I’m looking for a way to apply FXSound audio effects only to specific applications, like YouTube in my browser, instead of the entire system. Is there a method to route audio per process using FXSound, virtual audio cables, or other tools?
Sorry I don’t think that’s something FxSound can do.
There is no such feature at the moment, so the question is whether it will be available soon, because honestly, you are the best app of this type, but it is a shame that it is not per app, only for the browser, because I think it is feasible, but it requires: capturing individual Windows Audio Sessions (WAAPI) and applying effects only to selected processes,
or creating several virtual devices and dynamic routing (which is what Voicemeeter, CheVolume, Audio Router, etc. do).
Because, frankly, your repo has been practically dead since 2024. So what do you have to lose by trying to add per-app?
WAAPI had to be on a stable version, i.e. 24h2, although it is not known what Microsoft will do.
If you want some specific applications to not use FxSound, then you can filter those applications from system volume mixer. You can select the application and choose the input and output audio device from volume mixer. Select an output device other than default and FxSound Speakers if you do not want FxSound to process the audio for that application.
But by default, when FxSound is running it would become the default output device.
I suppose that’s one way to look at it, but what do you really think about my earlier comment?