The Kater Blau was founded in 2014. It was the successor of the KaterHolzig which, in its turn, came into existence from the Bar25. It is a club that is located directly on the shore of the river Spree. Due to the construction of buildings around the club the Kater Blau was dealing with a lot of complaints from the neighbors. The ongoing conflict led to tightened demands of the environmental administration. Even the construction department was threatening the club with a closure. The funding allowed the Kater Blau to invest in measures in the Acid Bogen and on the Hoppa Floor. The goal was the reduction of sound immissions with a focus on the low-frequencies.
In the Acid Bogen modal vibration absorbers on the back wall of the stage and on the opposite wall, absorbers in the sound trap and an ANC-system in the sound trap and the emergency exit were installed. Additionally a cardioid expansion of the low-frequency-sounds was used to lower the immissions to the northern side. On the Hoppa Floor an ANC-system in the sound trap and the emergency exit with an expansion on the buildings weak points was installed in addition to the modal vibration absorbers on the back wall of the stage and on the opposite wall.
The combination of these active and passive measures shows a significant reduction of the sound immissions. This was measured during the programming of the ANC-systems. All in all, the situation was significantly deescalated thanks to these measures.