Submix notes

Mac volume mixer: is there one, how to open it, and the four real ways to get per app volume

macOS ships no volume mixer: nothing in System Settings can turn one app down on its own. Here is why Core Audio never had one, what Apple changed in macOS 14.2, and the four real ways to get a per app volume mixer on a Mac today, two of them free.

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macOS does not ship a volume mixer, and no setting changes that: one slider moves every app at once. Windows has had a per app mixer since Windows Vista. On a Mac you get one of four other ways, two of them free, and every modern mixer is built on an API Apple only opened in macOS 14.2.

Taperlark makes Submix. This post names other apps, including free ones. Prices and version numbers were checked on the date shown and link to each developer's own page. If we got something wrong about your app, email support@taperlark.com and we will fix it and say what changed. Product behaviour describes Submix as it builds today, and more on the app itself lives on the Submix blog.

Is there a volume mixer on Mac?

Not built in, no. Open System Settings, then Sound, and you get an output picker, an input picker, and one slider. That slider moves everything at once: music, a call, a game, a system alert, all together. No per app row hides behind an Advanced toggle. What Sound settings shows you is exactly what macOS tracks about audio at the process level. Nothing.

The answer does not stop at no, though. Four working replacements exist, two of them free, and the newest kind installs like any ordinary app, with no driver and no admin password. If you only need one specific app made quieter today, the shortest paths to that are collected separately.

Does Mac have a sound mixer hidden in Audio MIDI Setup?

The tool most often pointed to as the hidden mixer is Audio MIDI Setup, tucked inside Applications then Utilities, and it is not one. It lets you combine physical outputs into one logical device. A Multi-Output Device duplicates one signal across every device in the set. An Aggregate Device merges several devices' channels into one. Neither looks inside a single app's stream, because both sit one level below any given program, the wrong level for a control meant to follow one process around. Building a bigger pipe is not mixing. One app on the speakers while another goes to headphones is routing, which has its own answer.

The Windows volume mixer equivalent on a Mac

The mixer you are missing sits one click off the speaker icon in the Windows taskbar, and has since Windows Vista. Every app currently making sound gets its own slider there: Spotify at 40 percent, a browser muted, a game at full volume, each independent of the others and of the master level.

The Mac equivalent of the Windows volume mixer is a third party app, and the absence of a native one is structural rather than an oversight. Windows treats a running program's output as its own audio session, with a volume that belongs to the session rather than the shared mix. Core Audio's hardware abstraction layer has never had an equivalent object. What lives there is devices, streams and mix stages, not a handle tied to one process's output. A slider needs something to grab onto, and Core Audio gave outside developers nothing at the process level to grab. A Mac sound mixer like the Windows one therefore comes from outside the OS, through one of the four routes below.

Why macOS has no volume mixer, and what changed in 14.2

Sonoma 14.2 put a hook into the layer that had none. The entry point is a process tap, created by calling AudioHardwareCreateProcessTap against a CATapDescription that names one process by its Core Audio object id. Wrap that tap in a private aggregate device and you get something new: a device whose only job is carrying one app's audio, isolated from anything else the machine is playing. Submix is built directly on that API with no fallback path, which is why its macOS floor, listed on the app page, is the release that introduced the tap. On Sonoma 14.1 or older, Submix does not work, and neither does any other mixer built the same tap based way, because the API underneath it simply is not there yet. That is not true of the whole list below, though. An app's own built in volume control has never depended on any Core Audio API at all, and Background Music's driver based approach predates the process tap by years: its README states plainly, "Requires macOS 10.13+" (Background Music project README, checked 23 July 2026).

How to open a volume mixer on Mac: the four real ways

One. Turn it down inside the app itself

The free option that needs no download: plenty of apps ship a volume control of their own, sitting in Settings or Preferences. If the loud app happens to be one of them, you are already finished. Most apps never bothered to build one, which is why a whole category of Mac utilities exists.

