MetaSounds DSP — Node Graphs & Signal Design

Design MetaSounds audio graphs: choose nodes, wire signal chains, configure DSP parameters, and generate Builder API command sequences.

Data Types

Audio, Trigger, Float, Int32, Bool, Time, String, WaveAsset, UObject, Enum (+ Array variants)

Type rules: Audio-rate cannot connect to Float. Use correct node variant (e.g.,

Multiply (Audio)

Multiply (Float)

Asset Types

Type	Use	Interface
Source	Standalone playable asset	UE.Source.OneShot or MetaSound
Patch	Reusable subgraph (no play)	Custom
Preset	Parameter overrides of existing Source/Patch	Inherits parent

Interfaces

```
MetaSound
```
— Standard audio output
```
UE.Source.OneShot
```
— OnPlay trigger in, OnFinished trigger out
```
UE.Attenuation
```
— Distance input for volume falloff
```
UE.Spatialization
```
— Azimuth/Elevation for 3D positioning

Node Categories (144 nodes, 20 categories)

Generators

Sine, Saw, Square, Triangle, Noise, LFO, Additive Synth, SuperOscillator, WaveTable, Perlin Noise

Wave Players

Wave Player (mono), Stereo Wave Player, with loop/pitch shift/concatenation

Envelopes

AD Envelope (Audio-rate), AD Envelope (Float), ADSR Envelope, Crossfade, WaveTable Envelope

Filters

Biquad Filter, State Variable Filter, Dynamic Filter, Ladder Filter, One-Pole HPF, One-Pole LPF, Band Splitter, Bitcrusher

Delays & Time

Delay, Stereo Delay, Pitch Shift, Diffuser, Grain Delay, Flanger

Dynamics

Compressor, Limiter

Math (Audio)

Add, Subtract, Multiply, Mix — all have

Primary Operand

Operand

pins

Math (Float)

Add, Subtract, Multiply, Divide, Modulo, Map Range, Clamp, InterpTo, Linear To Log Frequency

Triggers

Accumulate, Any, Compare, Control, Counter, Delay, Filter, Gate, Once, OnThreshold, OnValueChange, Pipe, Repeat, Route, Sequence

Spatialization

ITD Panner, Stereo Panner, Mid-Side Encode/Decode, Doppler Pitch Shift

Music

Frequency↔MIDI, MIDI Quantizer, Scale to Note Array, BPM to Seconds, Metronome, Quartz Clock

Effects

Plate Reverb, Ring Modulator, WaveShaper, Chorus, Phaser

Utility

Crossfade, Envelope Follower, Wave Writer, Random Get, Trigger On Threshold

SIDKIT (Custom)

SID Oscillator, SID Envelope, SID Filter, SID Voice, SID Chip

Signal Flow Patterns

Basic: Generator → Envelope → Output

Sine → Multiply(Audio) × AD Envelope → Out Mono

Subtractive: Osc → Filter → Amp → Output

Saw → Biquad Filter(LP) → Multiply × ADSR → Out Mono
         ↑ Cutoff Frequency

Additive: Multiple Oscs → Mix → Output

Sine(f) + Sine(2f) + Sine(3f) → Add → Multiply × Envelope → Out

Triggered: Event → Sample Player → Processing

OnPlay → Wave Player → Biquad Filter → Compressor → Out
                         ↑ Pitch Shift for variation

Modulated: LFO → Parameter Control

LFO → Map Range(0-1 → 200-2000) → Biquad Filter Cutoff

Key Pin Names (Authoritative)

Node	Inputs	Outputs
Sine/Saw/Square/Triangle	Frequency, Phase Offset, Glide, Bias	Audio
Noise	Seed	Audio
AD Envelope	Trigger, Attack Time, Decay Time	Out Envelope
ADSR Envelope	Trigger Attack, Trigger Release, Attack Time, Decay Time, Sustain Level, Release Time	Out Envelope
Biquad Filter	In, Cutoff Frequency, Bandwidth, Filter Type	Out
State Variable Filter	In, Cutoff Frequency, Resonance, Band Stop Gain	HPF, LPF, BPF, BSF
Wave Player	Play, Stop, Wave Asset, Start Time, Loop, Pitch Shift	Out Audio, On Finished
Multiply/Add (Audio)	Primary Operand, Operand	Out
Map Range	Value, In Range A, In Range B, Out Range A, Out Range B, Clamped	Out
InterpTo	Target, Current, Speed, Interp Delta Time	Value
Clamp	In, Min, Max	Value
Compressor	Audio, Ratio, Threshold dB, Attack Time, Release Time, Sidechain, Wet, Knee	Audio
ITD Panner	Audio, Angle, Interaural Delay, Head Width	Left, Right
Trigger Repeat	Start, Stop, Period	RepeatOut
Trigger Sequence	Trigger, Reset	Out 0, Out 1, ...

