Audio Priority

A small macOS menu bar app that keeps the default microphone and sound output on the best available device, by a priority list you control. Plug a USB mic in and it becomes the mic; unplug it and the next one in the list takes over. Put AirPods in and sound goes there; take them off and it goes back to the monitor or the speakers. macOS itself has no notion of priority: it picks whatever was connected last, and falls back to whatever it likes.

It also fixes the classic Bluetooth headphone problem: after a call, macOS often leaves the headset in the low‑quality headset profile (16 kHz, mono) instead of stereo. Audio Priority notices and puts it back.

Privacy: the app never reads audio, never records, never uses the network. It only changes the “default device” settings through public CoreAudio APIs, so there are no microphone permission prompts.

• One Swift file, no dependencies, ~15 MB of RAM, 0 % CPU when idle (event driven, no polling)
• macOS 13 Ventura or newer; Apple silicon and Intel
• MIT license

Install

Download

1. Get AudioPriority-<version>.zip from Releases, unzip, move AudioPriority.app to /Applications.
2. The app is not notarized (no Apple developer subscription), so the first launch is blocked. Either open System Settings → Privacy & Security, scroll down and click Open Anyway, or clear the quarantine flag once in Terminal:

   xattr -dr com.apple.quarantine /Applications/AudioPriority.app

3. Launch it. The microphone icon appears in the menu bar and the Priority window opens once. Tick Start at login in the menu to keep it running.

Homebrew (builds from source, no Gatekeeper dialog)

brew install petrochen/tap/audio-priority
audio-priority --register        # start now and at login; --unregister to stop

From source

git clone https://github.com/petrochen/audio-input-priority.git
cd audio-input-priority
make install        # builds ~/Applications/AudioPriority.app, enables start at login, starts it

Needs the Xcode command line tools (xcode-select --install).

The menu bar

The icon shows the type of the current microphone (USB mic, laptop, AirPods, headphones, camera, iPhone…). It turns yellow when something is wrong (headphones stuck in headset mode, built‑in mic selected with the lid closed) and gets a small dot when the app is not fully automatic (automation off, or holding a manual choice). Hover for the current mic and output.

The menu:

• In use by: Zoom — which apps are recording right now, or Nobody is recording.
• Yellow warnings, when any.
• Microphone / Sound output: every device with its icon and a checkmark on the current one, the Bluetooth sample rate (16 kHz = headset mode), lid closed and not in list markers. Click a device to select it by hand. The app keeps that choice, whatever the device, until something is plugged in / unplugged or the lid opens / closes.
• A status line: automatic, holding your manual choice, or off. Back to automatic now appears while a manual choice is held; Fix headphones stereo now appears while a headset is stuck.
• Automatic priority — untick to switch the automation off. Notify on switch, Add new wired devices to the lists, Start at login. All survive restarts.
• Priority… (⌘,) opens the editor. Open config folder, Show log, Sound settings…, Quit.

The Priority window

Two lists, microphone and sound output, best first. Drag rows to reorder. ● means the device is connected now, ○ not connected. + offers devices connected now, devices seen before, and device classes; − removes a rule. Every change is saved and applied immediately.

Rules are matched top to bottom against the devices present; the first match wins. A rule is:

Rule	Matches
MacBook Pro Microphone	that exact device name
*Pods*	a glob (*, ?, case‑insensitive): any AirPods, however they are named
@wired	USB, Thunderbolt, PCI, FireWire devices
@usb	USB only
@builtin	the built‑in mic / speakers
@airpods	any AirPods
@bluetooth	any Bluetooth device
@display	a monitor over DisplayPort / HDMI
@continuity	an iPhone / iPad (Continuity)
@airplay, @aggregate, @virtual	AirPlay, aggregate devices, software devices (Teams, Zoom, BlackHole…)

Devices matching no rule are never selected automatically. That is the safety net: a Bluetooth headset you did not list will never become the microphone and get stuck in headset mode.

The defaults, created on first run:

# microphone               # sound output
@wired                     @airpods
@airpods                   @bluetooth
@builtin                   @wired
                           @display
                           @builtin

The lists live in ~/.config/audio-input-priority/devices and outputs, one rule per line, and can be edited by hand too; they are re‑read on every event. audio-input-priority --list prints every device with its class.

