The Smashing Pumpkins are an American alternative rock band from Chicago, Illinois, formed in 1988. The group consists of Billy Corgan (lead vocals, guitar), James Iha (guitar), Jeff Schroeder (guitar), and Jimmy Chamberlin (drums). Disavowing the punk rock roots of many of their alt-rock contemporaries, the Pumpkins have a diverse, densely layered, and guitar-heavy sound, containing elements of gothic rock, heavy metal, dream pop, psychedelic rock, progressive rock, shoegazing, and space rock. The band's style shifted over time. In the early 1990s, the band was a key player in the alternative rock explosion that began with Nirvana's breakthrough album Nevermind (1991). The success of Nevermind was followed by a string of successful albums by the Pumpkins and other alternative rock bands. By the end of 1996, however, the band had become less commercially successful; frontman Billy Corgan attributed this to a shift away from the guitar-heavy sound of their earlier work. In 1998, the band released its fourth album, Adore. A more subdued and introspective album, it was widely regarded as a departure from the band's previous sound. The following year, Chamberlin left the band; Corgan recruited Matt Walker to replace him on drums. The band's fifth album, Machina/The Machines of God (2000), marked a return to their earlier sound. It was a concept album about technology and its effects on humanity. The album was not as commercially successful as its predecessors, but was well received by critics. In May 2000, Corgan announced that he was taking a hiatus from the Smashing Pumpkins due to personal reasons; he did not elaborate further. James Iha and D'arcy Wretzky left the band in September 2000; they were replaced by Jeff Schroeder and Melissa Auf der Maur. Corgan returned to recording and touring in 2006 with a new lineup featuring Schroeder on guitar and Jimmy Chamberlin back on drums. The group's 2007 album Zeitgeist received mixed reviews; it debuted at number two on the Billboard 200 but quickly fell down the charts. In 2009, the band released its seventh album, Teargarden by Kaleidyscope, a 44-song project released one song at a time for free online. The first single from the album, "A Song for a Son", was released