Mac volume keys change everything at once? How to change just one app

Your Mac's volume keys move a single master level that sits in front of every app, so one tap scales the whole mix up or down together — there is no built-in setting that points those keys at one app. The fix is to install a per-app mixer that sits at the audio layer and then bind a separate keyboard shortcut to a single app. That shortcut moves only that app, while the volume keys keep doing what they always did. This guide shows exactly why the keys behave this way and how to set up per-app volume keys in a few minutes.

It is one of the first things that feels wrong when you switch from Windows, or just start doing calls and music at the same time. You reach for F11 or F12 to pull one loud thing down, and everything drops with it — the call, the music, the video, the alerts. The keys are not broken. They are doing precisely what macOS wired them to do, which is the whole problem.

What the volume keys actually control

On a Mac, F11 and F12 (or the dedicated volume glyphs on newer keyboards) are tied to the system output level — one master fader that every app plays through. macOS takes the audio from Spotify, your browser, Zoom, and system alerts, mixes them together, and applies that single level last, right before the sound leaves your speakers or headphones. The keys nudge that final number. Because it lives after the mix, there is no way for it to touch one app and leave the others alone. Same story for the slider in Control Center and the one in System Settings → Sound: all three are handles on the same master level.

So the honest answer to "how do I make the volume keys change just one app" is that you cannot, not the built-in keys — macOS gives them exactly one target. What you can do is add a second, app-specific control and drive it from the keyboard. That is the entire trick, and it is straightforward once you know the built-in keys were never going to do it.

Why remapping the keys does not help

A reasonable first instinct is a key-remapping tool like Karabiner-Elements: if the keys hit the wrong target, point them somewhere else. It does not work, and it is worth understanding why. Remapping only changes what a key sends. It cannot invent a "Spotify volume" or "browser volume" for the key to land on, because macOS has no such per-app level in the first place. There is nothing to aim at. You have to create the per-app level before any hotkey can move it — and the app that creates it is the one that ends up owning the shortcut anyway.

The fix: a per-app mixer with its own hotkeys

A per-app mixer sits at the OS audio layer and gives every running app its own volume level — the layer macOS never exposed. Once each app has a real level of its own, a keyboard shortcut has something specific to move. Bind a key to the browser's level and that key changes only the browser. The system volume keys stay on the master, so you keep both: whole-machine volume on F11/F12, and one app at a time on the shortcut you set. Three tools fill this gap, and they differ mostly in how you reach the control.

All three set a per-app level, and any of them ends the "everything moves at once" problem. If free is the priority, Background Music is a genuinely useful open-source utility with a per-app slider list in the menu bar. If you want deep control and do not mind a higher price, Rogue Amoeba's SoundSource adds per-app EQ and routing in a polished menu-bar panel. Both are good at what they do. The catch, if your goal was specifically "do it from the keyboard," is that both put the control in a menu-bar list you open with the mouse.

Setting up a per-app volume key, step by step

Here is the shape of it in a keyboard-first mixer like Fader — the steps are the same idea in any of these tools, minus the hotkey part:

1. Install the mixer and grant the audio permission it asks for on first launch. This is what lets it see each app's stream and give it a level of its own.
2. Open the mixer and confirm the app you care about shows up with its own fader. Anything currently playing audio appears automatically.
3. Assign that app a keyboard shortcut — an up key, a down key, and a mute key. In Fader the keys are laid out as columns, so one app is Q/A/Z, the next is W/S/X, and so on.
4. Test it: play two apps, hit the app's down key, and watch only that one drop while the other holds. Your F11/F12 keys still move the master on top of it.

That is the whole setup. From then on, "turn that one thing down" is a keystroke from inside whatever app you are in, without hunting for a menu or a slider.

Why the keyboard is the part that matters

Every option in the table can set a per-app level. What decides whether you actually use it day to day is how long it takes to reach the control. A menu-bar list is: move to the menu bar, click the icon, find the row, drag the slider, dismiss. That is five actions for an adjustment you make dozens of times a day, and it is the exact friction that made the volume keys feel so convenient in the first place — until you learned they move everything.

Fader's whole design is to keep that key-tap feel while making it per app. You hit a toggle hotkey, the keyboard becomes a mixer, and letter keys ride each app's level without your hands leaving home row. It is a paid app — $19.99 one-time, with a 3-day free trial and no account — because that keyboard-first workflow is the thing it is built around, not a feature bolted onto a menu. If you only need per-app volume once in a while and do not care about the mouse trip, Background Music does the job for nothing.

A related fix while you are here

The same master-versus-per-app split shows up in muting: if you only need to silence one app fast rather than ride its level, see how to set a keyboard shortcut to mute an app on Mac. And if you want the full picture of why the keys and Sound settings all move together, the explainer does the Mac volume key control individual apps? covers the underlying behavior.

Bottom line

The Mac volume keys change everything at once because they are wired to one master level that sits after the mix, and no built-in setting or key remap can point them at a single app. To change just one app, add a per-app mixer that creates a real level for each app, then drive that level from the keyboard. Background Music does it for free from the menu bar; SoundSource does it with more depth for $49; Fader does it from a keyboard shortcut so "just turn that one thing down" stays as fast as the key tap you reached for in the first place.