So, let's say it was the middle of the night. You're upstairs in your room, and suddenly someone knocks on the front door, which is downstairs. The rooms are set up like this: So, what would you HEAR? Would you hear the knocking going to the window, hear it from downstairs, or both? I honestly don't know why I asked this, but suddenly I just got curious about this. Why? I don't know.
I would imagine you could hear the knocking through the walls and floor. Sound doesn't just travel through air.