There are two main ways audio can be used in a vMix production, using either the built in audio mixer (basic) or an external mixer (advanced).
Both approaches are described below.
In the diagram above, all audio sources such as Microphones and Cameras run directly into vMix.
Make sure that vMix Audio is selected as the Recording Audio device within the Audio Settings
when using this setup.
This is the Master audio mix from all inputs in vMix, including Cameras, Microphones and Videos will be recorded according to the levels set in the built in Audio Mixer.
Make note of the Automatically Mix Audio setting as this determines if audio sources are automatically muted when not in use.
In the diagram above, all external audio sources such as Microphones are connected to a separate external Audio Mixer.
The Speaker Output of your PC should also be plugged into the external Audio Mixer and will contain audio from vMix inputs such as video clips.
The final output of the Audio Mixer should then be plugged into the microphone or line input on your PC.
Preventing audio loops and feedback is key. Make sure any external audio sources are connected to the external Audio Mixer
instead of vMix. When adding capture (camera) inputs in vMix, the audio source should be set to None.
The final step is to make sure that Microphone or Line Input is selected as the Recording Audio device within Settings - Audio
Under the above setup, the Microphone audio will arrive earlier than the cameras in vMix.
To compensate for this an Audio Delay value can be setup for the Recording and External Output in milliseconds.
The correct value to enter is a matter of trial and error, but should be approximately 120 for PAL and 100 for NTSC.
Once the Microphone audio is correctly in sync, the audio on video clips played in vMix may become delayed.
To compensate this set a negative audio delay under Settings - Audio - Default Input Audio Delay that matches
the audio delay above, for example -120 for PAL and -100 for NTSC.