At Deutsche Oper Berlin, the ensemble Le Balcon presented Mittwoch aus Licht, the final opera in its exploration of Karlheinz Stockhausen’s seven-part Licht cycle, which began in 2018. Performed five times between 19 and 27 September 2026, the production was the first staged presentation of the opera in the German-speaking world.
Conducted by Maxime Pascal, with stage direction by Susanne Kennedy and set design by Markus Selg, the production brought together vocal and instrumental performers, live electronics and the celebrated Helikopter-Streichquartett, in which four musicians perform aboard separate helicopters.
For Stockhausen, spatialization was never simply an effect. Sound positions, movements and trajectories were written directly into the score, making the sound system an essential part of the musical interpretation.
To realize this vision, Le Balcon worked with Deutsche Oper Berlin to deploy 60 Amadeus loudspeakers, complemented by four subwoofers from the venue’s inventory and a HOLOPHONIX Ultra spatial audio processor supplied by Le Balcon.
Bringing the Sound Back to the Stage
At the heart of the system are two frontal loudspeaker arrays operating in Wave Field Synthesis (WFS) through HOLOPHONIX. WFS reconstructs the wavefront of each source so that it is localized at its true position on stage, keeping the sound image consistent with the performers’ positions.
The lower array comprises 23 custom-designed Amadeus SR 790 modules installed along the front edge of the stage. Their front baffles follow the 17° rake of the auditorium seating, a configuration unprecedented at Deutsche Oper Berlin.
Above the stage, a second array of 11 Amadeus C 15-90 loudspeakers provides coverage for the balconies.
“The challenge is to ensure that, for every seat, the sound image appears to come from the stage without seeming too high,” explained Florent Derex, co-founder of Le Balcon and sound engineer for the production.
On stage, monitoring presented its own challenges.
“We had the floor cut to integrate a monitor, a little like a theatre trapdoor from which someone might whisper into a singer’s ear, like a prompter,” Derex explained.
A 24th Amadeus SR 790 module, identical to those in the front-stage array, was recessed into the stage floor. Eight C 8 R monitors and two C 4 loudspeakers dedicated to the synthesizers completed the onstage monitoring system. Three additional monitors from Deutsche Oper Berlin's inventory were also used onstage.
Beyond the frontal arrays, six Amadeus C 12-80 loudspeakers cover the sides and rear of the stalls, four C 8 R units serve the rear balconies, and four ceiling-mounted C 10 loudspeakers introduce a vertical dimension.
The choice of Amadeus was made almost two years before the production. On his first visit to Berlin, Derex found that the house’s existing loudspeaker inventory would need substantial additions for a project of this scale. With much of the system needing to be rented, Le Balcon chose Amadeus, drawing on its experience with the brand in previous productions.
The system was powered by nine Powersoft Ottocanali amplifiers supplied by Amadeus, providing 72 Dante-networked channels. As each C 15-90 required two amplifier channels, the amplification had to be planned very early. The racks were fully configured in ArmoníaPlus in Paris with Francesco Papaleo, Application Engineer at HOLOPHONIX, over two working days, and arrived in Berlin ready to run.
Multiple Spatialization Methods, One Musical Vision
Stockhausen’s score demands different approaches to spatial audio. While voices and instruments associated with performers on stage require precise localization, electronic material may need to envelop the audience or move through space.
HOLOPHONIX provided the central spatial audio processing platform, with Derex primarily using WFS for stage localization and k-nearest neighbors (KNN) for selected sound trajectories.
For the electronic elements, IRCAM computer music designer Augustin Muller employed Layer Based Amplitude Panning (LBAP) and Higher Order Ambisonics (HOA), selecting each method according to the musical material.
“It’s an expressive tool,” Muller explained. “I use three panning buses: a very precise LBAP bus for the octophonic material, a second, more diffuse LBAP bus, and an HOA bus for the Michaelion scene.”
In Michaelion, Muller used Ambisonics to move the synthesiser through the space. “The panning is smoother. It isn’t intended to be very precise; instead, it creates an atmosphere in motion,” he explained.
The different spatialization approaches allowed the team to combine accurately positioned sound sources with more diffuse electronic textures.
Four Helicopters, Sixteen Microphones
The production’s most complex sequence was Stockhausen’s Helikopter-Streichquartett, in which each member of the string quartet performs aboard a separate helicopter.
For the Berlin production, the sequence was captured at Schönhagen airfield during a public event that was also broadcast live. The footage was subsequently incorporated into the staged performances as a video projection.
