Background Music vs Fader: free vs fast, which per-app mixer to pick

Pick Background Music if free and open source is the priority and you don't mind reaching for the menu bar: it gives every app its own volume slider and even auto-pauses your music, at no cost. Pick Fader if you change levels constantly and want them under your fingers — it's a paid Mac App Store app that turns your keyboard into a per-app mixer and can also route each app to its own output. Both solve the same core problem; they differ on price and on how fast you reach the controls.

macOS still ships no built-in volume mixer — one master output, and that's it. Both of these apps exist to fill that gap, and both genuinely do. So this isn't a "which one works" question; it's a "which tradeoff fits you" question. Below is an honest look at each, including the parts of Background Music its own developers are upfront about.

What Background Music is

Background Music is a free, open-source macOS audio utility (GPLv2) from Kyle Neideck and contributors. It installs a virtual audio device, makes that your default output, and then gives you a per-app volume slider for everything playing through it. Its headline extra is auto-pause: it can automatically pause your music player when other audio starts and resume it when that audio stops. It can also record system audio and let you boost a quiet app above its normal level. All of this is free, and the source is on GitHub for anyone to read or build.

It's a genuinely useful, well-liked tool, and the price is unbeatable. A few things are worth knowing going in, and to its credit the project states them plainly. Its README still describes the app as being in alpha. Because it works by installing a virtual audio device, it requests microphone permission and relies on that device staying in place. Output is stereo-only, and the docs note that pushing app volumes high can cause clipping. None of these are dealbreakers for most people — they're just the shape of a free, driver-based tool, and you should know about them before you install.

What Fader is

Fader is a paid per-app volume mixer and audio router for Mac, sold on the Mac App Store for $19.99 one-time with a 3-day free trial. It does the same core job — every running app gets its own level — but its whole design is about reaching that level fast. You hit a toggle hotkey and your keyboard becomes the mixer: one column of letter keys per app, so you ride volumes without moving your hands to the menu bar or the mouse. It can also send each app to its own output device, so music can stay on speakers while a call goes to your headset. It runs on macOS 14.4 or later and, being a sandboxed App Store app, installs without you managing a separate audio driver.

Fader is not free and it is not open source, and it doesn't try to do everything Background Music does — it has no auto-pause and isn't a system-audio recorder. The trade is focus: speed of control and per-app routing, paid for once.

Side by side

Read the table honestly and the split is clear. Background Music does more for $0 — auto-pause and recording are real features Fader doesn't have. Fader does less, faster, plus routing. Which column matters depends entirely on how you work.

Why the keyboard is the real difference

Both apps can set Spotify to 30% and a call to 100%. The gap you actually feel is the number of steps to get there. With a menu-bar mixer, every change is: move to the menu bar, click the icon, find the app's row, drag the slider, dismiss the panel. That's fine a few times a day. If you're riding levels across calls, music, and a browser all day long, those five steps repeated dozens of times are exactly the friction that makes people stop using a mixer they installed.

Fader's bet is that the fastest controller you own is the keyboard already under your hands. Toggle it on, tap a couple of letter keys, you're done — no pointer, no hunting. If your honest usage is "set it and forget it," Background Music's menu bar is completely fine and free. If your usage is "constantly," the keyboard is the difference between owning a mixer and using one.

Which should you pick?

Choose Background Music if cost is the deciding factor, if you specifically want auto-pause or system-audio recording, or if you're comfortable with an alpha-stage, open-source tool that installs a virtual audio device. It's a great answer and it's free — try it first and you may be done.

Choose Fader if you change app levels often enough that speed matters, if you also want to route apps to different outputs, or if you'd rather have a sandboxed App Store install and pay $19.99 once than manage a driver. The 3-day trial means you can find out for yourself before paying. If you're weighing a wider field, see the SoundSource alternatives roundup, and if you just want the full menu of options, start with how to control individual app volume on a Mac.

Bottom line

There's no loser here. Background Music is a free, open-source per-app mixer that also auto-pauses your music — hard to argue with at $0, with the honest caveats that it's still alpha and built on a virtual audio device. Fader is the paid, keyboard-first take: fewer extras, but the controls live under your fingers and it routes audio per app. Free vs fast. Try Background Music if price leads; reach for Fader if you change levels all day and want them a keystroke away.