How it decides

Situation	Microphone	Output
Desk: USB mic or webcam, external monitor, lid closed	the USB mic (built‑in is skipped)	headphones if connected, else the monitor
Desk, lid open	the USB mic	headphones, else the monitor
On the go with AirPods	AirPods	AirPods
On the go, nothing connected	built‑in mic	speakers
Bluetooth headset not in the list (default)	never; the mic stays on a real one	the headset, in stereo
You picked a device by hand	your pick, until devices change	same

Other rules:

• Lid closed: the built‑in mic and speakers are skipped (the mic is muffled, the speakers are inaudible). macOS keeps them in the device list, so without this they would get picked. Opening or closing the lid re‑evaluates the lists. Can be turned off in the Priority window.
• Headset mode: when a Bluetooth output is at ≤ 16 kHz and nobody is recording, its sample rate is raised back to the maximum, which flips the headset back to stereo. Never during a call.
• New devices: a wired device the app has never seen is appended to the end of the lists, with a notification. A new Bluetooth device only gets a notification; add it in the Priority window if you want it chosen automatically.
• Manual picks: choosing a listed device in System Settings, Control Center or an app that sets the system default is respected until devices change. Unlisted devices picked that way are reverted, because that is exactly how headsets get stuck. A pick from the app’s own menu is always respected.

Command line

The binary inside the bundle works as a CLI (make install symlinks it to ~/bin/audio-input-priority, Homebrew installs it as audio-priority):

--list          devices with class, sample rate, current default, who is recording, warnings
--once          apply the lists once and exit (for scripts)
--register      enable start at login and start the agent
--unregister    disable start at login and stop it
--quiet         no notifications

Log: ~/Library/Logs/audio-input-priority.log. In the source checkout make status, make log, make stop, make start, make uninstall do what they say.

Limitations

• Per‑app routing (music to the headphones, calls to the speakers) is out of scope; macOS has no API for it short of capturing and replaying the audio. Most call and music apps choose their own device in their settings, and the app does not interfere with that.
• macOS does not expose whether AirPods are in your ears. Connected AirPods left in a pocket will be treated as present. Put them in the case, or pick another mic from the menu.
• “In use by” needs macOS 14 or newer; on 13 the line says nobody is recording.
• Not notarized. See Download above.

Uninstall

Untick Start at login, quit, delete AudioPriority.app. Settings live in ~/.config/audio-input-priority/ and in the com.apetrochenko.audio-input-priority defaults domain. From a source checkout, make uninstall does all of it.

Development

Everything is in audio-input-priority.swift (CoreAudio rules, menu bar, Priority window). Other files: Info.plist, AppIcon.icns (made by scripts/make-icon.swift), devices.example / outputs.example, Makefile.

Command	What it does
make app	build AudioPriority.app next to the sources (ad‑hoc signed)
make install	build to ~/Applications, symlink the CLI to ~/bin, enable start at login, (re)start
make status / make log	launchd state + --list; last 30 log lines
make stop / make start / make uninstall	stop until next login / start / remove everything
make icon	regenerate AppIcon.icns
make release	dist/AudioPriority-<version>.zip for GitHub Releases

State: rules in ~/.config/audio-input-priority/, toggles and the list of devices seen so far in the com.apetrochenko.audio-input-priority defaults domain (auto, notify, autoAdd, lidSkip, seen, onboarded), the LaunchAgent in ~/Library/LaunchAgents/com.apetrochenko.audio-input-priority.plist, the log in ~/Library/Logs/.

Releasing a version: bump CFBundleShortVersionString in Info.plist, commit, tag vX.Y.Z, push, make release, gh release create vX.Y.Z dist/AudioPriority-X.Y.Z.zip --notes-file CHANGELOG.md, then update url and sha256 in Formula/audio-priority.rb of petrochen/homebrew-tap (curl -sL <tarball url> | shasum -a 256).

Why not a notarized build: it needs an Apple developer subscription. The same reason the app writes its own LaunchAgent instead of using the system Login Items API, which pins the binary's code hash and refuses to launch an ad‑hoc signed app after every rebuild.

Contributing

Issues with the output of --list and the last lines of the log are the most useful. The whole app is audio-input-priority.swift; make app builds it, make icon regenerates the icon.

MIT © Alexander Petrochenko