After completing his undergraduate work and Organ Licentiates in South Africa, Jacobus Kloppers continued his studies in Frankfurt/Main: Organ with Professor Helmut Walcha at the Musikhochschule (1961-1965) and Musicology at the Johann Wolfgang Goethe University (1961-1966). His doctoral thesis Die Interpretation und Wiedergabe der Orgelwerke Bachs von Jacobus Kloppers (21MB pdf), focused on the performance of Bach’s organ music. It was printed by the Frankfurt University Press in German, reprinted 5 times, and was widely distributed by Bärenreiter Antiquariat. With permission, 100 pages of this Thesis were translated into English and included in Timothy Albrecht’s DMA Thesis: “Musical Rhetoric in Selected Organ Works of Johann Sebastian Bach” (Eastman School of Music, 1978). See discussion of the significance of Jacobus Kloppers’ Bach organ research in section below. Some of these topics were also explored in published articles (see list below).
From 1966- 1976 Kloppers taught Musicology and Organ at the University of the Orange Free State in Bloemfontein, South Africa (as full Professor since 1970), and gave lectures on Bach interpretation, Musical Rhetoric, and South African church music topics in South Africa. He also started to develop a Christian Philosophy of Music, based on that of Dutch philosopher, Herman Dooyeweerd, and applied it in his teaching.
Jacobus Kloppers served as Professor of Organ and Musicology and Chair of the Music Department at The King’s University College (currently The King’s University) in Edmonton, Alberta, Canada since its founding in 1979 until 2008. This Christian University is non-denominational, and based on the same Christian philosophy (one that explores the integrality of faith and learning) as Herman Dooyeweerd. During his tenure at The King’s University, he gave lectures on Bach interpretation and Musical Rhetoric and Symbolism, in Canada, West Germany and Austria. Until his retirement from Academia in 2013 he continued as Full-time Lecturer in Organ and Musicology at King’s as well as Adjunct Professor in Keyboard at the University of Alberta (a position he held since 1997).
Due to his administrative duties as Faculty Chair at The King’s University, lecture and teaching duties, compositional work, and position as church organist/choir director, Kloppers’ on-going Bach research had to be put on hold after 1982. He still critically addressed, however, various musicological topics in faculty colloquia, including a critical assessment of Friedrich Blume’s ‘new Bach image’. He also explored other areas of Musicology, developing a Christian Philosophy of Music, designed a textbook on Systematic Musicology, and developed textbooks for all his Music History courses. See details below.
SIGNIFICANCE OF JACOBUS KLOPPERS’ RESEARCH ON BACH’S ORGAN MUSIC
Jacobus Kloppers’ PhD research (1961-66), and published in 1966, Frankfurt, was the first historic-systematic approach to a stylistically-informed rendering of Bach’s organ music. It was also the first study of Musical Rhetoric as applied to Bach’s organ music, especially the free (non-textual) organ works. Key performance topics include:
- The question of stylistically-informed performance of Bach’s organ music.
Jacobus Kloppers’ Footnote (2019): I do not subscribe to the idea of a ‘stylistic authentic’ performance, but rather to a ‘stylistically-informed’ performance. We will never know what sound Bach envisioned in his imagination, but his imagination was certainly sparked by the instruments and sounds available to him. But it was not limited to these sounds or mediums that were available. Bach composed away from the instrument, which is liberating, and gives us, as performers, the opportunity for creative solutions.
- Understanding the organ music of Bach within the historic framework of Baroque music and Bach’s own development as composer.
- The style and character of the piece, including possible rhetorical devices. For the significance of this, and also addressing the issue of Bach as writer of absolute music, or as musical rhetorician and symbolist, see summary and listing of published papers below. Building on the foundational work done by scholars regarding the significance of musical rhetoric in the late-Renaissance and Baroque period, such as Arnold Schering (1908), Heinz Brandes (1935), Hans-Heinrich Unger (1941), Willibald Gurlitt (1944) and Arnold Schmitz (1950), Kloppers researched the impact of Musical Rhetoric in the organ music of Bach.
