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Audio Sweep (ESS)

Audio Sweep (ESS) · screenshot coming soon

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What this node does

Audio Sweep (ESS) synthesizes an Exponential Sine Sweep (ESS): a tone that glides smoothly from a low frequency up to a high one, followed by a silent tail. Play this sweep through a speaker/room/device and record the result, then feed both back into Audio Deconvolve (IR) to recover the impulse response. It takes no audio input — it is a pure generator — and outputs a COMFYTV_AUDIO snapshot. It has a ▶ Run. To feed the sweep to native ComfyUI AUDIO nodes, insert a Bridge — see bridges.md.

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When to use it

  • Capture a real reverb IR: play the sweep in a room, record it, deconvolve to get the IR.
  • Test the frequency response of a speaker, cabinet, or processing chain.
  • Provide a controlled excitation signal for measurement.

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Parameters

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duration_s

Length of the sweep in seconds, 1–30 (default 5.0). Longer sweeps give a better signal-to-noise ratio for the measurement.

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fmin

Start (lowest) frequency in Hz, 10–1000 (default 20).

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fmax

End (highest) frequency in Hz, 1000–20000 (default 20000).

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amp

Output amplitude, 0.01–1.0 (default 0.5). Keep below 1.0 to avoid clipping on playback.

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tail_s

Silent tail appended after the sweep, in seconds, 0–10 (default 5.0). Gives the reverb tail room to decay in the recording before the take ends.

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Outputs

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Tips

  • Match duration_s and the frequency range to the Audio Deconvolve settings you’ll use, so the deconvolution inverts the correct sweep.
  • Add enough tail_s to let the room’s reverb fully decay, or the captured IR will be truncated.
  • Keep amp conservative (~0.5) so the playback and recording chain stays clean.
  • Audio Deconvolve (IR) — recovers the impulse response from the recorded sweep.
  • Audio Convolve (IR) — applies the recovered IR to any source.