Why is sound important in TV drama?

 Sound is used to convey a certain feeling within the audience in a TV drama. For example, if someone was being chased down a street and you had calm classical music the audience wouldn't really feel anything and it wouldn't be appropriate whereas if you had fast paced spooky music then the audience would feel that something frightening is about to happen. A diegetic sound like a slamming door or a bang would also create this emotion as we still feel the emotion.

Diegetic:

Diegetic sounds are those in which both the audience and the character can hear, for example a scream within the movie/program, the audience would hear it and so would the character within the movie. Here's some examples from Doctor Who:

The Tardis- This sound effect is important within Doctor Who as it has an important role to play, the sound itself is very surreal and alien like which is the feel that the producers want to be conveyed. 

The Sonic Screwdriver- This is also a very important and like the Tardis, the screwdriver has a alien-like sound to it which once again conveys the emotion.

Non Diegetic:

These are sounds that only we (the audience) can hear, for example theme's of each character that play when they have a moment or the theme tune itself.

This is the Doctor's theme, when he has an important moment within the program this song plays, it's a fast paced exciting song which is used to make the audience feel excited.

This is the main theme tune to the program and it sounds quite alien and unusual which allows the audience to recognise the song and know where it's from making it a signature theme tune for the show.  For each carnation of the Doctor the theme tune alters slightly for that person's personality.