Chaotic Modulation for v0.6 firmware

Here’s a couple of custom units for v0.6 firmware: two chaotic modulation sources: One stepped values from a chaotic sequence (the logistic map equation), and one continuous source (naively) modelling a Lorenz System.

I’m a new ER-301 user and built these as a bit of a learning exercise. They’re using the new low-level API in v0.6.

There’s a some more detail at er-301-units/ at main · ljwall/er-301-units · GitHub

and package: Releases · ljwall/er-301-units · GitHub


Awesome! The lorenz especially looks like an excellent LFO


Thanks! Yeah that’s what I’m hoping.

I’ve found the the Logistic Map, with careful choice of r and some attenuation is good for feeding into a quantiser for pitch. Like shift registers and such like, it seems more musical than noise+s&h as you can get repeating phrases with intermittent variations.

Very cool! I’m often creating different kinds of chaotic modulation sources in my rack to use for various purposes, so this will be great for using inside the ER-301 without having to patch in some external source. I’m curious about one thing so I’ll just throw this out there; regarding the Lorenz system, have you looked into a way to adjust the range for any of the 3 parameters that allows them to be set anywhere from completely predictable and repeating to fully chaotic? I haven’t yet tried out this unit, so I’m sorry if this was already addressed.

I just downloaded it from your Github and I’m confused on how it should be installed? Since I started using V0.6 firmware, I’ve only installed new units meant for this firmware version that were .pkg types.

Hey @mattdrago , I think you should be able to download the pkg file from Releases · ljwall/er-301-units · GitHub and install it the same way as other packages.

Regarding the parameters, I’ve not done that systematically, though in playing around I have found settings where it seems to be oscillating around one point (rather than the usual two that create the chaotic behaviour). I didn’t make a note of them so I can’t say what they are, but I think they exist :grinning_face_with_smiling_eyes:

I do have in mind at some point to try to map out the parameter space a bit more, and maybe update the unit, or make another version where rather than setting rho, sigma and beta directly you have one or two macro controls that keep within the space where there is oscillation. And now you bring it up, a more/less chaotic would be a nice control to directly have!

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hello! thanks for those units! i love chaotic modulators! anyway i think there’s a bug in the lorenz one, i loaded it up and worked perfectly, then i tweaked the parameters and it stopped working, now it only produces modulation when i switch from x to y to z… gonna try a few times and see if the issue is recurrent.
EDIT: i think i found the issue, if you tweak the Sigma param down to 0 it stops working, even when you put it back to positive values.

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Hey! Thanks for testing it out and finding a bug :smile:

There’s definitely a lot of values of the parameters that make it stop oscillation. Most of the time I’ve found it restarts by going back to the original values, but I can well believe setting some params to zero would make it lock up completely.

I can definitely fix that so it always restarts

When I get a chance i’m going to do a bit more modelling in Python and try to dial in the parameter ranges a bit more too.

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