When the picture is "locked," the producers hand the show to the sound department, and the sound engineers cleans up the vocal tracks and adds sound effects. For most shows, the sound effects do a lot to determine the tone of a show. "'The Simpsons' is more cartoonish, which is reflected in its exaggerated sound effects," notes Micka, "Where 'King of the Hill' is more of a realistic show, and you hear stuff in the background like birds chirping, dogs barking, lawnmowers running."
"Music can make a great impact on a show's tone, as well," Micka adds. "The tone of 'King of the Hill' is often best served often by an acoustic guitar, although we have used full scale orchestras when it fit the story."
After the sound department assembles all the sounds, they mix the tracks to the appropriate level. It's important to makes sure a character's voice isn't covered by the background music, or that a sound effect isn't unnaturally loud.
After nine months of work, the episode is finally finished. The production company delivers a high definition master tape of the episode to the network, and the network broadcasts it over cable, satellite, and the airwaves. By that time, many more episodes have entered the pipeline and are moving along at various points in the production process.
For more information about various forms of animation, check out the links below.