The 1750 Joseph Gabler Organ at Weingarten

December 23, 2020

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)

Related Content

September 20, 2021
Editor’s note: the first part of this series appeared in the September 2021 issue of The Diapason, pages 14–21. RELATED: Part 1 This article…
August 22, 2021
Historical background The Old and Rare Books Department at the library of Vilnius Academy of Arts, Lithuania, stores a unique collection of drawings…
August 30, 2020
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…