Maurice Genevoix has joined luminary French writers Voltaire, Rousseau, Dumas, Hugo, and Malraux, and revered figures from culture, science, and politics in France’s secular temple, the Panthéon.

Marking the occasion, President Macron commissioned a work by German artist Anselm Kiefer and French composer Pascal Dusapin – the first public commission for the Panthéon since 1923. The sound used technology from Amadeus.

Dusapin’s creation, In Nomine Lucis, is a piece for a musical ensemble of singers reflecting Genevoix’s Ceux de 14 (The Men of 1914), recorded by the French chamber choir Accentus at the Philharmonie de Paris concert hall. To bring a more intimate human connection with the Great War into the Panthéon, nearly 15,000 names of soldiers who died for France have been read and recorded by French actors Florence Darel and Xavier Gallais. Visitors to the Panthéon will hear the names spoken as they walk through different parts of the building.

‘I wanted to make the stones of the Pantheon sing, to create a huge ‘vocal lung’ where everyone will hear different echoes of its past, and of its history,’ says Dusapin.

To support the new musical work, a bespoke sound system was designed and installed within the Panthéon, using 70 loudspeakers, designed and manufactured by Amadeus mounted around the transepts and dome, which reaches more than 35m in height. Coated in natural stone, these enclosures appear an integral part of the monument.

‘Amadeus became a space where technological innovations with arts and crafts, combine and complement each other,’ says Amadeus Marketing Manager, Gaetan Byk. ‘We take real pleasure in constantly surpassing and renewing ourselves, in exploring materials and technologies in all their forms, without limit. These 80 stone-finished speakers forming part of the monument are the purest expression of our know-how and the values we defend.’

The electroacoustic system is controlled an Amadeus Holophonix sound spatialisation processor: ‘This enables the sound spatialisation of the different choirs through its various onboard algorithms, in two or three dimensions,’ says Thierry Coduys, the project’sDirector of Technologies and Dusapin’s longstanding technical collaborator.

‘The position of the choirs, their trajectory and the other events that make up this electroacoustic score, are managed through the IanniX graphic computer sequencer – the processor receives, interprets and translates these millions of temporal and spatial messages.’

Designed by Amadeus in collaboration with IRCAM, the Holophonix immersive sound system is used by numerous performance venues, including some of the most prestigious in France. It uses algorithms and technological from the STMS (Sciences et Technologies de la Musique et du Son), a laboratory founded in 1995, affiliating the CNRS, Sorbonne Université, French Ministry of Culture, and the IRCAM Institute, bringing together Wave Field Synthesis, High-Order Ambisonics and Distance-Based Amplitude Panning forintuitive placement and movement of sources in a 2D and/or 3D space.

‘I worked closely with Thierry Coduys on selecting the most appropriate algorithm to accurately render the trajectories he wanted to apply to the sounds,’ says Clément Vallon, from the Technical Team at Holophonix. ‘We tried several solutions, and finally selected the “k-nearest neighbours” algorithm (k-NN).’

KNN selects the k loudspeakers closest to the source position and applies level differences between them. The gain differences are calculated based on the distance between the source and the selected loudspeakers. The quantity of loudspeakers (k) is chosen by the user with the ‘neighbours’ parameter, providing very flexible spatialisation, as the loudspeakers can have any layout.

‘It is an algorithm that is not used much for immersive concerts, but it offers great flexibility, perfectly suited to the geometry of the building,’ Vallon adds.

‘I mainly designed tools allowing the spatial writing of In Nomine Lucis,’ says Adrien Zanni, who joined the Holophonix Technical Team to design and develop ‘spatial writing’ tools and languages. ‘Pascal Dusapin and Thierry Coduys wished to create a unique and living experience. By adding a motion dimension to the choirs, visitors are invited to explore the monument in a different way. A melody can appear near us and disappear in the long resonance of an adjacent transept that we do not yet distinguish; inviting us to discover it.

‘Two approaches have been explored – the precise writing of trajectories, first, crossing the Pantheon from North to South, or from East to West, or from the ground to the dome, and the development of generative algorithms controlling the movement of multiple sound sources, mainly inspired by physical models, for example, a simulation of flocks of birds, or stochastic models.

‘We used two pieces of software for the development of these algorithms, IanniX and Max, the first one for the management of the trajectories and the second for the creation of the ‘playing’ interfaces, used by Thierry Coduys for the live spatialisation and mixing of the pieces.’

Fifty-four Amadeus C12 model speakers are installed on the imposts of the building’s columns 16m off the ground. The speakers feature an 60 x 60° conical waveguide to optimise the high-frequency directivity in such a reverberant space.

A further eight C15 speakers are installed at 35m above the ground, used in an ‘indirect’ configuration, aimed toward the glass windows of the dome, to maximise their diffraction.

‘Pascal Dusapin wanted something “angelic coming from the sky”, with precision in the mid/high frequencies, but not allowing people to precisely locate the sound sources,’ Zanni explains.

An additional eight C6 loudspeakers – six in a dark oak wood stain, two stone-covered – are installed 4m above the ground to play out the soldiers’ names.