The 1864 William A. Johnson Opus 161, Piru Community United Methodist Church Piru, California, Part 4

November 2, 2018

Michael McNeil has designed, constructed, and researched pipe organs since 1973. He was also a research engineer in the disk drive industry with 27 patents. He has authored four hardbound books, among them The Sound of Pipe Organs, several e-publications, and many journal articles.

Editor’s note: Part 1 of this article was published in the August 2018 issue of The Diapason, pages 16–19. Part 2 was published in the September 2018 issue, pages 20–25. See the October 2018 issue, pages 26–28 for Part 3.


A graphical analysis of William Johnson’s scaling and voicing

The graphical models used in this section provide a visual means of understanding the scaling and voicing of an organ. More importantly, they serve as a means of comparing other styles of scaling and voicing. From these models we can understand how the tonal structure of an organ can be designed to suit any desired outcome.

The graphical data of Johnson’s 1864 Opus 161 at Piru Community United Methodist Church are presented side-by-side with data from E. & G. G. Hook’s Opus 322, built for the Church of the Immaculate Conception in Boston, Massachusetts, in 1863. Unfortunately, no recordings of Johnson’s Opus 161 are known, but the Samuel Green organ originally built for Litchfield Cathedral and now located at the Church of St. John the Baptist, Armitage, Staffordshire, bears a striking resemblance to the scaling, voicing, and tonal quality of the Johnson. The Green organ can be heard in the CD listed in the section on Recordings at the end of this article.

Normal Scale tables were copied into a spreadsheet and restructured in a manner that would allow an Excel matching function to find the Normal Scale values of the Johnson data. The spreadsheet for the Johnson data calculates mouth width fractions of the pipe circumferences, C values of the pipe toes, toe areas, flueway areas, and ratios of toe areas to flueway areas. The spreadsheet generates graphs for Normal Scale pipe diameters, Normal Scale mouth widths, Normal Scale mouth heights, toe C values, flueway depths, and ratios of toe areas to flueway areas. Spreadsheets of both the Johnson and Hook organs may be obtained at no charge from the author; see References at the end of this article.

Scot L. Huntington carefully documented the restoration of Johnson’s Opus 16 on pages 163–207 in the book, Johnson Organs 1844–1898, co-authored with Barbara Owen, Stephen L. Pinel, and Martin Walsh (see References). The only important data missing from this work are pipe flueway depths, but the flueway data on Opus 161 likely provides a guide for Opus 16 as well. The basis for this assumption is the similarity in scaling and voicing of the two Johnson organs, both of which show a significant reduction in power as the pitch of the stops in the principal chorus rises, and both are very unlike the Hook. The reader can find Huntington’s tabulated data in the new book.


Pipe diameters

The Normal Scale of pipe diameters is a way to visualize relative power, where a flat line from bass to treble will produce relatively constant power. Pipes extending higher in the graph will produce more power. Each half tone on the vertical scale is worth 0.5 dB of power. Interested readers can refer to The Sound of Pipe Organs for a discussion of the underlying theory and principles of all of the graphical models of the Johnson data. 

The scales of the principal chorus of the Hook in Figure 15 are relatively constant, i.e., they are the same for all of the pipes of a given pitch—only the Hook V Mixture is significantly narrower than the foundations. By contrast in Figure 14, the scales of the Johnson upperwork descend as the pitch of their stops rises, i.e., the scales of the 4Principal are narrower than the 8Open Diapason, and the 2Fifteenth is narrower than the 4Principal. The narrowest stop in the Hook chorus, the VII Cymbal represented by the blue line, was built by Johnson in 1870.

Note the extremes of Johnson scaling in the wide 8 Clarabella and the narrow 8Keraulophon. These stops share a common narrow bass, which was scaled to match the modest power of the Keraulophon.

Like Samuel Green, Johnson greatly widens his deepest foundation pipes; note the scale of the 16 Pedal Double Open Diapason at +9 half tones, the single blue data point in the upper left of Figure 14. This stop produces a strong tactile effect even in the dry acoustic of the Piru church, whose walls are too thin to reinforce bass tone.


Mouth widths

The Normal Scale of mouth widths operates just like the pipe diameters, where a flat line from bass to treble will produce relatively constant power. Pipes extending higher in the graph will produce more power. Each half tone on the vertical scale is worth 0.5 dB of power. 

