Once the script has been finalized, it's time to record the actors' voices. In order to eliminate any extraneous noise, the actors all record their voices in a recording studio. The exact process varies depending on the producer's preferences. Some shows record every actor separately, recording each line with a variety of tones and inflections. Some prefer to record the actors working together, in the same way classic radio shows were produced.
In any case, it is not necessary to have the entire cast present at the initial recording session. Some actors may be away on other jobs, or unavailable for other reasons. If that is the case, they can record their lines at a later date, and the new tracks can be inserted into the final recording.
After the actors record their dialogue, it's time to start putting together the show's audio track. "Editing the soundtrack is about a two week process," says Kenny Micka, Co-Producer of King of the Hill. "We'll take the parts that are recorded from the actors, assemble them, choose alternate takes, and cut it down to our target length of nineteen minutes and thirty seconds. We try to get the performances to cut together to satisfy the writers and producers, and then we send it on to Film Roman, our animation house."