What's the point of monitor ports in JACK/Pipewire?

With both JACK and Pipewire, you can connect a single input to multiple outputs, so monitoring should be as easy as connecting e.g. your mic input to both Ardour (for processing) and to your headphone output (for monitoring).

If that is the case, what’s the use case for separate monitor nodes and/or ports? I realize I can disable them, I’m just wondering what I’m missing here. They seem entirely redundant.

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They were a bad idea of mine when I originally wrote JACK. Hopefully they will go away or vanish.


Out of interest, what was the original intent?

And have you suggested to the Pipewire Devs that they remove them?



Except you will not hear any effect processing when you bypass Ardour’s processing for input monitoring. So no Gate, EQ, Compressor, etc (you could add a reverb in parallel).

There is no benefit of bypassing Arodur for monitoring, in fact additionally also copying the signal “around” Ardour to your headphones will ever so slightly increase processing.

Some hardware vendors do offer effect processing directly in the I/O box (and provide equivalent DSP as VST plugin). This allows for zero-latency monitoring with FX while tracking, and later using the same processing during mixing.

Oh, this is how they do it? I kind of assumed the VST acted as a send/return to the external DSP.



I understand that, and it does make sense! But it turns out I have only ever seen the Pipewire kind of monitor ports, i.e, the ones that are on playback devices. And after thinking about it a bit more, they do make sense to me now: I don’t always want to have to remember to make multiple connections if I want to monitor everything that’s going into a particular speaker. With monitor ports on that speaker node, I can connect thos to, say, my headphones once and call it a day. No need to touch the monitor ports ever again.

And now I wonder why @paul is thinking why they would be a bad idea, but I’m probably missing some context on the Jack side here.