Audio problem: Joker's TV debut as an opera singer isn't very convincing. Even through the partially-obscuring clown mask, you can see that his lips aren't moving at all. (00:22:30)
The Joker Goes to School (1) - S1-E15
Audio problem: As Susie deposits a dime in the coffee machine, the camera starts to pan down towards the opening where the cup will appear. You hear the cup then the quarters fall, but you can see the cup full of quarters is already in place before the sound is made.
Death in Slow Motion (1) - S1-E31
Audio problem: In the distance shot, when Robin responds to Batman's call, his lips don't move, but you hear him.
Answer: There wasn't one singular city used. It was shot in and around various locations in California, plus on a lot of sets and backlots. Ex. Some scenes were shot in LA, some in Pasadena, some in Santa Barbara, etc.
TedStixon