Here's a reasonable thing you might want to do: play music through your desk speakers while taking a Zoom call through your AirPods. The music fills the room, the call is private in your ears. Makes perfect sense.
macOS says no. When you select an audio output device, every app uses it. Switch to AirPods for Zoom and Spotify also switches to AirPods. Switch to speakers for Spotify and Zoom also goes to speakers. One output device for everything. No exceptions.
Why macOS can't do this natively
macOS routes all audio through a single selected output device. You choose "MacBook Pro Speakers" or "AirPods Pro" in System Settings → Sound → Output, and every app sends audio to that device. There's no built-in per-app audio routing.
This design makes sense for simplicity — most people want all their audio coming from the same place. But it falls apart the moment you want different apps on different outputs.
The aggregate device workaround
macOS's Audio MIDI Setup (found in Applications → Utilities) lets you create an "Aggregate Device" that combines multiple outputs into one. However, an aggregate device sends the same audio to all combined outputs — it doesn't let you choose which app goes to which output. It's designed for multi-speaker setups, not per-app routing.
The multi-output device workaround
Similar to aggregate devices, you can create a "Multi-Output Device" in Audio MIDI Setup. This sends identical audio to multiple outputs simultaneously. Again, it's the same audio everywhere — you can't route Spotify to speakers and Zoom to headphones this way.
What actually works: per-app audio routing apps
To truly route different apps to different output devices, you need a third-party audio routing app that intercepts each app's audio and sends it to the output you specify. Apps like SoundSource (from Rogue Amoeba) support this — they let you assign specific output devices to individual apps.
A simpler approach: volume-based separation
If your main goal is to hear your call clearly over your music (rather than routing them to physically different devices), per-app volume control solves the problem more simply.
SoundDial gives every app its own volume slider. During a call, you can:
- Set Zoom/Teams/FaceTime to 100%
- Lower Spotify to 20%
- Mute everything else
Your call is crystal clear. Music is a subtle background. No device switching needed.
Even better: SoundDial's auto-ducking does this automatically. When you join a call, it detects your microphone activating and lowers all background apps to a level you configure (default 30%). When the call ends, everything returns to normal. No manual slider adjustment needed.
For most people, this solves the actual problem — "I can't hear my call over my music" — without the complexity of routing different apps to different physical devices.
Get SoundDial on the Mac App Store — €14.99 one-time purchase, no subscription, macOS 14.2+.