
Test cases:
Test 1: Consonance and dissonanceCompositions:
Equinox
Test 1: Consonance and dissonance
Swarm behaviours that encourage tight (but not overlapping) dwelling over goal locations
tend to cause clusters of notes with small pitch class intervals, which creates structures
that suggest dissonance.
Adding strong repulsion from other agents and urging agents to move quickly toward
distant goals has the opposite effect, creating large intervals and complex, rapidly changing
melodies. The result is not strictly harmonic, but suggests a more stable tonal foundation,
giving the impression of relative consonance.
Test 2: Industrial percussion
When the stylistic requirements of a musical piece are strict, constraints on swarm behaviour
and interpretation can ensure that the complex and organic behaviour of the swarm can still
produce useful output.
MIDI-compatible drum machines often map different drums in a kit to notes in pitch class
space, making drum sounds explorable by the swarm. Strong attraction to a single value in
timing space causes the swarm to produce stable, rhythmic pulsing; while encouragement to
move in pitch space allows the swarm to trigger different drum sounds, creating dynamic
but robotic sounding industrial beats.
Test 3: Counterpoint
This piece exploits flocking behaviours to keep two agents relatively close to one another,
each following the other's movements while dancing about wildly due to strong, random forces.
A single goal is used to encourage consistent timing, while conflicting forces of random
motion, neighbour avoidance and directional alignment cause the two agents to play melodies
that develop randomly, but frequently synchronising for brief moments. The result is a
dual melody line reminiscent of counterpoint, both following and changing directions
whimsically.
Equinox
A live synthesiser composition using multi-swarms to produce lead and accompaniment sections,
combining aesthetics of early 90s house music and ambient electronica.
Two distinct groups of agents are guided by goals to occupy different areas of pitch space
and timing parameters, separating the sounds into foreground and background. Slowly changing
dynamics come from changes in timing goals, when agents go from a flurry of activity to
a softer lull, playing with musical tension while developing the musical soundscape.
The circling sun
A multi-swarm composition that maps each swarm to a separate MIDI instrument. A large population in
rapid motion plays notes in a pentatonic scale, evoking the sounds of traditional Chinese guzheng
music, played with the instruments of the contemporary orchestra.
A large repulsor is placed in the centre of pitch and time spaces, while one swarm is guided to move
to the centre of the repulsor itself. Unable to reach the centre due to the repulsor's influence,
the agents are instead deflected and begin to move in orbits around the goal, creating oscillations
in multiple parameter spaces. The alignment behaviour in both swarms causes the second swarm,
situated far from the orbiting swarm, to 'catch' the orbital motion, making it move in similar
patterns despite its distance from the first swarm.