Years ago, I lived in a townhouse above the an old couple that were the landlords. This was in the historic section of Albany, NY near the park. The landlords were in their sixties, maybe early seventies. This place actually had a plaque on the front of it saying it was built in 1880-something and that some rich state senator had lived there. There's places like this all over the area that had been subdivided and rented out.
I lived there for a year and every now and then, always while I was trying to sleep, I would hear faint, organ music accompanied by some rhythmic banging sounds. I always have slept with a fan to drown out any ambient noise and sleep better. This music was just...floating through my room. No one was above me. Just the old people who went to bed at nine below me. I would get up and try to find the source of the sounds but it just seemed like it was everywhere and nowhere.
Since I never heard any music or anything from any other room, and I never heard that music during the day, I concluded that it was the ghosts of previous occupants that had lived there decades before. This actually affected my decision to live there again when my lease was up. The old couple even offered to knock \$50 a month off the rent if I resigned. That would have amounted to nearly a month of total rent over the course of a year. I thanked them, but declined, opting instead to live in a newer place.
Flash forward a couple of years. My friend is having a party. He invites some coworkers that he used to work with at the state. I'm talking to one dude about all the places in Albany I had been in. He's lived in several, too. After some conversation, we find out that one of his friends used to live in that exact same apartment before me. I've never told anyone about the music and banging I would hear there but I just have to ask this guy if his friend ever said anything about the place being haunted. His eyes light up when I ask him.
"You're not going to believe this!" he says and starts thumbing through the contacts list in his phone. He dials his friend. When the guy answers, he gives him a brief overview of the conversation we had been having then hands me the phone.
"What's up, man? Yeah, I lived there in 2003. You heard the music, too? That was the landlords having sex below you. I swear to God. I actually asked about them about it the morning after I had heard it for the tenth time. The old man sheepishly explained that he was banging his old lady. He apologized and said they'd keep it down. The funny thing is, it seemed to get louder and louder over the last couple months I lived there. It was almost like they wanted me to hear."
The mystery was solved. That organ music I had heard was literally organ music that the old people would have sex to. Somehow, that was creepier than it being ghosts.