We lived in Davis for many years where there is only the public display but you can hear the mortars they use pretty much everywhere in town. We have been in Ventura for past couple of years for dog shows and they also only have public displays but they also have several shows within a 10 mile or so radius and the mortars are clearly audible.
My husband and I strive to expose our puppies to lots of noises when they are here. We get the holiday poppers and watch loud action movies with the surround sound on so the pups learn it is no big deal, just everyday kind of things because you just never know when they may be exposed to loud noises again.
Some people say they have good results playing the loud action movies on the 4th so that by the time the fireworks start the dogs just think it part of the show.