Chaos Patches

bryan · Joined: May 28, 2008 Posts: 8 Location: some furniture

Hi all. 'Tis a nice forum with substance so I figured it would be a good place to glean some ideas on this. There's not too much out there on chaos synth patches so maybe we could compile some stuff here..

To start.. 2 basic chaos patches that yield good results:

VCO square/pulse wave out into VCF. VCF low pass out back into CV or FM in of the same VCO. Change input levels, and resonance and cutoff of VCF to get a range of chirping at low VCO frequencies to abrasive noise at high VCO frequencies

3 (or more) VCO's cross modulating each other via waveform output into CV/FM in of the next VCO, linked in a chain so that any one VCO's settings can have an effect on all the others.

Slew limiting might be nice to slow things down for a sort of chaotic LFO.

What else?

EdisonRex · Posted: Wed May 28, 2008 2:04 pm Post subject:

Hi, and welcome to electro-music.

I don't think what you are doing is chaotic, at least not in my understanding of how real chaos works.

Noise (analogue) tends to be more chaotic than periodic sources, even periodic sources which modulate.

Digital noise tends to be periodic after a fashion. I don't think it works as a source here.

noise, into a filter, sent to a lag, would be a fair source.

To be fair and respectful, what you describe does yield less predictable results, but I'm being a bit pedantic in saying it's not exactly chaotic.

What your describe are complex systems, though, and I think they are useful, fun, and possibly musical.

If I wasn't so tired I'd try to explain their periodicity, maybe tomorrow if someone else doesn't do it instead.

Welcome to the forums, though, I hope you enjoy it here. Interesting point you are making. I do get that, but I do think it is not chaotic in the literal sense.

blue hell

bryan · Joined: May 28, 2008 Posts: 8 Location: some furniture

Hi EdisonRex, thanks for the welcome...

andrewF · Posted: Thu May 29, 2008 5:02 am Post subject:

Hi Bryan
if you haven't read Dan Slater's article, you will enjoy it -
http://web.archive.org/web/20011112115517/www.nearfield.com/~dan/music/chaos/Chaosrel.htm

Also a google for Sprott and chaos will be fruitful. I have spent the past few months experimenting with Sprott's ccts, they are VERY interesting and simple to build

An Integrator can be made with a capacitor on the feedback path of an opamp, maybe a slew module or LPF would give a similar effect.

The easiest way to chaos in electronic ccts is to implement non-linear feedback. check out Ian Fritz's designs for some good chaos examples (the best!).

Maybe your idea of feeding the vcf back into the vco could really get interesting if you 1st feed the vcf output thru another module, then to the vco.

bryan · Joined: May 28, 2008 Posts: 8 Location: some furniture

Andrew, thanks for the great recommendations. I found Sprott's web page and it has some fantastic resources. The Dan Slater article is really good and something I sought out before.. you gotta love the archived web pages.

Since you mentioned Ian Fritz, reading about his circuits on the forums here directly inspired me to post about this. I've built a few simple circuits before but I'm excited about assembling some of these chaotic ones, including his.

Jari Jokinen · Posted: Thu May 29, 2008 1:20 pm Post subject:

I am not familiar with "chaos theory", but I think, that a "chaotic" event can be totally deterministic.

When I tried the three VCO chain frequency modulating patch, it always stabilized after a while. Before that it sounded interesting though.

dougcl · Joined: Feb 08, 2008 Posts: 33 Location: Portland OR

Anyone have a reference on how to get a 1st order system modeled on a synthesizer? Perhaps you rewrite everything as integrals and use slew limiters (?) as signal integrators. A suitable example would be the equations for the lorenz attractor. Seems like this would make a good first project.

blue hell · Posted: Thu May 29, 2008 4:53 pm Post subject:

Here are some chaotic differential equations that I worked out for the G2, you'll want the G2 editor software or the G2 demo software to be able to see the patches. Both can be found here.

dougcl · Joined: Feb 08, 2008 Posts: 33 Location: Portland OR

Awesome. Thanks! I'll try this out in the demo software. Just thinking about this some more, perhaps operating on three VCLFO's is best. Then use the signals as pitch CV on three VCO's (don't get the VCO's themselves wrapped up in the feedback).

it seems one would need:

3 VCO's
3 VCLFO's
3 voltage inverters
1 ring mod
3 CV mixers
3 (?) multiples

andrewF · Posted: Thu May 29, 2008 5:52 pm Post subject:

For me, some of the images in the Slater article link didn't appear. If you have access to scholar's databases like Jstor you can see the full version.
One patch suggested by Mr Slater is below. The chaos CV in on the 3rd VCA is just a CV signal to control the level of chaos, it is not a chaotic signal itself.

Another way to try is use a state variable filter with HP, BP and LP outputs. plug the LP out into something that will alter it ...but not too much, maybe a ring mod, Harry's Morph Lag might be good. feed the output of this back into the filter, either mixed with the original signal in a mixer, or thru the CV input (just an idea - untested)

I have found it more interesting to try and get chaotic CV signals rather than audio. At audio frequencies it just seems more like distorted waveshapes. Doing it to control voltages, and then using them to drive an oscillator sounds like your synth has glossolalia Shocked

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dougcl · Joined: Feb 08, 2008 Posts: 33 Location: Portland OR

Yep, those pics didn't show up for me. Thanks for posting that. I need to see if I have access to the original articles. Suddenly it occurs to me that VCLFO's (or any LFO) doesn't belong in the lorenz patch. Not sure what I was thinking.

bryan · Joined: May 28, 2008 Posts: 8 Location: some furniture