Notre-dame de paris

Save the monumental sounds of Notre-Dame de Paris

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As France celebrates a year since the hell that ravaged Notre-Dame de Paris, a team of specialists has used sound data collected seven years ago to create a virtual reconstruction of a concert reminiscent of the monumental acoustics of Cathedral.

In April 2013, Brian Katz and his team at Sorbonne University in Paris performed acoustic measurements in Notre Dame Cathedral as part of a project to improve 3D audio through headphones.

However, following the catastrophic fire on April 15, 2019, measurements, revealing how sound traveled from different locations inside the cathedral due to its geometry and materials, became a record. treasure of a threatened cultural heritage.

Now, to commemorate the one-year anniversary of the Notre Dame fire, Katz and his team have used their measurements to create a virtual reconstruction of a concert in the cathedral.

Sound engineers ran the acoustic measurements and recording of the National Conservatory of Music’s original concert on a computer model, effectively recreating the audience’s listening experience at the performance seven years ago.

“We wanted to give people the experience of the concert, let them sit and listen to the performance as it was in 2013, and also highlight the difference in acoustics at different locations in the cathedral,” says Katz.

Recreating the monumental acoustics of Notre-Dame: Brian Katz and his team’s virtual reconstruction of a recent performance allows the listener to compare the sound of a concert in different parts of the cathedral. © Notre Dame Acoustic Working Group

Listeners can choose to hear the virtual concert from one of four different positions: back, middle, front and conductor’s stand.

In addition to providing unique access to sounds from the past, these virtual acoustic reconstruction tools will also aid in the restoration of the famous structure.

“We have proposed the use of these simulation models to see how changes in the cathedral will affect how sound travels. For example, if the architects want to change the stone or change the shape of the vault, we can adjust our computer model to show and even listen to how the acoustics will change,” Katz explains.

Complications of containment

France’s coronavirus lockdown measures complicated the researchers’ effort. When the project kicked off in early February, the team aimed to produce additional elements, such as dynamic 360-degree sound and a wider range of listening positions.

The Notre-Dame Acoustic Task Force installed and ready to record.
The Notre-Dame Acoustic Task Force installed and ready to record. © Notre-Dame Acoustic Working Group

However, the lockdown meant they couldn’t access their powerful computers and mixing consoles.

“We had no choice but to work on our personal computers at home, which was very time consuming. For example, instead of using a big computer to mix sounds all at once, our engineers had to remix four or five sections at once and recombine them.

“It took me two days to run a computer simulation of the cathedral on my home computer compared to the few hours it would have taken on the university machine,” Katz remarks.

Despite the technical limitations, the team was highly motivated to complete the project for the anniversary and are happy to have completed it on time.

The project is an extension of the Ghost Orchestra 2013-2017 production, which resulted in a 360° video in virtual reality with spatialized sound and an overview of the orchestra, and a visit to the virtual cathedral.