External Monitor Speakers Too Loud or Stuck on Mac

If your Mac's volume keys are greyed out or do nothing for a monitor connected over HDMI or DisplayPort, that's usually not a bug. Many displays take digital audio at a fixed level and expect you to set the volume on the monitor itself. The fix is to adjust the display, or send audio to a device macOS can control.

Why the Mac volume keys stop working over HDMI/DisplayPort

HDMI and DisplayPort carry audio as a digital stream. Many monitors receive that stream at a fixed level and handle loudness on the display. When that's the case, macOS doesn't offer its volume slider for the device, and pressing the volume keys shows a "not available" symbol.

That's the display's design, not a setting you missed. Knowing that saves you from chasing the wrong fix.

Fix 1: Use the monitor's own controls (OSD)

This is the real solution for most people. Nearly every monitor with speakers has an on-screen menu driven by buttons or a joystick on the back or underside.

• Press the menu button to open the monitor's settings.
• Look for an Audio or Volume section.
• Lower the level there. This is the control that actually works over HDMI/DP.

Some monitors also have a companion app or support DDC/CI, a standard that lets a computer adjust display settings. Third-party Mac utilities that use DDC can control the monitor's volume from the Mac, which is worth trying if you don't want to reach for the buttons.

Fix 2: Check Audio MIDI Setup

Open Audio MIDI Setup (Applications > Utilities). Select your monitor in the device list. If a volume slider appears for it, drag it down: some displays accept a software level even when the volume keys don't work. If there's no slider or it's greyed out, the display only takes fixed-level audio, and you should use the monitor's menu.

While you're there, check which device is the output. It's common for audio to go to a monitor you forgot was connected, which explains sudden loud or missing sound. You can also check this in System Settings > Sound > Output.

Fix 3: Send audio to something you can control

If your monitor's speakers aren't great anyway and their volume control is clumsy, the cleanest fix is to stop using them:

• Plug speakers or headphones into the monitor's headphone jack, if it has one. That output can often be adjusted from the display.
• Use USB speakers, a USB audio adapter, Bluetooth headphones or speakers. These usually give macOS full volume control, so your keys work again.
• Use your Mac's built-in speakers for everyday sound and keep the monitor for video.

Once you're on an output macOS can adjust, the system volume keys work and you get fine control instead of the monitor's coarse steps.

Once output works, control volume per app

A controllable output fixes the "too loud / stuck" problem. But macOS still gives you only one volume level for everything, so a loud video, a game and a quiet call all share the same slider.

That's the gap SoundDial fills. It's a menu-bar app that gives each app its own volume slider: turn a browser down without touching your music, mute one app, or boost a quiet one up to 200%. More on this in per-app volume control on Mac.

To be clear about scope: SoundDial adjusts each app's volume on your Mac. It doesn't change the monitor's own volume setting; for a display that ignores the Mac's volume, the monitor's menu or a different output is the fix. SoundDial's panel does have an output picker that switches the Mac's system output, which is a quick way to move off the monitor speakers, and a master volume slider, but that slider can't control a display that only takes fixed-level audio.

Quick checklist

• Keys greyed out over HDMI/DP? Use the monitor's own volume. That's expected.
• Check Audio MIDI Setup for a software volume slider.
• Confirm the right output device is selected.
• For full control, use the headphone jack, USB or Bluetooth.
• Then set individual apps with a per-app mixer.

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.

Get SoundDial on the Mac App Store.