Soundpixel Aura calculata is a system of autonomous individual electronic devices, known as 'sound pixels' [SP]. These circular electronic devices, designed specifically for aura calculata, can adopt two states: when active, an SP lights up and plays a tone; when inactive, the SP remains silent and dark. In the loudspeaker version, the sine tone is generated by an integrated function generator. In the organ version, a sound magnet is switched on, which regulates the air supply to the corresponding organ pipe.
Control Only important parameters, such as the respective neighbourhood rule and the clock signal indicating when the rule is to be executed, are transmitted centrally via a control unit. When a SP receives a clock signal, it evaluates the states of its neighbours and uses this information to calculate its own next state.
States The course of the activity can be expressed by a sound pixel in various ways: by changing the pitch of the sine wave, by changing the water level through inflow and outflow, but also by the colour of a light-emitting diode.
Sound & lighting For the sine wave variant, the artist designed cylindrical loudspeaker sculptures made of translucent acrylic glass, which also function as illuminated objects. Roth, on the other hand, used transparent acrylic glass and metal elements to create an organ sculpture that focuses minimalistically on the technical necessities and makes the entire water and wind system transparent. The organ pipes, arranged in a circle around the central water reservoir, are attached to a scaffolding structure made of acrylic glass tubes and metal half-couplers.
Menage á 2, 3 or 4 The neighbourhood is determined by the direct cabling of the SPs to each other. Usually, the SPs are linked to two neighbours each to form a circular arrangement. In principle, an SP has four connections, so it can be linked to up to four neighbours.
Wind & water Tim Otto Roth and his team created the water organ with its water and wind system in his Black Forest studio. The timbre of the pipe varies with the water level. This changes depending on the opening intervals of the inlet and outlet valves and the pressure of the water columns in the respective pipe body and water reservoir. This means that the entire system changes depending on the activity or inactivity of all pipes.
Organ voicing & best tone The pipes were built and voiced by the Waldkirch organ builders Jäger & Brommer, who discovered something special: organ pipes are generally voiced to a so-called best tone that is tailored to their scale, with a balanced ratio of a saturated fundamental tone and the respective overtones. However, these pipes with variable volume could be voiced in such a way that an ideal tone is played at two specific water levels.
Micro-processor: Atmega 328
Control: Manual switches and buttons (Arduino) or touch display (RPI)
Power supply: 24V