Thanks.
The noise was actually not that bad. Turns out my kid wanted to go into the Kids Pit and I let him, with no adults in that area there was no risk of him getting trampled. I crouched down and went in with him for a minute, the height difference really does something to the sound levels. And the max level in the audience closest to the speakers was kept at 85dB as promised.
That's very nice. I am glad he could have fun, and you were able to do so as well.