Calendar

The concert Ode to the Classics presents contemporary compositions that are firmly rooted in the tradition of classical music and have been specially written for the Fokker organ. The programme includes several new works with microtonal sonorities that sound both familiar and surprising at the same time. Neo-baroque, romantic and early twentieth-century styles are interwoven with the microtonal possibilities of the Fokker organ, allowing the audience to experience a rich palette of harmonies and contrapuntal structures. The programme shows how microtonal compositions and classical styles can meet, how old traditions find new forms, and how the Fokker organ, with its unique 31-tone tuning, forms a source of inspiration for both established and emerging composers. Flautist Raymond Honing, who is highly experienced in performing microtones, once again joins resident organist Ere Lievonen in this remarkable concert.

The opening work by Clive So marks the beginning of this musical adventure. So combines his classical organ training with a strong curiosity about microtonal possibilities. His Courante from 2019 demonstrates how, using the 31-tone system, he creates a coherent harmonic world inspired by the classical tradition yet entirely free from conventional boundaries. His studies in counterpoint and harmonic experimentation result in a work that brings out the unique possibilities of the Fokker organ to full effect.
The programme continues with Piers Hudson’s Gigue from his Suite in 31edo for Fokker organ (2020). Hudson, who originates from the United Kingdom and specialises in counterpoint, describes this movement from his suite as a ‘microtonal neo-baroque dance suite for Fokker organ’, in which subtle elements of minimal music can also be discerned. His work combines harmonic and contrapuntal elements and shows how complex polyphony can be realised on the Fokker organ in a microtonal context.
The French composer Charles Delusse wrote a short and curious work in the middle of the eighteenth century in which enharmonic notes are chromatically displayed by the flute, entitled Air à la Grecque. This composition appears to be an ode to the classics, but in reality it dates from the period of French classicism. Delusse was an important figure in the history of the flute in mid-eighteenth-century Paris. In 1760/61 he published ‘L’art de la flute traversiere’, an extensive treatise containing new ideas such as overtones, microtones and tonguing techniques that were previously unknown.
The initiator and designer of the 31-tone organ named after him, Adriaan Fokker, wrote short compositions under the pseudonym Arie de Klein in order to demonstrate this remarkable instrument. These were often given titles referring to classical music, such as his Toccata from 1957, which is included in this morning’s programme.
This is followed by Michiel Mensingh’s The Bad-Tempered Clavier from 2010, a playful parody of the famous chromatic theme from the Fugue in D minor (BWV 875) from Book II of Das Wohltemperierte Klavier (1740–1742) by Johann Sebastian Bach. In this work, the Amsterdam-based Mensingh allows a well-known Bach theme to derail in a mischievous manner, after which it continues on its own path through modern, techno-like sounds. The result is a mix of humour, musical inventiveness and respect for the classical tradition, with the Fokker organ being fully controlled by laptop.
As a sequel to Mensingh’s composition, the concert also includes a special historical moment with the brilliant unfinished fugue Contrapunctus 14 from Die Kunst der Fuge (1740–1746) by Johann Sebastian Bach. Bach’s famous contrapuntal material, after a brief silence, receives a modern classical continuation in the 31-tone system with Halluzination im Anschluß an Bachs unvollendete Fuge (2024) by composer Sander Germanus, in which the organ, like a hallucination, automatically begins to play on and leaves the organist ‘astonished’. In this way, a bridge is built between the classical past and the microtonal experiments of modern times, with the listener recognising the contours of Bach while at the same time experiencing a new harmonic dimension via all 31 fifth tones in less than a minute, ending, like Bach, in D major.
The Passacaglia by the Canadian composer John L. Baker from 2020, inspired by a classical form, has never been performed before. Unlike the other works, this piece is not tonal, but it is carefully written for the twelve notes of meantone tuning, with septimal intervals and clear, ‘classical’ polyphony. This premiere forms a restrained moment within the programme.
This is followed by the seven-movement organ suite from Ode to Andreas Werckmeister (2018) by Gerard van de Meerakker. Van de Meerakker, a retired physician with a profound fascination for historical tunings, combines his ideas about Werckmeister’s ‘well-tempered’ tunings with a literary inclination. The original composition follows a poem by the famous German organ builder Arp Schnitger (1648–1719), in which he honors the equally famous music theorist and organist Andreas Werckmeister (1645-1706). In this version on the 31-tone organ, the composition unfolds through a series of fugal passages towards a grand and chaotic conclusion, resulting in a hymn of praise to Werckmeister himself.
