If you've experimented with settings in the output mixer section of your profile and want to reset all of the output mixer to default settings, the tutorial below will be helpful.
Click the settings button on your profile
Select the 'Output Mixer' tab
Click the 'Tuning Wizard' button.
Select 'Reset To Defaults' and click 'Next'-->'Finish'
All settings in your output mixer have now been reset to factory defaults for the selected profile.
Alternatively, you can simply delete a profile by hovering over it, selecting 'Delete' and then auto-detecting new games by following these simple steps: https://www.simxperience.com/slides/slide/how-to-auto-discover-games-profiles-47?search_category=44
This would reset the entire profile, not just the output mixer.