Jacobus Kloppers’ Footnote (2018): One significant finding of my rhetorical study of Bach was the recognition that Bach’s so-called “Dorian Toccata” BWV 538 was not based on a concerto-model (it neither resembles the mosaic-like concerto grosso model of Corelli nor the new Rondo-like construction of Vivaldi) but is based on a rhetorical debate according to a rhetorical “Elaboratio” using various Tropes and Figures of Rhetoric. Bach provided the manual changes highlighting this discourse. In this regard I want to stress that this work does not represent a kind of “tone painting” or ”scene”. The Toccata evolves organically from a purely instrumental, figurative motif (thus abstract), but its subsequent development takes place according to the usual rules of dialectics/debating: Introduction – Main thesis (Dispositio) – Confutatio (analysis, breaking up of ideas, refutation of contrary ideas) – Confirmation – Peroration.
In contrast to this rather intellectual study in logic (though not devoid of emotional intensity) in the Dorian Toccata, Bach’s Fantasia in G minor BWV 542 is a very passionate work, a kind of instrumental oratorio with the structure of Recitativo – Introspective comment (type of Fugato) – Recitativo – Introspective comment – Recitativo, somewhat akin to the St. John’s Passion written in approximately the same time period.
Rhetoric is only one of many aspects/qualities found in Bach’s composition, but it is not prominent to the same degree in every work, where other qualities may be in the forefront. In this regard my thoughts and formulation on this developed later in the 1970s with my engagement with the philosophy of Herman Dooyeweerd of the Free University, Amsterdam.
In my thesis various symbols in the organ music are also discussed. They occur mostly in text-based chorale preludes. In some works the idea is presented both symbolically and rhetorically (according to the “affect” or mood suggested in the text), e.g. in the Orgelbüchlein chorale preludes “Jesus Christus unser Heiland” and “Erschienen ist der herrliche Tag” (see Kloppers article in Man and Nature 1984). Hidden number- and cabalistic symbols were also in use in Bach’s time and certainly used by Bach, but I steered away from this and concentrated more on the rhetorical aspects of moods and mood-inducing rhetorical figures which are directly experienced by the listener.
In the 1990s many studies were produced which reduced Bach’s instrumental works to cabalistic symbols, e.g. 14 for Bach, 41 for J.S. Bach etc. Much of this is speculative and some of the leading Bach publications (as found in e.g. the Bach Yearbook) started to avoid publishing these studies – which is understandable, though too severe. They promoted research topics which adhere to the idea of music as “autonomous”/ “absolute”, and even avoided or suppressed studies that suggest something contrary, such as musical rhetoric, even though Bach’s knowledge and application of rhetoric is historically documented (by, for example, Birnbaum (in 1739) – see Scheibe’s ‘Critischer Musikus’ (1745); and also by Bach’s sons – see Forkel’s ‘J.S. Bach: Leben, Kunst and Kunstwerke’ (1802)). For detailed discussion see Kloppers’ Musical Rhetoric and Other Symbols of Communication in Bach’s Organ Music (pdf).
The divisive debate regarding the autonomy/heteronomy around Bach’s music and music in general is rather meaningless since it is based on a false dichotomy, i.e. of music being either “without content”, being “absolute” (“autonomous”, “music is music) or “with content”, “programmatic” (“heteronomous”; music “expressing” something which is not music or “embodies’ something which is not music). Music is neither “autonomous” nor “heteronomous” and it does not have a “content” but reflects many aspects/qualities, from the numerical, kinetic, energetic, biological, psychological, linguistic, logical etc. to the aspect of faith but in a uniquely musical way. Much of the dualistic thought stemmed from the Ancient linguistic custom i.e. to turn adjectives into abstract nouns: “Living” became “life”; “dead” became “death”; “beautiful” became “beauty”, “truthful;” became “truth”. Instead of stating “this work contains beauty” (dualistic statement), the dualism is resolved in restating it as “the work is beautiful”. (See also Kloppers’ article on “Dualistic Thought in Music” written in Afrikaans). See also the opening chapter of Kloppers’ Systematic Musicology (MUSI 495) Text book (pdf).
