The German Museum of History (DHM) in Berlin uses Clearsorber foil in its courtyard. Clearsorber foil is a thin perforated foil that can be used for acoustics. In this specific project the designer build a glass ceiling to make the courtyard an interior space. The space was to be used for concerts and events. After inclosing the courtyard it turned out to have horrible acoustics. The solution was to install Clearsorber foil in front of the ceiling. It helps improve the acoustics but still keeps the design intent.