Tonewheels is an experiment in converting graphical imagery to sound, inspired by some of the pioneering 20th Century electronic music inventions. Transparent tonewheels with repeating patterns are spun over light-sensitive electronic circuitry to produce sound. This all-analog set is performed entirely live without the use of computers, using only overhead projectors as light source, performance interface and audience display. In this way, Tonewheels aims to open up the "black box" of electronic music and video by exposing the working processes of the performance for the audience to see.

Up until now, Tonewheels has been realized as a live performance or a workshop (at WAVES, Dortmund, May 2008). However, for Access Space, Holzer has decided to create a playable installation based on these simple optoelectronic principles. Users of Access Space will be invited to produce patterns for the spinning tonewheels as well as graphical scores to be projected on the instrument in order to play it.

The inspiration for this installation comes from the ANS synthesizer. The ANS is a pioneering electronic music instrument conceived and built by Evgeny Murzin in the Soviet Union during the late 1950's. It is also one of the first experiments in direct graphical composition. To compose with the ANS, the user scratches lines through the opaque black covering on a glass plate. Light shines through these lines as the plate passes through the machine, and activates photocells inside it. Lines at the bottom of the plate produce low tones, while lines at the top of the plate produce high tones.