You may have noticed that in every audiovisual work, characters seem to have music playing in their heads at all times. It's not music playing on a radio in their car and they aren't at a concert. It's not songs they've heard. Not even classical tunes they��ve listened to. These are tunes that seem to just come out of nowhere, off the top of the character's head.
This technique is used because it makes you sympathize with a character's emotions. Without this music, you might not be able to connect with characters and feel their emotions quite as easily.
When music is used in movies and TV shows, there's two types: in-universe music the characters hear and music that the in-universe characters don't hear, because it's for the audience only. The first type is Source Music, aka "diegetic music", which is music you hear that comes from an in-universe source, such as the character's car radio as they're driving, a band at a bar, a street musician outside, or an instrument the character is playing.
If music is shown in one character's perspective, but then the perspective switches to another character who can't hear the music, that's Sudden Soundtrack Stop.
The pieces that are most closely tied to characters or events are Leitmotifs. If music is meant to make us think of a certain character's name, that's Fanfare.
Specific instruments and Standard Snippets are used to create a Mood Motif.
Usage of background music dates back to pre-antique times. For an example, classic Greek plays had usually music in the background.
Background music is a staple trope in some media such as films and video games. The usage of background music in these types of media is so omnipresent that its absence is often more notable than its presence.
For further exploration of this topic, listen to Anna Russell's "The Ring of the Nibelungs (An Analysis)".
This page lists lampshades of the phenomenon, such as when characters hear the background music, often Played for Laughs; straight examples are too many to count. For subversions, see Left the Background Music On. For aversions, see Reality Has No Soundtrack.
Compare Mickey Mousing, for when music that is meant to set the mood is actually being played by a character in-universe.
See also Background Music Override, Variable Mix, Diegetic Switch, Theme Tune, and Image Song.
Examples:
- Puella Magi Madoka Magica The Movie: Rebellion: In the movie, Mami hums her theme music while brushing her hair.
- The Far Side has several gags where characters can hear the background music:
- One featured a shot of Tonto knocking on an outhouse door, whispering, "Kemosabe, hurry up, the music's starting!"
- A group of cowboys at camp looking around: "There it goes again — whenever we settle in for the night, that harmonica starts up!"
- A gal standing in the aftermath of a huge bar brawl recounts it to the police: "So this little sailor dude whips out a can of spinach, this crazy music starts playin', and... well, just look at the place!"
- RWBY: The Abridged Series: The series has utilized a few licensed tracks here and there, but to avoid getting blocked for copyright, have mostly stuck to using original music written by Stormy's band, Eris and the Pantheon. These songs usually appear in action scenes during episodes.
- Phineas and Ferb: Star Wars: It wouldn't be a Star Wars crossover without John Williams' iconic score, would it? But in addition to the familiar themes, some of Danny Jacob's regular themes from Phineas and Ferb are made to sound more orchestral to match. This is noticeable whenever Candace's "Busting Theme" plays and doesn't sound electronic.
- Deadpool: After teaming up with X-Men Colossus and Negasonic Teenage Warhead, Deadpool turns to the camera and says "cue the music." "X Gon' Give It to Ya"
by DMX kicks in.
- Joker (2019): Lampshaded when Joker starts dancing to it on a staircase.
- Not Cool: Tori snarks "Cue The CW soundtrack" during an emotional moment when, indeed, the actual soundtrack of the movie is playing sappy background music, one of the movie's many moments of Bathos.
- Shirley Valentine: At one point, while being seduced on a boat with nobody but the two of them for miles, the titular character gets distracted wondering where the romantic music is coming from).
- Spiderman 3: Lampshaded when Peter starts dancing to it in the middle of the street. He gets lots of odd looks from passerbys.
- One Farscape episode had Crichton humming along with the show's music while on a bad trip.
- The Musical Episode of Star Trek: Strange New Worlds, "Subspace Rhapsody", has BGM playing diegetically whenever someone is about to break into song, courtesy of a nearby Negative Space Wedgie. This gets lampshaded early on, with the characters reacting each time the music starts up.
Pike: Where's that music coming from?
Ortegas: Not from anywhere on the ship. - Young Sheldon: Discussed in "A German Folk Song and an Actual Adult". When Sheldon recaps Beverly Hills, 90210 for Missy, she notes that he's omitting the subtext of each scene because he can't tell social cues. Missy tells him to pay attention to the music, which informs what the characters are actually thinking. Later, when Mary tells Brenda that she's fine, adult Sheldon points to the viewers that the music actually means she's not fine.
- Urinetown: At the end when Sally complains that the show should have a happy ending because the music is so happy.
- Banjo-Kazooie: In the second game—Kazooie observes when the music changes, signifying new events.
- Chrono Trigger: After Dalton modifies the Epoch and gets ready to test it, the Heroic Theme plays, to which he exclaims "No, no, no! Stop the music!" at which point the crisis theme starts and he comments "Ah! Much better!".
- In Luigi's Mansion: Dark Moon, Luigi will hum what is actually the background music in an attempt to maintain morale.
- In The Reconstruction, whenever a character joins the guild's roster, there's a little fanfare that plays. When the starting cast joins in the beginning, Qualstio says "Is that nauseatingly cheerful music gonna play every time someone joins?" at one point. Kulkumatz also asks "What was that sound?" when he joins.
- Archer: When Carol/Cheryl hears ominous "tension music", she tells herself "Just ignore it, it's not diegetic.", and later screams "God damn it! Shut up, John Williams!" and "Please tell me you guys heard that!" for the next times it plays again.
- Danger Mouse (2015): In "Very Important Penfold", the narrator tries to turn on the closing music for the credits... only for nothing to happen. He scrolls through several random sound effects before declaring that someone else can find the correct music, and leaves angrily.
- The Simpsons: In "Lisa's Belly", the Simpsons watch a documentary on Riot Rivers, a water park, with dramatic music. Homer says "No, it didn't happen that way. There was different music."
- SpongeBob SquarePants: One of the main aspects of the sieres is their unique use of background music. Unlike many other TV shows, SpongeBob mostly takes music from different stock audio companies, including APM. Much of the background music focuses on the mood of the characters which makes the show’s background music special.
- Musical composers reportedly do hear music in their heads all the time.