“talkie” cartoons, but Sullivan refused. Further disputes led to a break between Educational and Sullivan. Only when Walt Disney’s Steamboat Willie made cinematic history as the first talking cartoon with a synchronized soundtrack did Sullivan see the possibilities of sound. He managed to secure a contract with First National Pictures in 1928. However, for reasons unknown, this did not last, so Sullivan sought out Jacques Kopfstein and Copley Pictures to distribute his new sound Felix cartoons. On 16 October 1929, an advertisement appeared in Film Daily with Felix announcing, Jolson-like, “You ain’t heard nothin’ yet!”
Unfortunately, nothing good was heard from Felix’s transition to sound. Sullivan did not carefully prepare for Felix’s transition to sound, and added sound effects into the sound cartoons as a post-animation process . The results were disastrous. More