audio-signal-flow-explainer

name

audio-signal-flow-explainer

description

Traces and documents signal paths, bus/aux architecture, and sidechain connections in audio systems. Surfaces hidden coupling between audio components. Use when the user asks to trace a signal chain, explain audio routing, understand an audio graph, locate sidechain sources, or describe how audio flows through a plugin or engine. Trigger on phrases like "trace this signal chain", "explain this audio routing", "what calls what in this audio graph", "where does the sidechain come from", "how does audio flow through this plugin".

Audio Signal Flow Explainer

Core principle: Audio signal flow is a directed graph. Tracing it reveals hidden coupling, latency paths, and places where the signal can be corrupted.

Step 1 — Map the graph

• Find all sources (oscillators, audio inputs, file readers, generators)
• Find all processors (filters, effects, gain stages, dynamics)
• Find all routers (bus sends, parallel splits, sidechain taps, mixer channels)
• Find all sinks (audio outputs, recorders, meters, analyzers)
• Note parallel paths — any branch that rejoins a main path
• Note feedback loops — any path where output feeds back into an earlier node
• Note sidechain connections — signals that control a processor without passing audio through it

Step 2 — Identify each node type

Node type	What to note
Source (oscillator, audio input, file reader)	Sample rate, channel count, sync source
Processor (filter, effect, gain)	In/out channel count, latency added, stateful or stateless
Router (bus send, parallel split, sidechain tap)	Where signal copies go, gain staging at split
Sink (audio output, recorder, meter)	Expected format, callback timing, buffer size

Step 3 — Surface issues

• Latency compensation mismatches on parallel paths
• Channel count mismatches between connected nodes
• Sidechain input not wired — processor receives silence as control signal
• Uninitialized state in feedback loops (DC buildup, NaN propagation)
• DC leaking into output (missing highpass or DC-blocking filter)
• Sample rate mismatch between source and downstream processor
• Gain staging that causes clipping before a later limiter or saturation stage
• Missing denormal protection in recursive filter paths

Step 4 — Write the signal flow description

Use this format:

## Signal Flow: [component/system]

### Graph
Source → [gain: 1.0] → [Biquad LPF] → [Comp sidechain tap] → [Output]
                                            ↓
                                       [Compressor] → [Output]

### Latency path
Source → LPF (0 samples) → Compressor (64 samples lookahead) → Output
Total: 64 samples

### Issues found
- Parallel path to Output has no latency compensation for the 64-sample compressor delay

Quick reference

Pattern	What to check
Parallel split rejoining	Latency of each branch must match before summing
Sidechain compressor	Verify sidechain input is connected and level-matched
Send/return bus	Check send gain, return gain, and whether send is pre- or post-fader
Feedback loop	Confirm a delay of at least 1 sample exists to break algebraic loop
Multi-rate graph	Confirm resampling nodes at every rate boundary