Sollmann and Sprenger's Modular Organ System

Creating sound environments for concert spaces
by Daniel Barbiero
(June 2025)

The history of music sometimes seems like the history of the eternal return. New approaches - to compositional forms and instrumentation, for example - recapitulate, revive, or reconfigure old ones, while old and more-or-less abandoned practices and principles come back to prefigure solutions to current problems. There's something of a metaphorical ouroboros here -- the serpent swallowing its own tail in a closed circle, where its end is its beginning and its beginning is its end. Such at any rate appears to be the case with the modular organ, the intricate sound system invented by Phillip Sollmann and Konrad Sprenger. This radically new instrument, with its broad range of polytonal sound, brings forward the spirit of the traditional pipe organ and embodies it in a contemporary technology created with a contemporary sensibility. In the process, it puts into practice principles of tuning that had been eclipsed by the adoption of equal temperament.

Sollmann and Sprenger are long-time friends who have worked together as early as 2013, with the Autotune project. At around the same time that the modular organ was conceived, the two were two-thirds of a trio with Australian composer/musician Oren Arambachi, the product of which was the 2018 EP Panama/Suez. The modular organ project in a sense represents a deepening of their musical partnership - a complementary one in which each brings something of substance to the whole.

Sollmann is originally from Kassel, in central Germany, but is currently living and working in Berlin. His background contains a diverse mix of formative influences and interests: although he is perhaps best known for his music production, techno DJing, and releases done under the alias Efdemin, he was trained as a cellist and has a degree in electroacoustic composition. He has been drawn to the more exploratory side of music, particularly where music interfaces with research into the nature of sound. In a project roughly contemporaneous with his work on the modular organ, Sollmann experimented with acoustics, alternate tunings, and unconventional instrumentation in a creative synthesis drawing on physicist Hermann von Helmholtz's research into sound, composer Harry Partch's microtonalism, and instrument inventor Harry Bertoia's metal sound sculptures. Some of the results of Sollmann's efforts in these areas can be heard on the 2020 album Monophonie.

"Konrad Sprenger" is the alias of Jörg Hiller, a native of Lahr, in western Germany. Sprenger, like Sollmann, is now based in Berlin. In addition to being a composer, producer, and curator of his Choose record label, Sprenger is an instrument builder and performer. On live dates, he plays a digitally directed, multi-channel electric guitar of his own design, which he often uses to create a music of algorithmically complex, pulsating rhythms. Since 2000, he has collaborated with the Berlin-based American expatriate double bassist and minimalist composer Arnold Dreyblatt, in whose Orchestra of Excited Strings, Sprenger plays percussion and computer controlled guitar. Since 1999, Sprenger also has participated in the activities of the Honey-Suckle Company, a multi-media Berlin artists' collective whose installations often include sound components.

Given both Sprenger's and Sollmann's interest in sound research and instrument invention, it would seem a natural turn of events that they would collaborate on a project like the modular organ. Sprenger, in fact, first built an organ in 2002, fifteen years before the modular organ's 2017 debut. In a way, the modular organ seems to be a scaling up not only of that instrument, but of Sollmann's own experiments building modular systems. In addition, the modular organ reflects both Sollmann and Sprenger's interest in exploring the nature of tuning systems, as well as Sprenger's past work creating sound environments with the Honey-Suckle Company.

The modular organ in fact is, in essence, a system for creating sound environments customized to the acoustic and architectural contingencies of the performance spaces it occupies. Although it's based on the same principles as a conventional pipe organ, it's a very different thing. A standard church organ is an immobile instrument of fixed dimensions, and virtually a permanent part of the church's structure. By contrast, the modular organ is a site-specific sound installation of flexible form. Its modular construction is such that its various parts - pipes, blowers, horns, motors, and such, some of which were taken from church organs - are separable and can be assembled and combined in configurations to fit the size, layout, and acoustics of a given space. It differs from a traditional pipe organ as well by virtue of its computerized control and use of unconventional materials such as fiberglass. But like a traditional pipe organ, it uses pipes, vibrating reeds, and air pumps to create sound; to that extent, it's best thought of as the extension of a traditional instrument into new territory rather than as a radical break from precedent. As Sollmann put it in a 2020 interview with Dragoș Rusu of The Attic magazine, "even if it is controlled by computer, it's completely unamplified; it's just pure mechanical sound by the pipes." As groundbreaking as is its concept as well as some of its technologies and materials, the modular organ ultimately is an acoustic instrument that creates its sounds the traditional way, by moving wind through tubes of different lengths. It may do so in the service of a nontraditional aesthetic program, but it still is recognizable as part of a lineage that stretches as far back as Ktesibios's experiments with proto-organs in third century B.C. Alexandria.

