In this video I’m going to show you an easy way to record audio sources independently in OBS. This will make adjusting levels in post a breeze.
Advanced audio properties
Right-click in the Audio Mixer and select Advanced Audio Properties. 
Selecting tracks
Select the tracks you want to record. In this example I’m recording Game Audio on track 3 and Microphone on track 2.
Note: I’ve left track 1 selected since it’s the default mixdown track for live streaming. 
Advanced output
Head over to Settings > Output > Output Mode and change it from Simple to Advanced. 
Recording tracks
Now that the Output Mode is set to Advanced you will have access to the Recording tab.
Pick the tracks you wish to record by selecting them in the Audio Track section.
Adjusting levels in post
If everything went to plan your recorded video will have two audio tracks that can be adjusted independently.
