Audience laughter on a traditional sitcom sounds implausibly responsive, arriving instantly and stopping cleanly. It is real, and it is also heavily processed.
The audience is genuinely there
Multi-camera sitcoms are shot on a stage with seating, in front of a few hundred people who watch the episode being made.
Several cameras run simultaneously so a scene can be played through continuously, which is what makes a live audience workable at all.
The format exists because performers respond to laughter, and comic timing built in a silent room is measurably different.
The evening is long and stop-start
A taping can run for hours, because scenes are reset, lines are re-shot and technical problems interrupt constantly.
A warm-up comedian works the audience throughout, keeping energy up during the waits and explaining what is happening.
By the fourth take of a line, spontaneous laughter has gone, and what remains is an audience being encouraged to respond as they did the first time.
Writers watch from the floor and rewrite between takes, so a joke that failed can be replaced and performed again within minutes, which is the real reason the format survives.
Editing assembles the reaction
The finished episode is cut from multiple takes, and each take carries its own audience track.
Joining two takes joins two laughs, so the audio has to be smoothed until the response sounds continuous.
Laughter is also shortened, since a real laugh runs longer than the edit allows and would push the episode past its running time.
Trimming it changes the rhythm of the scene, because the actors originally waited for a response that the finished version no longer contains.
Sweetening fills the gaps
Where a joke played better on set than it reads on camera, or where a scene was shot without an audience, recorded laughter is added.
Scenes on location or involving effects cannot have an audience at all, and those need a reaction constructed entirely.
The practice is standard and largely undisclosed, which is why the distinction between a live audience and a laugh track is less clean than either label suggests.
Why single-camera comedy sounds different
Comedy shot without an audience uses pauses differently, leaving space where a laugh would have gone or removing it entirely.
That changes the writing, favouring dry lines and visual jokes that do not need a response to register.
Neither approach is more honest than the other. One records a room reacting and edits it, and the other builds the same rhythm without a room to record.