# gate2 Managed audio asset. Edit the `.metadata` `settings` block to change compression.

# hollow <!-- zero:scaffolded-readme --> <!-- Replace the line below with what this module provides and who consumes it, then delete both comment lines. --> TODO: describe this module.

# death Managed audio asset. Edit the `.metadata` `settings` block to change compression.

# sound.library One recipe per name in `Hollow.SOUND_NAMES` — thirty-four of them, written as stacks of `sound.synth` layers. ```lua local Library = require("sound.library") local canvas = Library.render("bellRing") -- ready for the codec ``` The crypt has a tonal centre. The great bell's prime sits at `Library.BELL_HZ` (110 Hz, so its hum is A1), and the hammer, the gates, the Sexton's armour, the shrine and the Bellwarden's own bronze are all tuned off it — so the place rings in one key instead of thirty unrelated ones, and a fight and the bed underneath it agree. ## How they are grouped - **the screens** (`ui.*`) — small, close, dry, no reverb; they are in the player's hands, not in the room, and they sit under everything else. - **the Lamplighter** (`strike`, `strikeHit`, `cleave`, `flare`, `flask`, `heroHurt`, `heroDie`, `heroStep`) — the hammer is iron with a lamp on it, so every swing has air in it and every landing has bronze. - **the congregation** (`tolled*`, `ringer*`, `sexton*`) — the Tolled are voice, the Ringer is glass and chime, the Sexton is iron plate. - **the crypt** (`gateOpen`, `shrine`, `gold`, `pickup`, `relic`) — stone, hinges, coin and reliquary. - **the Bellwarden** (`boss*`, `bellRing`) — the lowest and longest things in the game. `bellRing` is the signature: eleven partials, a cracked twin beating against them, five seconds of tail. ## Rendering `Library.render(name, rate?)` builds the canvas, saturates it, normalises it to 0.88 and takes its edges to zero, at `Library.RATE` (32 kHz) unless told otherwise. `Library.names()` lists what it covers. A name with no recipe returns nil rather than silence, so the caller can say so.

# bossDeath Managed audio asset. Edit the `.metadata` `settings` block to change compression.

# sound.synth The synthesiser Hollowbell's sound is made of. Pure arithmetic over a mono f32 canvas: no source files, no service, no network, so it runs identically in a browser, headless, and offline. ```lua local Synth = require("sound.synth") local c = Synth.canvas(0.4, 32000) -- 0.4 seconds at 32 kHz Synth.tone(c, { freq = 220, amp = 0.5, decay = 0.15 }) Synth.noise(c, { amp = 0.3, lp = 4000, lpEnd = 600, decay = 0.04 }) Synth.reverb(c, { mix = 0.25 }) Synth.normalize(c, 0.88) ``` Every call **adds** to the canvas, so a sound is written as a stack of layers and the order does not matter. ## What it makes - **`tone`** — a sinusoid with an attack, an exponential decay, and optional pitch glide, vibrato and FM. The FM is what turns a sine into something metallic or growling. - **`bell`** — bronze. Eleven inharmonic partials at the ratios a cast bell actually rings at, each with its own decay so the high ones die first, plus the clapper's knock. `crack` adds a detuned twin on the mid partials whose beating is the buzz you hear in a cracked bell — which is the whole premise of this game, so it is a first-class argument rather than an effect. - **`noise`** — filtered noise through a one-pole pair that can sweep. This is every impact, whoosh, footstep and breath. - **`reverb`** — four combs and two allpasses. A crypt is small, hard and wet, so the combs are short and the tail is long. ## What makes a loop loop `Audio.looping` wraps the whole clip, so the join between the last sample and the first is heard once a lap. Two calls are built to survive it: - **`drone`** snaps its frequency to a whole number of cycles across the buffer, so a sustained partial arrives back exactly where it started. - **`loopNoise`** generates two laps of noise and cross-fades the second over the first, so the wrap is continuous rather than a step. Interior loop points are not the answer here: a `.soundClip` stores `loopStart` / `loopEnd` and no playback surface reads them, so a bed has to be seamless end to end. `audio.loopSeam(zaud)` reads whether it is. ## Baking without dropping a frame A bed is hundreds of thousands of samples. Set `Synth.cooperative = true` inside a task and each layer hands the frame back once it has spent its sample budget, so a long bake costs frames rather than one stall. Set it false to bake in one pass when the caller would rather take the hitch. ## Finishing `normalize` scales to a target peak, `saturate` is a gentle soft clip so a stacked layer never arrives as a hard one, `trimEdges` takes the first and last few milliseconds to zero (a one-shot that starts on a non-zero sample ticks — but never call it on a loop, where an edge fade IS the dip), and `measure` reports peak, RMS and how many samples came out non-finite, which the codec refuses.

