No laughing here at all, I had the exact same worry when I was pregnant with Zander. We have an annual festival that has fireworks & I was nervous about that to start with. The next week we went to see the Queen musical & OMG was it so loud, the seats were vibrating!! I was worrying the whole time so held both my bag & my jacket over my belly JIC. Even though at the end of the show Zander was bopping away to the music I was still worried! At my next antenatal appointment I asked my Dr and he said that there is enough fluid & other sounds going on in there that all bub would hear is muffled sound.