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Audio Echo

Audio Echo · screenshot coming soon

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What this node does

Audio Echo applies FFmpeg’s aecho delay/echo filter (or a native feedback delay) to an audio track. You pick a preset or dial in your own delay time, feedback, and gain. Presets like mountains produce long, decaying reflections; robot and doubled are short slapback-style repeats. It takes a COMFYTV_AUDIO snapshot (or a COMFYTV_VIDEO, whose audio track is used) and outputs processed COMFYTV_AUDIO. It has a ▶ Run (FFmpeg does the work). A source is required. To feed native ComfyUI AUDIO in or out, insert a Bridge — see bridges.md.

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When to use it

  • Thicken a dry vocal with a short doubled slapback.
  • Add spacious, decaying echoes for an ambient or cinematic feel.
  • Create rhythmic feedback repeats that trail off over time.

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Parameters

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preset

Chooses the echo character. Options: custom, feedback, plus four built-in aecho recipes — doubled, robot, mountains (default), mountains2 (two-tap). Pick custom to use the four manual sliders below; pick feedback to use a native feedback delay driven only by delay_ms and decay.

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in_gain

Input signal level fed into the echo, 0.0–1.0 (default 0.6). Used only when preset = custom.

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out_gain

Level of the echoed (wet) signal in the output, 0.0–1.0 (default 0.3). Used only when preset = custom.

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delay_ms

Delay time before the first repeat, in milliseconds, 1–90000 (default 1000). Used by custom and feedback. Short values (a few ms) give slapback/robot tones; long values (hundreds of ms) give distinct echoes.

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decay

How much each repeat fades relative to the previous one, 0.01–1.0 (default 0.5). Higher = longer, more sustained tails. Used by custom and feedback.

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Outputs

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Tips

  • The built-in presets ignore the manual sliders — set preset = custom to hear your gain/delay/decay values.
  • feedback mode only reads delay_ms and decay; the gains do nothing there.
  • Very short delays (under ~10 ms) start to sound like comb-filtering/robotic coloration rather than distinct echoes.
  • Muse Reverb (FDN) — for dense, smeared reverberation rather than discrete repeats.
  • Audio Convolve (IR) — real-space reverb from an impulse response.
  • Audio Modulation — chorus/flanger for a different kind of “thickening.”