The National Institute on Deafness and Other Communication Disorders has a list of activities that can impair hearing, including target shooting and hunting, snowmobiling, riding go-carts, woodworking and playing with power horns, cap guns and model airplanes. Noisy devices include vacuum cleaners, garbage disposals, gas-powered lawn mowers, leaf blowers and shop tools.

Many people complain about the volume at which movies are played, but the reality is they're quieter than most people think. And movie trailers, traditionally viewed as louder than the flick itself, in two of three cases were softer than the movies were.

Stephen Pendrey, a projectionist at the local Megaplex theaters, said most movie houses follow a "very well set standard." Theater levels are set at 85 dB (over time) with a fader set at 7, to match the levels at which a movie was actually produced. "That way, you are hearing it as the producers intended and theaters nationwide are set to that level."

There's some variation, but it's usually in a downward direction, he said. Most of the local complaints are about the previews before the movies, which are recorded louder. Megaplex usually turns those down to about 75 dB, which may be why they came in softer than the feature films. And since the theaters went digital, "we've had fewer volume complaints than fingers on my right hand," Pendrey said.

Century theaters use a slightly less precise formula but also get few complaints, said Stephen Collins of the chain's corporate office. The sound level used "varies based on occupancy," since more bodies absorb more noise.

An F-16 flyover in Rice-Eccles Stadium registers 102 dB, said Mike Halligan, associate director for environmental health and safety at the University of Utah. A Utah touchdown registers at 101.7 dB — a noise level that includes the announcer's voice and screaming crowd when measured in the fourth-floor box seats.

"It's loud, but we don't always score touchdowns," Halligan joked. But his point is clear: You won't be subjected to a non-stop 102 dB at every game, just loud spurts.

It's hard to say whether people could hurt their ears at a fireworks show. Fireworks experts pay attention to sound when they create shows, with particular worries about eardrums and not breaking any windows in nearby buildings, said Ken Lantis, owner of Lantis fireworks.

"Part of the tradition of fireworks are the booms. Without them, we've had major complaints, because it's lacking something, no matter how pretty it was," Lantis said. "I would be very suspicious if someone came up to me and said, 'We were at one of your shows and we broke an eardrum.' I would say, there's probably no way . . . it would register that high."

But that doesn't mean fireworks are totally safe.