Utopia IV may be performed by one, two or three trumpeters/speakers. Utopia is an open piece: before any performance, one has to determine which sounds are combined in which manner. Due to the numerous possibilities of combination, the piece will sound differently at each performance. The players may choose between three groups with every new bar. By rolling dice, it is decided beforehand which group is played. Additionally, they articulate platonically shaped fragments from Thomas More’s work Utopia through tubes. The sounds are permanently transformed by means of so-called acoustic filter trees. In order to do so, a construction is installed in front of the players. It allows them to filter the sounds in five different ways. Five round boxes are supposed to hang on a frame while the middle “box” is a snare drum (con corde). With regard to this, it is exactly notated which movements the trumpeters execute with their instruments.