The audio engine was written a few years ago, and does need a revisit 
This configuration is just there to allow the scene object to have a “main sound track” that is user (or developer)-defined. It is a container for every sound created
No, you don’t. The main sound track will be created for you, and any new sound that is created in the scene will be added to it. There is no need on your part to define a new soundtrack.