It depends greatly where you sit. Where we sit, the average age is probably mid-30s. My dad is probably the oldest guy in our area, mid-60s, but there are a lot of 20-somethings, too. Mostly 30-50 is my guess.
Outside the stadium seems to be about the same as in, but that also depends on what tailgate or tailgate area you go to. We usually go to a couple of tailgates and one has older folks, 50+, while the other is mostly 30s-ish aged.
Inside the stadium ALL WE HEAR is the stupid sound system in the North end zone. It drowns everything out. You can hear the announcements, and then just the hubbub of 80,000 voices.
Outside the stadium.... you hear all kinds of things. Not sure what you're asking here.