Why won't macOS let me set volume per app?

macOS won't let you set volume per app because every built-in control — the volume keys, System Settings > Sound, and Control Center — moves one master level for the whole machine, not a level per app. Apple never shipped a consumer panel with a slider per application, so there's no native way to set Spotify to 30% while a call stays at 100%. The capability exists in Core Audio under the hood; it just isn't exposed on any screen Apple ships. To get real per-app volume, you add a small third-party mixer that puts a face on what's already there.

If you've landed here, you've probably already tried the obvious things and watched every one of them fail. You turned down the volume to quiet a loud app and your music went with it. You dug through System Settings looking for a per-app list and found one slider. You opened Control Center hoping for a hidden panel. None of it does what Windows switchers expect, and it isn't because you missed a setting. It's because macOS is built around a single output level by design. Here's exactly why each path you tried doesn't work — and the one approach that does.

The core reason: one master level, mixed before it reaches your ears

macOS treats sound as a single shared resource. There is one selected output device and one master volume in front of it. Every running app's audio is mixed down into that one stream before it hits your speakers or headphones. By the time the signal reaches the volume you control, the individual apps have already been blended together — so the only thing left to turn is the whole mix at once.

That's why turning the system down to take a call ducks your music too, and why there's no obvious place to say "this app quieter, that one loud." The knob you're reaching for sits at the wrong point in the chain. It adjusts the finished blend, not the ingredients. Apple designed it this way on purpose: one slider, one place, predictable for everyone. It's simple until the day you actually need two apps at two different levels.

Why each built-in control fails you

Every native path leads back to that same single master level. It's worth walking through them, because each one looks like it might be the answer right up until it isn't.

The volume keys, the Sound pane, and Control Center are three doors into the same room — they all move the master level. An app's own slider (Spotify's, a browser tab's, VLC's) does control just that app, but only apps that ship a slider have one, and system alerts, games, and plenty of utilities don't. Audio MIDI Setup looks promising because it's the deepest audio tool Apple ships, but it manages devices and sample rates, not per-app playback volume. There's genuinely no built-in screen where you set one app's level against another.

The part that surprises people: the Mac can already do it

Here's the twist. The limitation is in the interface, not the engine. Core Audio — the low-level audio system inside macOS — can absolutely apply volume on a per-app basis. That's not a workaround or a hack; it's the exact mechanism every third-party mixer uses to give each app its own level. If the Mac truly couldn't do per-app volume, those apps couldn't exist.

So "macOS won't let me" is really "macOS won't surface it." Apple built the plumbing for per-stream volume and routing, uses it internally, and simply never put a consumer-facing panel on top. Your Mac is perfectly capable of holding a call at 100% while music plays at 30% — it just won't do it from any menu Apple ships. For the fuller story on Apple's reasoning, see why there's no Windows-style volume mixer on macOS.

The fix: add the panel Apple left out

Because the capability already lives in Core Audio, closing the gap doesn't take a kernel extension or a risky hack. It takes a small app that puts a face on what's already there. These tools sit at the OS audio layer and give every running app its own level in one place — including the apps that have no slider of their own. That's the only approach that works system-wide, and the only one that lets you set a mix once and reach it again instantly.

All four are honest options and they overlap more than the marketing suggests. Background Music is free and open source, and if a menu-bar list of sliders is all you want, it does the job at zero cost. SoundSource is the deep, polished choice — routing and a real EQ in one panel — and its $49 one-time price reflects that. The three mixers all set per-app volume; the difference you feel day to day is how fast you can reach the control.

Why reaching the control fast is the whole game

Setting a level once is easy. The friction is doing it twenty times a day. A menu-bar list means move to the menu bar, click the icon, find the row, drag the slider, dismiss — five actions for a change you make constantly. That's the gap between "I have a mixer installed" and "I actually use it."

Fader's bet is that the fastest controller you own is already under your hands. You tap a toggle hotkey, the keyboard becomes a mixer — the Q/A/Z column is one app, W/S/X the next — and you ride levels with letter keys without leaving what you're doing. It's the same per-app control the others give you, reached in a keystroke instead of a hunt. If you want the plain "yes, and here's how" version of this, read can you have different volumes for different apps on a Mac.

Bottom line

macOS won't let you set volume per app because its built-in controls only ever move one master level — the finished mix, not the individual apps. It's a UI decision, not a capability gap: Core Audio can already do per-app volume, and third-party mixers prove it daily. For an occasional tweak, an app's own slider is free and fine. For a real per-app mix across calls, music, and everything else all day, add a dedicated mixer. If reaching that control in a single keystroke is what you care about, that's exactly what Fader is built for.