# Every sound effect in Lantern Valley is a function

> Lantern Valley has no audio files for its effects: each sound is built from oscillators and noise by a small Web Audio synth, one file per domain.

Canonical page: https://andersonmancini.dev/blog/lantern-valley-sound-effects-as-code

Published: 2026-10-01 · 1 min read · Tags: web-audio, game-dev, javascript, lantern-valley, audio

The sound effects of [Lantern Valley](https://andersonmancini.dev/blog/lantern-valley.md) are not files. Each one is a function that calls a small Web Audio synth, so there is nothing to download, nothing to license and nothing to re-export when a sound needs a tweak.

## The toolbox

A `Synth` is wired to an audio context and a bus, so the same sound can play in the game or in an offline context for auditing. The original three verbs are `tone`, `noiseHit` and `voice`, and everything else builds on them: bells, plucks, arpeggios.

A `tone` takes a frequency and an envelope (attack, decay, gain), plus a pitch slide, a detune and a stereo pan. Notes come from MIDI numbers:

```js
const midi = (n) => 440 * Math.pow(2, (n - 69) / 12)
```

## A registry, one file per domain

Importing the sfx index registers every sound. There is one file per domain: player, world, UI, animals, fishing, farming, cooking, the boat, herding and more, and a new island adds its own. Sounds are looked up by name through a small registry.

## Details that make it feel alive

- **Variation per play.** The engine draws a new pitch factor and volume factor for every play, so repeated sounds do not machine-gun.
- **A voice limit.** The synth tracks when each source ends and can say how many are still sounding.
- **Pan by source.** A sound that comes from one side goes through a stereo panner.
- **A dry path.** Some sounds bypass the room reverb and go straight to the effects volume.

## What it costs

Synthesis happens at play time, so the cost is a few nodes for a few hundred milliseconds. In exchange, the audio weighs nothing in the bundle.

The saving side of the project is in [the save post](https://andersonmancini.dev/blog/lantern-valley-save-that-never-loses-progress.md). The game is on its [project page](https://andersonmancini.dev/projects/lantern-valley.md).

## Related projects

- [Lantern Valley](https://andersonmancini.dev/projects/lantern-valley.md) — Cozy adventure game for the browser