Kahle Acoustics was approached by the Konserthus in order to improve the hall acoustics as well as ensemble conditions. After a first investigation the lack of resonance was caused by the way the ceiling was constructed; a small coupled volume separated by a steel mesh. The ceiling acted as an absorber. In order to correct this, microphones were placed under the mesh and loudspeakers above the mesh, creating with this a MCR system. The negative absorption of the system corrected the absorption of the ceiling and so the balance was restored. This was done first as a test (see photo), later a permanent system system was installed.
During this project it was discovered by investigating several level distribution settings within the MCR system that the distribution of the energy plays a major role in the perceptual quality of the sound in the hall and also ensemble conditions. This resulted in a paper “Perceptual Relevance of the Location of Reverberation in Concert Halls” published in Psychomusicology, Music, Mind and Brain, to the remembrance of the 100th anniversary of Leo L. Beranek.
view at the hall towards the stage with the Kungliga Filharmonikerna
the digital mixing console on which the temporary MCR system was configured