College football referee

Those of you who follow college football closer than I do, was the PA announcer out of line? Ref make the right or wrong call?

I was watching the game on ESPN. It was the correct call to give a warning. They do the same thing for sideline encroachment. Basically, you are not supposed to create artificial noise when the team on offense is at the line of scrimmage. Things like the band, the PA announcer, cow bells would be included…

I didn’t watch much of the game, but legit call by the ref.