Mac Audio Mixer for Streamers: Mic, Game, Music

When you stream from a Mac, at least four sources compete for your ears and your viewers' ears:

• Your mic, which has to sit clearly on top
• Game audio, loud and full of sudden spikes
• Background music, which should stay under your voice
• Alerts and chat: Discord, follower alerts, notifications

macOS gives you one output volume for all of it. Windows has a built-in volume mixer; the Mac does not. So the levels have to be set in a few different places. Here is where each one lives.

1. Set your mic level in macOS and OBS

Your microphone is an input, not an app playing sound, so it is set separately:

• In System Settings > Sound > Input, pick your mic and set its input volume so your voice is strong without clipping when you get loud.
• In OBS, the Audio Mixer panel shows each audio source in your scene, including the mic. Adjust its fader there, and use OBS's filters if you want to shape your voice further.

No per-app volume app changes your mic level. That job belongs to macOS input settings and OBS.

2. Use each app's own volume where it has one

Many sources already have a slider of their own:

• Games usually have separate music, effects and voice volumes in their audio or sound options. Turning game music down there often fixes the "music under music" problem.
• Spotify and Apple Music have their own volume slider in the player.
• Discord has an output volume in its voice and audio settings, and you can right-click a user in a voice channel to change how loud that person is for you.

Set these first. They stay where you put them inside each app, and they often affect what OBS captures as well.

3. Set stream levels in OBS

OBS decides what goes out to your viewers. Its Audio Mixer lets you set each captured source (desktop audio, mic, or individual apps if your capture setup supports it) at its own level for the stream. Check the OBS documentation for the capture options available on your version of macOS.

Before going live, do a short test recording and listen back. It is the only reliable way to hear what viewers will hear.

4. Set what you hear, per app

The part macOS leaves out is controlling how loud each app is on your own Mac: the game a bit lower, Discord a bit higher, music almost silent while you talk. That is what SoundDial does.

It lives in the menu bar, and every running app gets its own slider:

• Turn one app down (the game during a loud cutscene) without touching Discord or your music
• Mute one app with one click, for example a browser that starts playing something mid-stream
• Boost a quiet app above 100%, up to 200%, when a game or video is too soft even at full volume

You can set the levels by hand as the stream goes, or save a mix as a profile and apply it with one click. Note that auto-duck is on by default: while Discord or another call app uses your microphone, SoundDial lowers your other apps to 30% of their level and restores them afterwards. If you don't want that while streaming, turn it off or change "Duck to" in Settings > Auto-Duck. It works per app, not per browser tab, so all tabs of one browser share a slider. It does not record anything.

Whether these per-app levels also change what OBS captures depends on how your capture is set up, so check it in your test recording rather than assuming. More on the basics in how to control per-app volume on Mac.

A simple order of operations

1. Mic: set input volume in System Settings, then its fader in OBS.
2. Game, music, Discord: set their own in-app volumes.
3. OBS: set the stream mix, then test record.
4. Your ears: use per-app sliders for what you hear on your Mac while live.

Getting SoundDial

SoundDial, a per-app volume mixer for Mac, needs macOS 14.2 or later and costs €14.99 one-time purchase on the Mac App Store, no subscription. See how per-app volume control on Mac works, or get SoundDial on the Mac App Store.