CHAPTER 1:
AESTHETICS AND PHILOSOPHY OF SHAPE

Feedback as a Natural Metaphor

Use of the words “habitat” and “environment” in the SHAPE acronym (Sound and Habitat Audio Prototyping Environment) are meant to evoke a broad sense of human interrelatedness with nature and the project’s science-related underpinnings. “Feedback,” a well-known phenomenon in many scientific fields of study, is the primary design principle implied in all SHAPE works. By initiating continuous change inside a network, feedback is considered the cause of emergent systemwide characteristics, much like the frequency of an oscillator circuit or repeating pattern of a biological cycle. This phenomenon could be described as a kind of “flow” or “cycle” in any given timescale.

Some examples are described below by comparing natural processes to audio processes. Two natural processes concerning feedback, among others, are well-known in environmental science: fruit ripening and bird flocking. As self-reinforcing phenomena, these processes give rise to collective or cumulative effects, particularly from the perspective of an observer. I liken these natural processes to musical interplay, which is often “greater than the sum of its parts” in group performance. Sound amplification with electroacoustic systems can have similar effects when inherent resonances are explored dynamically.

Fruit Ripening and Feedback

In the example of fruit ripening, a positive feedback loop occurs. It begins with a single fruit which spreads a chemical to all other nearby fruit over days. The cycle is a chain reaction which slows and stops when all fruit in the area are ripened and decay sets in. Apples, specifically, follow a process of synchronization which is contingent on one apple initiating the transference of ethylene. Other nearby apples (and fruits generally) contacted with this airborne chemical begin to ripen rapidly and ethylene accumulates [Fig. 1, left].

The same positive feedback principle could describe an audio system configured in loop (i.e., loudspeaker pointed at microphone). Energy accumulation starts at a single resonant frequency and increases in gain exponentially until attenuated. The result is an acoustic tone [Fig. 1, right].