TDU2 Car Sound Mods

Source: TDU2 modding workspace notes.

A car sound pack is a WAV directory plus two files that describe how the game plays those WAVs: CarVSTConfig.json (the editable source) and CarVSTConfig.xmb (the compiled binary the game loads). Export and import between the two with TDU2Emploder.

Pack layout

File	Role
CarVSTConfig.json	Editable sound config. Uses typed wrappers.
CarVSTConfig.xmb	Compiled config loaded by the game.
*.wav	Sample files referenced indirectly through the target BNK's WAV table.

Typed wrappers

Every value in CarVSTConfig.json is wrapped in a typed object. Do not flatten or remove the wrapper, the game parser requires it.

{
  "_PrimitiveType": "TYPE",
  "Value": 0
}

Key fields

Field	Meaning
nWaveIndex	Index into the target .bnk's own internal WAV table, not the filesystem.
nCarID	Target vehicle slot. Sound mods are replacements by default.
Links[].Physic	Driving channel: 0 = RPM, 1 = speed, 3 = throttle.
Links[].Audio	Output: 0 = interior, 1 = exterior.
Links[].CurveSet	Interleaved [x, y] physics-to-gain points.

nWaveIndex resolves through the BNK

nWaveIndex does not point at a file path. It indexes the target .bnk's own internal WAV table, which is visible with a hex editor. Each BNK has its own table order, and that order differs between BNKs and from filesystem order. The same WAV set reordered into a different BNK will not play the same.

sSampleName labels in the JSON are informational only. The game does not reference them.

nCarID and slot injection

nCarID is the vehicle slot the pack replaces. All sound mods are replacements by default. Add-on cars that occupy a new slot need slot injection, which is done with external tools (the PP2 framework).

Curves and channels

Links[].CurveSet is an interleaved list of [x, y] points mapping a physics channel value to an output gain. Links[].Physic selects the input channel (0 = RPM, 1 = speed, 3 = throttle) and Links[].Audio selects the output (0 = interior, 1 = exterior).

Engine sample layers (pitch chain)

Engine samples are layered by pitch, stepping down 25% per layer:

onhigh → onmid (-25%) → onlow (-25%) → onverylow (-25%, often empty) → onidle (separate sample)

Sample naming follows EngineLoad_N / EngineUnload_N, where N is the layer:

N	Layer
0	idle
1	verylow
2	low
3	mid
4	high

Conventions and traps

The SLK55 trap. A Mercedes SL500 mod broke because the modder copied SLK55 filenames 1:1. The SL500 is a convertible and needed different internal names to work. Never assume another car's naming convention maps directly, verify per target. (Discovered by Nikki [MEOW].)

• Sound files are often cannibalized from other games (NFS Carbon and others) and keep misleading original filenames. The names are not authoritative.
• Do not rename WAV files. The filename is the only human-readable semantic hint, but the actual nWaveIndex → WAV mapping comes from the BNK's internal WAV table order, which is not filesystem order and is not consistent between BNKs.