Mouth widths are nearly always a better indicator than pipe diameters of power balances; this is because mouth widths can be designed to vary considerably within the same diameters of pipes. Narrower mouths will produce less power. 

The Johnson principal chorus in Figure 16 remains mostly unchanged, but the 8Clarabella mouths are now slightly narrower than the 8Open Diapason. 

Note that the bass of Johnson’s 8Open Diapason is as wide as the Hook 8Open Diapason in Figure 17—this is remarkable when we consider that the Johnson was built for a much smaller acoustic. Again note that the Johnson VII Cymbal in the Hook chorus in Figure 17 is the narrowest stop in that chorus, even though it was designed for the large and vibrant acoustics of the Church of the Immaculate Conception in Boston, the original home of the Hook. We can see how Johnson compensated for the larger acoustic at Immaculate Conception by observing that he scaled this VII Cymbal slightly wider than the 2 Fifteenth in his Opus 161 in Figure 16.

The wind pressure of the Johnson was probably about the same pressure as the Hook (76 mm) in its original state. The reduction of the scales of Johnson’s upperwork stops shows that he wanted a very refined chorus, and indeed the Johnson chorus is never overbearing. Like Samuel Green, Johnson provides grandeur to his chorus by making his basses extremely wide and powerful; note how the mouth widths of the Great Open Diapason increase rapidly from the tenor to the bass, and also note how the mouth width of the Pedal Double Open Diapason (the single data point in the upper left of Figure 16) extends this trend linearly to 16 low C.


Mouth heights and toe diameters

Mouth height, or “cutup,” as it is commonly called by voicers, is the primary means of adjusting the timbre of a pipe. Low cutups will create a bright tone with many higher harmonics, while high cutups will produce smoother tone. It is not uncommon to find flute pipes cut as much as 12 half tones higher than principal pipes in many classical pipe organs.

In the Normal Scale of mouth heights, a higher cutup value on the vertical scale will result in smoother tone. Cutups may be adjusted higher for one or both of two reasons: the voicer wants a smoother timbre, or the voicer wants more power at the same timbre. More power means more wind, and this means a larger toe opening (or deeper flueway) to admit more wind and raise the pressure at the mouth. More pressure at the mouth will always produce a brighter tone, so the voicer can make a pipe louder and preserve a certain timbre by opening the toe and raising the cutup until the timbre is restored.

Pipe toe diameters can be normalized to the diameter of the pipe, the width of the mouth, and the depth of the flueway. Higher values of C indicate larger toes with more flow of wind and higher pressures in the pipe foot. 

Now we can understand the graphs. In the Hook graph of mouth heights (Figure 19) and toe C numbers (Figure 21) we see very high values. Hook was after power, and these graphs show how you get it, even on a modest pressure of 76 mm.

In the graphs for Johnson’s mouth heights (Figure 18) we see that the mouth heights are cut lower as the pitches of the stops rise. This would normally make the upperwork brighter, but Johnson also reduces the toe C numbers (Figure 20) as the pitches of his stops rise, and this keeps the timbre constant. The net effect is that Johnson’s upperwork is significantly reduced in power; the 4 Principal is quieter than the 8 Open Diapason and the 2 Fifteenth is quieter than the 4 Principal. This fits the description of Samuel Green’s work by Stephen Bicknell perfectly.

We can see how Johnson compensated for the larger acoustic at Immaculate Conception by observing that the toe C numbers of his VII Cymbal in Figure 21 are as wide as the Hook voicing and as fully winded as the Hook pipes—these VII Cymbal toe C numbers are much larger than the toe C numbers of the Opus 161 2 Fifteenth in Figure 20. In contrast, Johnson’s VII Cymbal in the Hook chorus in Figure 19 has lower mouth height than the Hook voicing, and it is indeed brighter than the Hook mixtures.

Note the mouth height of the low C of the Johnson Pedal 16Double Open Diapason in the extreme upper left of Figure 18. At a value of +11 half tones, this stop produces copious power on full wind without harmonic stridency, a further extension of the balances sought by Green.


