Designing Dynamic Audio Feedback Loops

Construct feedback delay networks within MetaSounds to generate complex, self-oscillating textures that react to real-time input signals.

In this lesson, you will learn how to architect self-oscillating feedback delay networks within MetaSounds to create living, evolving sound textures.

The Anatomy of a Feedback Loop

A feedback loop in MetaSounds occurs when the output of a delay line is routed back into its own input. By passing this signal through filters and gain stages before it re-enters the buffer, you create a system that can sustain, evolve, and "ring" indefinitely. Unlike standard echo effects, these networks generate complex harmonic textures that react instantly to changes in your input parameters.

Constructing the Network

To build this, you need a circular signal path. You will use a Delay node, but instead of sending the signal directly to the output, you feed it back into an Add node that combines the incoming dry signal with the delayed, processed signal.

The Delay Line: Place a Delay node. Set the feedback amount (the gain of the routed signal) to slightly less than 1.0 to prevent runaway digital clipping.
The Processed Path: Insert a One Pole Filter or Resonant Filter within the feedback path. By modulating the Frequency parameter of this filter via your MetaSound inputs (like an LFO or a trigger-based envelope), the feedback loop will change its harmonic character as it repeats.
The Feedback Tap:

[Input Signal] -> [Add] -> [Delay] -> [Filter] -> [Add] (Feedback Tap)
                     ^________________________|

By increasing the gain on that feedback tap, the signal accumulates, creating a "tail" that never dies. If you place a Gain node in the loop tied to a MetaSound Input, you can use your UI sliders or game logic to "freeze" the audio or clear the buffer entirely.

Why This Matters for UI

When applied to UI interactions, these loops allow your interface to feel "alive." Instead of triggering a static "click" sound, a button press can inject a transient into an ongoing feedback loop, causing the sound to ring out and morph based on the button’s current visual state. Because the loop is self-oscillating, it maintains a continuous audio presence that feels physically connected to your UI logic.

Key Takeaway: By routing a MetaSound’s output through a filtered feedback path and modulating the loop gain, you transform static sound triggers into evolving, reactive audio textures.