Continuity mistake: When Jerry finds The Soup Nazi's recipes in the armoire he hands Elaine at most 4 pieces of paper, but when the shot changes to Elaine the number of recipes in her hands has increased dramatically.
Continuity mistake: When the NBC executives introduce themselves to Bania at the comedy club, their last names have swapped since season 4. Jay introduces them as Jay Chermak and Stu Crespi, when in Season 4, they were Jay Crespi and Stu Chermak.
Continuity mistake: Kramer takes an awkward Polaroid of Jerry for his wall, but the photo on display is an ordinary print. (00:09:45 - 00:12:00)
Continuity mistake: When Elaine is sitting with Puddy in the restaurant when they get back together, the amount of wine in Elaine's wine glass keeps changing.
The Chinese Restaurant - S2-E11
Continuity mistake: Elaine is talking quite loudly about to go eat at Sky Burger; the payphone is not in use. Jerry replies he does not want to, and suddenly a person is on the phone. (00:19:30)
The Chinese Restaurant - S2-E11
Continuity mistake: Elaine is by the table with the 6 people and start whispering through her teeth her proposal to cheat at the dare, The Old Man puts his hand on his wife's hand in one shot, but he's simply gesturing close to her in the next. And that woman is holding the fork in hand or not, depending from the angle. (00:07:20)
The Chinese Restaurant - S2-E11
Continuity mistake: Jerry is explaining to Elaine what to do for eggroll dare. She listens and uncrosses her arms. When he says the words "I'll give you 50 bucks" there's a cut, and Elaine's arms are again folded. It happens again right after when Jerry says she'll give the people at the table a story to tell. (00:06:10)
The Chinese Restaurant - S2-E11
Continuity mistake: When Elaine says that the hungriest should be served first, George is holding his phone book against his body, but in the immediate follow-up he's just holding it at distance. (00:05:40)
The Chinese Restaurant - S2-E11
Continuity mistake: After the 4 people bypass Jerry and Elaine, George is trying to get the attention of the man at the phone, who just turns the other way. George angrily licks his lip and leans against the corner. Cut to Jerry, and in the background George is repeating the action of leaning, in a different way from before. (00:03:50)
Continuity mistake: When the cable guy tells Jerry it'll cost him 400 bucks, he is holding the plate with the cake in his right hand, but in the following shot the left hand is holding just the fork. (00:19:10)
Continuity mistake: George walks confidently to his ex and calls her by name. Leslie's friend is taking a bite from a little celery stick, but in the following shot her hand is lowered in front of her chest. (00:16:45)
Continuity mistake: In the opening shot of The Baby Shower party, Leslie turns towards her friend and starts talking as a ponytailed woman walks in the background. The same happens in the close-up that follows. (00:12:35)
Continuity mistake: Kramer keeps pestering Jerry with the offer of the illegal cable. On the table behind Jerry, the position of the remote and the cable keep changing between shot in the first part of the scene. (00:06:00)
Continuity mistake: George sits in Elaine's spot and puts his wallet close to a glass of water and a used tissue. When he gets up in the next shot, the glass is further back on the table, past the small plate and closer to Elaine and Jerry. (00:05:40)
Continuity mistake: Elaine sits by Jerry to ask him permission to hold The Baby Shower at his place. Jerry is holding a morsel of food in his hand, gone at the first cut. (00:04:20)
Continuity mistake: Reminiscing about the incident with the performance artist, George says that she was aiming at him with the chocolate syrup "like she was putting out a fire." Notice Jerry has nothing in hand. Next shot and he's clenching a paper tissue. (00:02:40)
Continuity mistake: Kramer just gave Elaine the bench she wanted. The Apartment door is open. Cut to Jerry who says all salty "Well, goody for you!", and the door is closed. It is open again next time it is in frame. (00:17:40)
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