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Noise Reduction (Spectral)

Noise Reduction (Spectral) · screenshot coming soon

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What this node does

Noise Reduction (Spectral) removes broadband, steady-state noise (hiss, hum, air-con drone) using a spectral-gate approach: it builds a noise profile and attenuates frequency content that matches it, leaving the wanted signal. You can either let it estimate the noise from the track itself, or hand it a dedicated noise_sample (a snippet of noise-only audio) for a cleaner profile. It accepts a COMFYTV_AUDIO snapshot or a COMFYTV_VIDEO (its audio track is used; audio takes priority), with an optional second COMFYTV_AUDIO for the noise sample. It outputs processed COMFYTV_AUDIO and has a ▶ Run. To feed native ComfyUI AUDIO in or out, insert a Bridge — see bridges.md.

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When to use it

  • Clean up hiss or steady room tone under a voice or music recording.
  • Remove air-conditioner or fan drone captured during a take.
  • Use a silent-but-noisy passage as a noise_sample to precisely target that noise.

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Parameters

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reduction_db

How much the matched noise is attenuated, in dB. Range 1 to 48, default 12. Higher removes more noise but risks artifacts and a hollow, “underwater” sound.

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sensitivity

How aggressively frequency content is judged to be noise. Range 0.5 to 24, default 6. Higher classifies more as noise (more removed); lower is more conservative and preserves detail.

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freq_smooth_bands

Smoothing of the noise gate across neighboring frequency bands. Range 0 to 12, default 6. More smoothing reduces “musical noise” (tinkling artifacts) at the cost of some sharpness.

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noise_sample

Optional second audio input: a snippet containing only the noise. When provided, the profile is built from it instead of estimated from the main track, usually giving a cleaner result.

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Outputs

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Tips

  • Start with reduction_db around 12 and raise only as needed; over-reduction sounds artificial.
  • If you hear tinkly “musical noise” artifacts, increase freq_smooth_bands.
  • A dedicated noise_sample almost always beats self-estimation — grab a second of the room tone before/after the take.
  • Audio Denoise — FFmpeg-based afftdn/anlmdn denoisers and a silence trimmer, an alternative approach.
  • Audio Stem Split — isolate the wanted stem, which can be a cleaner starting point than denoising a full mix.