There are several types of sound used in TV ;
Diagetic sound - Natural sounds that are sourced within the scene e.g people having a conversation, radio playing in the background, doors open/shutting, bullet shots in a war programme. In this clip all the sounds are diagetic; nothing has been added to create a specific atmosphere.
Non diagetic sound - Sound added to create atmosphere or tension e.g Theme tunes.
A potential problem with non diagetic sound is that it may make it less realistic, yet the potential benefit is it can make it more dramatic. The man overspeaking and the dramatic 'Jaws' theme tune added tension to this advert.
Sound bridge - Sound which carries on over two scenes, literally creating a bridge between events.
Indicental music - Short sequence of sound to create an emotion / feeling. e.g sad slow music to emphasise a character being upset.
Asychronous sounds -A 'natural ' sound out of place and without a source.
Contrapunctual - Sound which creates an opposite emotion to the one on screen. e.g a happy scene with sad/slow music playing.