Rocking Chairs

interactive soundwork

coproduction & design chair by Christian Grässli CH

Imagine making music while leisurely swaying back and forth in a rocking chair. Ever since the development of digital controllers composers have wanted to devise ways in which they can have music created and manipulated through physical movement. Many of the musical pieces that Jeroen Strijbos and Rob van Rijswijk make involve movement of the audience. People may be invited to move between various stations distributed over a room, weaving their way through non-linear narratives in sound. In another piece GPS navigation determines sonic events linked to spots in an open space that people, walking around the location, experience through a headset connected to a smartphone.


Rocking Chairs is an interactive installation work that may comprise between two and five chairs, coproduced and designed by Christian Grässli (CH). Each consists of wooden slats fitted to an open chrome steel frame. A cylinder holding a smartphone and a loudspeaker is hung from coil springs underneath the seat. This placement makes the sound diffuse and enables the person who sits in the chair to hear the music coming from the other chairs. Through app-software patch-designed by Hans Timmermans (NL), the smartphone registers the angle and movement of the chair as it rocks, modifying effects, such as reverb and filtering, in a composition that progresses through consecutive levels.


The music that Strijbos and Van Rijswijk compose for the chairs is to a large extent specific for the site and the number of chairs in the installation. They can introduce sounds that correspond with the environment in which the installation is placed. Moreover, the density of the music in each individual chair decreases as the number of chairs in a specific installation goes up.


This composition, clouds of notes that move in waves, is different for each chair. Together the chairs, analogous to an ensemble, produce a piece that is shaped by the movements of the people sitting in them. The people rocking the chairs may discover how they can influence the music they make together by coordinating the movements, and how they can progress in the music of their particular chair from one level to the next. In that sense their active involvement completes the composition.

patch design iOS: Hans Timmermans, technical support: Jeroen Croonenberg