README.md
Fader
A macOS menu bar app for audio output switching and per-app volume. Switch the output device in one click, connect Bluetooth headphones, set a separate volume for every app, and play audio to several devices at once. Site: fader.pantafive.dev.
No telemetry, no kernel extension, no virtual audio driver — the source is open, check for yourself. Requires macOS 15+ on Apple silicon.
Install
| 1 | brew install --cask pantafive/tap/fader |
Or download the latest dmg. The app updates itself.
Features
- Output switching — headphones, speakers, displays, and AirPlay targets, one click each. Paired Bluetooth headphones connect from the same list.
- Auto-switch — drag rows to rank devices; Fader follows the best one present.
- Several outputs at once — drag a device onto the Output section and both play together, each with its own slider.
- Per-app volume — a fader and mute for every app that plays sound; levels persist. Apps at full volume play untouched, bit-perfect.
- Per-app output — drag one or more devices onto an app to play it through exactly those outputs, each with its own volume; everything else stays on your main output.
- Microphone — switch the default input, set gain, and see which apps are listening.
- In sync — system volume follows the volume keys and Control Center; scrolling over any slider adjusts it.
Permissions
Only per-app volume needs one: macOS gates audio taps behind the System Audio Recording permission, requested the first time you move an app's fader. The tapped audio never leaves the Mac.
Development
| 1 | brew install xcodegen swiftlint swiftformat |
| 2 | make run |
Swift 6, strict concurrency. The Xcode project is generated from project.yml — edit that, not the .xcodeproj. make drives local work: gen, build, test, lint, run, clean. Pushing a v* tag builds, signs, notarizes, and publishes a release.
Contributing
Bug reports and pull requests are welcome; for anything bigger than a fix, open an issue first. make test and make lint must pass; commits follow Conventional Commits. The real-time audio callback allows no allocation, locks, Objective-C, or logging — changes there get extra scrutiny. Anything that phones home will be declined.
Security
Report security issues privately via GitHub security advisories, not public issues.