3. Computers can compose music if programmed
accordingly
However AI systems only imitate composers of well
established musical styles
Conversely, whether computers can create new kind of
music is harder to study and judge
A solution is Program computer with abstract models that
embody the dynamics of compositional processes
From mathematical models to a more efficient and
flexible model -cellular automata
4. Granular synthesis Cellular automata for
method to translate
truly new music, pleasing
pattern into signal that
to ears
can drive a speaker
Chaosynth
- the
softsynth
5. Granular synthesis
Works by generating a rapid succession of very short sound
bursts called granules ,that together form larger sound events
Ear has a time threshold for discerning sound properties like
frequency and spectrum , below which any sound is a click.
Results exhibit a great sense of movement and sound flow
Here , no chopping and reassembling of pre-recorded
sound, but sound from scratch
6. Cellular automata – ChaOs -the neural reverbatory
A discrete dynamical system circuit
n- dimensional grid 2-dimensional grid of
of cells identical electronic circuits
called nerve cells
States-
Finite number of quiscent, depolarised and
states burned
Cells constituting Interact with
neighbour 8 neighbour
through
electric
current flow
Collection of rules
7. State of a nerve cell..
Vmin and Vmax threshold values characterise the state of a cell
quiescent(or • Internal voltage Vi below Vmin
polarised) • Potential divider aimed at maintaining Vi below
Vmin
State 0
• Vi between Vmin(inclusive) and Vmax
Depolarised • Electric capacitor regulates rate of depolarisation
State 1…n-2 • Increasing depolarisation is the tendency
Burned • Vi reaches Vmax, nerve cell fires
State n-1 • Next tick, replaced by a new quiescent cell
8. 0 : Polarised
If
m(t)=0, m(t+1)=int 1 : Depolarised
(A/r1)+ int(B/r2)
2 : Burned
If 0<m(t)<n-
1, m(t+1)=int(S/A)
+k
If m(t)=n-
1, m(t+1)= 0
Burned to polarised
9. Mapping to waveform parameters
• 1 cycle, 1 • Each
• Each waveform • Each
granule possible
produced granule produced
composed by a digital cell state
by CA associated
of several oscillator, n
spectral eeding 3 with a
componen parameters frequency
t -frequency value and
waveforms , amplitude oscillators
and associated
duration to number
of nerve
cells
10. Mechanism - an example
Frequency of each oscillator – arithmetic mean At each cycle, spectrum of signals produced
over frequency values associated to states of by oscillators of each sub-grid add up to give
cells of corresponding sub-grid spectrum of respective granule
11. Setting the parameters
Control panel ,the
user interface provides
adjustment for size of
grid , specify ChaOs
parameters - resistance
and capacitance, size of
granules(in sec) and
number of iterations
The oscillator panel
specify amplitude of
each oscillator
Frequency panel set
number and range of
frequencies and
associating each with a
state
Set waveform
Apply filters and
envelopes
12. to
Random initialisation of
states in grid produces
Settle to an oscillatory
initial wide distribution
to cycle
of frequency values
Characterstic of a
Noise attack of a vocal
sustained tone
sound
Variations in rate of transition obtained by
changing r1, r2 and k
13. Taxonomy for the design of complex sounds
General
Fixed mass Flow Chaotic Explosive textures
Lighten Cascade Insects Metallic
Landing Textures
Darken Melos Woody
Raising
Dull Boiler Glassy
Lift
Elastic Windy Blower
Crossing Effects
Melted Drift Noises Drum
14. Pleasing to
the ears
when
blended in
compostion
Fit no known
category
when isolated
15. References:
(1) Miranda, E.R., “The art of rendering sounds from
emergent behaviour: cellular automata granular
synthesis”, Euromicro Conference, proceedings of the 26th
5-7 Sept, page(s):350 - 355 vol.2, 2000.
(2) Correa, J. ,Miranda, E.R. and Wright, J., Categorising
Complex Dynamic Sounds,2001.
(3) Miranda, E.R., “On the Music of Emergent Behaviour
What can Evolutionary Computation bring to the
Musician?”,Gecco,2003.
(4) “Composer scores advance in high-tech
tunes”, Electronic Engineering Times January 6, 2003.
(5) http://x2.i-dat.org/~csem/UNESCO/9/9.pdf
(6) http://www.sonicspot.com/chaosynth/chaosynth.html
(8)http://www.nyrsound.com/Chaosynth/CsynInformation.h
tm
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Queries ?
