confusing "Audio source" setting

[climbTheStairs]

I'm quite confused by the options for "Audio source" in the app settings.
For example, what does "Android default" mean, and why isn't it the default option?
I've tried testing with different options and I can't hear any difference.

Could this setting be made clearer, perhaps with information about what each option means and how one would choose an audio source, or at least an entry in the FAQ?

[inson1]

@climbTheStairs SMT apps were sold to ad company. Fork is here https://github.com/FossifyOrg