There are two distinct types of noise; indoor noise and outdoor noise.
Indoor noises are created in the adjacent room or in the same room where noise is noticed. The sources of indoor noises are moving of people, crying of babies, playing of radios, banging of doors, traffic in staircase, movement of furniture, conversation of the occupants, operation of cisterns and water closets, noise of typewriters, working of machines nearby, etc.
Outdoor noises are created from nearby streets and the largest source of outdoor noise is generally the automobile traffic on the road. The other sources of outdoor noises are railways, aeroplanes, loudspeakers, and machines in nearby factories etc.
Noise is transmitted to the room through walls, ceilings ...