- Characteristics of the types of organs that Bach worked on or designed, and the innovations that he brought to organ design during his lifetime. Bach clearly moved away from the too-contrasting timbres of the high Baroque organ, to a more flexible mixing of tonal colours. The idea of an ‘ideal Bach organ’ and tying the organ piece to the organ available to Bach at the time of its creation is flawed. As with much of his other music, Bach composed away from an instrument and his approach to performance was a very flexible one.
- Criteria for manual change in Bach’s organ music. There is evidence that many of the preludes and fugues were performed without manual change. Manual changes were not so much used to highlight various themes in a piece (which leads to a kind of vivisection), but rather to highlight dialogues (for example ‘the Dorian Toccata’) as a musical debate, or to emphasize changes in mood, style and/or character, and where the texture allows such manual change.
- Organ registration (which covers timbre and dynamics) that befits the style and character of Bach’s organ music. Historic evidence showed that Bach’s registrations did not follow stereotypes of his time, but were adjusted to the instrument available. This refutes the idea of trying to prescribe so-called ‘historic authentic’ registrations. Many of the free works may be played with a plenum without registration changes. However, additions or removal of stops to highlight subtle changes or climactic endings can be used.
Jacobus Kloppers’ Footnote (2018): In my thesis, my intention was not to suggest the performance of all of Bach’s free organ music should be without registration changes, and I never performed his works that way. This should rather be determined from one piece to another. Apart from a change in style or mood within a piece, which calls for an appropriate stop change, there is also often a climactic built-up, which is thoroughly enhanced by subtle additions of stops. I find the frequent performance of all of Bach’s free works with the same unchanged (often a plenum) registration dull and wearisome. An example of this kind of unimaginative and unsubtle approach to Bach’s organ music is often heard in the performance of his Passacaglia and Fugue. I also find it strange that the idiosyncratic character of the organ, with its rich palette of timbres and transparency, is sometimes denied in the performance of his Trio Sonatas where the movements are performed with only 8′ foundational stops, in imitation of string trio playing. The bright transparent colours, used e.g. by Helmut Walcha in his performance, are much more attractive.
- Organ tuning (temperament) and its implications for mood creation.
- The study of tempo, in light of ‘tempo ordinario’ and the few tempo indications in Bach’s organ works. These tempi cannot be predetermined in a systematic way, but have to be guided by the meter, character, dynamics and registration of the piece.
- Ornaments in Bach’s organ music were never intended as superficial decorations, but were there to enhance the mood (Affekt) of the piece. They are, just like the tropes in rhetoric, ‘deviations’ from a dry literal reading, and should be performed likewise.
- Articulation of Bach’s organ music is based on the idiosyncratic character of the organ, which allows for legato playing, but it is enhanced by devices such as leggiero, marcato and staccato. Idiomatic borrowing in organ music from other instruments such as the violin, choral music, harpsichord, etc., can influence the articulation. A vocal style of playing is essential (‘He who cannot sing, cannot play’), with breathing and shaping of the lines. (In all of this, Kloppers was very much indebted to his professor at the Musikhochschule, Frankfurt, Professor Helmut Walcha).
Jacobus Kloppers’ Footnote (2017): In the 1970s, other scholars embraced a new theory i.e., that a basic organ legato approach stems from the 19th Century. They stated that articulation in all baroque organ music was not legato, but a so-called ‘structured legato’, which imitates tonguing on individual notes (as on a flute or trumpet), which brings tiny separations between notes, and that legato was only permitted where slurs were used in Bach’s notation. We are indebted to these scholars for highlighting an articulation device that was very important in Bach’s time. Kloppers recognizes the value of a structured legato and also applies it in his own playing where the character or style of the music supports it. Many of Buxtehude’s short, playful motifs for example, lend themselves to a structured legato, and in Daquin’s ‘Noel in G’ everything is structured legato, except for 2- or 3-note groupings in Variation 1 and 3. As Bach’s style evolved to incorporate the Italian singing style of Vivaldi, the approach to articulation is very different, since singing suggests a much more legato style. Kloppers therefore rejects the universal application of a ‘structured legato’ where no slurs are notated.
