How to quiet Slack notifications without muting your music on Mac

Slack only lets you turn its notification sound on or off — there is no volume level for it in Slack or in macOS. So if a Slack ping or huddle is louder than your music, your two real choices are: silence Slack's sound entirely with the built-in toggle, or give Slack its own volume with a per-app mixer so you can pull it below your music instead of killing it. Turning down the Mac volume keys won't work — they lower Slack and your music together.

This trips up almost everyone on back-to-back calls. You want the little knock when a message lands, but not at the same level as the track you're working to — and definitely not so loud it clips over a huddle. macOS gives you one master output for everything, so the obvious move (nudge the volume down) drags your music down with it. Here's what actually works, from free to fast.

First, know what Slack actually gives you

Slack's notification sound has an on/off switch, not a dial. Open Slack, click your profile picture, choose Preferences → Sound & appearance, and you'll find checkboxes like "Mute all messaging sounds from Slack" and "Mute all huddle sounds from Slack." On macOS 12 and later, the banner sound is also governed by System Settings → Notifications → Slack → Play sound for notifications. Every one of these is a toggle. None of them is a slider. Slack cannot make its own ping quieter — only present or gone.

That's the crux of the problem. "Quieter than my music" is a level, and neither Slack nor macOS exposes one for it. So the fix depends on which you actually want: the sound off, or the sound down.

If you just want the ping gone (free)

If the honest answer is "I don't need the sound at all, just the badge," the built-in toggles are the right tool and they cost nothing:

• In Slack: Preferences → Sound & appearance → check "Mute all messaging sounds from Slack." Your music keeps playing; only Slack goes silent.
• In macOS: System Settings → Notifications → Slack → turn off "Play sound for notifications." You still see the banner, without the sound.
• Set a channel's own preference: right-click a channel → Notifications → mute or change its alert so only priority channels make noise.

This is the cleanest free path, and it only touches Slack. The limit is obvious: it's all-or-nothing. You lose the audible cue entirely. If a quiet knock is genuinely useful to you, off isn't what you wanted.

If you want Slack quieter, not silent (a per-app fader)

To keep the ping and hold it below your music, you need something Apple never shipped: a per-app volume control. A per-app mixer sits at the audio layer and gives every running app its own level in one place. Slack's audio — huddles, calls, and the in-app message sounds it plays through its own output — goes onto its own fader. Pull Slack to, say, 40% and leave Spotify at 100%, and the two finally stop fighting.

This is also the only approach that handles Slack's huddles and calls, which are full audio streams, not just a one-shot ding. A toggle can't ride those; a fader can. Tools that do per-app volume on a Mac include Background Music (free, open source), SoundSource by Rogue Amoeba (paid, deep, with EQ), and Fader (paid, keyboard-first). They all set a level — where they differ is how fast you reach it.

Why the keyboard matters here

Slack loud isn't a one-time setting — it's a moment-to-moment thing. A huddle starts and you want it up; a song hits a quiet passage and Slack's knock suddenly feels loud; someone joins a call and you want to duck your music. If reaching the control means going to the menu bar, clicking an icon, finding Slack's row, and dragging a slider, you won't bother — you'll just yank the master and lose your music mix again.

Fader's whole bet is that the fastest controller you own is the keyboard already under your hands. You hit a toggle hotkey and the keyboard becomes a mixer: one letter column is Slack, the next is your music, and you ride levels with keystrokes without leaving what you're doing. You can also bind a per-app mute key, so "silence Slack right now, this call just got serious" is one keypress — and your music never moves. That's the difference between owning a mixer and actually using it twenty times a day.

A quick setup that just works

1. Decide the split. Notification cue, or full huddle audio? A cue you can often solve with Slack's own channel settings; a huddle needs a fader.
2. Keep your Mac's master output where your music sounds right. Don't use it to quiet Slack.
3. Give Slack its own level in a per-app mixer, set a comfortable ceiling (many people land around 30–50%), and leave your music app alone.
4. If you want it faster, bind a mute or a nudge-down hotkey to Slack so you can duck it mid-call without touching your music.

If your bigger problem is that system beeps and alerts also step on your music, the same principle applies — see how to keep system alerts loud while music stays quiet on Mac. And if a single global mute key is all you're after, here's how to set a keyboard shortcut to mute an app on Mac.

Bottom line

Slack gives you an on/off switch for its sound, never a volume. If silent is fine, the free toggle in Slack's Sound & appearance settings — or the sound switch under System Settings → Notifications — does the job and leaves your music alone. If you'd rather keep Slack audible but quieter than your music, that's per-app volume, and it's exactly the gap macOS leaves open. A per-app mixer fills it; if reaching the control in a keystroke is what you care about, that's what Fader is built for.