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  1. 1. Cellular automata synthesis of acoustic particles
  2. 2. Computers can compose music if programmedaccordinglyHowever AI systems only imitate composers of wellestablished musical stylesConversely, whether computers can create new kind ofmusic is harder to study and judgeA solution is Program computer with abstract models thatembody the dynamics of compositional processesFrom mathematical models to a more efficient andflexible model -cellular automata
  3. 3. Granular synthesis Cellular automata for method to translate truly new music, pleasingpattern into signal that to ears can drive a speaker Chaosynth - the softsynth
  4. 4. Granular synthesisWorks by generating a rapid succession of very short soundbursts called granules ,that together form larger sound eventsEar has a time threshold for discerning sound properties likefrequency and spectrum , below which any sound is a click.Results exhibit a great sense of movement and sound flowHere , no chopping and reassembling of pre-recordedsound, but sound from scratch
  5. 5. Cellular automata – ChaOs -the neural reverbatoryA 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
  6. 6. State of a nerve cell.. Vmin and Vmax threshold values characterise the state of a cellquiescent(or • Internal voltage Vi below Vmin polarised) • Potential divider aimed at maintaining Vi below Vmin State 0 • Vi between Vmin(inclusive) and VmaxDepolarised • Electric capacitor regulates rate of depolarisationState 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
  7. 7. 0 : Polarised Ifm(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)= 0Burned to polarised
  8. 8. 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
  9. 9. Mechanism - an exampleFrequency 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
  10. 10. Setting the parametersControl panel ,theuser interface providesadjustment for size ofgrid , specify ChaOsparameters - resistanceand capacitance, size ofgranules(in sec) andnumber of iterationsThe oscillator panelspecify amplitude ofeach oscillatorFrequency panel setnumber and range offrequencies andassociating each with astateSet waveformApply filters andenvelopes
  11. 11. 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
  12. 12. Taxonomy for the design of complex sounds GeneralFixed 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
  13. 13. Pleasing to the ears when blended in compostionFit no known categorywhen isolated
  14. 14. References:(1) Miranda, E.R., “The art of rendering sounds fromemergent behaviour: cellular automata granularsynthesis”, Euromicro Conference, proceedings of the 26th5-7 Sept, page(s):350 - 355 vol.2, 2000.(2) Correa, J. ,Miranda, E.R. and Wright, J., CategorisingComplex Dynamic Sounds,2001.(3) Miranda, E.R., “On the Music of Emergent BehaviourWhat can Evolutionary Computation bring to theMusician?”,Gecco,2003.(4) “Composer scores advance in high-techtunes”, Electronic Engineering Times January 6, 2003.(5) Any Queries ?