
Hi Mistyweather
You may find this
LINK useful. At the bottom of the article are several links which take you to examples of potentially worrying noises (to the dog), which may help you desensitise your dog(s)
with careful introduction. Don't try to rush a process such as this. It takes time for the fear to become established and so will take time for you to help work through the natural response to fear which would normally be to hide, run away or fight off the source of fear. Noises within the home mean none of these options are available and so it is even more confusing for a dog.
Sensitivity to certain sounds - often high velocity sounds - as you've already described, typically happen with something obviously traumatic such as fireworks or gunshot but then other noises which we wouldn't expect can start to gradually set off a fear response too.
Hopefully the link will help - although from a breed specific website, noise sensitivity and the fear responses exhibited affect many dogs, regardless of breed, multi cross etc.
best wishes, Teri