SonarPreviewFilter

If you've ever built a noise chain with this pack's power-filter nodes and stared at the result wondering what the filter is actually doing, this node is the answer. SonarPreviewFilter renders the inside of a Power Filter as an image so you can see it instead of guessing, then hands the filter straight through so nothing in your chain breaks. It's the node you reach for while debugging, not while generating.

The short version: wire a SONAR_POWER_FILTER into it, get a visualization, and keep the filter flowing onward. It's a pure display/passthrough node - nothing about it changes your generation.

What you actually set

• sonar_power_filter - the filter to preview. This comes from a power-filter source like SonarPowerFilter; you're not creating filters here.
• filter_gain (default 0.333) - how loudly the "filter part" of the preview renders.
• kernel_gain (default 0.333) - same idea for the "kernel part" of the preview. The two gains are separate because a filter and its kernel are different things and one usually drowns out the other at equal strength.
• norm_factor (default 1.0) - normalizes the filter before previewing. 1.0 means fully normalized; drop it if the preview is washing out.
• preview_size - the preview resolution, in latent pixels. For most models one latent pixel equals eight image pixels, so 128x128 here is roughly 1024x1024 in image space. Don't set this to your final render resolution or you'll just be burning VRAM on a thumbnail.

The only output is the same SONAR_POWER_FILTER you fed in. Treat it as a through-wire - the node is "output" in the graph sense, but the filter exits unharmed so you can keep building the chain it belongs to.

Installing it

This is part of the ComfyUI-sonar pack, so it comes down with everything else. Easiest route is ComfyUI Manager - search for "ComfyUI-sonar" and install. Manual route:

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

Restart ComfyUI (or hit Reload), and it shows up under advanced/noise. There's no requirements.txt and nothing to download - the pack is pure Python, and this node specifically has zero heavy dependencies.

Notes and gotchas

Being an output node, if the preview box is empty the usual suspects apply: check the node isn't bypassed/muted and that a filter is actually connected. And set expectations - the preview shows the filter's shape in frequency space, not what your final image will look like. It can look like abstract static and still be exactly right. One more thing worth knowing about the pack in general: blepping calls ComfyUI-sonar "janky" in the README and warns that inputs shuffle around between versions. Fine for exploration, don't build a production pipeline on it.