I have 4 hounds. One of them (teddy) prefers not to hear it, but copes, 2 of them get upset but somehow manage (Beau and CHloe) but Polli, my 10 year old brood mom can not tolerate it. The first time we saw her reaction, I was afraid she would have a heart attack. It was so pathetically sad and hard to watch and no matter how I tried to comfort her, her fears were out of control. There was nothing I could do but administer valium which helped so much. Now, we always have it in the house. I tried the cape, a tee shirt and it did nothing.
We have a firecracker freak who lives 2 doors away and fortunately, it is not legal here so I make sure I call the police at the first sound off, because you know if there is one, there is more to come. He only does it for July 4 but to an extreme and because we live on the water, they like to set them off into the water.
Anyway, make sue you have valium in the house. Ask your vet. 10mg is all they need. They handle it differently than humans.