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Hans Klotz's Stop List

PostPosted: Sun May 23, 2004 9:46 am
by stenberg
In a previous post I mentioned that according to the German organ theorist Hans Klotz a minimum of 25 stops were required to enable an organist to perform chamber music as well as symphonic pieces.

I have since received several private requests to make Hans Klotz’s stop list available, so here follows the relevant extract from his oeuvre “The Organ Handbook” published in 1969 by Concordia Publishing House, 3558 S. Jefferson Avenue, St. Louis, Missouri 63118-3968.

Library of Congress catalogue Card No. 69-11068

In order for the stop list to make total sense, rather large chunks of “prelude” and “postlude” texts are required, so here goes:

The characteristic tonal palette of an organ is contingent upon the beauty, balance, and multiple usefulness of its mutations and reed stops. Mutations such as the Quinte, Terz, Nasat, Sesquialtera, Rauschpfeife, Terzian, Mixture, Scharf, and Zimbel, as well as reeds such as the Trompete, Posaune, Dulzian, Krummhorn, Barpfeife, zink, and Sordun, must blend well with all other stops. They must not sound so obtrusive as to be unusable in chamber music. If they are built as “fortissimo formants,” they become useless for the genuine art of registration.

We established earlier that the Hauptwerk and the large Positiv must be dynamically well balanced, so as to be on par; only then can the tonal resources of an organ be realized to the fullest. That does not mean, of course, that these two corpora should be composed of identical stops; rather, they should be made up of stops of equal dynamic strength but of different tone colour: contrast of colour but equality of dynamic level. The registration of preludes and fugues presupposes a quite different sound of the mixture plenum of the Hauptwerk versus that of the Positiv; when coupled, the two plena must produce yet a third new quality of sound. Contrast in dynamic level traditionally is furnished by the small Positiv, the Brustwerk.

Only the large Positiv is the logical division to be enclosed; such an arrangement is the only basis for a healthy dynamic conception, an only in this way does the organist have at his disposal artistically useful dynamic steps consisting of the three basic “forte” categories:

Mixture plenum (les pleins jeux)
Reed plenum (les grands jeux), and
Foundation stops (les grand fonds).

The dynamic proportions of the individual divisions must be so designed that the Hauptwerk and the Schwellwerk (enclosed division) with open shutters are equal; the small Positiv must rank dynamically a measured step above the closed Schwellwerk in the three aforementioned categories (but still below the Hauptwerk), but for chamber music of solo and ensemble nature, it must be on the same level with the Hauptwerk for the purpose of well-balanced duo and trio registrations. With such a design the organist is furnished the means for chamber music as well as symphonic playing; he has at his disposal simultaneously contrasting and characteristic tone colours as well as flexible dynamics.

More Rules for Specifications

The following rules apply to specific aspects of specification: Each of the three corpora – Hauptwerk, Schwellwerk, and Positiv – should contain the three aforementioned registrational categories – mixture plenum, reed plenum, and foundation stop ensemble; in addition, each must furnish solo possibilities for cantus firmus, duo, and trio registrations as well as accompanimental stops; the Pedal needs, in addition to the simple bass ranks, cantus firmus stops and a mixture for pedal solos. All of this can be achieved with a minimum of 25 stops, providing that correct scaling and voicing prevail; the example below illustrates this:


Principal 8’
Octave 4’
Mixture IV 2’
Bourdon 16’
Gedackt 8’
Flöte 4’
Nachthorn III
Farbenzimbel II
Trompete 8’


Principal 4’
Scharf VI 1 1/3’
Offenflöte 8’
Dulzian 16’
Trompete 8’
Viola da Gamba 8’

Principal 2’
Zimbel III 1’
Gedackt 8’
Flöte 4’
Krummhorn 8’ (French)


Offenbass 8’
Choralbass 4’
Rauschpfeife IV 2 2/3’
Subbass 16’
Posaune 8’

It will be noticed that our specification assigns considerably more stops to the Hauptwerk than to the other divisions. This is explained by the fact that those Positiv stops which constitute the mixture plenum are also usable for solo purposes, a feature not achievable by the corresponding Hauptwerk stops; thus the Hauptwerk and Positiv are the most important divisions for solo registrations, as the two lower keyboards lend themselves best to the difficult technique of trio playing.

