Germany - St Hedwig’s cathedral in the heart of Berlin is modelled after the Pantheon in Rome. Construction work began in 1747, finally opening its doors to worshipers in 1773. The building is highly regarded by the people of Berlin, and to preserve its rich history, it has just undergone an extensive renovation period that’s seen the entire interior transformed. Holoplot has been chosen to supply the audio solution, delivering its X2 Matrix Array system for seamless, unobtrusive spoken word reinforcement.
The brief for the publicly funded construction work was exceptionally detailed, with high expectations. St Hedwig’s is benefitting from a complete renewal, the new look reflecting the cathedral’s history. The nave sees big changes, whilst the original interior layout returns, but now with seating in the round. The aesthetic is clean and simple with white walls, clean lines, and minimal internal details - with strictly no option for visible loudspeakers.
Circular in shape, with a 30m diameter, the central space rises to a dome that peaks at a total height of 33m. The huge parabolic space has renowned acoustics for music and is well-suited for performances from the Klais Opus organ. For spoken word, however, the reverb times negatively impact intelligibility and the echo bouncing back to the altar in the centre posed a considerable challenge.
Sichau & Walter Architects, who won the redesign contract back in 2014, required an invisible solution that would solve these issues while being flexible enough to adapt to the variety of choral, concert, and spoken word content as their founding partner, Peter Sichau, expands.
“Worship architecture fundamentally differs from secular architecture, because its primary purpose is to create a framework, so that the celebrant, in this case the priest, can deliver mass in a way that offers worshipers a religious experience," he says. “Our methodology required the architecture and the space to be recognizable solely by the atmosphere and the acoustic of the space, which is very complex and challenging in this case.”
The Holoplot team modelled various design options that could meet this exacting brief. As Jakob Greif, Holoplot applications engineer and technical lead for the project, explains, the final system design is a true example of working with a building to achieve the very best for the whole community.
“Circular buildings are not new to Holoplot, but the difference here was the position of the altar and therefore main microphone positions. Having spoken word coming from the center of the space, with the audience ‘in-the-round’ and no possibility of adding localized loudspeakers, created a unique situation we had to try and solve.”
To address the space's positional challenges and 6.5-second reverberation time, Greif and the Holoplot team designed a system based on the X2 Matrix Array. X2 is Holoplot’s compact Matrix Array loudspeaker, equipped with power over ethernet, enabling it to receive audio and control signals, and power through a single cable, simplifying installation and, in combination with the unit’s slim profile, enabling flush mounting. These features allow the arrays to disappear behind custom screens, in narrow, recessed wall cavities, so as to not interfere with the building’s smooth, mute colored lines, something that was very important to the project.
X2’s size and rotation flexibility enabled the team to utilize the modules in a variety of positions, including fixed in portrait orientation behind the main columns. 3D Audio-Beamforning then solved the positional issues created by having the altar located centrally, as Greif continues.
"Our priests will finally be able to speak comfortably at the altar and that is possible thanks to the way Holoplot has designed the active beams,” notes Johannes Rogge, technical and media integration lead for the St Hedwig project. “I am really impressed by how that works; to be able to hear the difference just by moving a few meters, is amazing.”
