Thank you for your reply. After Instantiate dsgc, the music is added to MasterAudio-GroupControl. Press the Play button on the inspector to get the music. I do MasterAudio.PlaySound in the script, the music won't come out. But the inspector marks "1". Is there any problem you might think of?
Ok, so then the problem is that it was too far away from the Audio Listener to be audible. If you didn't really want 2d sound, then switch back and adjust the Audio Source template (or make your own) and apply it to the Sound Group with a much shorter Max Distance.
I also wanted to mention, since it's related, that I'm finishing up Addressable support for Master Audio. It should be ready in a week or 2. That means you will no longer need to write code to load Asset Bundles if you mark the assets as Addressable. It's a new "Audio Origin" to go along with Resource Files and Audio Clips. Resource Files can also be marked as Addressable but we will keep the Resource File mode for backward compatibility for awhile.
It's taken me about a month to get this done on Addressables and it was pretty difficult due to lack of documentation.