Not in OBS. You'll probably need to use a loopback audio driver in some way.
If you're on Windows, you can install this:
If you're on Linux, you can google how to configure your native audio system to do that all on its own.
If you're on Mac, VB claims to work for you too, but I've never tried it. And there are others too, that may or may not have other features and/or support.
In any case, once you have the loopback, you can send audio to a virtual speaker from one app, as if it were a physical speaker, and pick it up from a virtual mic in a different app. This is often used to get game audio into OBS, without the desktop notifications that people inexplicably leave on (know and control your rig!), but it also works the other way too. Send audio from OBS's Monitor or from this plugin to a virtual speaker, and pick it up from the virtual mic in a different app.
If you're on Windows, you can install this:
If you're on Linux, you can google how to configure your native audio system to do that all on its own.
If you're on Mac, VB claims to work for you too, but I've never tried it. And there are others too, that may or may not have other features and/or support.
In any case, once you have the loopback, you can send audio to a virtual speaker from one app, as if it were a physical speaker, and pick it up from a virtual mic in a different app. This is often used to get game audio into OBS, without the desktop notifications that people inexplicably leave on (know and control your rig!), but it also works the other way too. Send audio from OBS's Monitor or from this plugin to a virtual speaker, and pick it up from the virtual mic in a different app.
Audio Monitor
Plugin for OBS Studio to add Audio Monitor dock and filter. It allows you to put the audio of a OBS source to an audio device by adding the Audio Monitor filter on the Source in OBS Studio. This can be useful in different use cases...
obsproject.com