This happened when I was quite young, so my mom told me this story.
When I was really little, I had a sound machine in my room. My mom still occasionally uses it, but I don't use one anymore. (If you haven't read my other story about this house I lived in, check out "Little Boy In the Corner") So my sound machine always played whenever I slept.
So how about we ACTUALLY get to the story eh? One night, My mom heard my crying in my room. She ran towards my room and as she got closer she heard a loud blaring sound. She opened my door and saw me crying as the sound machine blared a really, REALLY loud static sound. She looked at my sound machine and saw that the volume had been kicked up to full blast. She wouldn't have put the volume that high, and nor would I because well, I was trapped in a crib. She set the sound again to the waterfall sound and turned the volume down.
The next night, the exact thing happened, except the volume kept rapidly going up and down. Mom figured that this was a problem with the sound machine. So she stuffed the sound machine in her closet and put the one she used in my room. For the rest of the night it worked.
Everything was going fine for a few days until the EXACT same thing happened. The volume was going up and down rapidly and the blaring loud static noise was playing. Mom got worried because she knew it was not a problem with the machine itself, but someone playing with it.
My Mom had experienced another happening with a ghost in this house with my sister, I even posted a story of it. (Little Boy In the Corner) So my mom called one of her friends that was very interested in supernatural phenomenon. Her friend told her to be firm with the ghost and tell it to STOP.
When Mom got home, she went into my room and said "Whoever you are, STOP. This is BAD. You're breaking RULES and being DISRESPECTFUL. You better stop today!" After my mom did this, this issue never occurred again.