What Is Meant by Deadening a Floor or a Wall?
Reading edition
By deadening a floor, for instance, we mean inserting between the ceiling of the room below and the floor above, or in the instance of a deadened wall, between the two sides of the wall, some substance like felt, paper or other non-conductor of sound, which will prevent the sound waves from passing through. This deadens them to the passing of sound or makes them sound-proof.