It is important that the solo stops are distributed on Hauptwerk and Positiv in reasonably equal proportions. For a proper relationship of mixture and reed plena, trumpets and mixtures must be dynamically equivalent. Furthermore, the Krummhorn in combination with the Gedackt and flöte must yield a good accompanimental level for the Hauptwerk reed plenum; in turn, the Hauptwerk Principal must serve as accompanimental stop for the Krummhorn of the Positiv.

The Subbass, Offenbass, and Choralbass of the Pedal should adequately support the mixture and reed plena of the coupled manual divisions; at the same time, however, the Offenbass, alone or in combination with the Subbass, should furnish a good bass level for a trio registration. Incidentally, in this respect the pedal coupler of the unused manual division offers additional possibilities. The Choralbass should serve as a solid cantus firmus voice in trio textures; the Posaune 8’ must sustain a cantus firmus against the mixture plena of the coupled manual divisions.

The Schwellwerk is assigned to the top keyboard, the Hauptwerk to the middle keyboard, and the Positiv to the bottom keyboard; this arrangement facilitates the performance of Bach’s works, because the organ builders in Bach’s Saxony assigned the Oberpositiv to the top keyboard and the Brustwerk to the bottom keyboard. This, incidentally, corresponds to an extent with the contemporary English practice of assigning the Swell to the top, the Great to the middle and the Choir to the bottom keyboard.

The voicing of the individual stops must be precisely interrelated:

- The Gedackt must well sustain any other stop;
- c’’ of the Bourdon and c of the Flöte must correspond to c’ of the Gedackt;
- c’’’ of the Bourdon must correspond to the c’’ of the Gedackt, and so forth
- c of the Octave must correspond to the c’ of the Principal, and so forth.
- c’ of the Nachthorn (Kornett) must be related to the pipes g’’, c’’’, and e’’’ of the Gedackt
- the C of the Mixture must be related to the pipes c, g, c’, g’ of the Octave, and so forth.

Regarding the number of stops and pipes, the following distribution is recommended: the total number of stops should be compounded of 45% foundation (labial) stops, 35% labial stops of pitch levels above 4’, and 20% lingual stops. Half of the total number of stops should belong to the family of Principals.

Got it?

Gunnar Stenberg

An American Alternative Organ

PostPosted: Sun May 23, 2004 7:41 pm
by Jim Reid

I would like to propose an alternative to the Klotz instrument; one
which has several added stops, probably up to around 39 or so!
And these will be "extended" and some unification will be used.
This is based completly upon the work of many famous American
builders and Henry Willis III of England. It is a "result" of some 312
letters of correspondence exchanged among these men; primarily
between Ernst M. Skinner (1866 - 1969) and Henry Willis III (1889 -
1966) the grandson of Father Willis who built many of Englands
most important organs. The letters are contained in a book, obtainable
even today from the Organ Historical Society: "The American Classic
Organ, A History in Letters", by Charles Callahan, 1990, OHS publisher.

The organ design proposed here is NOT in that book, but I believe
represents a reaonalbly sized realization of the ideal discussed among
Skinner, Willis, G. Donald Harrison, Sen. Emerson Richards,
Lynnwood Farnam, Carl Weinrich and William King Covell in the
few hundred letters included in the book. The stopplists of many organs
by these men are given in the Appendix section of the book. So have
a read of that book from OHS for background of what is to follow.

First, Klotz's material may be difficult for some Americans to really
understand, so what follows will offer a bit more explanation. I should
also mention that the work of Robert Hope-Jones is discussed from
time to time in the lettes, but he is not included in the conversations.
However, his work obviously had great impact on the "Classic
American Organ", and of course, the Theatre Pipe Organs built primarily
during the first third of the 20th century both in American and in England.

Now, a proposed stoplist, with explanation along the way.

