Following the reopening of Notre-Dame de Paris after the devastating 2019 fire, the cathedral faced a unique technical challenge: delivering reliable wireless audio across one of the world’s most complex and sensitive architectural spaces without compromising its historic fabric or day-to-day accessibility.
Working with integrator Novelty, Sennheiser deployed its Spectera wideband wireless system to support services, concerts, and live broadcasts across the cathedral’s 100-metre span, achieving full coverage with just four discreet antennas.
The new specifications included sound reinforcement for mobile celebrations, where the priests or the archbishop would move about whilst still being heard clearly without any dropouts. In addition, the use of new spaces such as the side chapels had to be factored in. In a nutshell: RF coverage had to be ensured throughout the entire length of the cathedral, from the entrance of Notre-Dame to the chapel of the Crown of Thorns reliquary located at the very back, and across its width, where obstacles like wooden partitions and massive stone pillars had to be overcome.
In view of the new requirements and the exceptional operating conditions, the question was which wireless system to use? Notre-Dame’s old system relied on an analogue two-channel Sennheiser 3000 series receiver and a pair of active directional antennas placed at the centre of the liturgical podium.
In view of the specifications, the team planned to wire the entire Notre-Dame cathedral with fibre rather than RJ45
“When Sennheiser confirmed that a fibre extension works perfectly by simply adding a fibre media converter from the list of models they had tested, we realised that Spectera was the solution we were looking for.”
On paper, the further the study progressed, the more the system seemed perfectly suited to Notre-Dame de Paris, but the stability of Spectera’s RF transmission still had to be verified on site. A full-scale test was therefore organised in early 2024 in a cathedral still under construction.
Today, liturgical life has resumed at Notre-Dame, with rhythm given by the five daily services. “Every morning before the first mass and every evening after the last mass, worshippers and visitors are welcomed in the narthex for the Angelus prayer,” explains Prades. On the technical side, the choice of microphone varies according to preference, with some priests using a handheld microphone and others a bodypack transmitter with an MKE 40 clip-on microphone, which is appreciated for its discretion and sound quality.
The cathedral also has an audiovisual control room, from which the teams of television channel KTO provide daily broadcasts. “When unobtrusive sound capture is required, the microphone chosen for the altar of Notre-Dame, the MEB 114 boundary microphone, is the most suitable because it is both aesthetic and precise, with very consistent directivity across the entire spectrum. The wireless microphones can also be used for the hosts of concerts by the “Maîtrise Notre-Dame de Paris” choir.