Windows has had a per-app volume mixer since Vista. The Mac, twenty years on, still has one slider that moves everything at once. Turn the music down for a call and the call goes quiet too. Mute the system alerts and you mute the film. People have solved this with third-party mixers that install audio drivers, and those work, but a kernel-adjacent driver is a heavy thing to install for a volume slider. Since macOS 14, Apple's audio taps make the same result possible without one. Audio Control is that, in the notch.
The situations one slider cannot handle
Music under a call. You want the playlist at a third and the meeting at full, and the system slider cannot express that. A game with a loud soundtrack and a quiet voice chat. A YouTube video that is mastered hot next to a podcast that is not. Notification sounds from a chat app landing on top of a film. Every one of these is a ratio between two apps, and a single slider can only set the total.
The usual workaround is to go into each app and find its own volume control, if it has one. Browsers do not. Many chat apps do not. The ones that do bury it. A mixer moves that control to one place, which is where a control like this belongs.
How the droplet works
- One slider per playing app
- Open the shelf and the Audio Control card lists every app currently producing sound, each with its own slider. Apps that go silent drop off. Apps that start playing appear.
- Remembers levels
- Set Spotify to forty percent once and it is forty percent next time it plays, next week, after a restart. The system slider still sets the ceiling; the per-app level is a proportion of it.
- Smooth gain ramps
- Dragging a slider ramps the level rather than stepping it, so there is no zipper noise, the crackle cheap mixers make when the gain jumps.
- macOS audio taps
- The droplet uses the tap API Apple added to Core Audio, which lets an app observe and adjust another app's output with the user's permission. No driver, no virtual device, no reboot, nothing leaves the Mac.
The point of a mixer in one drag: one app moves, the other does not. Audio Control remembers the level you land on.
What it does not touch
Audio Control changes how loud each app is. It does not change which device the sound comes out of on the Mac, which stays a system choice, and it does not route apps to different outputs. It also leaves the master volume alone: the keyboard keys and the system slider still set the ceiling for everything, and each app's slider is a proportion of that. If you set an app to half and then turn the Mac up, the app gets louder with it, as you would expect from a mixer channel under a master fader.
Permissions and privacy
macOS asks once whether Droppy may record system audio, because that is the permission an audio tap technically falls under. Audio Control uses it to adjust levels, not to store anything. Nothing is written to disk and nothing leaves the Mac; the droplet has no network component at all. If you deny the permission, the card explains that and points at System Settings, and the rest of Droppy is unaffected.
From the iPhone
Pair Droppy for iPhone and Audio Control becomes a remote for the Mac's overall volume, mute and output device. The per-app sliders stay on the Mac, where the apps are; the phone gets the three controls you want from across the room: quieter, silent, and send it to the TV instead of the laptop speakers. The wider set of things the phone can steer is in controlling your Mac from your iPhone.
| System volume slider | Driver-based mixer | Audio Control | |
|---|---|---|---|
| Per-app levels | No | Yes | Yes |
| Install | Built in | Audio driver, often a restart | Built in, a permission prompt |
| Remembers per app | No | Usually | Yes |
| Where the control lives | Menu bar | Its own window | The notch, and the iPhone |
| Output device from a phone | No | No | Yes |
Beside the media controls
Audio Control is about loudness, not playback. Droppy's media HUD handles play, skip, artwork and queue for Apple Music, Spotify and the rest, described in controlling Spotify and Apple Music without leaving your work. The two live on the same shelf, so the pattern is: pick the track with the media HUD, set how loud it is against everything else with Audio Control, and leave the system slider alone.
The system volume HUD itself, the translucent square that has looked the same since Tiger, is a separate story, told in the volume HUD post. Droppy replaces that too, which means the whole loudness story on the Mac, master and per-app, can live at the top of the screen.