Great - The following pircipal chorus would not be under expression, not
in a "swell box":

P Violone 16' (extension from the Pedal division)
P Diapason 8'
P Octave 4'
P Twelfth 2 2/3 '
P Fifteenth 2'
P Mixure III (19-22-26)

The above stops, identified by the P comprise the Primary
flue chorus of this organ. I am unsure if Klotz would call
such a set of stops on the Hauptwerk as the "Mixture plenum
(les pleins jeux)" or possibly what he calls, "Foundation stops
(les grand fonds)." No mater.

The great manual also needs a secondary chorus, and this would
be under expression, maybe in the Choir "box" if built by Skinner
or Harrison.

S Diapason Conique 8'
S Harmonic Flute 8'
S Quintadena 4'

These form the secondary chorus playable from the Great manul with
expression possible. And completes the Great manual stop list.

Now to the lower of this three manual organ, the Choir,
or even Choir-Positiv division.

p Bourdon 8'
Salicional 8'
Salicional Celeste 8'
p Nachthorn 4' [I have no idea what Klotz has in mind in his
Hauptwerk spec when he shows a Nachthorn III, a mixture??]
p Oktav 2'
p Zimbel III (26-29-33)
Krummhorn 8'
Bombarde 8' (extension from the Pedal)

This completes the Chori-Positiv stop list where the stops
indicated with the "p" comprise the Positiv chorus.

Now the top manual, Swell division stops.

sf Viola 8'
Voix Celeste 8'
sf Hohlfloete 8'
Dolce 8'
Dolce Celeste 8'
sf Prestant 4'
C Rohrflute 4'
C Nasard 2 2/3'
C Flautino 2'
C Tierce 1 3/5'
sf Mixture III (15-19-22)
Clarinet 16 '
Clarinet 8' (unified/extended from above 16' stop)
Trumpet 8'
Clarion 4'

This completes the Swell stop list where the stops indicated
by "sf" comprise the Swell flue chorus. Those indicated by
the "C" assemble the Cornet voice.

The Pedal division adds nine more stops plus some unification/
extension from the manual divisions.

Diapason extended to play at 16, 8, and 4' pitches
t Violone extended to play at both 16 and 8' and "unified" to the Great.
Gedeckt from theChoir with 12 added notes to play at 16 and 8'
Nachthorn 4' unified from the Choir
t Mixture III (17-19-22)
Bombarde extended to play 16, 8, 4' and unified to the Choir-Positiv
(The Bombarde is the loudest stop of the instrument)
Clarinet 16' unified from the Swell
Trumpet 8' unified from the Swell

The stops indicated with a "t" above would be used in playing
Bach's Trios, for example, in the polyphony.

I believe the above comprises a more complete and suitable organ
for both baroque and symphonic music than that proposed by Klotz;
but that is just my own opinion! It would be capable of much
greaer dynamic volume range, is not constrained with all voices
being on nearly the identical "loudness", differing only in tone color
as Klotz proposed is desired. This suggestion includes the grandest,
most dramatic of organ "effects", and the softest of organ tone.
In between these power boundaries lies the utmost in flexibility,
blend and contrast, with a very complet high, low and middle pitch

I look forward with much anticipation to the organ voices of the
E. M. Skinner organ from Milan Dgital Audio products!
For comparison with what is outlined above, have a look at
the forthcoming Skinner stop list:

How much longer to wait??

PostPosted: Mon May 24, 2004 1:18 am
by Jim Reid
Sharp eyes will by now have detected that there is NO pedal division
mixture in the Milan Digital Audio samples referenced in the above.

That is because the samples are from a Skinner organ of 1928. However,
old EM ddidn't get around to putting a mixture into the Pedal division,
at least per Callahan's book, until 1932 in the organ at Harvard in
March of 1932! And not into most organs until the later '30s.

What we should hope for out in the future, is for Brett Milan to sample
and provide some of the later G. Donald Harrison, Aeolian-Skinner
rebuilds/augmentations of the early E.M.Skinner instrumetns. Perhaps
then some of the "re-builds" in New York City, easy to get to, but
maybe not easy to get permission to spend hours, days, weeks
sampling! How about:

1. Fifth Church of Christ Science, rebuilt 1954, New York City
2. Hill Auditorium, U. of Michigan, Ann Arbor, rebuilt 1954 (oops, well
not in New York!)
3. St. Thomas Church, New York City, rebuilt 1955

Now, yes these are all HUGE organs, but they represent the
penultimate of Skinner, under G. Donald H. at Aeloian Skinner,
of that organ design philosophy. I believe these represent a true
part of what Milan Digital Audio is attempting to chronicle.

