The Trip (1) - S4-E1
Continuity mistake: While discussing Candice Bergen with Jerry, George picks up a menu and places it on the table; both he and Jerry have a menu. In the next shot showing the table (when George says, "I can't believe I missed Kramer,") both menus are flipped: in the first shot, white pages are facing up, and a yellow page is on the back of George's menu as he picks it up; in the second, the yellow sides are facing up. (00:01:02)
Continuity mistake: During a conversation with Kramer, Jerry is holding a drink in his left hand. Although he is never seen setting it down, the drink disappears in the next shot and he has his arms crossed. (00:02:10)
Continuity mistake: After Kramer walks into Jerry's apartment, he shuts the door. However, in another shot a couple seconds later, the door is inexplicably wide open. (00:01:45)
Continuity mistake: When Kramer is telling the fantasy camp story to Jerry and Elaine, the suitcase in the background is open different amounts during different shots. (00:09:55 - 00:10:40)
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