Growth: a living reaction-diffusion field that drives a five-stage effect chain

[noahrbc]

Hi all,

I run a small plugin label called Reactive Audio, and I just released Growth, an effect built around a living reaction-diffusion field that generates its own modulation.

Instead of LFOs and envelopes, Growth runs a reaction-diffusion simulation, the same math behind coral, animal markings, and Turing patterns. The field grows, drifts, and reorganizes continuously, and it never loops. You don't drive it like an X-Y pad; you drop readers onto it and let the moving pattern flow through them:

• Probes read the field at a point and route that motion to any effect parameter.
• Edges link two probes and derive a new signal from the relationship between them, the contrast or flow along a bendable path.
• Scans are paths you draw on the field; a scanner travels your drawing and turns the values it passes into a modulation waveform. Free-running or tempo-synced.
• Proximity measures how close two scans get, giving rhythmic pulses at the beat frequency between them.
• Envelope follower routes the level of your audio, so the effects follow your playing.

All of that modulates a built-in chain: a morphing multimode filter, a granular texture, a frequency shifter, a reverb with tempo-synced delay, and stereo width/pan/tremolo. Every parameter is a modulation target, and the whole interface shows the field moving so you can see what is shaping your sound.



Features

• Reaction-diffusion field with pattern presets (spots, coral, stripes, cells, pulse, drift)
• 4 probes, 4 relational edges, 3 drawable scans, proximity, and an envelope follower
• Five-stage chain: multimode filter, granular, frequency shifter, reverb + synced delay, stereo
• Tempo sync, global dry/wet, auto-gain for fair A/B, transparent safety limiter
• 8 factory presets, resizable UI, render-accurate (an offline bounce matches playback)

Formats: VST3 / AU / Standalone
OS: macOS (universal) + Windows 10/11
Price: $20 intro for the launch window, then $30. One-time purchase.
Free demo: fully functional, mutes 0.5 s every 30 seconds.

Buy: reactiveaudio.lemonsqueezy.com
Product page and free demo: https://reactive-audio.netlify.app

Happy to answer any questions here.

[noahrbc]

Working on implementing a reactive field for v1.1 which would allow for incoming MIDI notes (or audio transients) to inject seed patches into the field at note-mapped positions, so it visibly blooms where you play, and note pitch can drive a field or effect parameter.

[noahrbc]

Growth v1.1 is out, and it adds a reactive field.

Until now the living field drifted on its own. In v1.1 it responds to your performance: play a MIDI part into Growth and each note injects a fresh seed into the field, with pitch mapped low-to-high across the surface and velocity up the vertical. The pattern blooms where you play, and because the probes, edges, and scans read the field, that motion flows straight into the effect chain. A ripple marks each note on the visualizer, so you can see the performance hitting the surface.

It still runs in audio time, so offline renders match playback.

Free update for v1 owners. Growth is $20 for the launch window (then $30), VST3 / AU / Standalone, macOS + Windows, with a full free demo.