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Audio Duck

Audio Duck · screenshot coming soon

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What this node does

Audio Duck lowers a main track’s volume in response to a second “sidechain” track, so the main audio ducks out of the way when the sidechain gets loud. It is classic sidechain ducking: point the sidechain at your narration and the music underneath automatically drops during speech, then recovers in the gaps. Both the main and sidechain inputs accept a COMFYTV_AUDIO snapshot or a COMFYTV_VIDEO (its audio track is used; the audio input takes priority). It outputs the processed main track as COMFYTV_AUDIO and has a ▶ Run (FFmpeg does the work). To feed native ComfyUI AUDIO in or out, insert a Bridge — see bridges.md.

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When to use it

  • Duck a music bed under a voiceover so narration stays intelligible.
  • Drop ambience or SFX whenever dialogue plays.
  • Podcast/vlog mixing where the backing track should yield to speech.

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Parameters

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threshold

Sidechain level at which ducking begins. Range 0.001 to 1.0, default 0.05. Lower = the ducker triggers on quieter speech.

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ratio

How hard the main track is pushed down once the threshold is crossed. Range 1 to 20, default 8.0. Higher = deeper ducking.

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attack

How fast ducking engages when the sidechain gets loud, in milliseconds. Range 1 to 2000, default 20. Short = the music drops almost instantly.

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release

How fast the main track recovers after the sidechain goes quiet, in milliseconds. Range 10 to 9000, default 400. Longer = smoother, slower return.

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makeup

Make-up gain applied to compensate for the level lost to ducking. Range 1 to 8, default 1.0 (no boost).

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mix_back

When on (default), the processed (ducked) main track is the result. This controls whether the ducked signal is mixed back into the output.

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side_gain

Gain applied to the sidechain before it drives the ducker. Range 0 to 4, default 1.0. Raise it if a quiet voice isn’t triggering enough ducking.

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Outputs

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Tips

  • If the music “pumps” audibly, lengthen release and/or lower ratio.
  • If ducking lags behind the voice, shorten attack.
  • No separate sidechain? Wire the same voice track into both the main mix (via Audio Mix) and this node’s sidechain input.
  • Audio Mix — combine the ducked music with the voice into a final stereo mix.
  • Audio Crossfade — blend two clips in sequence rather than duck one under another.