Two. Install a virtual device and make it the default

Background Music takes the oldest route here. Kyle Neideck's project installs its own virtual audio driver, BGMDriver, and asks you to set it as your default output, so every app's sound lands there before Background Music mixes it and hands the result to your real hardware. It is free and open source under GPLv2 or, at your option, any later version (project README and GitHub license metadata, checked 23 July 2026). Its README calls itself "still in alpha," and under its own known issues heading states that volume above 50 percent on one app can cause clipping, and that only two channel stereo output is supported (checked 23 July 2026). It also requests microphone permission for a reason unrelated to listening to you: the README says it gets your system audio from its own virtual input device, which macOS classifies as a microphone regardless of what is recorded (checked 23 July 2026). When it stops working after a macOS update, what is fixable and what is architectural is covered separately.

Three. Trade an admin password for a plug in

SoundSource goes through a plug in instead. On macOS 14 and later, Rogue Amoeba's own ARK plug in performs the audio capture and routing, and the company states plainly that ARK has to be installed for SoundSource to work at all (Rogue Amoeba support documentation, checked 23 July 2026). Rogue Amoeba's documentation also states that installing or updating it needs the Mac's administrator password, and that the app separately needs two permission grants, System Audio Access and Microphone Access for ARK (Rogue Amoeba support documentation, checked 23 July 2026). Rogue Amoeba lists a mature feature set behind that: per app volume, per app output redirection, and a 10 band equalizer with Audio Unit support (rogueamoeba.com, checked 23 July 2026). That costs $49 USD one time, with a $25 USD upgrade for existing SoundSource 5 or 4 owners (rogueamoeba.com, checked 23 July 2026). One correction worth making plainly: this is not a 14 day trial. Rogue Amoeba documents that after 20 minutes, noise is overlaid on any audio being adjusted, and relaunching resets it (Rogue Amoeba support documentation, checked 23 July 2026). The 14 days belongs to the refund policy instead, case by case (Rogue Amoeba refund policy, checked 23 July 2026). If the price gives you pause, the SoundSource alternatives get their own honest comparison.

Four. Tap the process instead of rerouting the machine

The fourth route is what macOS 14.2 made possible: reach into the one process you care about instead of rerouting everything. FineTune, a free and open source mixer by Ronit Singh, is built on Apple's Core Audio process tap APIs together with aggregate devices, and its repository contains no audio server plug in, kernel extension or system extension. That is my own finding from reading its source, not a claim the project makes about itself (source inspection, checked 23 July 2026). Submix works the same way, and it is the approach I chose to build. Each controlled app gets its own tap, created with a CATapDescription scoped to that process and marked private, wrapped in a private aggregate device whose main sub device is your real output. An IOProc on that aggregate reads a gain value, multiplies every sample by it, and tracks the peak in the same loop so the meter costs nothing extra. Nothing in that chain installs a driver, kernel extension, or system extension. If you also need one app sent to a specific output device rather than just turned down, Submix does that too, covered separately in a piece on sending one app to a different output.

Every audio mixer for Mac shares three costs

A purple dot you cannot turn off

macOS shows a purple recording indicator in the menu bar whenever an app captures audio through the system, and everything here that reaches into another app's stream trips it in some form. Rogue Amoeba documents that the indicator is entirely controlled by Apple, and that hiding it is not currently possible (Rogue Amoeba support documentation, checked 23 July 2026). Background Music is a partial exception: its own release notes for version 0.5.0 state that it now stops processing audio when nothing is playing, specifically so its microphone indicator will not show at those moments, and that it still shows while audio is actually playing (Background Music v0.5.0 release notes, checked 23 July 2026). Submix needs the same permission, macOS Audio Recording, and because there is no public way to check for it in advance, it resolves a private symbol inside TCC.framework with dlopen and dlsym, falling back to a short, unmuted capture probe if that symbol cannot be found. The permission check and the fallback probe behind it are covered in full elsewhere. The permission text is set at build time and reads, word for word: "Submix reads app audio so you can set each app's volume independently. Nothing is recorded, saved, or sent." I did not soften that copy for this post.

