contents
1. abstract
2. programme notes
3. details
4. performances
abstract
Rozalie Hirs’ hilbert’s hotel for 31-tone Fokker Organ and electronic sounds (2015) takes its inspiration from the mathematician David Hilbert’s famous paradox of the infinite hotel, as well as the concept of Hilbert spaces in higher-dimensional mathematics. The work explores musical “rooms” created by comparing overtone spectra and allowing only shared partials to sound. These spectral intersections generate unique harmonic environments that shift and expand across the 31-tone organ, extending to the limits of human hearing. Through calculations in OpenMusic and sound synthesis in SuperCollider, Hirs renders infinite mathematical ideas perceptible as evolving soundscapes. Hilbert’s Hotel was premiered at the Muziekgebouw aan ’t IJ, Amsterdam, in April 2015.
programme notes
The title of Rozalie Hirs’ hilbert’s hotel refers to a thought experiment devised by mathematician David Hilbert to illustrate the strange logic of infinity. In his 1924 lecture Über das Unendliche, Hilbert imagined a hotel with infinitely many rooms: even when every room is occupied, new guests can always be accommodated simply by shifting the current occupants further along the corridor. This paradoxical scenario was later popularised by George Gamow’s book One Two Three… Infinity (1947).
Hirs’ composition draws on this idea of infinite extension, while also alluding to Hilbert spaces — mathematical constructs that generalize familiar Euclidean space into infinite dimensions. In hilbert’s hotel, the composer imagines a fictional Hilbert wandering through multidimensional musical landscapes. These sound worlds emerge from her exploration of overtone series: by comparing different spectra and allowing only the partials they share to resonate, Hirs creates distinct harmonic “rooms” for listeners to inhabit — each with its own timbre, colour, and scale.
The 31-tone equal-tempered Fokker Organ provides the means to navigate these spaces. Through careful calculations in OpenMusic, Hirs traces the shifting intervals between harmonic spectra, rendering them perceptible as dynamic sonic architectures. These processes could, in principle, unfold endlessly, echoing the infinite capacity of Hilbert’s imaginary hotel. The work also stretches the audible range of the instrument to its extremes, probing the threshold of human perception.
The electronic part was realised in SuperCollider and played through Protools, with the Fokker Organ controlled via MIDI during performance. hilbert’s hotel was premiered on 26 April 2015. The photograph below shows Hirs herself next to the console of the organ alongside her laptop.
details
commission
Hilbert’s Hotel Hilbert’s Hotel for Microtonal Fokker Organ and Electronic Sounds (2015) was composed by Rozalie Hirs on commission from the Huygens-Fokker Foundation, with financial support from the Fonds Podiumkunsten.
instrumentation
Fokker organ with electronic sounds
technical requirements
Fokker organ (microtonal organ with 31 tones per octave)
Stereo speakers, subwoofer
MIDI interface, laptop with ProTools installed
duration
The total duration of the composition is approximately 8 minutes.
special thanks
Special thanks to Casper Schipper for assistance with the sound synthesis.
performances
19 October 2025, 11:00 AM, 75 Years of the Fokker Organ!, Muziekgebouw aan ‘t IJ, Piet Heinkade 5, Amsterdam – Rozalie Hirs (laptop)
1 October 2017, 11:00 AM, Fokker Organ XL, Small Hall, Muziekgebouw aan ‘t IJ, Piet Heinkade 5, Amsterdam – Rozalie Hirs (laptop)
20 March 2016, 11:00 AM, Het woord aan het woord, Muziekgebouw aan ‘t IJ, Piet Heinkade 5, Amsterdam – Rozalie Hirs (laptop)
26 April 2015, 11:00 AM, Reflexions Sonores, Muziekgebouw aan ‘t IJ, Piet Heinkade 5, Amsterdam – Rozalie Hirs (laptop)