Carroll Holmes Pratt (April 19, 1921 – November 11, 2010) was an American sound engineer who, along with laugh track inventor Charley Douglass, pioneered the use of prerecorded laughter.

[1] After serving in the United States Air Force during World War II, Pratt began working as a sound engineer at MGM Studios.

[citation needed] Douglass trained Pratt in his methods of adding laughter to existing soundtracks.

Pratt spent his first two years under Douglass' guidance, laughing up the integrated commercials that television programs used to include, in which the actors of the shows would promote the shows' products sponsors; afterwards, Pratt was assigned to laughing entire programs when Northridge Electronics worked on the Screen Gems shows Bachelor Father (CBS, 1957–59; NBC, 1959–61; ABC, 1961–62), Leave it to Beaver (CBS, 1957–58; ABC, 1958–63), and Dennis the Menace (CBS, 1959–63), among others.

[1] In addition to regular laugh track editing, the Pratt brothers worked in Douglass' workshop during summer hiatuses, building and rebuilding machines.

Pratt officially retired from managing Sound One in 1989, but continued to consult with other editors, and occasionally laugh up programs until 1995.

[3] While Pratt was working on M*A*S*H, a woman wrote in to producer Gene Reynolds, begging him to stop using a laugh track on the show.