JACQUES SODDELL

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fungal music - jacques & fran soddell

MODELLING MICROBIAL GROWTH

models of filamentous microbes and their music

An honours thesis based on an investigation into modelling the growth of filamentous microbes using Lindenmayer systems was submitted by Fran Soddell to La Trobe University, Bendigo in 1993.

This thesis showed that it was possible to model microbial growth, producing "trees" that resembled colonies of growing microbes. The investigation also collected growth data on a live fungus, Mucor M41, and used these data to produce parametric L-systems to represent Mucor growth.

This page presents 2 models and the resulting sound files produced by Lsys2midi.

Dichotomous branching (branches at growing tip) occurs occasionally in fungi

L-system

/* * Fran Soddell * honours thesis fig 17 * fig17g * altered to make music * Date:11/01/00 */

#define maxgen 11

#define step 0.25

#define delta 25

START : F(step)b

p1: b -> [+(delta)F(step)b][-(delta)F(step)b]

sounds

F17 MIDI file    F17organ excerpt    F17db excerpt    F17goa excerpt

The midi file presented here represents the output from generation 12 using a general midi organ as the default instrument. The midi file contains 2 parallel sequences generated by the L-system, but differing by the defaults used in lsys2midi (different starting note and different range). The file produced some interesting "systems music" when used with different instruments. Presented here are excerpts using an XG organ. and three excerpt generated by the same midi file (generation 8 this time) using XG organs, a percussion patch on the cs1x synth and a goa trance track (with added beats not produced by the L-system). The piece called mycobeat uses the same MIDI sequence

F17slow MIDI file

The L-system above could be modified by changing the step length to show changes in growth rate of the organisms. This resulted in the same image, but the change in growth rate could be detected by changes in tempo.

Lateral branching (branches away from growing tip) is commonly found in fungi

L system

/* * Fran Soddell * honours thesis fig 16 * fig16 * altered to make music * 11/01/00 */

#define maxgen 7

#define step 0.5

#define delta 25

START : F(step)b

p1: b -> [+(delta)F(step)b]F(step)a

p2: a -> [-(delta)F(step)b]F(step)b

The L-system for dichotomous branching sounded similar to the L-system for lateral branching. Since it was difficult to tell the difference on casual listening we created a midi file that contain one dichotomous and one branching L-system. Can hear there are differences.

F16 and F17 MIDI file combined

Stochastic systems

each run is different

Every time a stochastic L-system is run, the output is different because of the random rules. This example contains two sequences derived from different runs of the same system. See the stochastic example in what are L-systems for the L-system for this file.

F24both MIDI file