SonarPowerFilter

SonarPowerFilter doesn't generate noise at all. It builds a filter - a shape in the frequency domain - that you then apply to noise with SonarPowerFilterNoise. Think of it as the "design the lens" node in a system where the other node is "point the lens at your noise." It's the most compositional node in the pack's power-noise family, and the payoff is that one well-tuned filter becomes a reusable recipe across many noise sources.

What you're actually designing

A power filter controls which spatial frequencies of your noise get through and how strongly. Frequency is the "how fine-grained" axis: low frequencies are big smooth blobs, high frequencies are fine texture. The inputs map directly onto shaping that:

• alpha - the tone knob. Positive values amplify low frequencies (softer, broader noise); negative values amplify high frequencies (crisper, finer texture).
• min_freq / max_freq - the band limits. The defaults, 0 to 0.7071, pass the whole usable band; tighten them to make a true band-pass filter.
• stretch and rotate - shape the filter anisotropically. This is how you get noise that's stretched horizontally or runs at an angle, which reads as directional texture (brush strokes, grain direction, fabric weave).
• pnorm - cushions the band-pass edges so the cutoff isn't a hard cliff (default 2).
• blur - slightly blurs the filter to reduce artifacts. Default 0.125.
• oversample - the filter's internal resolution. Default 4; raise it if you see filter-shaped artifacts.
• scale - overall filter strength. Negative flips it.

And compose_mode - max, min, add, sub, or mul - combines this filter with an optional second power_filter_opt input. Two filters multiplied or subtracted gives you shapes no single parameter set can reach, like a notch (everything except one band).

How to use it

Output is SONAR_POWER_FILTER, which wires into SonarPowerFilterNoise's sonar_power_filter input. The tooltips and the README's docs/advanced_power_noise.md walk through the full recipe; a good first session is alpha at +1 for soft dreamy noise, or -1 with a slight stretch for film-grain texture.

The gotcha

The filter exists in frequency space; oversample controls how finely that's sampled. Crank it too low and you get boxy, aliased noise instead of smooth filtering. If your filtered noise looks grid-like, that's usually oversample - not your alpha - and it's the first thing to raise.

Install

Part of the ComfyUI-sonar pack. ComfyUI Manager → search "ComfyUI-sonar" → Install → restart, or:

cd ComfyUI/custom_nodes
git clone https://github.com/blepping/ComfyUI-sonar

No models, no extra deps. The original SonarPowerNoise was contributed to the pack by elias-gaeros, and this filter object is the refactor he pushed for - separate filter from noise so you can build, preview, and reuse filters. If you want to see what your filter does before wiring it into a full chain, SonarPowerFilterNoise has a preview mode that displays the filter shape and a noise sample.