Just on going observations/comments.

PostPosted: Mon May 24, 2004 1:51 am
by stenberg

Klotz's Nachthorn III puzzled me too, but according to Encyclopedia of Organstops ( the name Nachthorn has been used over the centuries for at least three different stops:

According to Grove and Williams, in the 1500's it was frequently a type of Cornet mixture, especially in the Netherlands and northern France.

One common form is a stopped flute of very wide scale, a cross between a Quintaten and a Gedeckt, having a tone that some sources describe as somewhat horn-like. It was found at 4' and 2' pitch, and made of wood or metal. Wedgwood gives it a low cut-up. Grove and Williams date this form from the time of Praetorius (around 1600), and Williams puts it also in 18th century Austria. Skinner used this form, describing its tone as being suggestive of a hoot-owl. A synonym for this form may be Nachthorngedackt.

The other common form is an open flute of very wide scale, wider than any other stop according to Williams and Maclean. It generally has a low, narrow mouth, which gives it a soft voice in spite of its large scale. Grove and Williams date this form from the 17th century, where it was used as a solo stop in either manual and pedal. This seems to be the most common contemporary form of the stop.

Other forms have also been cited: a large-scale Rohrflöte with small chimneys (Williams), slightly conical (Irwin), and a reed (Wedgwood). Irwin claims that it is sometimes tuned as a slow celeste (see Cor de Nuit Celeste), and that it is sometimes found at 5-1/3' and 2-2/3' pitch, though no mutation examples are known. While most sources translate Nachthorn as “night horn”, Williams suggests that the name may derive from Nach-horn or Nachsatz (nach = “behind”), a stop taken from the Hintersatz (blockwerk). Most sources consider Cor de Nuit and Nachthorn to be synonymous, but some make a distinction; see Cor de Nuit.

Apparently Klotz refers to the original "Cornet" definition.

I think the above two "organ definition" files exemplify the two schools of thought which clashed at the beginning of the last century, the organ revival movement and the romantic symphonic organ movement.

Klotz obviously is a revivalist wanting to reestablish the organ as an instrument in its own right, whereas Willis and his school basically wanted a pneumatic synthesizer imitating a symphonic orchestra (exaggeration promotes understanding).

Luckily with Hauptwerk we don't have to choose sides anymore. We can have the best of both worlds. I too look forward to Brett's Skinner organ.


PostPosted: Mon May 24, 2004 1:22 pm
by Jim Reid

Thank you for the information about the Nachthorn and its' history.

To approach the Klotz organ type, I have ordered Ariaan Hoogendijk
CD for Hauptwerk containing the Marcussen Organ of
St. Stefanuschurch, Moerdijk, The Netherlands. Looking over the stop list, it is close
to the Klotz "ideal"; differing in the placement of the various stops,
but most seem to be in the instrument, have a look: ... tie_uk.htm

I also have on order two of the Silberman two manual instruments
now available for Hauptwerk; however, I am not going to be
hearing any of them until later in June! First must get "midi"
output from my manuals and
pedal board, and build up a suitable computer to deal with all of this
modern wonderfulness. I hope the weather in June will not be too
onerous as I will be puffing away inside the console adding midi,
and later, with Elaine, assembling a "super" computer.

Best to all,

PostPosted: Mon May 24, 2004 5:38 pm
by stenberg

I included the Marcussen organ my collection the moment it was released last year. You are right, it comes very close to the Klotz specification, which is not surprising since Marcussen along with Frobenius, another Danish organ builder, was among the first to join the revival movement. I am sure you will be very happy with this instrument.

I think Marcussen's North American counterpart must be the Canadian organ builders Casavant Freres, two of whose organs have been sampled to perfection by Brett Milan.

Don't complain about your Hawaiian climate. I spent 15 years in the tropics and after a long, drab Scandinavian winter my old bones really yearn for excessive damp heat and eternal sunshine.