Control only one app with your knob or hotkeys

Use your knob or hotkeys to control only Discord, Spotify or another app’s volume, even while you use another window.

1Open the app you want to control

Start Discord, Spotify or your chosen app and play some audio. KnobMixer works with apps that appear in the Windows volume mixer. Playing sound helps your app appear in the list.

2Set up a Specific apps knob

Open KnobMixer and click Add knob at the top of the main window. You can also click an existing knob to edit it.
Under What this knob controls, select Specific apps.
Below, you will see an Add app button. Click it and choose the app you want to control.
Set your controls below under Hotkeys: click the Vol − and Vol + fields to assign your knob directions or keys, and assign Mute if you want it. Click Add knob for a new knob, or Done if you are editing one.

Common questions

Does Discord or Spotify need to stay in focus?

No. A Specific apps knob keeps your controls assigned to the app you selected, even while you use another window. An Active Window knob follows the app currently in focus instead.

Can I use the same knob to control more than one app?

Yes. Add the apps you want to control to the knob’s assigned list. When Cycle between assigned apps is off, your volume controls adjust those apps together. Turn it on and assign a Cycle control if you want to switch between the assigned apps and adjust them one at a time.

Why does my app not appear in the list?

Open the app and play some audio, then check that it appears in the Windows volume mixer. KnobMixer needs the app to have an audio session before it can control its volume.

Why do my controls still change Windows master volume?

Make sure this knob is enabled, is set to Specific apps, has your app assigned and has both volume controls saved.

Also check that the app in focus is not running as administrator, such as Task Manager. To use your controls over administrator apps too, follow the Launch with Windows as admin guide.

If your input is not recognised, try Settings → Diagnostics → Knob check. If the issue continues, send a report from Settings → Diagnostics → Report a problem. Leave Include log files on and add your email so support can investigate and help resolve it.

Keys assigned to KnobMixer are used by KnobMixer while it is running. Choose keys you do not need for another action at the same time.

Next guideGetting started with KnobMixer →