the rank plays at 16′ and 4′ pitch in the Pedal, as a secondary unison reed and as a cantus firmus stop for chorale settings.

The mixtures

Why provide two generous mixtures when a single small one had been deemed too shrill? The effectiveness of mixtures is contingent upon their position, harmonic composition, scaling, mouth proportions, voicing methods, and tonal finishing. From time to time, theorists have campaigned aggressively to extirpate mixtures from the art of organbuilding, yet they inevitably return to the craft because they are too essential to the organ’s origin and design. The compositions of the Setauket mixtures favor unisons over fifths and are not terribly acute in their pitch bases, with the Great IV–V including a second 8′ Principal to add warmth and body to the right hand. They are polite but by no means weak, and weld to the ensemble rather than standing apart from it.

The Pedal

The unit pipe organ was an essential response to the growing market for artificial instruments as American postwar prosperity fostered suburban communities that built new churches and synagogues. Architects were encouraged to forgo space for a pipe organ in their modern, low-slung structures as the allure of compact, inexpensive imitations took hold. This gave birth to the twelve-pipe Pedal division, the delusion that extending the stoppered flute rank down to 16′ would provide sufficient bass to support the entire organ.

The chamber plan for Opus 24 reveals the structural obstacles that had to be skirted while granting safe and facile access. I could not provide full independence, so I had to assure that the pedal line could be heard moving against the manual textures. The dedicated 16′ Sub Bass exhibits a characteristic of many 16′ stoppered wood ranks in small, acoustically dead rooms: if the listener steps in one direction or another, or turns their head, a note can switch from booming to absent. I therefore added a 16′ extension of the Viole de Gambe, with Haskell qualifying tubes. It provides clean pitch definition and consistent acoustical reinforcement anywhere in the room, and is far more interesting to the musical ear.

The other independent Pedal rank is the 4′ Choral Bass (the twentieth-century name given to a 4′ Octave), an arrangement that prevents note robbing from the middle of the manual textures. It also is used at 8′ pitch, with the lowest octave borrowed from the Great 8′ Principal, a practice not uncommon in smaller mechanical-action work. Because of this shared bottom octave, the Pedal 8′ and 4′ principal unit is in the Great expression enclosure, and the remainder of the Pedal within the Swell.

The organ case

Setauket’s 1812 landmarked meetinghouse was not conceived for a pipe organ, and the congregation, founded in 1660, did not install their first organ, an eleven-rank tubular-pneumatic affair set partially into the tower at balcony level, until 1919. The 1968 instrument of sixteen ranks expanded that footprint at the sides and into the gallery. Pipes and speaker cabinets packed the chamber, and the organ could not be maintained effectively. There were no organ pipes to be seen, the works concealed by a metal mesh screen that covered an enormous black void. The console was placed in front, creating poor sight lines, unsafe fire egress, and irreconcilable imbalances between the choir and the organ. Those issues were completely resolved by building a mobile, elegant, unobtrusive console for the new organ and moving the choir to a side gallery.

My duty was to create an architectural solution half as tall as its width, and I arrived at a small façade centered upon a visually neutral backdrop. Initial designs were based upon Georgian chamber organs, but as I spent more time in the building, I saw that the space demanded a more restrained treatment, a contemporary interpretation of organ cases built in New York during the second quarter of the nineteenth century. It is a restfully proportioned quintipartite mahogany façade, devoid of carvings, with burnished front pipes that extend to the cornice.

Paradoxically, this visual treatment is an entirely deceptive set piece, yet respectfully complements the historic interior. The wall of painted joinery uses acoustically transparent grille cloth in place of solid panels, and the façade pipes do not speak on account of the enclosure of the entire organ. Whereas once there was no visual indication that an organ existed, there is now a correlation between what the eye sees and the ear hears, despite the grand body of tone that seems to issue from a chamber organ.

An assiduous client

The dedication and perseverance of the congregational leadership was remarkable, particularly amidst a global medical crisis fraught with uncertainty. Throughout the project’s development, they educated themselves about pipe organ building, and as the concept for the instrument grew, they twice offered to expand the space allocated for the instrument. Church and synagogue musician, international concert organist, and Juilliard faculty member David Enlow served as an informed and patient consultant, steering the proceedings toward a service, concert, and teaching instrument for future generations.

