Juggling Sound Ball Demo from STEIM Amsterdam on Vimeo.

Sounding Juggling Balls, minimalist music in projectile motion: At Patterns + Pleasure Festival in Amsterdam STEIM presented the premiere of several pieces written by Tom Johnson for the Gandini Juggling company. For these pieces STEIM developed a set of interactive juggling balls that react to movement by emitting sound. Tom Johnson is an American composer and former music journalist, credited with introducing the term “minimalist” into music criticism in the early seventies. Many of his pieces are based on simple mathematical procedures that give rise to self-similar structures. The Gandini company had already been making juggling renditions of Steve Reich’s Clapping Music when about two years ago Johnson approached the group and asked STEIM to develop a set of juggling balls that could produce simple tones based on the actions of the jugglers. At STEIM’s laboratory, Byungjun Kwon and Luuk Schipperheyn have designed and fabricated a set of sounding juggling balls that combine compactness with versatility. Each ball contains a chip with six oscillators connected to an embedded amplifier and speaker. A stream of data from a contact sensor and an accelerometer is processed to drive the oscillators. In the pieces performed in Amsterdam, each ball was programmed to play a tone whenever it fell back into the hand of a performer, so that the height of each throw determined the duration of a musical rest. As in his previous work “Galileo”, Johnson turned gravitational acceleration into rhythm. Hypnotically capturing eyes and ears, the synchronous movements of the jugglers provided a wonderful visualization of the mathematical processes employed by the composer.” - Matteo Marangoni, Neural.