Full reference:

scripts/ms_node_specs.json

(93 nodes, 464 pins from Epic docs)

Builder API Functions (68+)

Core

CreateSourceBuilder, CreatePatchBuilder, AddNode, FindNodeInputHandle, FindNodeOutputHandle, ConnectNodes, SetNodeInputDefault, Audition, BuildToAsset

Graph I/O

AddGraphInput, AddGraphOutput, RemoveGraphInput, RemoveGraphOutput, GetGraphInputNames

Interfaces

AddInterface, RemoveInterface, IsInterfaceDeclared

Variables (UE 5.7+)

AddGraphVariable, AddVariableGetNode, AddVariableSetNode, AddVariableGetDelayedNode

Presets

ConvertToPreset, ConvertFromPreset

Live Updates

SetLiveUpdatesEnabled

Templates Available (22 JSON)

Template	Nodes	Pattern
gunshot	7	Random → WavePlayer → Filter → Envelope
footsteps	8	Surface switch → per-surface chains
ambient	9	Looped layers + random details + LFO
spatial	6	ITD Panner + distance processing
ui_sound	5	Sine + AD Envelope (procedural)
weather	10	State-driven + crossfade + dynamic filter
vehicle_engine	14	Trigger Sequence → layered Wave Players
sfx_generator	25	7-stage synth (Gen→Spectral→Filter→Amp→FX)
preset_morph	8	Morph 0-1 → MapRange → filter params
macro_sequence	12	Graph variables → InterpTo → filter
sid_bass/lead/chip_tune	5-8	SID nodes for chiptune
wind/snare	6-8	From Epic tutorial exports

Templates at:

src/ue_audio_mcp/templates/

Graph JSON Spec

json

{
  "type": "source",
  "interface": "MetaSound",
  "nodes": [
    {"id": "osc1", "class": "Sine", "defaults": {"Frequency": 440.0}},
    {"id": "env1", "class": "AD Envelope", "defaults": {"Attack Time": 0.01, "Decay Time": 0.5}}
  ],
  "connections": [
    {"from": "osc1:Audio", "to": "env1:In"}
  ],
  "inputs": [
    {"name": "Frequency", "type": "Float", "target": "osc1:Frequency"}
  ],
  "outputs": [
    {"name": "Out Mono", "type": "Audio", "source": "env1:Out Envelope"}
  ]
}

Validated by 7-stage validator: required fields, asset_type, interfaces, node types, pin existence, type compatibility, required inputs, interface completeness.

Design Guidelines

Choose asset type: Source (playable) or Patch (reusable subgraph)
Select interface: MetaSound (general), OneShot (fire-and-forget)
Design signal flow: Generator → Processing → Envelope → Mixing → Output
Expose parameters Blueprint needs to control as graph inputs
Use
```
SetNodeLocation()
```
for editor layout visibility
Validate with
```
ms_validate_graph
```
before sending to Builder API
Consider AudioLink if routing to Wwise for mixing

Gotchas

AD Envelope (Float) for modulation chains, AD Envelope (Audio) for amplitude
InterpTo requires
```
Current
```
default value
Float→Audio connections are invalid — use Biquad Filter Bandwidth, not Multiply Audio
Dynamic Filter needs Audio-rate cutoff input; use Biquad for Float cutoff
Pin names from Epic docs may use shorthand — always verify against
```
ms_node_specs.json
```
Node class names: use display names from knowledge DB, or full
```
Namespace::Name::Variant
```
for direct lookup

Source Files

Node catalogue:

src/ue_audio_mcp/knowledge/metasound_nodes.py

(144 nodes, 798 pins)

Templates:
```
src/ue_audio_mcp/templates/
```
(22 JSON graphs)

Graph schema:

src/ue_audio_mcp/knowledge/graph_schema.py

Builder tools:
```
src/ue_audio_mcp/tools/metasounds.py
```
Scraped pins:
```
scripts/ms_node_specs.json
```

$ARGUMENTS

ue5-metasound-dsp

NPX Install

Tags

SKILL.md Content

MetaSounds DSP — Node Graphs & Signal Design

Data Types

Asset Types

Interfaces

Node Categories (144 nodes, 20 categories)

Generators

Wave Players

Envelopes

Filters

Delays & Time

Dynamics

Math (Audio)

Math (Float)

Triggers

Spatialization

Music

Effects

Utility

SIDKIT (Custom)

Signal Flow Patterns

Basic: Generator → Envelope → Output

Subtractive: Osc → Filter → Amp → Output

Additive: Multiple Oscs → Mix → Output

Triggered: Event → Sample Player → Processing

Modulated: LFO → Parameter Control

Key Pin Names (Authoritative)

Builder API Functions (68+)

Core

Graph I/O

Interfaces

Variables (UE 5.7+)

Presets

Live Updates

Templates Available (22 JSON)

Graph JSON Spec

Design Guidelines

Gotchas

Source Files