 The following July, Case joined Fox Film, Hollywood's third largest studio, to found the Fox-Case Corporation.The system developed by Case and his assistant, Earl Sponable, given the name Movietone, thus became the first viable sound-on-film technology controlled by a Hollywood movie studio.The following year, Fox purchased the North American rights to the Tri-Ergon system, though the company found it inferior to Movietone and virtually impossible to integrate the two different systems to advantage.