Historical evidence to this point can be quoted from:
-Burney’s account of Couperin’s nephew Armand-Louis’ organ recital in Paris in 1770, in which he describes Couperin’s use of legato as ‘the true organ style’.
-Ernst Ludwig Gerber (‘Historisch-Biographisches Lexicon der Tonkuenstler’, Leipzig, 1790) criticizes a detached way of organ playing and refers to his father’s study with Bach, and Bach’s own legato treatment of the organ.
-Daniel Gottlob Tuerk (‘Klavierschule’, 1789) describes all these various articulation devices and lists structured legato as the ‘usual one’, but then says that composers do not indicate articulation, and that the articulation has to be determined by the composer, by the nation, and by the genre. And in each case, he lists Bach with a legato performance.
-Bach’s pupil, Johann Christian Kittel (Choralschule), states that in hymn playing there should be not the slightest separation of notes in the melodic line.
-Often baroque fingering is mentioned as a justification of a ‘universal structural-legato’, but this is not borne out by research. Just the fact that Francois Couperin uses silent finger exchange is evidence of ensuring a legato sequence.
-Dom Bedos de Celles in his work ‘L’art du facteur d’orgues’, 1766-78, provides examples of music created by barrel organ in which there is a clear case for structured legato. However, the examples provided are of dance music that I (Jacobus Kloppers) would play with a structured legato, which supports my main thesis that the character and style of the work determine how it is articulated.
-Preserved organs from Bach’s time (like Schnitger) have manual and pedal keys that are shorter than those of the present day organs. The argument is made that crossing of the feet is not really possible on these organs and that the same foot is simply moved from one key to another with a structured legato effect. In Jacobus Kloppers’ experience in playing the historic organ of Schnitger in Cappel, Germany, it was possible to use crossing of feet and toe-heel methods without any problems.
The case is made that in singing, consonants provide natural separation of vowels’ sound, which is similar to a structured legato. However, many consonants provide continuous sounds (i.e. ng, m, n, z, l). In singing, even chanting on one note provides the effect of a continuous legato sound, so the consonants do not create the effect of discontinued sound. Leopold Mozart wrote in 1756 that “The human voice glides quite easily from one note to another, and a sensible singer will never make a break unless some special kind of expression or the divisions of rests of the phrase demands one.” Kittel’s note that in hymn accompaniment there should not be the slightest break in the melody line, further supports this assertion. Of all the instruments, the organ as a wind instrument is perhaps the closest to the human voice.
Idiomatic borrowing can lead to a ‘structured legato’, or non-legato articulation where for example, the tonguing in wind instruments or the up or down bowing of the violin is imitated (but even here the bowing can be done in a way that sounds legato). The idiosyncratic character of the organ with its unique legato property should never be negated. (Note: The current idea that also the voice must imitate the effect of the Baroque violin and bow (instead of the violin played in a singing style), especially the artificial ‘ballooning effect’ used by ‘period ensembles’ (usually in their early years) with an exaggerated increased volume on each note, is highly manneristic and does not serve Bach’s music well).
Finally, the introduction of the modern meter in the late Baroque, with ‘good or bad’ beats within the bar is quoted as justification for a continuous ‘structured legato’. In the modern meter within a 4:4 bar, the first note after the bar line is a strong/’good’ beat, and the third beat is a strong beat but less than the first beat; the 2nd and 4th beats are weak or ‘bad’ beats. This is all clearly stated i.e. in Johann Walther’s handbook for the young Prince of Weimar ‘Praecepta der musicalischen Composition’ (1708) as well as by other late Baroque writers. To achieve, on the organ, the effect of accented and non-accented notes within the bar, it is argued that the notes have to be separated since there is no other way to distinguish longer accented notes from shorter un-accented notes. This new concept was in its infancy around 1700, but composers like Bach moved way beyond this and created highly complex and stylized music in which the original rhythms of even dance music often become more obscured. In Jacobus Kloppers’ view, the organization of ‘good’ and ‘bad’ beats does not justify the promoted separation of the beats in the bar because it vivisects the melodic line. The awareness of accented or non-accented notes can be deduced from more subtle articulation or from a wider musical context. Even in an early work of Bach such as the ‘Passacaglia and Fugue’, Bach demonstrates slurring from a weak beat to a strong beat in the main counterpoint to the main theme of the Fugue:
Slurring over a bar-line is common in Bach’s music as well. For example, in the left-hand accompaniment of his organ chorale prelude ‘Schmuecke dich, o liebe Seele’, the beginning of the motif indicated by Bach with a preceding rest, starts on a weak beat and ends in the next bar (Kloppers demonstrates this with the red commas inserted below):
The effort of so-called ‘authentic interpretations’ which creates automatic artificial breaks of a melodic run before a bar-line, is simply unmusical.