The programme concludes with a cunning little work by the American keyboardist, composer and musician Aaron Krister Johnson, who has devoted himself to promoting music in alternative tunings. His The Juggler (2003) for harpsichord and flute breathes a neo-medievalist atmosphere and explores the 19-tone system with striking modulations that continually stimulate the ear. Although an electronic version of this work has been known for some time, the acoustic performance for harpsichord and flute was not premiered until 2019 in the Kleine Zaal of the Muziekgebouw.
All the works in this programme together form a balanced journey through past and present, in which the Fokker organ demonstrates how classical forms and microtonal sound worlds can naturally enrich one another.

For the Fokker organ, the retro-futuristic ensemble gamut inc is developing a new composition in which the pipe organ is approached as an acoustic synthesiser as well as a sampler. This full-length concert programme consists of original works, specially written for the microtonal 31-tone organ. Thanks to the close approximation of just tuning offered by the organ, the instrument opens up a sound world that recalls the early days of electronic music, as developed in the studios of Cologne and Warsaw in the 1950s.
That the organ can be regarded as a form of additive synthesiser has long been recognised: organ pipes with different timbres are combined to create complex sound mixtures. But gamut inc take this a step further. Inspired by the phonorealistic concepts of Peter Ablinger, they investigate how audio data can be converted into overtone structures. In this process, the organ functions not only as a synthesiser but also as a sampler, in which sounds are reproduced and transformed using additive and subtractive techniques. By making use of the microtonal gradations of the 31-tone steps, resynthesis techniques emerge, along with complex beating phenomena, spectral interferences and slowly shifting harmonic fields, built up from precisely tuned layers of chords.
The duo gamut inc was founded in Berlin in 2013 by Marion Wörle (computer musician, graphic designer and composer) and Maciej Śledziecki (composer and guitarist). Together they develop electroacoustic music, innovative music theatre and computer-controlled musical machines. Since 2019 they have been working intensively with computer-controlled pipe organs, travelling worldwide to realise new compositions for so-called ‘hyper-organs’ in churches and concert halls. In 2021 they also initiated their own festival, AGGREGATE, devoted to computer-controlled organ and electronics, for which they invited international guest composers.
In this concert, Wörle and Śledziecki focus on the Amsterdam Fokker organ, which since its renovation in 2008–2009 has been equipped with a MIDI interface and was identified in a Harvard study in 2008 as one of the first hyper-organs in the world. MIDI technology, developed in the 1980s, makes it possible to control the organ via computer, with algorithmic composition software offering an intuitive and flexible way of composing. Thousands of notes and parameters can be generated and manipulated in real time, while the sound is still produced physically in the acoustic organ pipes.
With its nineteen additional tones within the octave, the 31-tone organ creates new technical and sonic possibilities, including the refined creation and manipulation of overtone structures. In their compositions, Wörle and Śledziecki explore stylistic means that are only possible thanks to programmability and computer control: automated registration changes, simultaneous tempi, shimmering masses of sound, complex polyrhythms, fluttering sound patterns and sliding transitions between tonal, noise-based and rhythmic material. The pipe organ is deployed here as a sound machine and acoustic synthesiser. The result is an organic, futuristic organ sound that reinvents the familiar instrument and gives it a radically contemporary voice.

Organist Laurens de Man, baritone Ben Kazez and violinist Eva Saladin present a special concert centred on the music of Constantijn Huygens. This Dutch poet, diplomat, scholar, architect and composer, and father of the physicist Christiaan Huygens, who became known in the musical world as the inventor of the Dutch 31-tone tuning, composed what appears to have been an enormous musical oeuvre. Very little of this, however, has survived. Fortunately, the intriguing collection Pathodia sacra et profana, containing 39 pieces for voice and basso continuo, has endured through the centuries and thus forms an excellent point of departure for this concert. In the intimate acoustics of the Kleine Zaal at the Muziekgebouw, and with the expressive meantone tuning of the Fokker organ, his music is particularly well suited to its surroundings. Alongside music by Constantijn Huygens, works by contemporaries will be heard, as well as the only surviving work by his son Christiaan, namely the Courante in E minor from 1661, in an arrangement by Laurens de Man. The programme also includes more modern works, among them Lamentations from 2014 by the French composer Charles van Hemelryck and Vues des Anges from 1959 by Hans Kox for baritone and violin, both composed in 31-tone tuning.
