Some time ago, I bought an acoustic drum set but I lived in a building. In spite of being a musician, I don't like to disturb people when I have to do my practices and I decided to look for something that would serve as an acoustic insulator. I was told that the best insulator for the floor was cork and so I put cork on the floor of the room and egg cartons on the walls. In spite of this, I always used to ask the neighbors if they were bothered by any noise from my apartment and fortunately the answer was always negative :)