JACOBUS KLOPPERS’ THESIS AND OTHER MUSICOLOGICAL PUBLICATIONS
Kloppers, Jacobus. PhD Dissertation. Die Interpretation und Wiedergabe der Orgelwerke Bachs. Ein Beitrag zur Bestimmung von stilgerechten Prinzipien. Bildstelle der J.W. Goethe-Universität, Frankfurt/Main: 1966. 390p.
Kloppers, Jacobus. Retoriek en Musiek. ‘n Kort Betragting van die samehang tussen die twee kunste. Acta Germanica, 5 (1970), 43-59. (Rhetoric and Music: A Brief Consideration of the Relation between the two Arts)
Kloppers, Jacobus. Die Suid-Afrikaanse gereformeerde kerkmusiek en resente ontwikkeling op die Europese vasteland. Acta Academica, 3 (1971), 43-55. (Church Music in the South African Reformed Churches in the Light of Contemporary Developments in Continental Europe)
Kloppers, Jacobus. Die verband tussen musiekestetiese beskouing en vertolking, soos geillustreer aan die werk van J.S. Bach. Professorale intreerede, University of Free State (U.O.V.S.), August, 1971), 25pp. (Interpretation and Rendering of Music and its Aesthetic Basis Illustrated by the Works of J .S. Bach. Inaugural Address, University of Free State (U.O.V.S.), August, 1971.)
Kloppers, Jacobus. Wysgerige grondprobleme in die Musiekwetenskap, in Op al sy akkers, feesgeskrif vir Prof. H. J. Strauss. Onder redaksie van Prof. Frans Wessels. Sacum, Bloemfontein, 1975, pp. 124-33. (Philosophical Foundational Issues in Musicology, in On all his Fields, Festschrift in honour of the Dean, Faculty of Arts, Prof. H. J. Strauss.)
Kloppers, Jacobus. A Criterion for Manual Changes in the Organ Works of Bach. Organ Yearbook VII. Buren, The Netherlands. Uitgeverij Frits Knuf, 1976. pp. 59-67.
Kloppers, Jacobus. Musical Rhetoric and Other Symbols of Communication in Bach’s Organ Music. Man and Nature / L’homme et la nature, Volume 3, 1984, p. 131-162. [PDF download]
Kloppers, Jacobus. Probleme rondom die vertolking van Bach se orrelwerk. VirMusiekleier 62, 1986. pp. 37-61.
Kloppers, Jacobus. The importance of musical rhetoric for the performance of Bach’s organ music. VirMusiekleier 20, 1993.
Kloppers, Jacobus. Musical Rhetoric and Other Symbols of Communication in Bach’s Organ Music. Ars Nova (Unisa Musicologica), Volume 33, 2002, p. 11-29. [PDF download].
Kloppers, Jacobus. Dualistiese Benaderings ten Opsigte van Musiek en Kerkmusiek (A critical evaluation of dualistic concepts in music and church music). G.G. Cillié Address at SAKOV Conference receiving honorary SAKOV membership, Pretoria, 2015. [PDF download] in Afrikaans.
