Continuity mistake: When George and Jerry are discussing Elaine's poor dancing, The Keys that are sitting on Jerry's kitchen counter inexplicably disappear between shots. (00:04:10)
Continuity mistake: In the theater, before The Movie starts, Brodie has his right hand on the outside of the candy bag in one shot, and suddenly in the next shot his hand is reached into the interior of the bag. (00:07:20)
Factual error: In the scene where Anna is standing with George beside his father's GTO, Elaine suddenly runs in and pries her away from George. Elaine and Anna get into the cab. As the cab pulls away, the side door is marked as an NYC cab with a taxi license number, etc., but the license plate in the back is a California plate.
Character mistake: When George tells Jerry about his date with Anna, he says he is picking her up in his father's 1968 GTO, but the car he is leaning on in the park is a 1967 GTO, which has a completely different body style.
Answer: Composer Jonathan Wolff used a synthesizer, although in seasons 7-9, a real bass is used in addition. Wolff also recorded himself making hundreds of mouth noises, pops, and slaps to add to the synthesized bass licks so that each episode has a different theme. The only real "back-story" is Jerry Seinfeld was having trouble coming up with a theme song and talked to a friend who happened to know Wolff. They wanted to avoid that cheesy late 80's sit-com theme song and Wolff came up with what we enjoy now. Jonathan Wolff has also talked about this further in interviews, recently Reed Dunela interviewed him, so for a fuller account of his story; check out "The Wolff of 116th street".
Bishop73