Flueway depths

Like the pipe toe, the flueway depth controls the flow of wind and strongly correlates to the power and the speed of the speech of the pipe. Both organs, the Johnson in Figure 22 and the Hook in Figure 23, exhibit flueways that are deep enough to claim that power is not at all regulated by the flueway. These flueways are characteristic of Romantic and Classical French voicing. Power in these pipes is regulated at the toes. The flueways of the Johnson 4 Principal and 2 Fifteenth in Figure 22 are wide even by normal Romantic standards. Classical Germanic voicing typically maintains an open toe and controls power at the flueway. Gottfried Silbermann is the famous exception to the Germanic custom; he learned organbuilding in France.

In his book, The Johnson Organs, John Elsworth noted that the Johnson pipemakers would set the flueway and the Johnson voicers would adjust the toe and mouth height. It is probably safe to assume that a Johnson voicer would adjust the flueway depth if it were needed, but Elsworth’s description of this process is interesting—it is the exact opposite of Germanic practice.


Ratio of toe and flueway areas

Once the scaling is set, the flow of wind and the available range of power are controlled by the voicer at the toe and flueway of a pipe. The ratio of the area of the toe to the area of the flueway is important. If the area of the toe is less than the area of the flueway, which is a ratio less than 1:1, the speech will be slower. “Slowness” in this instance does not refer to the voicer’s term (which reflects how the voicer adjusts the relative position of the languid and upper lip) but rather to the effect of resistances (the toe and flueway areas) and capacitance (the volume of air in the pipe foot). These resistances affect the rise time of the buildup of sound to full power. The ratio is exactly 1:1 when the area of the toe and flueway are equal, and this is the normal lower limit for pipes with prompt speech. For example, the vast majority of the principal chorus pipes in the range of 4 to 1 pitch in the Isnard organ at St. Maximin, France, exhibit a value of almost exactly 1:1, with higher pitches approaching a value of 3:1. This gives the Isnard foundation pipes a lovely “bloom” to their speech.

The speed of pipe speech is important. A well-knit chorus of pipes may have slower pipes or faster pipes, but never both. The ear is very sensitive to the speed of pipe speech—it can sense changes in milliseconds.

With this background in mind, we can see that the speech of the Johnson chorus is slower than the Hook chorus. Indeed, the voicing of the lovely Johnson chorus works well with the relatively low resonant frequency of its wind system to impart what the author noted in 1976 as a “light ‘give’ on full organ, a relatively fast buildup to full flow.” The Johnson 8Open Diapason is a bit faster with toe-to-flueway ratios above 1:1, but the upperwork is slower with ratios well below 1:1.

The Hook speech is very fast. The Hook chorus develops a lovely surge on full organ; this is not due to the voicing but rather the lower resonant frequency of its wind system. 



The William A. Johnson tonal design is eminently suited to the dry acoustics of most American churches. Johnson’s VII Cymbal in the Hook organ provides us with a window into Johnson’s thinking on the scaling and voicing for a much larger and reverberant acoustical setting.

Whatever the reader’s opinion of the aesthetic value of the Johnson chorus, its documentation has proved to be quite valuable. The Piru church disregarded the advice of the author to engage the services of Manuel Rosales for the maintenance of the organ when the author departed California in 1993. Some time after the Northridge, California, 6.7-magnitude earthquake in 1994, the church contracted a different Los Angeles firm to rebuild Johnson Opus 161; Piru was approximately 30 miles distant from the epicenter. The work had not been completed by the summer of 2017 when Manuel Rosales was contracted to perform an inventory of the organ and assess its condition; the organ had been dismantled leaving only the windchests stripped of their topboards and sliders in the frame. The pipes, topboards, sliders, and most of the mechanical parts, stored in trays in the parish hall, were suffering damage from constant handling. In an effort to keep the pipework intact, Kevin R. Cartwright has been engaged recently by the church to reinstall the pipework in the organ; there is no funding to make it playable. The documentation in this essay has provided a useful reference during the reassembly. Mr. Cartwright has twenty-one years’ experience in organbuilding, the last three of them working as a contractor to Manuel Rosales.32

This essay on Johnson Opus 161 was a considerable effort. The goal was to provide a template for the documentation of important and historically valuable organs. Such documentation is often the only insurance we have against well-intentioned modernizations. It is the author’s hope that this essay will inspire more thorough documentation of the world’s priceless gems.

