I was on the lower level near 1st base and could make out about every third word he was saying between songs.
This was a combination of:
1. Poor acoustics. Very few reflections outdoors.
2. The infield delays. I could hear that they were working, they're supposed to be somewhat transparent to the main house hangs, but it didn't help very much.
3. The crowd bullshitting with each other loudly between songs (and during the non-"Yellow Album" songs for that matter)