I've heard 2 sonic booms. My first thought was that my son blew up the kitchen. When I ran to the kitchen and he was standing there wondering what the noise was, another boom hit. That one sounded like a semi-truck hit our house. We all ran outside to find the whole neighborhood outside looking at the sky wondering what was going on.

This was when 2 jets blew past my tiny town to try to intercept a stolen Frontier plane from SeaTac.

Mileage may vary, I don't know what an actual blown up kitchen or crashing semi-truck would sound like (not counting the semi in that Duel movie). Until you know what's going on, you're pretty much in a type of shock.