Patch from Scratch: Analog Feedback Loop in Eurorack

Patching up an analog feedback loop in Eurorack with some generic modules.

I don’t do a lot of videos talking about Eurorack for two main reasons:

(1) I’ve actually only been doing Eurorack for a couple years now, even though I’ve been doing digital synthesis and sound design for decades, and

(2) I don’t want my videos to be about any particular piece of hardware that you need to get (as always, I’m not sponsored by anyone).

But, the patch I put together in this video could be done by any number of modules, all I have is a sine wave, a ring modulator (multiplier), a reverb, a filter, and a limiter/compressor/saturator (anything to stop hard clipping). Put them together, feed them back, and you have some dynamic, analog generative soundscapes.

Previously, I’ve shown how to do the same thing in Pure Data, In Kyma, and in Reaktor.

Oh, and you can control it with an accelerometer too!

Audio Feedback Loops in Digital: Cybernetic Music in Symbolic Sound Kyma 7

Building some feedback loops in the digital domain using Symbolic Sound’s Kyma 7.

In audio feedback loops, the output of the system is fed back into an input. We’re probably most familiar with this when we put a microphone in front of a speaker and we get the “howling” sound. Here, though, I’m intentionally building digital feedback loops in order to explore the sonic possibilities of these rather unpredictable systems.

In order to keep my feedback loop interesting, though, I need to keep it from dying away to silence, or blowing up into white noise. By considering the different processes we apply to the audio in the loop (are they adding spectral complexity or removing it?), we can try to make feedback patches that are dynamic and interesting over time.

0:00 The Continuum of Spectral Complexity
3:13 Staring with an Sine Wave in Kyma
4:45 Delay with Feedback
5:49 Building Feedback Loops Manually
8:40 Ring-Modulating the Feedback
11:20 Gain and Saturation
14:22 Exploring the Sound
16:16 Filter Bank
19:05 Jamming with the Patch
22:18 Thinking about Control
23:25 Performing the Sound
26:34 Feedback Loop with Reverb
28:10 Making it into IDM with the Chopper
29:22 So What? Next Steps

More Kyma Videos:

More audio cybernetics and feedback:

New Music: “Cybernetics & Feedback”

I’ve released a new collection of pieces, “Cybernetics & Feedback”, available on bandcamp:

Cybernetics & Feedback

Inspired by the cybernetic and feedback works of Roland Kayn, Éliane Radigue, Bebe Barron, and Jaap Vink, and embracing an anything-goes noise music aesthetic, this collection of works from early 2022 explores analog feedback loops and self-regulating patches in Eurorack modular.

In these pieces, audio signals are routed back into themselves, and used to control processes and trigger events. While these are performed improvisations, “performance” in this case does not mean strict control, since these systems influence themselves as much as the performer does.

One of my sketches. I think this is Track 6.

A quick acknowledgement that these noisy soundscapes might not be for everyone. Don’t worry. I won’t be offended.

I do have something a little more crowd-pleasing:

Ambient Chiptune (for Studying)

As a bonus, I’ve put up all the audio tracks from my “Ambient Chiptune” videos as a free/pay-what-you-want download.

(Definitely easier listening on these!)

Enjoy!

Eurorack Neural Network Jam: “An Explanation of the Universe”

A mess of Eurorack CV feedback that’s not random. It’s chaotic!

This instrument creates chaotic synthesized music that I interact with using four knobs. The music that this synthesizer creates is not random. It is determined by a set of “rules” created by the different components interacting with each other. However, because each of these modules influences and is influenced by several others, the interconnected network of interactions obfuscates the rules of the system. This leads to the instrument’s chaotic, incomprehensible behavior.

As with all chaotic systems, though, if it were possible to understand all of the different components and their relationships, and do complex enough calculations, we would be able to predict the outcome of all of our interactions.

Patch notes: ….Uh…. I just kept patching things back into each other, and this is where I ended up.

Synthesis, Cybernetics, and Feedback

In my recent explorations of analog synthesis (as a former dyed-in-the-wool digital synthesist), I’ve found that feedback loops are one of the things that particularly different to explore in analog.

Inspired by the YouTube channel, La Synthèse Humaine, I’ve been doing a lot of feedback patches in Eurorack, with no-input mixing, FX pedals, and even digitally in Pure Data.

Better explained on the La Synthèse Humaine channel, “cybernetics” here follows Norbert Wiener’s definition: “control and communication in the animal and the machine,” since these audio feedback systems are “self-regulating” (self-controling?) sonic ecosystems.

Anyway, I’ve put together a playlist of my improvisations, collaborations, and ramblings about feedback and cybernetic systems. Enjoy!