AP:

Two firefighters from nearby Steubenville, Ohio, who were at the rally told the AP that they helped people who appeared injured and heard bullets hitting broadcast speakers.

“The bullets rattled around the grandstand, one hit the speaker tower and then chaos broke. We hit the ground and then the police converged into the grandstands, said Chris Takach.

“The first thing I heard is a couple of cracks,” Dave Sullivan said.

Sullivan said he saw one of the speakers get hit and bullets rattling and, “we hit the deck.”

...

"After we heard the shots got fired, then the hydraulic line was spraying all around, you could see the hydraulic fluid coming out of it. And then the speaker tower started to fall down,” Sullivan said. “Then we heard another shot that, you could hear, you knew something was, it was bullets. It wasn’t firecrackers.”

“They weren’t super loud shots,” he said.

“You could hear it landing, ammunition landing, on metal,” Takach added.