The modular organ is optimized to provide an immersive listening experience. A large pipe organ in a church or other resonant space is optimized toward the same end. But here too differences between the conventional pipe organ and the modular organ emerge. While the former projects sound from a static bank of pipes, the latter positions its pipes at different points or nodes within its installation space. It's as if a pipe organ had been taken apart - dismantled and turned inside out - and had its pieces distributed throughout the listening environment. Audiences consequently can move around among the organ's parts and take an active part in shaping what it is they will hear, with their audio perspectives changing as their movements take them toward and away from individual nodes.

A few examples of the modular organ's configurations from past performances will give an idea of its versatility and adaptability:

• At Hear Here in Leuven in 2022, Sollmann and Sprenger had a relatively restricted space in which to work: a tall rotunda affording them a limited footprint but a generous vertical opening. They took advantage of the layout by taking of one of the organ's modules - a tower containing several trombone-like horns pointing in different directions - and locating it in the center of the room. They additionally placed individual vertical pipes against the walls at wide intervals.
• For Berlin's Modular Music, also in 2022, Sollmann and Sprenger had a large rectangular space to use. They made full use of the floor, situating a number of horns either directly on or just above it. The tower of horns featured at Here Hear were present but in a more peripheral position; the centerpiece was a module made up of a single rank of a dozen organ pipes in front of which an array of horns were fanned out on the floor in front of it.
• For the 2021 After Berlin installation, undertaken in collaboration with visual artist Nico Ihlein, soft materials predominated: curvilinear tubes snaking across the floor with a large, white, possibly fiberglass, horn on a stand providing a visual focal point.
• One of the modular organ's earliest incarnations, in the Hannover Kestnergesellschaft's white gallery space in 2017, recalled a minimalist sculptural installation: an austere, symmetrical arrangement of widely spaced, wooden rectangular modules, three with projecting metal pipes, forming a semi-circle around a central control station.

In all of these installations the instrument's visual aesthetics made a strong impression in their own right: the modular organ is as much a work of changeable sculpture as it is a musical instrument.

Although the modular organ is best heard live in a three-dimensional space in which the listener can move around, we can get a reasonable approximation of its sound from Modular Organ System, an album released as a limited edition LP in December of 2023, as well as from video excerpts of past performances.

What that sound essentially is, is a variety of minimalism in which harmonic complexity emerges from simplicity. Unlike sculptural minimalism, whose objects largely eschewed complex internal relationships, the modular organ's musical minimalism depends on the knotty relationships of pitches and overtones woven into a thick texture. We get an initial impression of a static drone, but once the ear acclimates to the sonic whole, we begin to hear individual tones asserting themselves and standing out within the aggregate. The drone contains an inherent harmonic instability as its tones slowly change pitch and move into and out of the audio foreground. The tuning systems Sollmann and Sprenger use are essential to the drones' tectonic movements, which drift in microtonal increments as the sound moves from consonance to dissonance, from the soothing to the unsettling. The overall effect is hypnotic, but with an abrasive edge. While the LP doesn't give us the full effect of the live performances' perspectivalism, its sounds do shift between channels to simulate spatial movement. Even given the reduced scale of a recording, a listener is likely to come away with an impression of the massiveness of the sound available to the modular organ. We can get a hint of its physicality, that it's something to be felt as well as heard - not unlike the effect of a pipe organ playing forte in a church.

Which brings it back from the edge of sound exploration and puts it at least in view of the mainstream of traditional organ music, albeit on its own terms. What's old is new, and what's new is old as the cycle of change comes back around - refreshed.

Sources:

Dragoş Rusu, "Utopian Music: An Interview With Phillip Sollmann," in The Attic Magazine, 8 Sept 2020 https://theatticmag.com/features/2365/utopian-music.-an-interview-with-phillip-sollmann.html

The Sollman-Sprenger website has several pages on modular organ installations between 2017 and 2024, with images and links to videos. https://sollmann-sprenger.com/