The various architectural examples through the centuries teach us the importance of the influence of architecture on the natural acoustics of concert halls. If, following this observation, it seems essential that architect and acoustician work together when designing rooms, for a long time they lacked the practical tools of this close collaboration. However, with the emergence of acoustic science and the appearance of the profession of acoustic engineer, the acoustic treatment of rooms was no longer the responsibility of the architect. During the separation of these professions, the absence of collaboration tools unfortunately produced working methods where architectural and acoustic considerations were separated. It will be necessary to wait until the 21st century with the democratization of the digital tool and the emergence of acoustic models for tools conducive to collaboration to be created. Nevertheless, reluctance still persists too often to apply a more collaborative working method. However, when these barriers to innovation are overcome, these tools and methods revolutionize the design of rooms. The collaboration between architect and acoustician ensures a symbiosis between aesthetic and acoustic choices for the benefit of the quality of the room.
Over the centuries, the understanding that architects had of the acoustics of concert and performance halls has infused the choice of hall forms. Having neither acoustic technical materials nor a sound system at their disposal, it was essential that the architecture take into account the natural acoustics of the room so that the experience of the spectators is optimal. First understood as responding to the same laws as optics, the architects designed rooms in a parabolic shape to obtain a “megaphone” effect for the orchestra. This is how the 17th century saw the advent of Italian-style opera houses. Then from the 19th to the 20th century, to imitate the phenomena of amplification and echo produced in places of worship such as churches, architects favored rectangular concert halls. With the specialization of the profession of acoustician and the refinement of the understanding of acoustic phenomena, researchers Burgtorf and Séraphin, as well as G.Bekesy and L.Cremer identify the importance of the temporal ordering of acoustic reflections in the phenomena of perception. sound. This is why the 20th century saw a turning point in the design of concert and performance halls through the construction of the Berlin Philharmonic. Its architect, Bernhard Sharoun, jointly designed with the acoustician Léotard Cremer an arena-shaped room so that the walls of the stands are used as reflectors. Since then, the performance halls in the form of terraced vineyards have been regularly reproduced in order to design rooms favoring as much the sound power, the clarity of the sound as the acoustic envelopment of each spectator.
However, these arena-shaped rooms are not necessarily synonymous with impeccable acoustics. It is still necessary, in fact, to take care of the cutting of the steps so that the work on the near and distant lateral reflections is optimized. In addition, the choice of materials and the details of moldings play a significant role in the acoustic performance of performance halls, depending on their degrees and angles of reverberation. This is why the architecture of a room defines its natural acoustics. Therefore, it seems essential that architects and acousticians work together in the design of these rooms. However, working tools and methods are essential to ensure this joint work.
Planète Acoustique has been developing digital tools for 3D modeling of rooms in operation for 30 years using the finite element meshing technique: Hall Acoustics®. Thus, we can model the acoustic performance of theaters according to its uses, but also its shape, its materials to the details of the moldings. By using these 3D models from the design phase, we provide the architect with a visual communication platform which is the foundation of our joint working methodology. Since we are able to predict the acoustic performance of rooms in operation, we anticipate trade-offs and offer solutions that we can co-design to measure. From then on, the acoustic solutions are no longer constrained or conspicuous, but integrated and aesthetic.
Finally, this culture of made-to-measure and integration of acoustic solutions have been the drivers of our international success. It is thanks to our tools and methods that we have been able to dialogue easily with many architects with different know-how and have been able to adapt to construction markets and cultural differences.
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