Day traders: keep alert sounds cutting through your music on Mac

To keep a price alert loud while your focus music stays low on a Mac, you need per-app volume — macOS only ships one master level, so raising the alert raises the music with it. The fix: install a per-app mixer, pin your alert app (TradingView, thinkorswim, TWS, or your broker) near full, and hold the music app at 30–40%. Now the alert cuts through every time, and a single hotkey can duck the music the instant a setup fires.

If you trade with a chart on one screen and lo-fi or a podcast in the background, you already know the failure mode. You turn the music up enough to enjoy it, and now the alert ping is buried under it. You turn the music down so you never miss a fill, and the desk is silent all session. There is no comfortable middle with one volume knob — and macOS gives you exactly one knob.

Why your Mac buries the one sound you can't miss

macOS mixes every app into a single output at one master level. The volume keys, the Sound menu, the slider in Control Center — they all move the same number. There is no native Volume Mixer like Windows has, no per-app slider, no way to tell the system "the browser tab with my alerts is important, the music is not." Your $200/hour attention sound and your background playlist are treated as equals.

That is fine for casual listening. It is the wrong model for trading, where one specific app needs to reliably interrupt everything else. You want the alert to behave like a smoke detector: quiet room, loud alarm. The default Mac behavior is closer to turning the whole room's volume up and down together.

The fix: give the alert app its own volume

A per-app volume mixer sits at the macOS audio layer and gives every running app its own level in one place — the control Apple never shipped. Once it is installed, the setup is simple and you do it once:

• Set your alert source (see the table below) to 100%, or boosted above 100% if the app is quiet by nature.
• Set your music or podcast app to something you can talk over — 30–40% is a good start.
• Leave the system master where you like it. You are shaping the balance between apps, not the overall level.

Now the alert ping lands at full strength over quiet music, without you ever touching the master. When you step away from the desk, you turn the whole thing down with one key and the ratio is preserved when you come back.

Where trader alerts actually come from

The "alert app" depends on your platform. Point the mixer at whichever of these produces the sound you can't afford to miss:

One wrinkle worth planning around: if both your alerts and your music live in the same browser, they share one channel and can't be split apart at the app level. Move one of them out — run music in a dedicated app, or your charts in the TradingView desktop app — so the mixer has two separate channels to balance. Splitting audio inside a single browser between tabs is a harder problem; the clean answer is to not put both in the same app.

Why a keyboard beats a menu-bar slider mid-trade

Any per-app mixer can set a level. The difference you feel is how fast you can change it when the market moves. A menu-bar list means: reach for the mouse, travel to the menu bar, click the icon, find the row, drag the slider, dismiss the panel. That is five or six actions at the exact moment your hands should be on the order ticket.

Fader's approach is to make the keyboard the mixer. You hit a toggle hotkey and letter keys become faders — one column is your music, another is your alert app — so you can drop the music to near-zero the instant an alert fires and bring it back when the trade is placed, without your hands leaving the keyboard. You can also bind a dedicated mute key to the music app: one keystroke silences the playlist so an alert has the whole room, and one keystroke brings it back. For something you do dozens of times a session, that speed is the difference between a mixer you configured once and forgot and one you actually ride all day.

If your priority is the reverse — keeping system and app alerts audible over media in general — the approach carries straight over. See how to keep system alerts loud while music stays quiet on Mac for the same idea applied to notification sounds.

The honest option map

You have real choices here, and not all of them cost money. Here is the fair comparison — pick on how you want to reach the control and what you want to spend.

Background Music is genuinely free and open source, and it will give you per-app sliders in a menu-bar list — a solid choice if you set the balance once and rarely touch it, and don't mind the occasional rough edge that comes with unpaid software. SoundSource from Rogue Amoeba is the polished, feature-deep option at $49 one-time, with per-app EQ and routing on top of volume; if you want a full audio toolkit and the price isn't a factor, it's excellent. Fader is $19.99 one-time and bets on one thing: reaching the control faster than anything with a mouse, because a trader changes the balance constantly, not once. All three do real per-app volume — the choice is about speed and price, not capability.

What about sending alerts to a different device?

Some traders want alerts on their desk speakers and music in their headphones, or the reverse. That is routing, not volume — sending one app to a different output device — and macOS won't do it per app either. A mixer with routing can pin your alert app to the speakers so a ping fills the room while music stays private in your headphones. If that's your setup, read how to send an app's audio to a different output on Mac.

Bottom line

One master volume can't serve both a price alert you must hear and background music you want quiet — that's a macOS limitation, not a settings problem you're missing. Give the alert app its own level with a per-app mixer, hold the music low, and the ping always cuts through. Background Music does this for free; SoundSource does it with the most features. If you want to drop the music and bring it back in a single keystroke the moment a setup fires — without lifting your hands off the keyboard — that reach-it-fast angle is exactly what Fader is built for.