—Sebastian M. Glück

President and Artistic & Tonal Director

Glück Pipe Organs

The Glück staff

Matthew Deming

Joseph DiSalle

Sebastian M. Glück

Roderick Gomez

John Kawa, Project Manager

Chad Kranak

Nathan Siler

Matthew Yohn

 

Suppliers

Organ Supply Industries, Inc.

Peterson Electro-Musical Products, Inc.

Aug. Laukhuff GmbH & Co.

 

www.gluckpipeorgans.com/

 

25 ranks, 39 stops, 1,392 pipes

Electropneumatic action, wind pressure 4 inches throughout

 

Cover photo by John Kawa

All other photos by Sebastian M. Glück, except as noted

 

GREAT (Manual I)

16′ Violone (a) 12 pipes

8′ Principal 58 pipes

8′ Flûte Harmonique (b) 47 pipes

8′ Holz Gedeckt 58 pipes

8′ Viole de Gambe (from Swell)

8′ Voix Céleste (from Swell)

4′ Octave 58 pipes

4′ Flûte Octaviante (ext 8′ Fl) 12 pipes

2′ Fifteenth (ext 8′ Princ) 24 pipes

Fourniture IV–V 256 pipes

8′ Trumpet (from Swell)

8′ Clarinet (ext Sw 16′ Basset) 12 pipes

Tremulant

Great Silent

Swell to Great 16

Swell to Great 8

Swell to Great 4

Chimes

 

SWELL (Manual II – enclosed)

8′ Principal (fr 4′ Principal; 1–12 from 8′ Chimney Flute and 8′ Viole)

8′ Chimney Flute 58 pipes

8′ Viole de Gambe 58 pipes

8′ Voix Céleste (TC) 46 pipes

4′ Principal 58 pipes

4′ Night Horn (4/5 taper) 58 pipes

2-2⁄3′ Nazard (2/3 taper) 58 pipes

2′ Recorder (ext 8′ Chim Fl) 24 pipes

1-3⁄5′ Tierce 58 pipes

1-1⁄3′ Larigot (c) (ext 2-2⁄3′ Naz) 8 pipes

1′ Fife (d) (from 8′ Chim Fl)

Mixture III–IV 179 pipes

16′ Basset Horn 58 pipes

8′ Trumpet 58 pipes

8′ Oboe 58 pipes

Tremulant

Swell to Great 16

Swell Silent

Swell to Great 4

PEDAL

16′ Violone (from Great)

16′ Sub Bass (wood) 32 pipes

8′ Principal (e)

8′ Viole de Gambe (from Swell)

8′ Gedeckt (from Gt Holz Gedeckt)

4′ Choral Bass 32 pipes

4′ Flute (from Gt Holz Gedeckt)

16′ Trombone (ext 8′ Trumpet) 12 pipes

16′ Basset Horn (from Swell)

8′ Trumpet (from Swell)

8′ Oboe (from Swell)

4′ Cantus Firmus (from Sw 16′ Basset)

Great to Pedal 8

Swell to Pedal 8

Swell to Pedal 4

Chimes

(a) with Haskell qualifying tubes; extension of Swell 8′ Viole de Gambe

(b) C1–A#11 from 8′ Principal

(c) F#55–A58 repeat

(d) top octave repeats

(e) 1–12 from Great 8′ Principal, 13–32 from 4′ Choral Bass

 

Great Fourniture IV–V

C1 19 22 26 29

C13 15 19 22 26

C25 08 12 15 19 22

C37 01 08 12 15 19

C49 01 08 12 15

 

Swell Mixture III–IV

C1 15 19 22

C37 12 15 22

G44 08 12 15

C#50 01 08 12 15

F#55 01 08 15

John Bishop

How does it work?

It happened again. I sat at this desk for days mud wrestling with an unruly topic for this column. Twice I had more than a thousand tortured words on the screen, went upstairs for a break, and came back to Ctrl-Shift-A-Delete. But Anthony Tommasini, music critic for The New York Times, came to my rescue with his article under the headline, “Why Do Pianists Know So Little About Pianos?,” published November 12, 2020. This article was born as the outbreak of COVID-19 got rolling in New York City last March and his piano needed tuning, but his apartment building was locked down and workers from outside were not allowed in except for emergencies. “An out-of-tune piano hardly seemed an emergency.”

