It was the composer Henry Flynt who described the music of his friend Catherine Christer Hennix as “tuned texture rather than thematic articulation”. Hennix, who has died aged 75, was a Swedish musician whose work was profoundly informed by her background in mathematics, philosophy, linguistics and Sufism.
Her music explored sound, light, drones, the pure intervals of “just intonation”, time and spirituality, inspired by her musical studies with La Monte Young, who introduced her to the work of the Indian singer and teacher Pandit Pran Nath.
In a repurposed Berlin cemetery church named Silent Green a few years ago, a rare Hennix concert, part of the annual MaerzMusik festival, featured the composer seated at ground level with a two-manual electronic keyboard, flanked by a computer programmer. In the upper balcony were five brass players: two trumpets, a trombone, a French horn and a microtonal tuba.
Some of the audience lay on Persian rugs. Others assumed yoga positions. The majority took their seats in the lower balcony. For three hours most were transfixed by music that proceeded in a stately arc from a foundational drone through slowly evolving non-tempered harmonies that ebbed and flowed with variable intensity, at some moments achieving wall-shaking volume, at others content to hover with quiet patience while the next shift prepared to emerge.
Born Christer in Stockholm to Margit Sundin-Hennix, a jazz composer, and Gunnar Noak Hennix, a doctor, she identified as male until around 1990, when she took the name Catherine Christer. “My brain is the same as before – I didn’t change my brain,” she said in an interview with the Wire, dismissing the label of male or female as irrelevant to her work.
It was thanks to her mother that as a teenager in the early 1960s she heard and met leading exponents of the American jazz avant-garde, including Eric Dolphy, John Coltrane, Archie Shepp and Cecil Taylor, during their visits to Sweden, where they found receptive audiences. Having started out as a drummer in her brother’s jazz combo, Hennix studied with the American trumpeter Idrees Sulieman, who made his home in Stockholm between 1961 and 1964.
While studying mathematical logic, biochemistry and linguistics at Stockholm University, she joined Stockholm’s Electronic music studio, where she worked on making music with computers. Moving to New York in 1968, she met a group of composers including John Cage, Flynt, Terry Riley, Walter De Maria (who had been the original drummer with the Velvet Underground) and Young and his wife Marian Zazeela, whose Theatre of Eternal Music group investigated the mathematical properties of the non-tempered scale through the use of sustained drones produced by voices and electronic sources.
Young, Zazeela and Hennix travelled to Saint Paul de Vence in the south of France in the summer of 1970 to hear Pran Nath perform his slow-moving ragas at the Fondation Maeght. Hennix became a disciple and later that year Pran Nath moved to New York, where he established his Kirana Centre for Indian Classical Music.
In the early 70s Hennix studied at Berkeley College in California before returning to Sweden, where she studied at Uppsala University. She organised a 10-day festival to which she invited Young and Riley and at which she also presented her own work for keyboard and sine-wave generators, The Electric Harpsichord. Her activities also included the performance of the first of several theatre productions in the Japanese Noh style.
In 1978 she accepted a position as a professor of mathematics and computer science at the State University of New York at New Paltz, while also working at the Massachusetts Institute of Technology’s artificial intelligence laboratory and making a recording with Flynt under the name of the Dharma Warriors. After a year she returned to Europe, studying Lacanian psychoanalysis in Paris and undertaking research at Amsterdam University’s institute for logic, language and computation.
A revival of her recording and performing career began in 2005 when, after meeting the Berlin-based English trombonist Hilary Jeffrey, she formed an ensemble called the Chora(s)san Time-Court Mirage. There was further interest when, with Flynt’s encouragement, the original recording of The Electric Harpsichord was released for the first time in 2010, followed by the release of further music from the same event by her three-piece the Deontic Miracle, featuring renaissance oboe and Chinese sheng.
The Chora(s)san Time-Court Mirage ensemble’s performance of her piece Blues Dhikr Al-Salam at the Grimmuseum in Berlin in 2011, celebrating Young’s 70th birthday, was also later released as an album, as was a performance at the Issue Project Room in New York during the Ultima festival in 2014, in which the group included the trumpeter Amir ElSaffar and the singer Amirtha Kidambi. Solo for Tamburium, recorded in Berlin in 2017 and sending the sound of 88 Indian tamburas through a keyboard interface, was released this year.
An exhibition of her visual art, called Traversée du Fantasme, begun with her then partner, the photographer Lena Tuzzolino, in the 90s and resembling coloured renditions of mechanical punched cards, was exhibited in 2018 at the Stedelijk museum in Amsterdam and the Empty gallery in Hong Kong. Her books and essays included Poësy Matters and Other Matters, a two-volume collection published in 2019.
Involved in Sufism since her studies with Pran Nath, Hennix made a formal conversion to Islam before moving for her final years to Istanbul.
• Catherine Christer Hennix, composer, poet, visual artist and mathematician, born 25 January 1948; died 19 November 2023