Challenge

This multi-purpose worship hall in Zurich hosts sermons, choir performances and community events. Its tall curved masonry walls caused severe low-frequency resonance. During preaching, speech lost clarity; while choir singing became muddy, lacking definition. The client refused heavy-looking acoustic treatment that would damage the classic interior. They needed resonant panels that can tune reverberation for both spoken voice and live vocal music.

Solution

Grooved and perforated MDF resonant acoustic panels are mounted on rear and side curved walls. Cavity depth and perforation ratio are calibrated by acoustic simulation to absorb low-mid standing waves. Selected sections of ceiling adopt smooth flat fiberglass acoustic tiles, non-textured and non-fibrous, to control overhead reflections. Panel finishes are customized to match existing timber trim. All materials meet EN 13501-1 B-s1,d0 fire standard.

Result

Reverberation is adjustable and stabilized between 1.6s–2.2s, the sweet spot suitable for both sermon speech and choral music. Speech intelligibility improves, choir vocals sound layered and transparent. The perforated panels integrate seamlessly into the traditional hall decoration without altering the building’s architectural character.