This only works for MBG; MBP removed the function.
I don't remember quite fully how I did it before, so I apologize.
However, I can tell you this:
A. To make sounds at the start of a level.
1. Open Level Editor.
2. Go onto Creator mode.
3. MissionObjects > Environment > AudioEmitter
4. Type in anything for Object Name
5. Under sound profile, click the sound that you want to hear at the beginning.
6. Choose AudioLooping2D for theSound Description.
7. Tick the use profile's desc? box.
8. Untick the Is 3D sound? box.
9. Click OK.
10. Save the Level.
11. Reload the Level.
13. Keep tinkering with this to further discover.
14. Post any new discoveries here.
15. Thank you.
16. Very Much.