A laugh track (or laughter track) is a separate soundtrack for a recorded comedy show containing the sound of audience laughter. In some productions, the laughter is a live audience response instead; in the United States, where it is most commonly used, the term usually implies artificial laughter (canned laughter or fake laughter) made to be inserted into the show. This was invented by American sound engineer Charles “Charley” Douglass.

An example laugh track recorded in 2009
The Douglass laugh track became a standard in mainstream television in the U.S., dominating most prime-time sitcoms from the late 1950s to the late 1970s. Usage of the Douglass laughter decreased by the 1980s when stereophonic laughter was provided by rival sound companies as well as the overall practice of single-camera sitcoms eliminating audiences altogether.

From the late 1950s to the early 1970s, Charley Douglass had a monopoly on the expensive and painstaking laugh business. By 1960, nearly every prime time show in the U.S. was sweetened by Douglass. When it came time to “lay in the laughs”, the producer directed Douglass where and when to insert the type of laugh requested. Inevitably, disagreements arose between Douglass and the producer, but the producer had final say. After taking his directive, Douglass went to work at creating the audience, out of sight from the producer or anyone else present at the studio.

Critic Dick Hobson commented in a July 1966 TV Guide article that the Douglass family were “the only laugh game in town.” Very few in the industry ever witnessed Douglass using his invention, as he was notoriously secretive about his work,[14] and was one of the most talked-about men in the television industry.

Douglass formed Northridge Electronics in August 1960, named after the Los Angeles suburb in the San Fernando Valley where the Douglass family resided and operated their business in a padlocked garage. When their services were needed, they wheeled the device into the editing room, plugged it in, and went to work. Production studios became accustomed to seeing Douglass shuttling from studio to studio to mix in his manufactured laughs during post-production.

The sophisticated one-of-a-kind device — affectionately known in the industry as the “laff box” — was tightly secured with padlocks, stood more than two feet tall, and operated like an organ. Only immediate members of the family knew what the inside actually looked like (at one time, the “laff box” was called “the most sought after but well-concealed box in the world”). Since more than one member of the Douglass family was involved in the editing process, it was natural for one member to react to a joke differently from another. Charley Douglass was the most conservative of all, so producers often put in bids for Charley’s son Bob, who was more liberal in his choice of laughter. Subtle textural changes could have enormous consequences for the ethical situation suggested by a laugh track.

Douglass used a keyboard to select the style, gender and age of the laugh as well as a pedal to time the length of the reaction. Inside the machine was a wide array of recorded chuckles, yocks and belly laughs; exactly 320 laughs on 32 tape loops, 10 to a loop. Each loop contained 10 individual audience laughs spliced end-to-end, whirling around simultaneously waiting to be cued up. Since the tapes were looped, laughs were played in the same order repeatedly. Sound engineers could watch sitcoms and knew exactly which recurrent guffaws were next, even if they were viewing an episode for the first time. Douglass frequently combined different laughs, either long or short in length. Attentive viewers could spot when he decided to mix chuckles together to give the effect of a more diverse audience. Rather than being simple recordings of a laughing audience, Douglass’s laughs were carefully generated and mixed, giving some laughs detailed identities such as “the guy who gets the joke early” and “housewife giggles” and “the one who didn’t get the joke but is laughing anyway” all blended and layered to create the illusion of a real audience responding to the show in question. A man’s deep laugh would be switched for a new woman’s laugh, or a high-pitched woman’s giggle would be replaced with a man’s snicker. One producer noticed a recurrent laugh of a woman whom he called “the jungle lady” because of her high-pitched shriek. After regularly complaining to Douglass, the laugh was retired from the regular lineup.

There was also a 30-second “titter” track in the loop, which consisted of individual people laughing quietly. This “titter” track was used to quiet down a laugh and was always playing in the background. When Douglass inserted a hearty laugh, he increased the volume of the titter track to smooth out the final mix. This titter track was expanded to 45 seconds in 1967, later to 60 seconds in 1970, and received overhauls in 1964, 1967 and 1970. Douglass kept recordings fresh, making minor changes every few months, believing that the viewing audience evolved over time. Douglass also had an array of audience clapping, “oohs” and “ahhhs,” as well as people moving in their seats (which many producers insisted be constantly audible).

Douglass knew his material well, as he had compiled it himself. He had dozens of reactions, and he knew where to find each one. Douglass regularly slightly sped up the laughter to heighten the effect. His work was well-appreciated by many in the television industry. Over the years, Douglass added new recordings and revived old ones that had been retired and then retired the newer tracks. Laughter heard in sitcoms of the early 1960s resurfaced years later in the late 1970s. Up to 40 different laugh clips could be combined and layered at one time, creating the effect of a larger, louder reaction when in fact the same laughs were later heard individually. Douglass also included examples of laughter of people from other cultures, whose sounds were noticeably different from Americans.

Douglass’s “laff box” was purchased, unseen, at auction in 2010 when its owner failed to pay rent on the storage locker where it was housed. It was later discussed, and demonstrated in a June 2010 episode of Antiques Roadshow from San Diego, California, where its value was appraised at $10,000.