Not unusual my wife was awake after midnight, when something as loud as a cannon was heard. She said it is so loud it makes it hard to say if it's on a upper floor
I suggested that we pay better attention.
When I have heard this, and I have 2 times. It's on the 2nd floor in the hallway. Guests hear it, and it's
crazy loud, bigger than a shotgun. One guy said he heard something being dragged down the hall after the bang, and then something heavy down the stairs.
I've not heard the dragging!