Chaos as an Ingredient
Chaotic FM by itself is just noise. Run it through a filter and envelope and you get evolving textures no conventional synth can produce. Chaos is seasoning, not the dish.
Raw vs. Tamed
In the last part you found the edge where feedback FM breaks into chaos. That sound is harsh and unusable on its own. But synthesis is about combining ingredients. A distorted guitar through a cabinet sounds nothing like the raw signal.
The Tame button below does three things at once: it applies a resonant lowpass filter to smooth the chaos, adds an amplitude envelope so the sound breathes, and mixes in a clean sub-oscillator one octave below for weight. The difference is dramatic.
Once tamed, try adjusting the filter cutoff, the chaos mix, and the envelope shape. You are shaping noise into something musical. These are textures that additive or subtractive synthesis cannot easily produce because the source material is inherently complex and non-repeating.
Try it. Hit Play to hear the raw chaos. Then hit Tame and hear it transform. Tweak the sliders to shape the texture. Play different notes on the keyboard.
Why This Matters
Every synth sound you have heard so far starts from simple, periodic sources: sine waves, sawtooths, pulses. These are predictable by definition. Filters and envelopes shape them, but the underlying material is always regular.
Chaotic FM gives you a source that is deterministic but non-repeating. It is not random noise from a noise generator. It is a signal that follows rules but never settles into a pattern. That is why it sounds alive when you filter it. Each cycle is slightly different from the last, so the filter catches different harmonics every moment. You get movement without an LFO.
This is one reason FM synthesis became so important. It can reach timbral territory that other methods cannot, and feedback FM is the most extreme example.