Need to record audio from an app, or route sound from one tool to another? Blackhole is an easy, free way to do that on the Mac, right through the latest macOS Catalina.
The utility Soundflower got some brand recognition among music and audio nerds after its introduction way back in 2004, and it does still have people working on support. Its original
Blackhole gives you more of that sort of simplicity, with modern updates – including full support for macOS Catalina that has eluded some other tools. Basically, look to Soundflower first for older OSes, and consider Blackhole for 10.10 (Yosemite) and later, especially if you’re up to Mojave or Catalina.
You get 16 channels of audio (configurable up to 256 if you need that for some reason), lots of sample rates, and – as with the other solutions mentioned here – zero latency.
It’s pretty simple stuff, and my initial tests suggest this it’s solid. I think given the pace of Apple’s updates, the actively developed Mac-specific tool here wins:
https://github.com/ExistentialAudio/BlackHole
This triggered a lively discussion after the developer mentioned it on Reddit:
Many, many readers wrote me to point to Rogue Amoeba’s Loopback, which I frankly had forgotten. I presume if people are using a paid tool over a free one, they’re finding some use for it. The main advantage would appear to be its graphical interface for routing. Since all of these tools run atop Apple’s own audio infrastructure, you should expect performance to be theoretically the same. I can’t speak to Loopback specifically, as I haven’t tested it. (JACK users will find the UI very similar to JACK!)
Windows
By the way, it’s interesting that users expect a tool made for macOS audio architectures to work on Windows. There really isn’t a way to make a generically cross-platform tool, because each OS has its own architecture (or apart from macOS, architectures, plural). On Windows, since most pro audio tasks rely on ASIO, you’ll want to use a tool that uses that API for inter-app audio routing.
On Windows and ASIO, for a cross-platform implementation, JACK really is your best bet. In the past, that meant some complex installation, but there’s now an easy guide:
https://jackaudio.org/faq/jack_on_windows.html
Some tools also come with their own virtual ASIO driver, like ReaRoute in Reaper:
https://wiki.cockos.com/wiki/index.php/ReaRoute
For a flexible driver that runs without requiring software to support ASIO, I recommend LoopBeAudio. It’s paid, but from a great developer who’s really focused on Windows support:
https://www.nerds.de/en/loopbeaudio.html
While you’re there, that’s also the best way to route MIDI between apps on Windows. Check out LoopBe1 – it’s good enough that I don’t even miss the native tools I use on macOS and Linux:
https://www.nerds.de/en/loopbe1.html
JACK remains the tool that works everywhere, but I do make use of these specific tools for the Mac and Windows. Let us know how Blackhole is working for you, if you’ve found an interesting use case, and if you run into trouble.