Each helicopter carried four microphones, capturing the instrument, the musician’s voice and the sound of the rotor. Sixteen audio signals were transmitted from the four aircraft, while a click track kept the musicians synchronized.
The rotor sounds were integral to Stockhausen’s composition, with their pitches and changes in rotational speed forming part of the musical structure.
“When you see it live, you realise they’re synchronized: they’re playing together, but in space, while flying,” said Derex.
For the opera performances, Muller spatialized the helicopter soundtrack using HOA, so that the four aircraft surrounded the audience while the projection showed them in flight. “The helicopters need to be localizable while seeming to come from everywhere,” he said. “The strings, by contrast, require a much more precise image.”
The Challenge of a Repertory Opera House
Unlike a venue dedicated to a single production, Deutsche Oper Berlin maintains a repertory of around 40 productions and presents some 25 of them each year. During the Stockhausen run, Lucia di Lammermoor, Tosca and the ballet Bovary shared the same stage and technical infrastructure.
For Andreas Gockel, Head of Sound at Deutsche Oper Berlin, integrating such an extensive spatial audio system into the venue’s daily operations presented a significant challenge.
“Everything had to be capable of being dismantled and reassembled, and we had to be ready to stage a performance within two or three hours,” he explained.
While a typical performance can be managed by two or three sound technicians, Mittwoch aus Licht required a team of eight or nine.
The complexity was particularly evident on the day of the helicopter performance, when the venue hosted a morning rehearsal, the live helicopter transmission in the afternoon, and a performance of Lucia di Lammermoor that evening.
The installation therefore had to deliver the precision required by Stockhausen’s score while remaining compatible with the practical demands of a major repertory house.
Spatial Audio as Musical Interpretation
At Deutsche Oper Berlin, the combination of Amadeus loudspeakers and HOLOPHONIX processing brought together precise stage localization, moving electronic textures and enveloping three-dimensional sound.
The result was a production in which sound was not merely reinforced but interpreted spatially, extending Stockhausen’s musical writing beyond the physical boundaries of the stage.
Technical Information
Production
- Venue: Deutsche Oper Berlin
- Production: Mittwoch aus Licht, Karlheinz Stockhausen
- Dates: 19–27 September 2026 (five performances)
- Musical direction: Maxime Pascal
- Stage direction: Susanne Kennedy
- Set design: Markus Selg
- Sound projection: Florent Derex, assisted by Nicolas Widmer
- Computer music: Augustin Muller
- Deutsche Oper Berlin Sound Department: Andreas Gockel (Head of Department)
Loudspeakers
- 24 × SR 790 custom modules, including one recessed stage monitor
- 11 × C 15-90
- 6 × C 12-80
- 4 × C 10
- 12 × C 8 R, including eight stage monitors
- 2 × C 4
- Total: 60 Amadeus loudspeakers
- 4 × d&b B1 subwoofers (Deutsche Oper Berlin inventory)
- Total system: 67 loudspeakers
Spatial Audio and Amplification
- 1 × HOLOPHONIX Ultra processor (supplied by Le Balcon)
- WFS, KNN, LBAP and HOA spatialization
- 3 × Powersoft Ottocanali 8K4 DSP+D and 6 × Ottocanali 4K4 DSP+D (supplied by Amadeus), 72 Dante-networked channels, preconfigured in ArmoníaPlus
- 1 × Powersoft T604 (supplied by Le Balcon)
Helicopter Capture (per aircraft)
- 1 × REMIC (V5200 for violins and viola, C5300 for cello)
- 1 × DPA 4099 (instrument)
- 1 × DPA 6061, cheek-mounted (vocal parts)
- 1 × Sennheiser MKH 516, externally mounted (rotor)
Technical support
On-site installation and system alignment by the Amadeus and HOLOPHONIX teams.
For more information about HOLOPHONIX and Amadeus, visit: https://holophonix.xyz/ and http://amadeuslab.com
About Amadeus
For over thirty years, Amadeus has designed, built, and marketed a wide range of electro-acoustical playback systems and high-end signal processing equipment, bringing together high technology, style, and emotion. The Amadeus brand has grown to become a leading supplier of high-end audio solutions and services for theaters, opera houses, concert halls, museums, recording studios, and research centers. All the development and product manufacturing are centralized in Amadeus headquarters in France, with field offices and authorized distributors in Europe and Asia. Visit http://amadeuslab.com/
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