In 1972, Isao Tomita's first electronic music album Electric Samurai: Switched on Rock was an early attempt at applying speech synthesis technique through a vocoder[citation needed] in electronic rock and pop music. The album featured electronic renditions of contemporary rock and pop songs, while utilizing synthesized voices in place of human voices. In 1974, he utilized synthesized voices in his popular classical music album Snowflakes are Dancing, which became a worldwide success and helped to popularize electronic music.