Can not deactivate World Audio Data Subsystem

Does anyone know how to deactivate the World Audio Data Subsystem?
I made a simple blueprint to run the ambient sounds in the City Sample. The sounds play with the activate functions but keep playing when I try to deactivate them :frowning_with_open_mouth:

WorldAudioDataSubsystem.cpp (18.0 KB)
Is there something wrong with this code? I don’t know programming and I don’t know what I’m doing.