Three apps,
three different jobs.

These three get put in the same list constantly, and they are not really the same kind of product. Sorting out what each one is actually for eliminates most of the choice.

The short version

SoundSource 6 — the deep one

Rogue Amoeba have been making Mac audio software for over twenty years, and SoundSource is the most mature product in this category by a wide margin. Version 6 arrived in December 2025 at $49 ($25 to upgrade), requiring macOS 15 and supporting up to macOS 26.

What you get for that:

• Per-app volume, per-app output redirection, and per-app effects.
• A 10-band equaliser and full Audio Units support — you can drop third-party plugins onto an application's audio, which is a genuinely different order of capability from a fixed band count.
• Grouped output devices — play through several outputs at once — and per-app AirPlay, so an application can go to a HomePod or a Sonos.
• Quick Configs for saving and loading complete audio configurations, system-wide effects, Shortcuts support, headphone EQ, and a cough button.

Where SoundSource wins outright: depth, track record, and the Audio Units support. If you want to run a real compressor or a specific plugin on one application's audio, or you want an app to play to an AirPlay speaker, nothing else here does that. It is also from a developer with a two-decade history of surviving macOS transitions — which, given what Tahoe did to audio capture, is worth real money.

The trade-off: $49 with no free tier, and a feature surface that is a lot to take on if all you wanted was to turn Spotify down.

Boom 3D — the enhancer

Boom 3D from Global Delight is usually filed under "per-app volume" and that is a misreading of what it is. It is a loudness and spatial enhancement app: a volume booster, a system-wide equaliser, and a 3D surround effect that spatialises multichannel content for headphones. Per-app volume is a supporting feature, not the point.

On the Mac App Store the app is free with a lifetime unlock as an in-app purchase — listed at $49.99 with a frequently discounted tier — and it also appears in the Setapp subscription bundle. It supports macOS 11 or later, which is a much wider net than the other two.

Where Boom 3D wins outright: if you want your Mac to be louder and more spacious, that is what it is built for. Its surround processing and boost do something neither of the other two attempts. It also supports far older Macs, which matters if you are on hardware that cannot run macOS 15.

The trade-off: it installs an audio component to do its work, and you may hit macOS's system extension approval flow along the way. Its EQ is system-wide rather than per app, so tuning music also tunes your notification sounds and your calls. And because boosting is the core idea, it is the wrong tool if your actual problem is balance between apps rather than absolute loudness.

MixPill — the narrow one

Ours, so here is the shape of it rather than a sales pitch. MixPill does one thing: every application that is making sound gets a row with a fader, a mute, a solo and a true dBFS meter.

• The free tier is not a trial. Per-app volume, mute, solo, metering, undo and keyboard navigation are free for unlimited apps, permanently, with no nag screens. Pro is $24 one-time and adds 5-band EQ with a noise gate, per-app output routing including channel pairs, Auto-Ducking, presets and Shortcuts/App Intents.
• Auto-Ducking works by observation. It watches for any process taking hold of an audio input rather than matching a list of conferencing apps, so Zoom, Meet in a browser tab, a Slack huddle and whatever ships next year all duck background audio to 20% without anyone adding support.
• DAW Direct. A switch on every row that keeps an application entirely out of the signal path — no tap, no processing. Logic, Ableton, Pro Tools, Cubase, FL Studio and Studio One are covered by default. It ships in the free tier deliberately, because a safety switch that only paying users get is not a safety switch. Why that matters.
• The engine runs in its own process. Quit or crash the menu bar interface and playback carries on at the levels you set.
• One permission, disclosed. System Audio Recording, which is what process taps require, plus Accessibility only if you want global hotkeys. Never the microphone — even Auto-Ducking works by asking Core Audio which processes hold an input rather than opening one.

Where MixPill loses: no Audio Units, no AirPlay routing, a 5-band EQ rather than 10, and — the honest one — it is new. SoundSource has twenty years of macOS transitions behind it and MixPill is in beta. If your work depends on this and you want the safest bet, that is a real argument and it does not point at us.

How to actually choose

• You want plugins, AirPlay, or the deepest feature set: SoundSource.
• You want more volume and bigger-sounding audio, or you are on older macOS: Boom 3D.
• You want per-app volume for free, a driverless install, and a DAW that is never touched: MixPill.
• You are not sure: all three have a way to try before paying. An afternoon with two of them settles it faster than any table.

And it is worth knowing the field is wider than three. SoundDial, Submix and others arrived after Apple opened the process tap API in 2024, mostly at lower prices with narrower scope. The category went from nearly nothing to crowded in about eighteen months, which is good for everyone reading this.

Common questions