Certain events in Left 4 Dead and Left 4 Dead 2 have associated audio cues. These take the form of sound queues that play when Special Infected spawn, or sounds that the special infected make while waiting to attack.
Special Infected Edit
Note: For those who are not quite as musical, each special infected has a different number of notes in their audio cue. A strings cue indicates the special infected has spawned far away, and a piano cue means that it has spawned nearby.
|Number of notes:||2||3||4||5||6||8|
|Infected Name||Idle sound file||Audio Cue (Piano)||Audio Cue (Strings)||Notes|
|Boomer||A low vomiting and belching sound||C D# E F E(sus)||C D# E F E(sus)||The audio cue is played 2 octaves down.|
|Charger||Hoarse yells||G# G A# A G G#||G# G A# A G G#||The audio cue is played 2 octaves down.|
|Hunter||A low growling sound||D C C#||D C C#|| The hunter will only make an idle sound while growling, which only occurs while he is crouched.|
The audio cue is played both 2 octaves up and 3 octaves up.
|Jockey||Hoarse, manic laughter||C C C C C# C B C||C C C C C# C B C||The audio cue is played 1 octave down and 2 octaves down.|
|Smoker||A dry cough||F-G# E||F-G# E||The audio cue is played 2 octaves down.|
|Spitter||A wet cry or gargle||A A# G# A||A A# G# A||The audio cue is played 2 octaves up.|
Boss Infected Edit
These infected do not have preset audio cues by the game, but they do have boss music and do make their own idle sounds.
|Infected Name||Idle sound file||Music||Notes|
|Tank||A deep nasal breathing or growling||A low mixture of bass, drums, and a capella mixture, with some light flute and piano||The idle sounds for a tank are very rare to be heard, and can only be heard for fixed tank spawns.|
|Witch||A keening wimper||A high mixture of a capella, drums, and some fast piano, with some string and wind instruments||None|