Some audio no tap can reach at all

There is a category of playback a tap was never going to see. A tap works by observing what another process is already rendering to a device, and content built to protect itself from other processes is not going to hand over its decoded samples just because a tap asked politely. I have not found an Apple page that states this in language I can quote, so I am not attributing a sentence to Apple here. What I can give you is the shape of the constraint, which follows from what a tap actually is, not from any test I ran.

One more pass before your audio reaches the speaker

Submix builds one tap per controlled app inside a private aggregate device whose main sub device is your real output, and that adds a callback the signal was not taking before. The cost is not zero. I have not published a number for it, because I have not measured one. It runs once per sample, for every app you are actively adjusting rather than leaving alone.

Two things Submix does not do, said plainly

Submix keeps per app volume, mute, live meters, per app output routing and boost genuinely working, and I would rather list what does not survive a restart than let you find out the hard way. Per app volumes and mute states live in an in memory dictionary the source comments as session only, with no disk persistence, so quitting Submix or logging out clears every adjustment you made. Set Chrome to 40 percent today, and tomorrow it starts back at 100. Boost is a straight linear multiply capped at 2.0x, with no limiter, soft knee, or clipping protection in the path, so a channel already near full scale will clip, because the only guard in that chain sits on the gain value, not on the samples it produces. Neither is a bug I have not gotten to yet. Both are the shape of the feature as it ships.

Which macOS volume mixer is actually right for you

If the loud app already has its own volume control, use it and skip the rest of this post. Want simultaneous output to two speakers without controlling apps independently? That is a Multi-Output Device, not a mixer, and it costs nothing. If a free driver based mixer works for you, stereo limit and alpha label included, Background Music is real. Need the deepest feature set and do not mind an admin password and a purple dot? SoundSource is a mature, paid product from a company that has built Mac audio tools for years. The tap based approach without paying is FineTune, free and built the same way Submix is. I built Submix for that approach, with the restore behaviour and the interface I wanted myself, and I sell it because getting that right took real work, not because the other three are wrong for everyone who is not me.

If option four is the one you are after, here is what Submix actually gives you.

Changelog: first published July 2026. September 2026: retitled and restructured around the questions people actually type.

Frequently asked questions

Does Mac have a volume mixer like Windows?

No. Windows has shipped a per app mixer since Windows Vista, one click off the speaker icon. macOS has never had an equivalent: System Settings controls one output device through one master slider. To mix apps independently on a Mac you need a third party mixer, and free options exist.

How do I open the volume mixer on a Mac?

There is nothing to open in macOS itself, because no built in mixer exists. Install one instead: a tap based mixer such as Submix or FineTune on a Mac recent enough for the process tap API, or the driver based Background Music, then open it from the menu bar to see a slider per app.

What is the Mac equivalent of the Windows volume mixer?

A third party per app mixer. Since macOS 14.2, apps can attach a process tap to one program's audio and scale it independently, which is the same job the Windows mixer does natively. Before that API existed, the only routes were a virtual audio driver or each app's own volume control.

Can Audio MIDI Setup mix the volume of individual apps?

No. Audio MIDI Setup builds Multi-Output and Aggregate Devices, which duplicate or combine whole output devices. Both operate below the level where individual apps exist, so neither can turn one app down on its own. It solves simultaneous output to several devices, a different problem from mixing apps.

Is there a free volume mixer for Mac?

Yes, two real ones. Background Music is a free, open source, driver based mixer with a stereo only limit its README documents. FineTune is a free, open source mixer built on the newer process tap API. An app's own built in volume slider, when it has one, costs nothing either.

Why does a Mac volume mixer need microphone permission?

Because macOS files system audio capture under the same permission category as the microphone. A mixer reading another app's output through a process tap, or through a virtual input device the way Background Music does, needs that grant even though your actual microphone is never touched.

  • SoundSource 6 is a trademark of Rogue Amoeba Software, LLC.
  • FineTune is a trademark of Ronit Singh.
  • Background Music is a trademark of Kyle Neideck.

Taperlark is not affiliated with, endorsed by, or sponsored by any of these companies.

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