The decibel level has been so high at times, we've had to leave. Now we wear special earplugs that lower the decibel level while still allowing us to hear the music clearly (not like normal ear plugs where everything is muffled).
Once when we walked out of a Starship concert with decibel levels of 110+ (unsafe when sustained for more than a few minutes), we walked back from Epcot to Studios and could clearly hear the music, to the point of being able to easily distinguish the lyrics, on the walkway between Boardwalk and Studios.
We love the concerts, and often go over to Epcot in the evening specifically for them and nothing else, but have been surprised that the sound engineers do not control the levels a bit better. Especially with so many children in the area - it can be quite damaging.