He quotes the brilliant Jeremy Denk as not knowing “the first thing about piano technology.” Denk, whose playing I admire deeply and who like me is an alumnus of Oberlin College, had the same issue as Tommasini when his building locked down, but convinced the superintendent of his apartment building that because playing the piano is his profession, his tuner should be accepted as an essential worker. It worked.

Tommasini singles out Mitsuko Uchida as one prominent pianist who is an intimate student of piano technology. He quotes her as saying, “you get stuck when the weight is different key to key, the piano has been sloppily prepared, and the dampers have not been adjusted—or the spring in the pedal.” She went on, finding trouble when “the pin underneath the key [guide pin] is dirty, or the other pin in the middle of the mechanism [balance pin] is dirty, rubbing, or slurping.” I love the word slurping in this context.

Tommasini reminds us that orchestral players know more about their instruments than most pianists, and that unlike pianists, orchestral players own their instruments and can carry them with them between performances. Vladimir Horowitz traveled with his own piano, but then, Horowitz was Horowitz. You tell him “No.” Unusual among modern pianists, Mitsuko Uchida travels with her own piano. When Tommasini asked her if the institutions where she plays cover that cost, she said “usually not.” But she went on, “I have no excess otherwise. I don’t need country houses, expensive jewelry, expensive cars, special collections of whatever.” I suppose her usual fees cover that cost and still provide her with lunch money.

Tommasini concluded the column: Back at my apartment, the technician finally dropped by, tuned my piano, and made mechanical tweaks to a few of the keys. Afterward, it felt and sounded vastly better. I have no idea what was involved.

Press the key and the pipe blows.

The pipe organ is the most complex of all musical instruments. It is such a sophisticated machine that other musicians, including some world-renowned orchestral conductors, consider it to be unmusical. While a violinist or clarinetist can accent a note by applying a touch more energy, what a single organ pipe can do is all it can do. The organist can accent a note by tweaking the rhythm—a nano-second of delay can translate into an accent—or by operating a machine. A twitch of the ankle on the Swell pedal does it, so does coupling a registration to another keyboard with a soft stop so a note or two can be accented by darting to the other keyboard. The creative organist has a bag of tricks that bypass the mechanics and allow the behemoth to sing.

I have been building, restoring, repairing, servicing, selling, and relocating pipe organs for over forty-five years, and I know that many organists have little idea of how an organ works, so I thought I would offer a short primer. If you already know some or most of this, maybe you can share it with people in your church to help them understand the complexity. In that case, it might help people, especially those on the organ committee, understand why it is so expensive to build, repair, and maintain an organ.

Pipes and registrations

A single organ pipe produces a tone when pressurized air is blown into its toehole. The construction of the pipe is such that the puff of air, which lasts as long as the key is held, is converted to a flat “sheet” that passes across the opening that is the mouth of the pipe. The tone is generated when the sheet is split by the upper lip of the mouth. This is how tone is produced by a recorder, an orchestral flute, or a police whistle. Organ pipes that work this way are called “flue pipes,” and there are no moving parts involved in tone production. Reed pipes (trumpets, oboes, clarinets, tubas, etc.) have a brass tongue that vibrates when air enters the toehole: that vibration is the source of the tone.

Since each pipe can produce only one pitch, you need a set of pipes. We call them ranks of pipes, with one pipe for each note on the keyboard to make a single organ voice. Additional stops are made with additional ranks. There are sixty-one notes on a standard organ keyboard. If the organ has ten stops, there are 610 pipes. Pedal stops usually have thirty-two pipes.

The Arabic numbers on stop knobs or tablets refer to the pitch at which a stop speaks. 8′ indicates unison pitch because the pipe for the lowest note of the keyboard must be eight feet long. 4′ indicates a stop that speaks an octave higher, 2′ is two octaves higher, 16′ is an octave lower. Some stops, such as mixtures, have more than one rank. The number of ranks is usually indicated with a Roman numeral on the stop knob or tablet. A four-rank mixture has four pipes for each note. The organist combines stops of different pitches and different tone colors to form a registration, the term we use to describe a group of stops chosen for a particular piece of music or verse of a hymn.

The length of an organ pipe determines its pitch. On a usual 8′ stop like an Open Diapason, the pipe for low CC is eight feet long, the pipe for tenor c° is four feet, for middle c′ is two feet, and the highest c′′′′ is about three inches. Every organ pipe is equipped with a way to make tiny changes in length. Tuning an organ involves making those tiny adjustments to hundreds or thousands of pipes.

