docs(presets): live continuous groove design

2026-06-30 09:57:46 +02:00
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+# Matrix `_live` section = continuous full groove (no intro/breakdown)
+
+**Date**: 2026-06-30
+**Status**: design approved, pending plan
+**Scope**: `sound_algo/data_only/matrix_presets/generate_presets.py` + `test_sections.py` + regenerated `*.matrix`. Follow-on refinement to presets v4.
+
+## Context
+
+In presets v4 each morceau is split into `_intro` / `_live` / `_outro`. The
+`_live` section reuses the morceau's original arc, which is a standalone 64-bar
+piece WITH its own intro: the grid starts near-empty and rebuilds (I=8, B=34, …,
+plateau P=133) and has a mid breakdown (K=30) — measured on `techno_drive_live`.
+So `_live` re-introduces instead of being the sustained groove the `_intro`
+builds up to. The user wants `_live` to be the **continuous full loop**: full
+from bar 0, no intro ramp, no breakdown — the intro builds to it, the outro
+descends from it.
+
+## Decision (from brainstorming)
+
+`_live` = the **plateau (P, bars 32-47) tiled across all 64 bars** — a clean,
+loopable full groove. No intro, no breakdown. Intro/outro sections unchanged.
+
+## Design
+
+### `make_live_continuous(g)` (generate_presets.py)
+Applied to the `_live` grid AFTER `apply_colors` (so it tiles the coloured
+plateau, which already carries the plateau's internal variation — e.g. the
+double-time hats on the plateau's second half):
+```python
+def make_live_continuous(g):
+    """Live = the plateau groove tiled across all 64 bars: full from bar 0, no
+    intro ramp, no breakdown. The intro builds to it, the outro descends from it."""
+    ps, pn = SECTIONS["P"]            # (32, 16)
+    for row in g:
+        plateau = row[ps:ps + pn]     # the 16-bar full-groove slice
+        for b in range(len(row)):
+            row[b] = plateau[(b - ps) % pn]
+    return g
+```
+`(b - ps) % pn` keeps the plateau anchored at bars 32-47 and repeats it to fill
+0-31 and 48-63, so each 16-bar block is the full plateau.
+
+### Wiring (`to_sc` + `main`)
+- `to_sc(name, arc_fn, instkit, melodies, extra, post=None)`: after
+  `apply_colors(g)`, call `post(g)` if given.
+- `main()`: `post = make_live_continuous if sec == "live" else None`.
+- intro/outro pass `post=None` (unchanged).
+
+## Testing
+
+- **`test_sections.py`**: mirror the generator — apply `make_live_continuous` to
+  the `_live` grid in `grid_of(...)` when `sec == "live"`. Then:
+  - existing checks hold: intro builds (late>early), outro breaks (early>late),
+    live is the densest.
+  - NEW: `_live` is FULL from the start — `active(live, 0, 16)` is within ~15% of
+    `active(live, 32, 48)` (no intro ramp); and `_live` has NO breakdown dip —
+    `active(live, 48, 64)` is also within ~15% of the plateau. (Tiling makes all
+    four 16-bar blocks equal, so these hold with margin.)
+- **SC**: `validate_presets.scd` → `84/84 PASS` + `DEFAULTS PASS` unchanged
+  (peak_drop_live grid changes but the voiceMods/voicePoses assertions are
+  unaffected — the transform only moves cells, doesn't touch mods/poses).
+- **Live smoke** (macm1): reload a `_live` preset → full groove from bar 0, loops
+  cleanly, no intro/breakdown; `_intro`/`_outro` unchanged.
+
+## Out of scope
+
+- Changing `_intro`/`_outro` arcs, the pattern families, or the per-voice
+  mods/poses.
+- Any new live dynamics beyond the plateau's own internal variation.
+
+## Decided defaults
+
+- `_live` = plateau tiled across 64 bars (full loop, no intro/breakdown).
+- Transform applied post-`apply_colors`, live section only, via `to_sc(post=)`.