Soundflower VS BackgroundMusic

If you're on a Mac, there's Soundflower. Though, according to their site, it hasn't been updated for Apple silicon yet.

For Snow Leopard you should have a look at Soundflower. It's the OG tool for recording desktop audio output, and should still work on Snow Leopard (if the version linked doesn't work then you can try building the version from 2008 in the command line, it doesn't seem to be too complicated).

For Windows: VB-Cable (https://vb-audio.com/Cable/) For Mac: Soundflower (https://github.com/mattingalls/Soundflower/releases)

Intel Mac → Soundflower: this virtual audio device will route one app’s audio to another

The first really cool software was Soundflower, but that seems to be limited to Catalina.

If Blackhole isn't working, or you've an older system, instead try Soundflower and follow these directions - even though they're old as grit, it lays out the basics of what you need to do the clearest.

Soundflower is open source but looks a little janky and doesn’t work with M1s yet.

For Mac: install SoundFlower

Install Soundflower from https://github.com/mattingalls/Soundflower/

For controlling a software defined volume like Windows has, try https://github.com/kyleneideck/BackgroundMusic

Download Background Music: LINK (free and open-source) Once downloaded, run it and you'll see it as an icon in your menu bar

Thanks for the comment. I checked out Rogue Amoeba's SoundSource, and BackgroundMusic. I think they're using some sort of virtual audio device or something to intercept applications' audio data, control each application's volume, and then send it to the speakers (or another output device).

I had an app called Background Music that I deleted a few days ago, but it still shows up as an audio output in the Sound menu bar menu as well as in Settings.

you can check BackgroundMusic : https://github.com/kyleneideck/BackgroundMusic

Tried https://github.com/kyleneideck/BackgroundMusic before. But didn't work for me.