Orbiters audio architecture

6. The model

A dimension is a chain

One serial chain, one to three modules, in a fixed type order — the signal must be created before it can be processed:

1. MIDI effect — optional. Operates on notes, so it sits before anything that produces sound.
2. Instrument — exactly one, in a head chain: one whose stage receives no signal. A chain that already receives signal (a downstream stage, or any Moon chain — its input is the send) is effects-only and may not hold an instrument.
3. Audio effects — optional, up to the chain limit. Downstream of the instrument only; their order among themselves is free and musically meaningful (filter → delay ≠ delay → filter).

Routing is between dimensions

Dimensions wire freely as an ordered list of stages: each stage holds one or more dimensions in parallel — they see the same input and sum — and stages run in series. Common shapes: I → II → III, I → II + III, I + II → III, I + II + III. Edit verbs: move earlier / later, parallel with previous, split to its own stage. Inside a dimension the chain is always serial — no wiring choice there.

In the World, dimension 1 carries the generator and is always first — anything upstream of it would receive silence. The Moon’s stages take the send as their input.

Mix — a third entity (to design)

Alongside World and Moon: 1–3 dimensions (author picks), X/Y/Z macros, no instrument. Its mappings target the high level — world level, moon level, the world↔moon mix (a level pair, not a new node), pan — plus body macros, so one Mix macro moves both bodies at once (Mix → macros → parameters keeps “one parameter, one macro” intact). Sends are not a Mix target. Own accent and glyph; the Instrument tab shows only the mapping list.

One panel per Orbiter

The panel — theme preset, colours, radius, font, ring — moves from the dimension to the Orbiter: stored once, applied to every view, edited above the body and dimension selectors. The per-dimension design block (orbiterFallback.js:49-72) goes away with the format change; migration keeps dimension 1’s panel and drops the rest.

Stored description

orbiter
├── panel                        theme, colours, radius, font, ring — one for everything
├── mix                          third entity — no instrument; macros → mixer + body macros
│   └── dimensions[1..3]         (open: a master effects chain?)
└── bodies                       planet (world), moon
    ├── routing                  dims serial | parallel (+ send pre/post-fader)
    └── dimensions[1..3]
        ├── enabled
        ├── chain                [midiFx?] → instrument → audioFx*   (≤3 modules)
        │   └── modules[]        module id, preset, parameter values
        └── macros
            ├── x → mappings[]   { module, parameter, min, equil, max, curveLow, curveHigh }
            ├── y → mappings[]
            └── z → mappings[]

The description is versioned from the first record written. Modules ship parameter tables only; no per-module macros, no factory presets.