SonarBlendFilterNoise

Colored-noise nodes shape the spectrum when they generate the noise. SonarBlendFilterNoise shapes the spectrum of noise you already have - and it's the one node in the pack that's as much about filtering as about generating. You feed it a noise chain and it runs a frequency filter over the result, then optionally blends that filtered version back with the original using a blend mode. It's the difference between choosing pink noise and deciding that this particular noise should keep its low frequencies and lose its high ones.

That "blend the filtered result back in" step is the useful bit. Pure low-pass noise can be mushy; mixing it back with the unfiltered original at the right strength keeps the energy while changing the texture. The affect input even lets you choose whether the filter applies to the input noise, the blended result, or both - so you can filter the source, blend, and filter again in one pass.

The inputs to care about:

• sonar_custom_noise - required input; the noise to filter. No noise, no node.
• ffilter - the frequency filter to apply. The available filters come from ComfyUI-bleh, which is why the schema's choice list comes back empty at scan time - install bleh and this dropdown fills in. ffilter_custom lets you name one directly if you know the id.
• ffilter_scale, ffilter_strength, ffilter_threshold - the filter's tuning: scale of the filtering, how strongly it's applied (0 = off), and a threshold that runs 1–32.
• blend_mode - simple_add (default) plus lerp, inject, subtract_b, with more arriving if ComfyUI-bleh is present.
• enhance_mode / enhance_strength - an enhancement step (the default none is the only one you'll see without bleh).
• affect - result, noise, or both.
• normalize_result / normalize_noise - separate normalization controls for each stage, because filtering tends to change the output's strength.
• factor - overall scaling.

Output is SONAR_CUSTOM_NOISE. Install is two repos if you want the full filter library, and the node still functions with the base modes on sonar alone:

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

The honest take: this is a power-user node, and its ceiling is tied to bleh's filter collection - without bleh you're stuck with the four base blend modes and whatever ffilter you can name by hand. If you're just starting with custom noise, SonarAdvanced1fNoise and SonarBlendedNoise will take you further with less frustration. But once you've decided "I want this noise, minus its high frequencies, blended back at 40%," this is exactly the node that sentence describes. Just remember the noise-injection rule - it only does anything on samplers that add noise - and the pack's standing reproducibility caveat when you're chasing a specific result.