This is a tired old riddle. I have it solved. Sound is the result of an event that made noise. It is a physical occurrence involving waves and particles. It does not require a hearer to exist.
Now, if you can be convinced that the sound does not take place unless you are there to participate, then be careful. You are ripe to be sucked into a philosophy and perhaps even a cult that takes a holographic view of the universe. You affect the world around you with your projected thoughts. You envision your success and then realize it.
Sometimes, celebrities are reinforced in this kind of belief system by their magnificent success. They espouse these principals until the devil calls in the note on their soul.