Parameter Priority

Every parameter’s final render value comes from exactly one layer — the highest active layer wins.

Precedence order

1. MIDI CC         ← highest (if bound, wins)
2. Modulation
3. Palette
4. Slider (stored)
5. ParamDef default ← lowest

Layer summary

Tier	Layer	When it’s active	Notes
1	MIDI CC	A MIDI control is bound to the parameter	Takes over completely. Unbind to release.
2	Modulation	At least one enabled mod slot targets the parameter	Multiple slots stack — last slot wins.
3	Palette	The parameter has a colorGroup and a swatch channel	Only affects colour params (colorRole h/s/b).
4	Slider (stored)	Always, as the base value	Your drags update this, even when a higher layer hides them.
5	ParamDef default	Fallback if the stored value is missing	Comes from ParamDefs.ts in the engine package.

Implementation pipeline

store → palette overlay → modulation overlay → MIDI write → render

Each overlay runs per-frame. Overlays return the original array reference if nothing changed (structural sharing), so unmodified parameters cost nothing. Overlays only push a new value when the change exceeds 1e-5 (delta gating).

Common “why isn’t my slider working?” causes

• A modulation icon is active next to the slider → modulation is overriding it.
• A palette channel chip is non-Off on a colour param → palette is overriding it.
• A MIDI binding label is shown on the slider → MIDI is overriding it.
• All three can be present simultaneously. MIDI still wins.

Related

• Parameter Priority concept — the full explainer with worked examples and rationale.
• The Modulation System — how tier 2 values are produced.
• The Palette System — how tier 3 values are produced.