Stereo Mix is the name of the output stream (virtual audio device) after all the channels are combined. This means that when you use this device as a recording device, everything that happens on your computer is routed through it. In a recording application like Audacity, you can choose Stereo Mix as the source instead of a microphone.
Stereo Mix is a feature in Windows 10 that allows you to record audio using another program as a source. If Stereo Mix in Windows 10 doesn’t work, doesn’t display, or doesn’t record sound from the source, here’s how to fix the problem.