Diegetic + Non- Diegetic

Sound 

Diegetic sounds: the real sounds that come from the scene. 

• Talking. 
• Screaming.
• Heavy breathing.
• Fighting sounds. 

Non- Diegetic sounds: the sounds that are added over the top of the real sounds, added after. 

• Music.
• Sharp sudden noises entended to frighten.

The lack of diegetic sound in a piece of media reinforces calm before the storm.