When I had my 14 year old Beagle/Bulldog mix, she would always run away and hide in my room whenever my mom would vaccum. Now I have two cats that aren't so much as fazed by it. Hell I had one time when my older fatter cat was sleeping on the vacuum WHILE I was using it. didn't even wake up until I finished and he sluggishly walked off only to lay back down in the hall I need to go :/
It drives me crazy when I'm trying to watch TV and my mom vacuums the carpet. I end up turning the TV up so loud that you can hear it on Mars or something just so I can still hear it.
my grandma has a HELLA old vacuum that basically sounds like it's yelling, but, we've taken carpet out of the living room and hallway, and our rooms are so packed we can barely see the carpet left in there.