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  • Transition of an Instrument:The aeo Sound Performance Project
  • Kazuhiro Jo (bio)

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aeo is a sound performance project consisting of three members: Eye, Taeji Sawai and myself [1]. aeo has performed at several international festivals [2]. Each member takes one of three roles: in this project, performer (Eye), sound designer (Sawai) and instrument designer (me). During aeo performances, the performer holds the instrument [End Page 46] in one hand and sways or shakes or swings it. These motions by the performer produce patterns of sound and light.

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Fig. 19.

(top left) 1st iteration; (top center) 2nd iteration; (top right) 3rd iteration; (bottom, left and right) 4th iteration.

Photos © Kazuhiro Jo

The instrument consists of two sets of hand-held plastic spheres, a converter and software. Each sphere contains a two-axis accelerometer, which converts the inclination and acceleration of each sphere into changes in analog voltage. Each sphere is connected to the converter with a cable. The converter provides the power for the accelerometers and converts the changes of voltage into signals. The software maps the signals onto sound parameters. The instrument has undergone a transition in function and form over four iterations (Fig. 19). I describe here the instrument's enduring features and its transition over four iterations with respect to its switches, bulbs, color, converter and software.

In the first iteration, in accordance with the progress of the performance, the sound designer controlled the sound patterns.

In the second iteration, a switch was added to one sphere, enabling the performer to control the sound patterns. The sound patterns were arranged in series, and the switch allowed the performer to choose the pattern with this switch. The performer also could use the switch to control the timing of changes in the sound patterns manually during the performance.

In the third iteration, two more switches were added for each sphere. The patterns of sound were independently arranged in series for each sphere, and the performer could adjust the sound patterns with these switches. In this iteration, the instrument transformed the performer's motions not only into sound but also into light. A small bulb was added to each sphere; the brightness of the bulb did not correspond directly to the signal from the accelerometer but instead corresponded to the amplitude of the sound. To provide high-current Pulse Width Modulation (PWM) for control of the brightness of the bulb, the converter model was changed from I-Cube X to Makingthings Teleo.

In the fourth iteration, one switch was removed from each sphere. The sound patterns for each sphere were combined and arranged in series. The performer could adjust the sound patterns with these switches. The cap of the switch was embedded into the sphere to prevent its dropping out during performance. The sphere was made semitranslucent to show the color of the bulb. The caps of the switch and the connector of the cable were colorized to differentiate each sphere.

In each iteration, the software was also modified to correspond to the changes in the switches, bulbs and converters.

Through the four iterations, I tried to make the instrument act not only as a tool that the performer uses to play sound but also an object that presents a combination of motion and sound to the audience. Although it is difficult to divide function and form, I aimed for a balance between the two. As a result, I added and removed switches, added bulbs and changed the color, converter model and software of the instrument. It may be helpful to consider the design of physical objects in music and sound art not only at the point of initial creation but also continuously through various transitions [3].

Kazuhiro Jo
Research Center for Advanced Science and Technology, University of Tokyo, 4-6-1 Komaba, Meguro, Tokyo, 153-8904, Japan. E-mail address: <>.
Kazuhiro Jo

Kazuhiro Jo is a Ph.D. student of Knowledge Interaction Design laboratory at RCAST, University of Tokyo. He is also a member of The SINE WAVE ORCHESTRA, a co-organizer of dorkbot Tokyo <


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