I started plugging your code into a B4A project here, and immediately fell over your .Initialize call:
and how the IDE pop-up help says to do the .Initialize call:
View attachment 163301
Are you using B4A (not B4I or B4J) and using the built-in internal Audio library? (shows as version 1.71 here, but any version should work)
Or are you using some third-party replacement library? What do you mean by fell over?