A laugh track (or laughter track) is an audio recording consisting of laughter (and other audience reactions) usually used as a separate soundtrack for comedy productions. The laugh track may contain live audience reactions or artificial laughter (canned laughter or fake laughter) made to be inserted into the show, or a combination of the two. The use of canned laughter to "sweeten" the laugh track was pioneered by American sound engineer Charles "Charley" Douglass.