Amadeus has completed the installation of a unique immersive sound system for Le Préau, the National Drama Center (NDC) in Normandy-Vire, France. The newly designed system uses a three-element ‘antenna’ system controlled by the company’s Holophonix spatial sound processor, and offers very high accuracy sound localisation for the audience in a theatre environment.
Under the direction of Lucie Berelowitsch since January 2019, Le Préau operates artist-in-residence programme alongside its performance productions. The first five NDCs were created between 1946 and 1952, as creative and production centres run by one or more artists involved in the theatre field, and remain major players in the design, manufacture and production of French theatrical work. Presently numbering 38, they are spread over France.
NDCs are also places of research, writing, creation, dissemination and training. For each NDC, a contract of ‘dramatic decentralisation’ is concluded between the Minister for Culture and the director of the venue, defining the commitments of each. ‘Le Préau is a place of creation and sharing, with a strong artistic permanence, to ensure a contemporary creation articulated around awareness and transmission, capable of covering its territory and opening up to the national level and ultimately to the European and international levels,’ says Berelowitsch.
The Main Hall at Le Préau has a capacity of 590 seats, with a 22m depth and 18m width. The electro-acoustic sound reinforcement system designed by Amadeus – in accordance with Technical Director Alexandre de Monte and Director Lucie Berelowitsch – offers very high accuracy of sound localisation for the audience, as well as high audiovisual correlation.
‘The sound system of our Grande Salle was installed in 1996. It was high time for a major investment in this technical domain, to replace our system. The project began in 2018,’ says de Monte. ‘Lucie Berelowitsch already had a very “spatial” approach to sound creation. It was natural to choose this type of technology, and we were encouraged in this choice by the successful and proven experiences of colleagues at the Théâtre National de Chaillot, the Comédie Française, La Scala, Les Champs Libres, Thélème, and Radio France.’
The Le Préau audio set-up is built around a Holophonix spatial sound processor, which was designed by Amadeus in collaboration with Ircam, using Wave Field Synthesis (WFS). Like visual holograms, this ‘holophonic’ process captures or creates a sound stage by preserving spatial information. This technique allows the creators to replicate the sound field’s physical properties. Wherever they are in the theatre, the listener in the audience has a coherent perception of the audio sources’ localisation.
‘I enjoy working on this system’ says Mikael Kandelman, a sound engineer who has worked closely with Lucie Berelowitsch for many years. ‘I can work at very low and very high sound pressure levels without any problem.
‘Object-based mixing in WFS is quite astonishing, especially with functions related to bus reverbs or source width. We have the feeling of being able to “thicken” quite accurately the sound masses on the stage. This makes it a very promising creative tool that I look forward to testing again.
The main audio system comprises three ‘antennas’ (arrays) of Amadeus loudspeakers. The first is made up of eight Amadeus C15 triaxial speakers flown above the front of the stage. These loudspeakers are evenly spaced across 15m, with identical spacing between each speaker in the array.
The Amadeus C15 speaker is based on a three-way, point source design with a 15-inch woofer and two neodymium diaphragm compression high-frequency drivers, coaxially mounted with a single acoustical output, and coupled to a single waveguide. It uses a diffraction horn, optimised to offer a vertical dispersion of 60° and horizontal dispersion of 90°, which can be rotating through 90° to reverse the dispersion characteristic. This type of load ensures uniform coverage and excellent spectral quality throughout the whole listening area.
The tweeter in the C15 gives a combination of extended frequency response, high efficiency, and wide dispersion. The driver employs two concentric annular ring diaphragms, each covering a limited frequency range for increased power handling, with high dynamics and extremely low distortion. The larger annular midrange diaphragm, featuring a 3.5-inch (90mm) voice coil, covers the frequency range between 800Hz and 6.5kHz, while the ultra-light annular diaphragm for the high range features a 1.75-inch (45mm) voice coil, which offers exceptional transient response with very high efficiency from 6kHz to 22kHz.
The second antenna of 24 point source transducers built into the front of the stage are variants of the Amadeus PMX 5 model, and form a ‘sound ramp’. They are evenly distributed across 16m, with 660mm between each adjacent speaker. This set-up has been specifically designed for the National Drama Centre of Normandy-Vire by Amadeus.
Each ‘module’ is based on two-point source speakers, inherited from the Amadeus PMX 5 reference, for a total of 24 transducers. The front panel is angled at 19° matching the bleacher’s curvature of the audience seating, allowing an acoustical centre of each speaker aiming the last row of seats.
Set in front of the curved proscenium, this large-scale front-fill system with limited depth offers three main functions: it naturally allows for perfect sound coverage of the lower half of the audience; allows the sound image to be lowered, to bring back sound coming from the stage, and thus to maximise the accuracy between sound and visual images; and offers very high spatial resolution, making their location almost imperceptible to the audience.
This front-fill system can be disassembled in a few minutes, should the proscenium need adjustment.
A third antenna, made up of the newest point-source loudspeakers, the Amadeus C6 is flown above the audience, between the second and third technical bridges. These mainly provide reinforcement for the low-mid frequency range, which is often necessary at the back of a theatre.
Low-frequency reinforcement is based on the new ABB 18 reference, using a total of four units. This new speaker model, with limited depth and extended height design, was derived from the standard reference Amadeus ML 18 used in the Théâtre de le Ville (Théâtre des Abbesses) installation. Additionally, two subwoofers are installed close to the front of the stage, one stage left and one stage right. Two furhter subwoofers are paired at ceiling level, above the audience.
Le Préau has also invested in a large quantity of point-source speakers, including Amadeus PMX 5, PMX 8, PMX 12 and PMX 15 models. These speakers are intended for use as stage monitors, or mobile systems during immersive sound creations.
These PMX speakers can be controlled by the Holophonix processor, offering 128 in/outputs, as well as a quasi-unlimited amount of spatialisation buses. Each bus can run embedded spatialisation algorithms, including Higher-Order Ambisonics (2D, 3D) Vector-Base Intensity Panning (2D, 3D), Vector-Base Amplitude Panning (2D, 3D), Wave Field Synthesis, Angular 2D, k-Nearest Neighbor, Stereo Panning, Stereo AB, Stereo XY, Native A-Format Ambisonics, Native-B Format Ambisonics, and Binaural.
More: http://amadeuslab.com
