Dr Giles R. Greenway

http://www.slideshare.net/gilesgreenway

Chaotic Music: Oblique Strategies Against Humanity

Not understanding music: axioms

http://www.slideshare.net/gilesgreenway

My God! What has sound got to do with music? -Charles Ives.What has music got to do with sound?

Simple ratios of frequencies sound aesthetic.

A doubling of frequency is an octave.

An octave has 8 notes.

An octave has 12 semitones.

Intervals of 3 tones are evil.

The circle of 5ths doesn't quite work.

Meanwhile, in 1963:

http://www.slideshare.net/gilesgreenway

Simplified model of convection currents.

Describes the rates of change of 3 variables, x, y and z.

There are no analytical solutions.

x(t) = ?, y(t) = ?, z(t) = ?

Simulate the system with numerical approximations.

Slight changes in the start-point cause dramatically different behaviour.

Deterministic Nonperiodic Flow, Edward N Lorenz, Journal of the Atmospheric Sciences, vol 20, pg 130 1963.

Meanwhile, in 1963:

http://www.slideshare.net/gilesgreenway

Euler's method: Assume the solution is linear over short time intervals.

Inaccurate, unstable

Use 4th-order Runge-Kutta.

http://www.slideshare.net/gilesgreenway

Initial coordinates each differ by 0.01.

Chart area is 80 x 60.

Change (almost) nothing and continue with immaculate inconsistency.

http://www.slideshare.net/gilesgreenway

Implement it on slow machines in low-level languages.

No chance of manipulating audio in real time.

Back in the good-old days...

Books on chaos, fractals, cellular automata and mathematical recreations contained pseudocode.

http://www.slideshare.net/gilesgreenway

Variables modify the frequency of sinusoidal oscillators.

These frequencies are modulated by other oscillators, whose frequencies are controlled by other variables.

x variable controls stereo panning.

Discard some axioms. Acquire some more axioms:

As many parameters of the mathematical system as possible should influence the sound.

Minimize arbitrary choices. Minimize your influence.

It should sound the way it looks.

Left channel, right channel, centre channel.

http://www.slideshare.net/gilesgreenway

Javascript!

BBC demos recreate Radiophonic Workshop sounds with the web audio API. http://webaudio.prototyping.bbc.co.uk/

Draw the attractor with scalable vector graphics. (SVG)

this.leftModOsc.connect(this.leftModGain);this.leftModGain.connect(this.leftOsc.frequency);

left mod osc

left mod gain

left osc

left gain

mixer

http://www.slideshare.net/gilesgreenway

http://augeas.github.io/Chaoscillator/

Square Waves Aren't Square.

http://www.slideshare.net/gilesgreenway

Pulse waves have an infinite series of harmonics. Therefore they sound interesting when filtered.Modulate the pulse width.

It's been done...

http://www.slideshare.net/gilesgreenway

Radio Web MACBA: COMPOSING WITH PROCESS: PERSPECTIVES ON GENERATIVE AND SYSTEMS MUSIC #8.1 http://rwm.macba.cat/en/composingwithprocess_tag

I never wanted a modular synth...

http://www.slideshare.net/gilesgreenway

A.C. circuits can be modelled by differential equations, so differential equations can be modelled by A.C. circuits.

For a time, both analogue and digital computers coexisted.http://blog.analogmachine.org/2012/03/15/analog-computers/

http://users.physics.harvard.edu/~horowitz/misc/lorenz.htm

It's almost too simple

http://www.slideshare.net/gilesgreenway

Use cheap analogue multipliers.http://www.logosfoundation.org/instrum_gwr/chi/AD633.pdfUse any old op-amps.Get nice capacitors.

Dual-rail power supply.Normalize to 0-5V.

Use outputs as control voltages for analogue synths.

http://www.slideshare.net/gilesgreenway

Control analogue instruments via Pygame's MIDI module.

Quantized to 128 values.

x variable plays Microbrute. (y and z control waveshaping and filter cut-off.)

y and z variables play Volca keys polyphonically. (x controls the filter.)

Trigger kick-drum on Volca beats when x changes sign.

Turn up portamento, hope for the best.

https://gist.github.com/augeas/574939b2a41572b4e33649db8afd01cd

Make an exhaustive list of everything you might do and do the last thing on the list.

Merry Christmas, Mr Lorenz

http://www.slideshare.net/gilesgreenway

https://soundcloud.com/giles-richard-greenway/merry-christmas-mr-lorentzThere's quite a nice build up of forms here that seem to culminate and then drift apart to sort of make a flag post around which the construction takes on a nice compositional form! It's impressive the ways in which the saw tooth waves are manipulated to conjure overlapping smoothness with harsh edges here and there. Really nice outcome with this track! -Will Connor https://soundcloud.com/willconnorseesarwww.perkelt.com/http://ewajustka.tumblr.com/http://daphneoram.org/

Notes from the Metalevel

http://www.slideshare.net/gilesgreenway

http://overtone.github.io/Overtone: Clojure library for controlling Supercollider. (Clojure is a Lisp-like language that compiles to Java. Clojurescript compiles to JS.)

Create buffers filled with Lorenz signals to use as LFOs.https://github.com/augeas/chaoscillator-ii

All right, I do want a modular synth.

http://www.slideshare.net/gilesgreenway

http://www.sound-machines.it/product/ns1nanosynth/Nanosynth: One variable controls pitch, one controls pulse width, one controls filter cut-off. Subtract x from 5V to control Werkstatt VCA for panning.

Werkstatt: Variables control pitch, LFO rate (to modulate pitch) and filter cut-off.