self-directing feedback


This experiment explores the possibility for what I might call 'embedded' generative systems, or transformative systems. Typically we conceive of a digital generative systems as something which creates data that is then mapped to parameters of a specific medium. The data generated by the digital process is then mapped to a particular media - pixels, samples etc. This is the typical approach taken in generative art.

In contrast under the approach explored here, the digital processis driven by the medium (in this case sound) and acts to re-arrange it. Rather than simulating an entire closed system, the aim is to mimic a particular ecosystemic process, creating an artificial system that diverts and alters the material of the real world.

The starting point of this experiment is the conviction that feedback (of one form or another) is a core organising principle of all complex adaptive systems. The broad goal was to make a self-directed system that played with the idea of feedback and stability - the maintenance of some internal invariant in the face of a potentially runaway mechanism.

After trying many different possibilities the end result is incredibly simple. Two delay lines are fed with one mic and output to separate stereo channels. Each has infinite feedback. This is typically managed with a form of watt governor that regulates the gain according to the current signal amplitude. In this case, blow out is avoided by altering the delay times. Each unit monitors the amplitude of its buffer and simply alters the delay time (always at audio rates) in proportion to the amplitude. You can think of this as two mics in a room that move left-a-bit right-a-bit when ever feedback starts growing.

Almost zen.

The system settles to dulcet drones or enters wild self-feeding oscillations. Try it outside with birds, or on headphones. Try running your hand over the mic.

*** warning the system seems pretty stable but can potentially explode. Hitting escape is the only escape. ***

This version is tweaked to work on a powerbook with the volume set to 12 bars (that's 4 from the top)
DOWNLOAD: a mac osx application here

Made at CEMA, Monash University, Melbourne and supported by Australian Research Council DP grant DP0772667.

© ecila. 2010