Front and back board: frame structure with multi-layered structure of perforated front and internal layer of rotatably areas and damped polyester fleece. The uniquely operating principle provides for a almost entirely sound absorption about the whole frequency area.
Field of application: The maximum of absorption area in a small room: with high-performed-cabinets of ROHDE & GRAHL in difficult acoustic problem cases can be achieved convincing results. In small and medium offices they can replace the acoustic ceiling. The intelligibility is increased significantly, a reduction of the sound pressure level as far as 5 dB is possible.