The basic idea of Filterspiel – Music for conferences was to partially resolve the problem that the original sound cannot be muted in instrumental performances. Therefore, in this piece, all percussionists are placed in interpreter’s booths. When the instruments resonate with a low dynamic level inside these, they can barely be heard from the outside. However, when picked up by microphones, the sound may be transferred to the concert hall. Nevertheless, the audience may still watch the percussionists perform. Hence the cabins serve as filters. Not only when they play softly, but also when loud sounds are produced, the interpreter’s booths filter certain frequencies. Microphones are filters as well. This is especially valid for the utilised contact microphones as their frequency range is very limited. Finally, digital filters are used to distort the sounds created by the percussionists. Hence the title Filterspiel (filter play) is programmatic in nature. It was selected cautiously, being derived from Kreuzspiel (cross play), Karlheinz Stockhausen’s first early work. The very same work was also partially processed in Filterspiel. In parts B/C, the cut-off frequencies and the durations of the filters were derived from this score. Moreover, the percussionists draw a tribute to Stockhausen on the instruments. Due to the interpreter’s booths, the piece is ideal to be performed on conferences.