for prepared organ
Siegfried Koepf 2002
Exactly ten years ago, I realized my sound installation Ohne Titel for the first time, in a concert at the music academy in Cologne (Musikhochschule Köln). It was an early result of my theoretical study of tonal systems as represented by historical instruments. Since then, many further versions of this work have been realised. The piece itself is more of an experimental concept than an actual composition. Each realisation of Ohne Titel is explictly based on a mechanical and combinatorial analysis of the organ being used. During the performance, selected control elements (keys, stops) are finely adjusted through a mechanical device to regulate the air supply to single pipes or groups of pipes. Type and sequence of these manipulations are partly predefined and partly improvised. The result is a sound process which is predictable to a certain degree.
From the program booklet of Ohne Titel, 2002.05.03, Cologne, Kunst-Station Sankt Peter