Together, the individual loudspeakers form a matrix along which sound is moved in different ways. Loudspeakers are not only featured in this composition as a sound reproduction medium, but rather form a "materially" sensible sound source themselves, an independent component of the composition, although loudspeakers themselves do not actually produce sound. The computer-controlled piano constitutes an additional, stationary and "real" sound source in TopoPhonicSpheres, part I and II.

Since 1991, I have been studying the specific options offered by the Bösendorfer computer-controlled piano. The digital control of the grand piano enables production of sounds displaying affinities to electronic music. However, since this computer-controlled piano may also be played as a "normal-sounding" concert piano, passages have been integrated in the composition which might be played by a piano player, but also passages requiring a virtuosity which is out of reach for human players.

The composition consists of three movements. Each of the movements displays a specific selection of sound material and thus is clearly detached from the other two movements. In part II - tribute to Dresden - among others, material borrowed from operas by Richard Wagner and Carl Maria von Weber as well as original quotations by former politicians of the GDR have been included. This material has been processed and mounted by a harddisk recording system and transferred to a multitrack machine. This audiotape has been combined with different digital sound producers to yield the radio play-like scenes characterizing this movement.

In every movement of the installation TopoPhonicSpheres, the sounding body goes through various phases, the characters of the individual phases being clearly distinct The abrupt changes - synchronized with the video image - will turn the transient character of the medium "sound" into a genuine component of the composition.