Just thought I'd share with others something I have discovered helps my dog during firework season. Basically I put on a film with lots of gun shooting, bombs going off etc and this drowns out the fireworks. I turn it down a bit and then if fireworks start I turn it up. Films I have found particularly good are 'black Hawk Down' and " 13 hours the secret soldiers of bengazi'. Both are pretty good films with lots of famous actors in them so not too hard to watch. I bought them both off Amazon and just play them over and over at this time of year.
Sadly my dog still got fireworks going off when we went out after 11 in the rain and now at quarter to one in the morning there are more going off outside. So the system is not completely firework proof but if you play them during key firework hours ie 5pm to 11pm it does help.