Music

 

The Butterfly Effect (1996)
for live-interactive MIDI hyperinstrument

Download: mp3 ( 3:44 )
Format: mp3, 128 kbs, 44.1kHz, joint-stereo

"...the notion that a butterfly stirring the air today in Peking, can transform storm systems next month in New York."

James Gleick, Chaos: Making a New Science

The fanciful notion described above is called the butterfly effect, a theory of sensitive dependence on initial conditions first described by M.I.T. scientist Edward Lorenz in his famous paper Deterministic Nonperiodic Flow (Lorenz 1963). Lorenz was using primitive computer models of weather systems to investigate his intuitive notions about the order he perceived in seemingly disorderly weather systems when he discovered that a very small adjustment in the input of a system could produce large-scale consequences in the output.

The Butterfly Effect (1996) attempts to breath life into Edward Lorenz's metaphorical butterfly. The butterfly is represented by the "melody" of the composition, a continuously sweeping glissando gesture that gives shape to the work. The glissando gesture is controlled by a performer whose instrument is a MIDI controller pedal connected to a synthesizer/computer. The pedal produces continuous values in the range 0-127. These values are used to control the pitch of the butterfly. The pedal value is mapped to the velocity value in the Doppler equation shown in Fig. 1 in real time.

Fig. 1. The Doppler equation (Halliday and Resnick 1988).

Johann Christian Doppler's famous equation describes the shift in pitch we perceive when we encounter a moving sound, like a train that passes by. At rest, the imaginary butterfly emits a 440 Hertz tone. When moving under the influence of the performer's pedal, however, the butterfly's pitch isomorphically sweeps up and down, constrained in its flight to a pitch sweep within the octave above 440 Hertz.

The butterfly is set against a deceptively simple sonic landscape: a Fibonnaci-inspired ostinato pattern whose spectral content, volume and spatial location is constantly shifting under the influence of the incoming stream of information provided by the performer.

James Gleick, Chaos: Making a New Science (New York: Penguin, 1987).

David Halliday and Robert Resnick, Fundamentals of Physics, Third Edition, (New York: Wiley, 1988).

Edward Lorenz, "Deterministic Nonperiodic Flow," J. Atmos. Sci. (Vol. 20, 1963), pp. 130-141.