Many organs have combination actions that allow an organist to preset a certain registration and recall it when wanted by pressing a little button between the keyboards (piston) or a larger button near the pedalboard to be operated by the feet (toestud).

Wind

When playing a piece of music on an organ, the little puff of air through each organ pipe to create sound is multiplied by the number of notes and the number of stops being used. Play the Doxology, thirty-two four-note chords, on one stop and there will be 128 puffs of air blowing into pipes. Add a single pedal stop to double the bass line and you will play 160 pipes. Play it on ten manual stops and two pedal stops, 1,384. A hundred manual stops (big organ) and ten pedal stops, 6,420, just to play the Doxology, a veritable gale.

Where does all that wind come from? Somewhere in the building there is an electric rotary blower. In smaller organs, the blower might be right inside the organ, in larger organs the blower is typically found in a soundproof room in the basement. The blower is running as long as the organ is turned on, so there needs to be a system to deal with the extra air when the organ is not being played, and to manage the different flow of air for small or large registrations. The wind output of the blower is connected to a unit that most of us refer to as a bellows. “Bellows” actually defines a device that produces a flow of air—think of a fireplace bellows. Before we had electric blowers, it was accurate to refer to the device as a bellows. When connected to a blower that produces the flow of air, the device has two functions, each of which implies a name. It stores pressurized air, so it can accurately be called a reservoir, and it regulates the flow and pressure of the air, so it can accurately be called a regulator. We use both terms interchangeably.

Between the reservoir/regulator and the blower output, there is a regulating valve. Sometimes it is a “curtain valve” with fabric on a roller that operates something like a window shade, and sometimes it is a wooden cone that seats on a big donut of felt and leather to form an air-tight seal. In either case, the valve is connected to the moving top of the reservoir/regulator. When the blower is running and the organ is not being played, the valve is closed so no air enters the reservoir. When the organist starts to play, air leaves the reservoir to blow the pipes, the top of the reservoir dips in response, the valve is pulled open a little, and air flows into the reservoir, replenishing all that is being used to make music by blowing pipes.

Weights or springs on the top of the reservoir regulate the pressure. The organ’s wind pressure is measured using a manometer. Picture a glass tube in the shape of a “U,” twelve inches tall with the legs of the “U” an inch apart. Fill it halfway with water, and the level of the water will be equal in both legs. With a rubber tube, apply the pressure of the organ’s wind, and the level of the water will go down on one side of the “U” and up on the other. Measure the difference and voilà, you have the wind pressure of the organ in inches or millimeters. It is common for the wind pressure to be three inches or so in a modest tracker-action organ. In a larger electro-pneumatic organ, the pressure on the Great might be four inches, six inches on the Swell, five inches in the Choir, with a big Trumpet or Tuba on twelve inches. The State Trumpet at the Cathedral of Saint John the Divine in New York City is on 100 inches. I used to carry a glass tube full of water into an organ, a risky maneuver. Now I have a digital manometer.

In a small organ, the blower typically feeds a single reservoir that regulates the flow and pressure and distributes the wind to the various windchests through wind conductors (pipes), sometimes called wind trunks. In larger organs, it is common to find a regulator in the basement with the blower, and big pipes that carry wind up to the organ where it distributes into various reservoirs, sometimes one for each keyboard or division. Very large organs have two, three, four, or more windchests for each keyboard division, each with its own reservoir. A large bass Pedal stop might have one reservoir for the lowest twelve notes and another for the rest of the stop. And speaking of big pedal stops, the toehole of the lowest note of something like a 16′ Double Open Wood Diapason can be over six inches in diameter. When that valve opens, a hurricane comes out.

Windchests

The organ’s pipes are mounted on windchests arranged in rows on two axes. All the pipes of one rank or stop are arranged in rows “the long way,” and each note of the keyboard is arranged in rows “the short way.” The keyboard action operates the notes of the windchests, and the stop action determines which sets of pipes are being used. Pull on one stop and play one note, and one pipe plays. Pull on five stops and play a four-note chord, and twenty pipes play. In a tracker-action organ or an electric-action organ with slider chests, the keyboard operates a row of large valves that fill a “note channel” when a note is played and a valve opens. The stops are selected by sliders connected to the stopknobs, which have holes identical to the layout of the holes the pipes are sitting in. When the stop is off, the holes do not line up. When the stop is on, they do, and the air can pass from the note channel into those pipes sitting above open sliders.

