Which producer of Zeitgeist was also the lead singer?
Zeitgeist (The Smashing Pumpkins album): Zeitgeist is the seventh album by American alternative rock band The Smashing Pumpkins, released on July 10, 2007 in the United States and Canada. Zeitgeist (The Smashing Pumpkins album):  The album was produced by Roy Thomas Baker, Billy Corgan, Jimmy Chamberlin, and Terry Date. Billy Corgan: William Patrick "Billy" Corgan Jr. (born March 17, 1967) is an American musician, songwriter, producer, poet, and entrepreneur. Billy Corgan:  He is best known as the lead singer, primary songwriter, guitarist, and sole permanent member of The Smashing Pumpkins.
Billy Corgan