The Mutabor Project
Bernhard Ganter, Rüdiger Krauße

The Mutabor project has its root in a cooperation between Martin Vogel (a music theoretist) and Rudolf Wille (a mathematician). Wille presented the first version of the microtonal MUTABOR keyboard instrument on the easter symposium on "Music and Mathematics" of the Herbert-von-Karajan Foundation in 1984.

The instrument is a modification of an electronic organ, with a usual 12-key-per-octave keyboard. Keyboard and sound generator are connected to a computer that can interpret the input and modify the output pitch to generate microtones. Depending on the respective computer program, the intonation can be modified at any time and depending on what has been played. During a piece of music there may be many different pitches associated to the same key of the keyboard ("mutating intonation"). This allows experiments with just intonation, for example.

Since 1984, the instrument has undergone a slow but steady development. In 1987, the MutaborII project was started, which resulted in a nice commercial version that offered a very convenient programming language for intonation logics (V.Abel and P.Reiss). This version was available for Atari computers and used Midi protocols.

In 1998 the new version,, has been completed and is now available for experiments. It uses large parts of the original MutaborII software, runs under Windows (3.11 and higher) and has additional features. In particular, can be used without extra hardware: the program takes Midi-files as input and can use a sound chip for sound generation.

A test version can be downloaded from