Cycle 1 · jazz-noir · shipped 2026-08-15

Vermilion Alley

The complete audio for a hypothetical stealth-investigation game: a detective tails suspects through rain-slick streets. A 58-bar swung score in D minor with a real form — theme, contrasting B-section, re-harmonised variation — four suspicion-driven state layers, layered rain + city ambience, and a seven-sound kit where the most frequent sounds carry the most craft.

Key D minorTempo 92 BPM swung Form 58 bars / 7 sectionsLayers 4 SFX 7 effects · 2–6 voices each Source 100% sampled instruments

Interactive player

Play/pause the score, drag the suspicion slider to move the layers, fire every SFX, click the timeline to jump sections. Keyboard: Space, arrows, 1–7, M.

Open player →

Musical form

Section	Bars	What changes
Intro	4	Solo piano arpeggi over a Dm pedal in the rain; bass slips in at bar 3.
A theme	16	Muted-trumpet melody over walking acoustic bass and brush-feel ride; ii–V chains in D minor with an F-major glimpse.
Fill	1	Tom cascade + harp sweep pivots on C13 into the new key.
B section	16	F-major lift: alto sax takes the lead in a higher register, bass opens in two-feel, piano pads smooth — different key, voice, harmony and rhythm.
Fill	1	Vibraphone tumbles down A7♭9 back toward D minor.
A′ variation	16	Theme re-harmonised — tritone substitutions and an Am→A♭→Gm→G♭ chromatic descent — with chromatic grace notes, the lift phrase an octave up, a vibraphone counterline answering every held note, and the drums trading the ride for closed-hat time with a side-stick backbeat.
Coda	4	Piano restates the opening cell alone, hangs on Dm(add9) with a harp shimmer, then loops back to A — never to the intro.

State layers — proven by the slider

Layer	Enters	Content
L0 rhythm	always	Walking bass, brush-pattern drums, piano comping.
L1 lead	suspicion < 65%	The melody voice — the detective's cool. It leaves when things get tense.
L2 tension	suspicion > 35%	Tremolo-string pad on the bar's harmony + denser ride skip-beats and bell.
L3 danger	suspicion > 70%	Timpani heartbeat on the chord root, floor-tom doubling, off-beat piano stab clusters.

Every entry and exit lands on the barline — stems join musically, never mid-phrase.
Impacts and stingers duck the music bus and release automatically.
Ambience intensity (rain density, city detail) follows the same suspicion parameter.

Sound kit — layered, varied, tuned to the key

Effect	Voices	Design
Footstep (most frequent)	3 × 4 round-robin bodies	Side-stick / conga / claves / floor-tom combinations under a low piano thump; ±45-cent per-hit drift, velocity 0.45–0.72, never the same body twice in a row.
UI move	2	Marimba + high woodblock; pitch walks a D-minor-pentatonic pool, never repeating a note.
UI confirm	4	Two-note marimba resolve onto D with woodblock body and a muted-triangle shimmer.
Clue found	6	Vibraphone arpeggio (3 variants, all in-key) + celesta echo + harp touch; softly ducks the score.
Camera shutter	3	Harpsichord pluck + closed hat + delayed woodblock — a mechanical clack with a wind-on.
Door	3	Pitched-down floor tom + low acoustic-bass staccato + latch side-stick.
Danger stinger	5	Tremolo-strings D–F–A♭ swell + timpani + china crash; ducks the music 55% for 1.2 s.

Audit

100% sampled voices — oscillator spy during playback and SFX confirms every audible voice is an AudioBufferSourceNode; oscillators exist only as inaudible LFOs.
Form verified numerically — Playwright plays each section and compares spectra: A, B and A′ are measurably distinct in register, harmony and orchestration.
Layers verified — rendered at suspicion 0% vs 100%: lead drops out, tension and danger stems appear, all entries bar-aligned in the event log.
SFX variation verified — 20 triggers per effect: every trigger ≥2 voices, pitch spread ≥ the designed cent range, round-robin never repeats.
Player checks — 60 fps scene, keyboard operation, visible play state, persisted volume + mute, first-gesture audio unlock.
Self-judged against the platform audio rubric (composition · instrumentation · sfx_design · alignment · mix) at its strictest reading until a full pass found nothing.