William Halstead (born William Storm Halstead, 1903 in Mount Kisco, NY – September 1987 in Los Angeles, CA) was an American inventor. Halstead was a prodigious inventor who held more than 80 patents involving radio and television development. In 1950, he pioneered stereophonic broadcasting. The process he developed allowed a station to use a sideband of its frequency to broadcast subsidiary programming. This process was called multiplexing, and once fully instituted removed the need for two stations, and thus two receivers at the listener's end in order to achieve a stereophonic effect.