The collection Pathodia sacra et profana appeared in 1647 and contains sacred psalms in Latin and secular airs and arias in French and Italian. Instead of the composer’s name, the score bears the cryptic word ‘occupati’, usually translated as ‘by a busy man’. With this, Huygens indicates that he is not a professional musician, but fulfils a ‘function for the public good’, and that it would be inappropriate for a gentleman of his standing to publish a collection under his own name. The word ‘pathodia’ is a contraction of ‘pathos’ and ‘odè’ (passion and song) and is described by the musicologist Rudolf Rasch as a ‘Huygenian neologism’. Rasch, who has written extensively about the music of Constantijn Huygens, is also the biographer of Adriaan Fokker, the initiator and designer of the Fokker organ, who in turn had this 31-tone organ built on the basis of ideas by Christiaan Huygens, the son of Constantijn.
The various sections from Pathodia sacra et profana are linked by Laurens de Man, on the basis of atmosphere and sonority, to the other works on the programme, such as the capriccios by the German composer and organist Johann Jakob Froberger, who was in contact with Constantijn Huygens and with whom he shared mutual musical admiration. Connections are also made with a canzona by the Italian composer and organist Girolamo Frescobaldi, who was Froberger’s teacher, and with movements from the Dutch anthology ’t Uitnemend Kabinet from 1649. In this way, a varied concert emerges.
Laurens de Man, resident second organist of the Fokker organ, is a versatile musician with an affinity for historical tunings and contemporary repertoire. As the winner of the Dutch Music Prize, he regularly performs seventeenth-century music with baritone Ben Kazez, an expressive singer who has already appeared on many international stages since obtaining his master’s degree at the Guildhall School in London in 2018 and becoming a Britten Pears Young Artist. He and Laurens regularly collaborate with the Spanish violinist and violist Paula Pérez Romero, who studied in The Hague and specialised in historical performance practice in Basel. Since 2019, she has been a member of the Orchestra of the Eighteenth Century and also plays the viola with the Geneva Camerata. Together, alongside a tribute to Constantijn Huygens, they bring to light the richness of early Dutch music through Pathodia sacra et profana.

This tribute concert celebrates the musical life of the still-living New York composer Joel Mandelbaum. The programme includes works by composers and prominent figures he met during his visit in 1963 to the 31-tone organ – which at that time was still housed in the Teylers Museum in Haarlem – including Professor Adriaan Fokker, organist Anton de Beer and composer Hans Kox. In addition, a work by Mandelbaum’s American colleague Abram M. Plum, who also engaged with the 31-tone system, will be heard.
Joel Mandelbaum was born in 1932 in the United States, where he earned his doctorate in music theory at Indiana University in 1961 with his dissertation Multiple Division of the Octave and the Tonal Resources of 19-tone Temperament. At Queens College of the City University of New York, he taught from 1961 to 1999 and served as chair of the music faculty there. His interest in microtonality was sparked by a lecture by the famous German composer Paul Hindemith, in which Hindemith enthusiastically outlined various historical tuning theories, only to then attempt to refute them in a rather unconvincing manner. Mandelbaum subsequently began a correspondence with Professor Adriaan Fokker, which led to a six-week stay in Haarlem in 1963, together with his wife Ellen. During that period he composed, under Fokker’s guidance, in Euler’s genera. The result was 10 Studies in 31-Tone Temperament, which premiered on the Fokker organ in Haarlem. He also had several meetings with the 31-tone organist Anton de Beer, from which the piece Speelmuziek 1 on the programme originates. Mandelbaum also had a warm and memorable meeting with composer Hans Kox and his then wife Anita Pereboom, as well as with the well-known violin duo Bouw Lemkes and Jeanne Vos, for whom this latter work was composed. The work Serenade for Two Violins in 31-tone tuning by Hans Kox will be performed in the programme.