SELECT REVIEWS AND COMMENTS ON JACOBUS KLOPPERS’ DISSERTATION
Stauder, Professor Dr. Wilhelm, Thesis Supervisor, Wolfgang Goethe University, Frankfurt am Main:
“Ín dieser ausgezeigneten Arbeit vermittelte er ganz neue Erkentnisse über die stilgerechte Wiedergabe der Bach’schen Orgelwerke, die bahnbrechend gewirkt haben. Dabei is ihm zugute gekommen, daß er einerseits ein ausgezeichneter Orgelspieler und Bachinterpret ist, zum andern alle anfallenden Probleme mit der erforderlichen Akribie anfaßt und zur Lösung bringt.” (Letter of Reference, Frankfurt am Main, December 27, 1974).
English Translation: “In this excellent piece of work he revealed totally new insights with regard to a stylistically faithful rendition of Bach’s organ music, which had a pioneering effect. At the same time he benefitted both from being an excellent organist and Bach-interpreter as well as his ability to engage with problems as they arise and to resolve them with the required meticulousness.”
Osthoff, Professor Dr. Helmuth, Second Supervisor and Ordinarius, Wolfgang Goethe University, Frankfurt am Main:
“Die Dissertation von Herrn Kloppers stellt insofern einen der wichtigsten Beiträge zur Bach-Literatur der letzten Jahrzehnte dar, als hier erstmalig eine umfassende ästhetisch-stilgeschichtliche Interpretation der Orgelkompositionen Bachs zusammen mit den sich daraus ergebenen Folgerungen für die pracktische Wiedergabe vorgelegt wurde. Besonders wichtig ist die Auswertung der aus der musikalischen Rhetorikforschung für die Interpretation Bachscher Orgelmusik gewonnenen Ergebnisse. Es darf gesagt warden, dass das Werk von Jacobus Kloppers sowohl für das Studium wie die praktische Wiedergabe der Orgelwerke Bachs von grundlegender Bedeutung is.” (Letter of Reference November 11, 1974)
English Translation: “Mr. Kloppers’ thesis represents one of the most important contributions to the Bach literature of the last decade, insofar as for the first time a comprehensive aesthetic and historic-stylistic interpretation of Bach’s organ music was presented combined with the resulting conclusions for its practical rendition. Of great importance is the research regarding musical rhetoric and its implications for the interpretation of Bachs organ music. One may state that the work of Jacobus Kloppers is fundamentally important for both the study and practical rendition of Bach’s organ works.”
Klotz, Hans, Organ Scholar in Baroque Music (1969)
“Der Wert des Klopperschen Buches liegt darin beschlossen, daß es gerade den verantwortungsbewußten Interpreten aud die Fülle der einschlägigen Gesichtspunkte hinweist und die Probleme von da aus in sorgfältiger Gründlichkeit bearbeteitet.” (Review in Die Musikforschung, 22. Jahrgang (Januar/März 1969, pp. 123-125)
English Translation: “The value of Kloppers’ dissertation is to be found in the way in which he directs the serious/engaged interpreters (of Bach’s Organ music) to the fullness of its relevant aspects as well as the manner in which he consequently addresses these issues carefully and thoroughly.”
Williams, Dr. Peter, Editor The Organ Yearbook:
“I recently received a copy of your dissertation-book, which I have long since known and admired. In fact, I consult it frequently in the course of my forthcoming 3-volume book JSB Organ Music.” (letter, October 23, 1974)
Gustafson, Professor Bruce, Division of Fine Arts, Bethel College, Mishawaka, Indiana:
“While studying under Anton Heiller at the Zomer Academia voor Organisten in Haarlem, this past summer, it was my good fortune to hear of your excellent dissertation Die Interpretation und Widergabe der Orgelwerke Bachs. I have since read and studied the work and find it extremely perceptive and valuable. Of particular interest to me was your exposition of how the rhetorical nature of the Bach works should influence the performance of these works. Your explanation of this point seems to me to be a most lucid and convincing argument, which makes both intellectual and musical sense.” (Letter , January 6. 1970)
Planyavsky, Peter. Anton Heiller: Organist, Composer, Conductor. Translated from German by Christa Rumsey. 2014, Eastman Studies in Music, Rochester, New York:
On p. 225 Planyavsky wrote: “The great breakthrough for musical rhetoric and especially its direct application to Bach performance was the book The Interpretation and Performance of Bach’s Organ Works by Jacobus Kloppers. Hans Hasselböck mentions how he introduced Heiller to this book and that he showed great interest”.
