# dsp The signal work behind every clip in *First Light: Goura*. ```luau local Dsp = require("game.sound.dsp") ``` Pure CPU maths over interleaved f32 `buffer`s — the shape `audio.encodePcm` takes, `asset.create("soundClip", …, { pcm = … })` takes, and `audio.decode` hands back. Nothing here touches an asset, an entity or the mixer, so it runs the same at author time in an `execute`, in a headless engine, and in a browser. ## Synthesis `Dsp.tone` and `Dsp.noiseBurst` write into a mono buffer: a frequency (or a glide between two), an amplitude, a start and a length, an attack, and either a linear tail or an exponential `tau`. `noiseBurst` takes one-pole `lowpass` and `highpass` corners. Both take `wrap = true`, which writes past the end of the buffer back at its start — the thing a looping bed's grains need so a cricket near the seam is not cut in half. `Dsp.rng(seed)` is a reproducible uniform source. Every bake on every machine produces the same bytes, which is what makes re-running the bake a no-op rather than a new asset checksum. ## Conditioning What a take needs before it can ship: `toMono`, `trimLead` / `trimTail`, `dcBlock`, `fadeEnds`, `normalise`, `limit`, and `checkFinite` — the last being the read that catches a filter which diverged, before `audio.encodePcm` refuses the buffer for it. ## `Dsp.seamless(buffer, rate, seconds)` The one that makes a loop a loop. It crossfades the last `seconds` of a take over its first `seconds` and drops them, so the sample after the last one in the result is literally the sample that followed it in the source — the wrap is continuous in value and in slope, and there is no click at the seam. This is why the beds need no loop points: a `.soundClip`'s `loopStart` / `loopEnd` are stored and read by nothing, so a bed that must loop is built to. ## Consumed by `game.sound.recipes` (which builds each clip with it) and `game.sound.bake` (which conditions generated takes with it). Nothing at runtime.