A set of relatively simple rules can often depict the complex patterns found in many natural phenomena. Among these, the relationships between individuals of a living society, like the one of a bacterial colony, have been studied for centuries. The famous Conway’s Game of Life is a prime example of how these behaviors can be simulated mathematically, and since its introduction forty years ago, it has given birth to a new family of algorithms called epidemic algorithms, or cellular automata, that have found their way into many fields of art. These algorithms have been mostly unknown to the musical instrument world until Martin Howse and the London based collective micro_research started using them. The idea of using viruses to generate music is not a new concept; in 2003, the Swedish artist Leif Ellgren released “Virulent Images/Virulent Sound”. The release contained a DVD and a CD of micro-recordings that demonstrated the sound produced by several bacterial colonies. These recordings are acknowledged in the micro_research website as one of the sources of inspiration for the realization of the Blackdeath Noise Synth, an open source module that lets the user manipulate and control epidemic algorithms for sound synthesis. Micro_research’s online documentation of the project does not give much insight about the module’s operation, and to understand how it works it has been necessary to read the C source code for the ATmega microcontroller around which the synth is built. The sound generation happens in two separate ways: through a granular re-synthesis of the input sound (8 Khz@8 bit), and through the internal noise/feedback generator. The controls allow the user to manipulate parameters such as the start and end points of the granulator, which samples the input in a succession of very short samples or “grains”. Other controls on the panel allow one to choose the specific epidemic algorithm to use and to control the parameters that affect its evolution. The input sound loses its sonic identity, and becomes just another parameter that influences the interaction among the individuals of the bacterial colony, creating ever-changing noise textures. The resulting sound is wild and evil, thanks also to the continuous clipping and aliasing, and the algorithms can be expanded by users who want to delve into the C source code.The synthesizer can be bought through the micro_research website. For those not scared of using a soldering iron, there’s the option of buying the printed circuit board alone and building the synthesizer using the open source schematics published on the website.

Alessandro Saccoia