v1.5.0-beta.3 — engine hardening + beta-ready docs

v1.5.0-beta.3 — engine hardening + beta-ready docs

First public-beta cut since v1.5.0-beta.2 (Apr 10). ~30 PRs of engine
fixes, ~50 new DSL fns, full parity-comparator tooling, and the
operational docs to triage incoming beta bugs.

TL;DR — what's in this release

Engine fixes (the 2026-05 audit pass)

• SP72: use_bpm / use_synth no longer leak from in_thread into
  nested live_loop registration (#280) — months of FX-comparator
  numbers were running web at half tempo
• SP78–81: four hot-swap state-hygiene bugs caught by Playwright +
  WAV reproducers (#283) — empty-cycle Updates, FX-scope inversion,
  stop-tail queue drain, per-loop state leakage
• SP70: lossless capture pipeline — Recorder.ts swapped MediaRecorder
  • opus codec for raw float32 → WAV, removing the codec damage that
    had been masquerading as "filter family broken" for weeks
• Per-loop audio isolation via private loopBus + monitor synth (#178)
  — first Sonic Pi implementation to ship this
• #199: nested live_loop hot-swap routes through scheduler.hotSwap()
  directly (#261)
• Sonic Tau mixer baseline: pre_amp=0.3, amp=0.8 — calibrated for
  browser-WASM headroom, not Desktop SP driver levels

DSL coverage: ~87% of upstream (148/170 user-facing fns)

• Tier A: 17 critical fns — recording, kill, current_*, define
  persistence (#213)
• Tier B: 27 fns across 3 PRs — ring/spread, tuplets, defonce,
  sync_bpm, dynamic eval (run_code/eval_file/run_file),
  live_audio control, load_example (#230, #234, #238)
• Tier C: 23 fns across 3 PRs — state wrappers
  (with_synth_defaults, with_sample_defaults, use_arg_checks
  family), sample/buffer registry, mixer + introspection helpers
  (#252, #254, #256)
• Help panel + autocomplete entries shipped for every new fn

Parity tooling

• A/B comparator rig (tools/capture-desktop.ts + spectrogram
  compare) — captures both engines, renders 3-panel mel-spectrograms,
  reports L2 + MFCC + per-beat metrics (#264)
• FX A/B inspector: npm run inspect opens a single-file viewer with
  desktop ↔ web <audio> players, sync-play, MFCC sidebar, verdict
  tiers HIGH/MID/LOW/INCONCLUSIVE (#277)
• WAV-verify sweep across 40 wired FX (#275) — current scores:
  4 HIGH / 26 MID / 8 LOW / 2 INCONCLUSIVE (composite ~89.5%)
• Capture tool: --batch <dir> for fixture-folder runs (#224),
  engine hooks for puts/cues instead of DOM slicing (#222)

UI / app

• Welcome buffer drop + Cm9 finale (#220)
• Preloader pulls forward CDN deps before App mount (#284)
• Live Mixer Pre-Amp / Amp sliders in Prefs push to scsynth on drag
• MIDI toolbar button hidden until Tier D ships (Web MIDI input via
  the engine API still works)
• README rebranded to "Sonic Pi Web"

Beta operational infrastructure

• KNOWN_ISSUES.md + TRIAGE.md + bug-template gates so triage
  isn't ambiguous when users report problems
• 8 Plausible custom events wired for beta-visibility analytics
• SuperSonic CDN version pinned end-to-end (v0.57.0)

Numbers

• 929 unit tests pass (was 805 at beta.2)
• 62/66 synths working end-to-end (3 upstream WASM LOAD-FAIL)
• 197/197 samples
• 42/42 FX wired, 40/42 WAV-classified
• ~148/170 DSL fns (~87%)
• 49 community forum compositions verified end-to-end in Chromium

Compatibility notes

• Mixer behaviour change: web output is ~0.19× Desktop SP's
  driver-attenuated level by default. Comparators should RMS-normalise
  before A/B. Override via Prefs → Audio → Mixer Amp.
• MIDI: Web MIDI continues to work via the engine API. Only the
  toolbar dropdown UI is gated until Tier D (midi_pc, midi_raw,
  midi_sysex, device picker).
• DSL: net additive — no upstream-compatible code that worked in
  beta.2 should break in beta.3.

Install

npm install @mjayb/sonicpijs        # latest tag now points here
npm install @mjayb/sonicpijs@beta   # beta tag — same version

Browser: https://sonicpi.cc

See KNOWN_ISSUES.md
for current beta blockers.