About his encounters in 1963 with Adriaan Fokker and others, Mandelbaum wrote the following: “This Dutch mathematician and music theorist invited me to Haarlem to compose on the microtonal organ of the Teylers Foundation and to introduce me to the possibilities of the 31-tone tuning, which he had inherited from seventeenth-century mathematicians such as Huygens and Euler. He himself and his closest collaborators – the violinists Bouw and Jeanne Lemkes, Jan van Borssum Buysman, curator at the Teylers Foundation, Hans Kox, fellow composer, and Anton de Beer, the resident player of the microtonal organ – were all very welcoming and helpful.”
During the presentation of the archifoon on 1 November 1970, the interrogation scene from his opera The Dybbuk premiered at the Teylers Foundation. Mandelbaum later also wrote other microtonal works in the 31-tone tuning, including 3 Dream Songs (1971), Four Miniatures for Archifoon (1979), Sonata in 31-tone temperament for Two Violins (1987) and Woodwind Quintet no. 2 (1991). Although the majority of his oeuvre is written for conventional instruments and tunings, in which he employs a predominantly conservative tonal language, he nevertheless makes regular use of the natural seventh overtone in some of these compositions.
At Mandelbaum’s initiative, George Secor realised a 31-tone variant of the Scalatron at Queens College, an electronic instrument with variable pitch used for demonstrations on the history of tunings and for performances of compositions. At the request of organist Ere Lievonen, the Prelude for Scalatron or other 31-tone keyboard from 1978 by Abram M. Plum is therefore also performed on the Fokker organ. Plum studied composition at the University of Iowa in Iowa City, where he earned his doctorate in 1962. In addition, he studied composition in 1956–1957 with Luigi Dallapiccola in New York. From 1965 to 1991 he taught composition, electronic music, music theory, non-Western music and piano at Illinois Wesleyan University in Bloomington, where he remained part-time as an accompanist from 1991 to 2002. Whether Abram Plum also met Adriaan Fokker and/or Anton de Beer can no longer be stated with certainty.
The concert is performed by violinists Jellantsje de Vries and Natálie Kulina, who already gained experience with the repertoire in 2025 during the concert 75 Years of the Fokker Organ. The experienced soprano Valeria Mignaco, a member of the resident ensemble Vokalprojekt 31 since its foundation in 2015, sings in the final work of the programme. All-rounder Ere Lievonen plays the Fokker organ.

With the concert Sumer is icumen in, Una Cintiņa returns to the Fokker organ with a programme that celebrates spring and the coming summer. The title of the concert means ‘Summer is come’ and is based on a song in Middle English, specifically in the dialect of the Wessex region in England. It is a famous rota (canon), on the one hand because it represents the oldest known polyphonic music for six voices from the mid-thirteenth century and demonstrates a lively musical culture in the Middle Ages, and on the other hand because secular English-language music from that period is extremely rare. The text of the music describes the arrival of summer and the flourishing of nature. Although the identity of the composer is unknown today, it could be W. de Wycombe or the monk John of Fornsete from Reading Abbey, a ruined monastery in the English county of Berkshire.
Alongside improvisations on the original theme of Sumer is icumen in by Una Cintiņa, the programme includes several works, among them the premiere of a new piece by the Latvian composer Madara Pētersone. Also featured is a work by the Dutch composer Henk Badings, who composed a relatively large amount of 31-tone music between 1952 and 1981. His composition Archifonica from 1976 was actually written for an electronic 31-tone organ from 1970, namely the archifoon, which, like the 31-tone organ, is owned by the Huygens-Fokker Foundation. Una Cintiņa performs this work, which consists of three separate pieces, for the first time on the Fokker organ. Another work to be performed is Sumer is Icumen in by the well-known Danish composer Ole Buck, who was inspired for this organ composition by both medieval music and the sounds of nature. Ole Buck was born in Copenhagen, studied piano from the age of twelve and composed for orchestra at a young age. His breakthrough came at the age of twenty with a composition for soprano and chamber orchestra, after which he became a leading Danish composer and, in the late 1960s, ushered in a new movement in Danish music known as the ‘New Simplicity’.
In addition to these three works, various other compositions will be heard, all performed by organist Una Cintiņa, whose passionate playing and crystal-clear musical interpretations guarantee an exciting listening experience that should certainly be experienced live.

