How to Route Audio Between Apps on Mac
On its own, macOS doesn't let you send audio from one app to another. With virtual audio devices and a routing matrix, you can connect your DAW, mixer, streaming and recording apps as if they were cables.
Sooner or later every engineer needs this: send the show mix to a streaming app, record a DAW's output in another app, run a virtual soundcheck or combine two interfaces. In macOS, each app picks one input device and one output device, and there's no virtual cable between them. That's where virtual audio devices come in.
What is a virtual audio device?
It's a sound card that exists only in software. To your apps, it looks like any other interface: it has inputs, outputs and channel names. Whatever one app sends to its output can be picked up by another app at its input.
With several virtual devices and a routing matrix, you decide which output goes to which input, channel by channel.
Common uses
- Live streaming: the mixer sends the mix to a virtual device, and the streaming app picks it up from there, with no cable and no noise.
- Multitrack recording: each channel of the show goes to a channel on the virtual device and is recorded in another app.
- Virtual soundcheck: the DAW plays back tracks recorded at the last show and sends them to the mixer's inputs, as if the band were playing.
- Multiple interfaces together: the matrix connects inputs and outputs from different interfaces, with sample rate conversion so different clocks don't cause clicks.
- Mix-minus for video calls: send a mix without the other person's own voice back to them.
What macOS already offers
Audio MIDI Setup, which comes with every Mac, creates aggregate devices: it combines two or more interfaces into a single device. That helps you get more inputs, but it doesn't send audio from one app to another and doesn't let you choose the path for each channel.
How to set up routing, step by step
- Create virtual devices with the number of channels you need: 2 for a stereo mix, 32 or 64 to record an entire show.
- Give them meaningful names, such as "Stream Mix" or "Record 32". Channel names show up in your other apps.
- Choose the devices in each app: the mixer outputs to device A, the streaming app takes its input from device A.
- Connect the paths in the matrix: each destination gets one source. One source can feed several destinations.
- Save it as a preset so you can open the same routing at the next show.
Tips to avoid problems
- Use the same sample rate in every app, preferably 48 kHz.
- Avoid feedback loops: don't send an app's output back into its own input.
- Check latency: every pass through a virtual device adds a little time. For in-ear monitors, keep the path short. See the guide to live sound latency.
- Choose a router that runs in the background. That way audio keeps flowing even if the app window closes.
Where AudiFlux fits in
AudiFlux is an audio router for Mac. It creates virtual devices from 2 to 128 channels, shows everything in a grid where one click connects a source to a destination, and lets you rename devices and channels, with those names showing up in other apps. Physical interfaces join the same grid, with sample rate conversion, and routing keeps working even with the window closed. It runs on Macs with Apple Silicon or Intel and macOS 12 or newer.
If your show also uses network audio, see the guide AES67 on Mac.
Frequently asked questions
Do virtual audio devices reduce sound quality?
No. Between apps on the same Mac, audio passes as data, with no conversion. Quality only changes if there's sample rate conversion between different clocks, and a good converter is transparent.
Can I use virtual devices together with my audio interface?
Yes. Your apps keep using the interface, and the matrix connects its inputs and outputs to the virtual devices.
How many channels can I send from one app to another?
It depends on the router. To record an entire show, look for devices with 32, 64 or more channels.