It is common in electro-pneumatic organs for there to be an individual valve under every pipe. There is an electric contact under every note on the keyboard, a simple switch that is “on” when the note is played. The current goes to the “primary action” (keyboard action) of the windchest. The stops are selected through various devices that engage or disengage the valves under each set of pipes. When a note is played with no stops drawn, the primary action operates, but no pipe valves open. The stopknobs or tablets have electric contacts similar to those in the keyboards. When a stop is turned on and a note is played, a valve opens, and a pipe speaks.

We refer to “releathering” an organ. We know that the total pipe count in an organ is calculated by the number of stops and number of notes. An organ of average size might have 1,800, 2,500, 3,000 pipes. Larger organs have 8,000 or 10,000 pipes, even over 25,000. The valves under the pipes are made of leather, as are the motors (often called pouches) that operate the valves. Releathering an organ involves dismantling it to remove all the internal actions, scraping off all the old leather, cutting new leather pieces, and gluing the motors and valves in place with exacting accuracy. The material is expensive, but it is the hundreds or thousands of hours of skilled labor that add up quickest.

It’s all about air.

We think of the pipe organ as a keyboard instrument, but that is not really accurate. A piano’s tone is generated by striking a string that is under tension and causing it to vibrate. That is a percussion instrument. The tone of the pipe organ is generated by air, either being split by the upper lip of the organ pipe or causing a reed tongue to vibrate. The organ is a wind instrument. When we play, we are operating machinery that supplies and regulates air, and that controls the valves that allow air to blow into the pipes. When I am playing, I like to think of all those valves flapping open and closed by the thousand. I like to think of those thousands of pipes at the ready and speaking forth when I call on them like a vast choir of Johnny-One-Notes. I like to think of a thousand pounds of wood shutters moving silently when I touch the Swell pedal. I believe my knowledge of how the organ works informs my playing.

A piano is more intimate than a pipe organ, though technically it is also played by remote control as a mechanical system connects the keys to the tone generation. I am not surprised, but I am curious why more pianists do not make a study of what happens inside the instrument when they strike a key. I believe it would inform their playing. A clarinetist certainly knows how his tone is generated, especially when his reed cuts his tongue.

I have always loved being inside an organ when the blower is turned on. You hear a distant stirring, then watch as the reservoirs fill, listen as the pressure builds to its full, and the organ transforms from a bewildering heap of arcane mechanical gear to a living, breathing entity. I have spent thousands of days inside hundreds of organs, and the thrill is still there. 

That’s about 1,800 words on how an organ works. My learned colleagues will no doubt think of a thousand things I left out. I was once engaged to write “Pipe Organs for Dummies” for a group of attorneys studying a complex insurance claim. It was over twenty-five pages and 15,000 words and was still just a brief overview. Reading this, you might not have caught up with Mitsuko Uchida, but you’re miles ahead of Jeremy Denk.

A postscript

In my column in the November 2020 issue of The Diapason (pages 8–9), I mentioned in passing that G. Donald Harrison, the legendary president and tonal director of Aeolian-Skinner, died of a heart attack in 1956 while watching the comedian-pianist Victor Borge on television. The other day, I received a phone message from James Colias, Borge’s longtime personal assistant and manager, wondering where I got the information. I have referred to that story several times and remembered generally that it was reported in Craig Whitney’s marvelous book, All the Stops, published in 2003 by Perseus Book Group. Before returning Colias’s call, I spoke with Craig, who referred me to page 119, and there it was.

I returned Mr. Colias’s call and had a fun conversation. He told me that he had shared my story with Borge’s five children (now in their seventies). He also shared that when Victor Borge was born, his father was sixty-two-years-old, so when he was a young boy, he had lots of elderly relatives. His sense of humor was precocious, and when a family member was ailing, he was sent to cheer them up. Later in life, Borge said that they either got better or died laughing. I guess G. Donald Harrison died laughing.

Photo: Tracker keyboard action under a four-manual console, 1750 Gabler organ, Weingarten, Germany. (photo credit: John Bishop)