Especially for the concert ‘Laboratonium 5: Piano versus Organ’, the concert stage is transformed into a sound laboratory. Here, new tonal worlds are put to the test, tuning systems collide, and unexpected alliances emerge between instruments that are rarely heard together. In this fifth edition of Laboratonium, an imaginary experimental laboratory of sound, microtonality, innovation and research take centre stage. Early music is re-examined through a contemporary lens, brand-new works are heard for the first time, and boundary-pushing instruments reveal their full potential. All of this is performed by the virtuoso musicians Anne Veinberg (piano) and Ere Lievonen (organ), with the participation of the dedicated English flautist Carla Rees and the experienced electronic composer and performer Felipe Ignacio Noriega.
At the heart of the programme is the encounter between two unique keyboard instruments: the 96-tone piano, also known as the Carrillo piano, and the 31-tone organ, better known as the Fokker organ. These instruments are heard both together and separately, demonstrating how different divisions of the octave can reinforce and challenge one another.
The concert opens with a special world premiere: Variation on Dufay’s Nuper Rosarum Flores (2020) by the American composer Bill Alves, a work that has never been performed before. In this composition, Alves’s post-minimalist idiom merges with the musical legacy of the fifteenth-century composer Guillaume Dufay from the Burgundian Netherlands. Fragments and sound ideas from Dufay’s famous motet are transformed and re-examined by Alves within the 31-tone system. The piece is written for four hands on the Fokker organ and is performed by organist Ere Lievonen and pianist Anne Veinberg, two musicians who have frequently performed together, particularly within the Fokker organ concert series.
The instruments then meet in Morpheus (2017, revision 2026) by the Dutch composer Sander Germanus. At first hearing, the work sounds rich and harmonious, yet it simultaneously contains a continuous, slightly unsettling shimmer that never fully comes to rest. Germanus plays with timbre and tuning, allowing the music to hover between familiarity and disorientation. Halfway through the piece, the organist leaves the organ and takes a seat at the Carrillo piano, after which Lievonen and Veinberg continue playing four hands. At that moment it becomes clearly audible how remarkably the 96 tones of the Carrillo piano align with the 31 tones per octave of the Fokker organ: two different systems that do not exclude one another, but instead deepen each other.
In a new work by Off <>zz (a premiere), Anne Veinberg steps into the intersection of instrument and algorithm. Off <>zz is the live coding duo formed by Veinberg together with the Mexican composer, programmer and laptop artist Felipe Ignacio Noriega. The two have been working together for many years on the project ‘CodeKlavier‘, a programming language that emerges from the interaction between piano and laptop. While playing the Carrillo piano, Veinberg generates computer code live, which is interpreted by Noriega in real time and transformed into electronic sound. The result is a constantly evolving soundscape in which human touch and digital logic are inextricably linked.
International new repertoire is also heard in this concert. Suite 36 for Lumatone and piano in 36-EDO (2025) by the Finnish composer Juhani Nuorvala has not previously been performed in the Netherlands. The work combines a conventionally tuned grand piano with the Lumatone, a digital keyboard instrument that can be programmed in virtually any alternative tuning. The Lumatone consists of a honeycomb of hexagonal keys which, thanks to their isomorphic layout, make complex intervals and microtonal structures clear and playable. In this work the instrument is tuned in 36-EDO, a system with 36 tones per octave, making sixth-tones possible as well. With electric piano sounds, these microtonal lines wind their way between the familiar pitches of the acoustic grand piano, creating a fascinating and constantly shifting interplay. Nuorvala, based in Helsinki, has built up an extensive microtonal oeuvre and has previously composed several works for instruments and ensembles of the Huygens-Fokker Foundation, performed within the concert series of the unique 31-tone organ.
The programme concludes with the somewhat modernist composition Amsterdamned (2025) by Edward (Eddie) Clijsen for Kingma system alto flute, Fokker organ and Carrillo piano, in which tension and harmony continuously flow into one another. In this microtonal work, Clijsen explores the expressive space that emerges when the octave is redivided into 24, 31 and 96 tones per octave, allowing, despite the increased complexity, a richer spectrum of timbre, harmony and texture to arise, which calls for new organisational principles and instruments. For this work, Clijsen employed both formal, systematic approaches and intuitive compositional methods to explore and fuse the subtle possibilities of these tunings.
‘Laboratonium 5: Piano versus Organ’ is a concert that not only reveals how rich and expressive microtonal music can be, but also how imagination, technology and craftsmanship can together create new musical worlds. Anyone curious about sounds beyond the beaten track simply should not miss this unique musical laboratory.