There exist two versions of the instrument to date which have been used in performance: SUM v0.1 and SUM v0.2. Furthermore version 0.3 is currently being development. The common ground between all is the basic elements of design: 3cm3 cubes made of 50% concrete 50% iron and a platform on which they are disposed or removed.
The third version uses the same kind of technology than its predecessors, although the cube itself is here the sensor. By means of Swept Frequency Capacitive Sensing, combined with Machine Learning, it is possible for the software to accurately recognize more variations in the interaction with the sensor. On the musical composition side, the gestures are translated to shifts in the auditory perception of the listening space, with the integration of audio signal processing techniques (Impulse Response, convolution and deconvolution) and psychoacoustic effects (auditory distortion6, streaming by spatial location7, microsound). The resulting composition will be presented as a performance and as a sound installation.
The platform of SUM v0.2 is layered with a narrow grid of capacitive sensors to detect changes in the field on and upon the grid. A PSoC (the chip contained in the transparent PVC cube below the platform) protocole is communicating the values to SuperCollider.
For the performance linked to this version of the instrument, we developed a SuperCollider patch translating the values from the sensors to a panel of waveforms, pulses and clocks that interact with a Hordijk modular synthesizer through a MOTU interface (CV control).
The performance itself is an interactive sonic game for two players – the stage design is reminding of a chess game. Thus while the game as no or few pre-defined rules other than evolving within the constraint of the time and space of the instrument and of the performance, the play is emphasized as a structural factor of the music produced.
The video is excerpt from the live performance with SUM v0.2 at LEAP for the 3DMIN Concert Series in May 2015. You can see the complete performance here.
For version 0.1 the transparent platform is 3×4 matrix of pressure sensors. the sensing values are going through an Arduino protocole and processed through a SuperCollider patch: a complex multi-layered digital feedback matrix.
The musical composition commissioned for this version of the instrument is entitled Shadows: „A light shines on a four-dimensional object in a four-dimensional world, casts a three-dimensional shadow.“ It aims to reveal hidden layers of the space by blending the physicality of the feedback and the psychoacoustic perspective twist made possible by use of loud high pitch frequencies (relative to otoacoustic). Therefore the whole set up plays as an oscillation between different proportions, from the object to the architecture as well as different tangible dimensions (virtual or not) of the space.
Watch a live excerpt from ‚Shadows‘ composed for SUM v0.1 from the live performance at Roter Salon / Volksbühne, 3DMIN Concert Serie, July 2014.