RFC-012 + RFC-013: Atmospheric audio identity + circular Knob UI (paired foundation)

[chipi]

Summary

Paired RFCs evolving the audio system from data-sonification to atmospheric backdrop with NI-quality UI controls. Ships together — the new audio identity needs new controls to feel right.

RFCs

• RFC-012 — Atmospheric audio
• RFC-013 — Editor controls: circular knobs

Scope — RFC-012

• Audio identity switch (ambient default; synthetic retained for legacy reproducibility)
• Five-layer hierarchy reordered: atmosphere → vocal → drone → pulse → accent
• Atmosphere bus: algorithmic reverb + seeded granular shimmer + Cloud Filter
• Vocal layer with multi-sample stack (humpback whale + soprano + water-adjacent field)
• Sample bank in `audio/vocal//metadata.yaml` with provenance, integrity hashes, sample lifecycle policy
• License gate at build time — CC0 / CC-BY / NOAA-PD only; CC-BY-NC / CC-BY-ND / CC-BY-SA explicitly rejected
• Drone demoted (presence 0.7 → 0.25, new `filtered_noise` waveform)
• Pulse + accent softened — bell/mallet samples, longer tails, optional atmosphere send
• Clean break: delete 11 legacy recipes, ship a new ambient-identity recipe set

Scope — RFC-013

• Reusable `` SVG component (sizes: sm / md / lg)
• Vertical-drag interaction with Shift fine-tune, double-click reset, keyboard parity
• Envelope-aware `modulation` prop (forward-compat for RFC-014, ships inert)
• A11y preserved: `role="slider"`, standard ARIA, identical to existing range inputs
• Replacement scope: audio controls only — AudioWaveform mix + EQ, new RFC-012 controls, CreativeControls sliders
• Unchanged: TimelineScrubber, ArcEditor 2D peak, pill groups
• Reserved: right-click context menu for modulation routing (binds wired in RFC-014)

Dependencies

Foundation pair. No upstream deps — entry point for the seven-RFC arc.

Closes into

• ADR-032 — Atmospheric audio identity
• ADR-033 — Vocal sample bank + provenance
• ADR-034 — Knob component contract + interaction model

Implementation tasks

Tracked in the project task list:

• drone reform
• atmosphere bus (reverb + granular + Cloud Filter)
• vocal/breath layer + multi-sample stack
• pulse + accent softening
• ambient preset family + migration
• circular Knob component + envelope-aware indicators