Feature Request: Per-Application Output Device Selection #831
Description
Summary
Currently, Background Music allows per-app volume control, but all applications are tied to the same output device set in macOS. It would be very useful to allow assigning different output devices to different applications.
Example Use Case
- Route Firefox audio to the built-in Mac Mini speakers.
- Route Chrome audio to a USB audio interface or USB microphone with a headphone output.
- Keep music apps (e.g., Spotify, Apple Music) routed to external speakers, while video conferencing apps (e.g., Zoom) use a headset.
Why This Matters
- Users often work with multiple audio devices simultaneously (internal speakers, USB DACs, HDMI monitors, Bluetooth headsets).
- Per-app device routing would eliminate the need for expensive third-party apps (e.g., SoundSource, Loopback).
- This feature would make Background Music a complete open-source alternative for professional and casual users.
Proposed Implementation Ideas
- Add a dropdown menu next to each app in the Background Music UI to select an output device.
- Allow users to set a “default device” fallback, while overriding specific apps individually.
- Optional: Save per-app routing as profiles (e.g., “Work”, “Entertainment”).
References / Similar Tools
- Rogue Amoeba’s SoundSource (paid) implements this functionality.
- Windows 10+ provides per-app output device selection in its sound settings.
Impact
This feature would greatly expand Background Music’s usefulness and adoption, especially among users who need professional audio routing but prefer free/open-source tools.