# bossCrack Managed audio asset. Edit the `.metadata` `settings` block to change compression.

# descend Managed audio asset. Edit the `.metadata` `settings` block to change compression.

# sound.beds Eight looping pieces: one per state of the run, plus the air of the crypt. ```lua local Beds = require("sound.beds") local canvas = Beds.render("belfry") ``` | bed | when it plays | what it is | |---|---|---| | `title` | the title card and the opening | the bell tower at night, open and patient, the crack already in it | | `nave` | chamber 1 | a slow pulse, like something breathing in the walls | | `cloister` | chamber 2 | standing water, moving when nothing is moving it | | `belfry` | chamber 3 | under the bell, a semitone away from agreeing with itself | | `boss` | the Bellwarden | 90 bpm, twenty-four beats to the lap, and a tritone | | `death` | the death card | two notes a few cents apart, beating slowly | | `victory` | the victory card | the one bed with a major third in it | | `ambience` | the whole descent | air through stone, the room's own note, water finding its way down | The crypt is in A, because the great bell's hum is A1 and the music should agree with the bronze rather than fight it. ## Why they loop silently `Audio.looping` wraps the whole clip, so the join between the last sample and the first is audible once a lap. Two rules keep it silent, both in the synthesiser rather than in a loop marker — a `.soundClip` stores `loopStart` and `loopEnd` and no playback surface reads them, so interior markers are not an option: - a sustained partial is snapped to a whole number of cycles across the buffer (`Synth.drone`), so it arrives back where it started; - noise is generated for two laps and cross-faded onto itself (`Synth.loopNoise`), so the wrap is continuous. A bell struck inside a bed is placed early enough that its tail has died before the end. Nothing is faded at the edges and nothing is trimmed: an edge fade is itself a dip once a lap. The Mix component proves each one with `audio.loopSeam` as it bakes and records the ratio in `sound.state`. All eight read seamless. They are baked as `codec = "pcm"` rather than Opus, because an Opus clip loses its first few milliseconds on decode and a looping bed hears that as a click at every lap.

# bossIntro Managed audio asset. Edit the `.metadata` `settings` block to change compression.

# gate1 Managed audio asset. Edit the `.metadata` `settings` block to change compression.

# sound.state What the mix knows about itself, in a place a query can reach. A component's locals are closed to anything outside it, so everything a reader needs in order to check Hollowbell's sound lives here instead: which clips baked, what each one measured, which bed is playing, which lines have a voice, and any name a slice asked for that the library could not answer. ```lua local State = require("sound.state") State.summary() -- { clips = 34, beds = 8, voices = 10, reported = 52, -- suspiciouslyShort = {}, bake = { ... }, now = { bed = "belfry", ... }, -- unanswered = {} } ``` | field | what it holds | |---|---| | `clips` | sound name -> `AssetRef<soundClip>` | | `beds` | bed name -> `AssetRef<soundClip>` | | `voices` | `Hollow.LINES` key -> `AssetRef<soundClip>` | | `report` | name -> what `audio.info` read off the payload: codec, sample rate, channels, frames, duration, plus the peak and RMS measured before encoding, and for a bed its loop-seam ratio | | `now` | the bed playing, whether it is mid-crossfade, whether the ambience is up, whether the mix is ducked, and which line is being spoken | | `levels` | the six channel levels as last applied, and the current duck | | `bake` | how many of each baked, how long it took, and any layer that failed | | `unanswered` | a name played that no clip answered, and how often | | `aliased` | a name outside `Hollow.SOUND_NAMES` and the clip that stood in for it | | `crowd` | how many one-shots piled up at once, and the gain the mix pulled the last one down to | `unanswered` is the one to read first: empty means every sound the game played was heard. Anything in it names either a missing recipe or a call site playing a name the vocabulary does not carry.

# bossToll Managed audio asset. Edit the `.metadata` `settings` block to change compression.

# victory Managed audio asset. Edit the `.metadata` `settings` block to change compression.

# opening Managed audio asset. Edit the `.metadata` `settings` block to change compression.