After a large-scale fire in Notre Dame Cathedral, the idea of not reconstructing the ancient building, but rebuilding it using modern methods is seriously discussed. This is beneficial from the point of view of increasing the durability and improving the functional qualities of the structure, enhancing the same fire safety. But there are a lot of nuances, for example, how to preserve the unique acoustics of the cathedral, which depends on a combination of architecture and no longer existing building materials?
Ancient cathedrals differ from other buildings, first of all, by a huge level of reverberation, and secondly, by the prohibitively complex internal geometry of space. For example, in Notre Dame, the reverberation at mid frequencies reaches 6 seconds, which is why normal human speech or playing ordinary musical instruments generates a cacophony of loud and fading notes. In contrast, this same scheme is almost ideal for Gregorian chants and organ music, which is what the cathedral was designed for.
Scientists and engineers are incredibly lucky - just two years before the fire, a complete acoustic model of Notre Dame was created. It was a breakthrough, the outstanding work of scientists Andrew Talon and Brian Katz, as well as many specialists from the Sorbonne University in Paris. Notre Dame Cathedral has become a kind of testing ground for measuring the acoustic profile, thanks to the complexity of the architecture, it allowed scientists to meticulously study the many nuances in this area.
As a result, Katz and his colleagues now have a detailed acoustic model of the cathedral and programs to reproduce it. It is already being used in the implementation of the "Ghost Orchestra" project, which allows holding virtual concerts, listening to any music, as if being inside the cathedral and even moving around it. And if engineers do decide to rebuild Notre Dame using some innovative polymers, scientists will help them select materials with properties that will match the model and sound of the ancient cathedral.