Adding volume control to unsupported devices

When connected to a Mac, many audio output devices fail to provide proper volume adjustment. Displays connected via HDMI or DisplayPort, as well as many other non-standard digital devices, simply offer no output controls. As a result, MacOS won't let you adjust the volume level for these devices, and the volume keys on your keyboard won't have any effect.

Our audio control utility SoundSource works behind the scenes to provide volume adjustments for all audio devices. This makes it possible to control the volume levels for any audio output, even those that don't allow it by default.

Basic volume control

With SoundSource running, the volume level of any output device can be adjusted, even those which ordinarily offer no volume control. When such a device is set as the system output, the slider in SoundSource's main window will adjust the levels heard through the device.

Volume controls for any system output device can be adjusted in the main window.

Just move this volume slider up or down to adjust the volume level heard through the device.

Make keyboard volume keys work too

Ordinarily, when using an audio device with no default volume control, pressing the keyboard's volume keys will result in no change to what you hear. Instead, this frustrating on-screen display is shown, indicating the volume level can't be changed:

From frustration…

With SoundSource's Super Volume Keys feature, this limitation is removed. After you activate Super Volume Keys in SoundSource, your keyboard volume keys will work exactly as you expect, adjusting volume levels up or down.

…to success!

Activating Super Volume Keys

To turn on Super Volume Keys, open SoundSource's Preferences window, and turn on the Super Volume Keys checkbox. Your keyboard volume keys will then be able to adjust any audio device you set as the System Output.

SoundSource’s preferences window, showing Super Volume Keys enabled.

When you first activate Super Volume Keys, a one-time authorization is required to allow SoundSource to control your Mac via the Accessibility controls. For more details, see this article.

Forcing volume controls on problematic devices

In rare cases, problematic audio devices incorrectly report volume controls to MacOS, but fail to respond to volume adjustments. This unusual error can prevent SoundSource from providing the volume adjustments you expect, even when Super Volume Keys is enabled.

Fortunately, SoundSource can work around the issue, using its Force software volume control option. When activated from SoundSource’s Debugging window, a software-based volume control will be applied to those problematic devices.

SoundSource’s debugging window, which includes the Force software volume control hidden preference

To access the Debugging window, start by clicking on the Options (Gear) menu in the SoundSource’s main window, then navigating to the Help menu. From there, hold the Option key on your keyboard, and you'll see the Contact Us option replaced with a Quit and Relaunch for Debugging option.

Selecting that will quit SoundSource, and relaunch it to the Debugging window. In the Hidden Preferences section, the Force software volume control option offers a pop-up button, which you'll use to select specific devices to have forced software volume controls applied.

Once you’ve selected the desired device(s), click the Done button to finish launching SoundSource. You will now be able to adjust the device’s volume as expected.