Sounds

sounds.ron maps every sound the game makes to its files and how it plays. The code only knows the names of the sounds (cues); everything about how they sound is here. Change a sound by changing its files.

(
    sounds: {
        Groan: (files: ["sfx/groan_1.wav", "sfx/groan_2.wav", "sfx/groan_3.wav"], volume: 0.42,
            pitch: (0.85, 1.15), reach: 40.0, muffle: 0.45, voices: 3),
        DoorClose: (files: ["sfx/door_close_1.wav", "sfx/door_close_2.wav"], volume: 0.7,
            pitch: (0.92, 1.08), reach: 35.0, voices: 3),
        // ...
    },
)

Field	What it is
files	Paths under the audio folder. One is picked at random each time.
volume	Loudness at the source, 0 to 2 (1 is as recorded).
pitch	Playback speed, picked in this range each time for variety.
reach	Metres at which it fades to nothing. It falls off with the square of the distance.
muffle	How much gets through a wall, shut door or window, low-passed.
voices	At most this many playing at once; the nearest win.

Cues

Every cue must be in the file:

Group	Cues
Moving	FootstepHard, FootstepSoft, Shuffle (zombies dragging their feet)
Fighting	SwingLight, SwingHeavy, HitBlunt, HitBlade, Punch, BodyFall, Stomp, Shove, PlayerHurt
Zombies	Groan, ThumpDoor, ThumpWindow
Doors and windows	DoorOpen, DoorClose, WindowOpen, WindowClose, GlassBreak, DoorBreak
Things	Rummage, Pickup, LevelUp
Ambience	Bird, and the loops Wind, Room (indoors) and Crickets (at night). These play where you are, so reach and muffle don’t apply.

Files

16-bit PCM WAV, mono or stereo, 8 to 96 kHz. A data folder with its own sounds.ron reads its files from an audio folder beside it:

mods/my-sounds/
  data/
    sounds.ron
    ...
  audio/
    sfx/groan_1.wav
    ...

The sounds in the game now are placeholders made by tools/audio/synth.py; the real ones replace them file for file. Every sound file in the repository needs a row in ATTRIBUTION.md.

Sounds are only what the client plays. What zombies hear is decided by the simulation (a door is 10 m of noise whatever it sounds like), so changing a sound never changes how the game plays.