I think if a noise is a constant thing, they tend to get used to the vibrations. Several of my snakes are in racks where the rest of the family is. These snakes tend to not notice we even exist, except on feeding day. We have 5 kids under the age of 13 and trust me, there is always some kind of loud noises. TVs, game systems, crying, yelling, stomping...you name it we got it. On the other hand, the snakes I have that are in a separate room where the children aren't allowed, seem to know as soon as I walk in the room and come to the front of their tanks to check me out. It's an interesting thing how they seem to learn what vibration means what.