Net_Derive poses an interesting set of compositional, aesthetic and technological challenges.  First, the materials with which one must compose are largely derived from unpredictable sources.  Second, the incoming data must control the visual and sonic instruments that realize the piece in creative and perceivable ways.  Third, these audio-visual real-time instruments must respect and support the conceptual motivations described by Petra Gemeinboeck and the mobile-culture aesthetics and technologies gathered and analysed by Atau Tanaka.  Finally, working with mobile technologies is simultaneously a glance into the future and a few steps into the past; many amenities of modern personal-computing technology on which we depend as new media artists are simply not available on mobile platforms.

My approach to meeting these challenges has been to attempt to bridge the gap between the outdoor space and gallery space as much as possible.  The sounds and images surrounding the mobile participants are the principal raw materials.  Analysis-resynthesis techniques are applied to these raw materials create variations and augmentations of the source sound that still retain their connection to the original.  For example, street sounds from the neighborhood are spectrally analyzed in real-time.  The analysis results are then applied to other audio instruments in order to harmonically tune them to the environmental sounds. Cartography and data visualization play important roles in the installation’s gallery visuals, whereas virtual audio instruments similar to those used by Tanaka and myself in performance sonify the mobile participants behavior during their walk.  Collective parameters like the area covered by all of the mobile participants or their average distance from the gallery affect the overall diffusion, presence, periodicity and reverberation of the gallery installation.  Simultaneously, each mobile player is also sonified indepentendly by a number of dedicated instruments;  indivudual parameters like each mobile participants level of activity, speed, or proximity to the other players are used to control these dedicated instruments.