Although drawings crafted on computers are visually pleasing, most organbuilders do not have the time or funding to make such graphics. If we want to see good documentation in print, we must also be willing to accept the lack of polish in hand drawings. The editorial staff of The Diapason has shown courage in their willingness to publish such drawings.

There is some evidence that the need for more thorough documentation is gaining traction in the organbuilding community. Pierre Chéron and Yves Cabourdin published complete scaling and voicing data on the Isnard organ at St. Maximin in 1991; Frank-Harald Greß published similar data on the organs of Gottfried Silbermann in 1989, although neither work addressed the documentation and analysis of wind systems. Of great importance is the work of William Drake, Ltd., in the United Kingdom. Their recent restoration of a 1755 Snetzler organ included documentation that has the depth of the data found in this essay on Johnson. This gold-standard level of documentation can be found on their website: If more organbuilders follow the lead of Drake we will begin to really understand how the sounds that inspire us are achieved.

Notes and Credits

All photos, drawings, tables, and illustrations are courtesy of the author’s collection, if not otherwise noted. Most of the color photos were unfortunately taken by the author with an inferior camera in low resolution. David Sedlak used a high quality camera, lenses, and film to produce the high-resolution color photos of the church and its architectural details; these are all attributed to Sedlak.

32. see



Preston, Simon. 5 Organ Concertos, The English Concert, Simon Preston, 1984, Archiv D 150066. The organ concertos of George Frederick Handel are played on the Samuel Green organ, 1789–1791, Church of St. John the Baptist, Armitage, Staffordshire, England. Although this organ was built for Litchfield Cathedral and was later moved to its present location in a smaller acoustic (lending more force to the impact of the organ), its sound bears a striking resemblance to that of William A. Johnson’s Opus 161. The Green organ on this CD is tuned in meantone, resulting in a gravity that enhances the already rich timbre of Green’s scaling and voicing. The Johnson organ would sound equally at home in this temperament. There are, unfortunately, no known recordings of Johnson Opus 161.

Murray, Thomas. The E. & G. G. Hook Organ, Immaculate Conception Church, Boston, Sheffield Town Hall Records, Album S-11 (ACM149STA-B), Santa Barbara, CA.

Murray, Thomas. An American Masterpiece, CD, AFKA SK-507. (E. & G. G. Hook Opus 322)



Bicknell, Stephen. The History of the English Organ, Cambridge University Press, Cambridge, 1996, 407 pp.

Cabourdin, Yves, and Pierre Chéron. L’Orgue de Jean-Esprit et Joseph Isnard dans la Basilique de la Madeleine à Saint-Maximin, ARCAM, Nice, 1991, 208 pp.

Elsworth, John Van Varick. The Johnson Organs: The Story of One of Our Famous American Organ Builders, The Boston Organ Club, 1984, Harrisville, 160 pp.

Greß, Frank-Harald. Die Klanggestalt der Orgeln Gottfried Silbermanns, VEB Deutscher Verlag für Musik, Leipzig, 1989, 176 pp.

Huntington, Scot L., Barbara Owen, Stephen L. Pinel, Martin R. Walsh. Johnson Organs 1844–1898, The Princeton Academy of the Arts, Culture, and Society, 2015, Cranbury, 239 pp. 

McNeil, Michael. The Sound of Pipe Organs, CC&A, Mead, 2012, 191 pp.,

McNeil, Michael. Johnson_161_170807, an Excel file containing all of the raw data and the models used to analyze the Johnson Opus 161, 2017, available at no charge by emailing the author at [email protected].

McNeil, Michael. Hook_322 Scales Voicing_170228, an Excel file containing all of the raw data and the models used to analyze the Hook Opus 322, 2017, available at no charge by emailing the author at [email protected].

Nolte, John M. Scaling Pipes in Wood, ISO Journal, No. 36, December 2010, pp. 8–19.

Owen, Barbara. The Organ in New England, The Sunbury Press, Raleigh, 1979, 629 pp. 

Michael McNeil has designed, constructed, and researched pipe organs since 1973. He was also a research engineer in the disk drive industry with 27 patents. He has authored four hardbound books, among them The Sound of Pipe Organs, several e-publications, and many journal articles.

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