Audio Pass

Audio Pass is a one-in, one-out audio passthrough: audio in, audio out, byte-for-byte unchanged. It's the audio member of this pack's passthrough family, and its entire job is to let an audio wire exist as a visible, nameable point in the graph. The mechanism is a straight hand-off - the source returns whatever came in, or None if nothing was connected.

Where it earns its keep is the same place every passthrough does, per the node-plumbing layer's framing: organization and forced connections. A long audio wire across a video workflow gets hard to read; Audio Pass breaks it into readable segments. And because the input is marked forceInput, it turns an audio value that lives in the graph into a socket that must be wired - handy when a downstream node only exposes an optional audio input and you want to guarantee the connection exists.

Two quirks worth knowing, and the first one is a genuine oddity of the pack:

• This pack ships Audio Pass twice. There's this node, hand-written in Audio_Pass.py, and there's wcx_AudioPassthrough, one of the twelve generated passthrough nodes in Any_Passthrough.py. Same category, same AUDIO-in/AUDIO-out contract, functionally interchangeable. The pack just... has both. Pick one and stick with it so shared workflows stay consistent.
• The input is optional. If nothing is wired in, the output is None, not a silent empty audio. That's intentional - it lets you use the node as a conditional gate: leave it unwired and downstream optional inputs read None and skip their work, wire it in and the audio flows.

It's a thin node, and it should be - passthroughs that do something are broken. Use it to organize an audio graph, to name a wire, or to force an optional audio socket into existence. Install is pack standard: ComfyUI Manager → search ComfyUI-Practical-Tools → install → restart, or git clone https://github.com/wenchengxiang/ComfyUI-Practical-Tools into ComfyUI/custom_nodes. No dependencies, no models. If the output is None, nothing was connected - that's the whole troubleshooting guide.