On p. 277, Planyavsky wrote the following footnote Chapter 9, #33: “An understanding of musical rhetoric is virtually considered indispensable among organists today. In June 1981, when I invited Jacobus Kloppers to lecture on his main topic at the Vienna Musikakademie, our students seemed just a little bored afterward – rhetoric is meant to be important in baroque music – so what?” Hans Hasselbock, ‘Die Begegnungen.'”
Horn, Victoria, ‘French influence in Bach’s Organ Works‘, in J.S. Bach as Organist, edited by G. Stauffer and E. May. 2000:
In Note #23 on p. 273: “Among the more important monographs dealing with Bach’s registrations are . . . . Jacobus Kloppers, ‘Die Interpretation and Wiedergabe der Orgelwerke Bachs,’ diss, Frankfurt University, 1965.”
OTHER MUSICOLOGICAL ARTICLES (IN SOUTH AFRICA AND CANADA) AND LECTURES
Kloppers, Jacobus. ‘n Kritiese evaluering van ‘Pop’ -musiek-strominge in kerkmusiek. Die Kerkbode, 1 (1973), 106-09. (Popular Music Trends in Church Music: a Critical Evaluation.)
Kloppers, Jacobus, en Barbara Louw, red. Liturgiese Orgelmusiek, Band 1: Musiek vir die kerklike huweliksbevestiging en begrafnisdiens. Kaapstad: Studio Holland, 1973, 58 pp. (as co-editor with Barbara Louw. (Liturgical Organ Music, Vol I: Music for Marriage and Funeral Services). Capetown, 1973.)
Kloppers, Jacobus. Klassifikasie en evaluasie van ‘Pop’ – musiek genres. Die Taalgenoot, 3 (1974), 12 pp. (A Classification and Evaluation of Popular Music Genres.)
Kloppers, Jacobus, en Barbara Louw, red. Liturgiese Orgelmusiek, Band 2: Verwerkings van die Geneefse Melodie van Psalm 42. Kaapstad: Studio Holland, 1975, 50 pp. (as co-editor with Barbara Louw. Liturgical Organ Music, Vol II: Chorale Preludes on the Bourgeois Melody of Psalm 42. Contains works by Goudimel, Le Jeune, Jeep, Pachelbel, Walther, Oley, Boehm, J. S. Bach, Reger, Kickstatt, Wieruszowski, as well as contributions by various South African composers. Capetown, 1975.)
Kloppers, Jacobus. A Philosophy of Music Based on a Christian World- and Life-View (pdf), 2013, based on a colloquium paper from 1991, and forms the basis for the Systematic Musicology textbook.
Kloppers, Jacobus. Systematic Musicology (MUSI 495 Text book) (pdf) The textbook explores the various aspects of music within the Christian philosophical moral, from the mathematical aspect to the aspect of faith.
Kloppers, Jacobus. Dualistic Concepts in Music (an English summary of an Afrikaans lecture delivered at South African Guild of Organists, Pretoria, 2015) Translation in progress.
ARTICLES ON JACOBUS KLOPPERS’ MUSICOLOGICAL WORK
Van Rensburg, Isabelle. Jacobus Kloppers se orrelkomposisies ná 1993 en sy filosofie van musiek: ’n gevallestudie. D.Mus Verhandeling (in prose), Universiteit Pretoria, S.A.. (Jacobus Kloppers’ Organ Compositions after 1993 and his Philosophy of Music – a Case Study. D.Mus-thesis in progress).
Viljoen, Martina (Ed.). A Passage of Nostalgia: The Life and work of Jacobus Kloppers Bloemfontein, South Africa: Sun Media 2020.
Stolte, Charles. Jacobus Kloppers and his Teaching of Musicology: A history and Impressions In A Passage of Nostalgia (Martina Viljoen, Ed.)pp. 145-168.
Strauss, Danie. Reflections on the philosophical paradigm underlying the Musicology of Jacobus Kloppers In A Passage of Nostalgia (Martina Viljoen, Ed.)pp. 169-200.