"Revolution 9" is a sound collage from the Beatles' 1968 self-titled double album (also known as the "White Album"). The composition, credited to Lennon–McCartney, was created primarily by John Lennon with assistance from Yoko Ono and George Harrison. Lennon said he was trying to paint a picture of a revolution using sound. The composition was influenced by the avant-garde style of Ono as well as the musique concrète works of composers such as Edgard Varèse and Karlheinz Stockhausen. The recording began as an extended ending to the album version of Lennon's song "Revolution". He, Harrison and Ono then combined the unused coda with numerous overdubbed vocals, speech, sound effects, and short tape loops of speech and musical performances, some of which were reversed. These were further manipulated with echo, distortion, stereo panning, and fading. At eight minutes and twenty-two seconds, it is the longest track that the Beatles officially released while together as a band. Background and inspiration "Revolution 9" was not the first venture by the Beatles into experimental recordings. The group had introduced avant-garde styling in their 1966 song "Tomorrow Never Knows" and, in January 1967, they recorded an unreleased piece called "Carnival of Light". McCartney said the work was inspired by composers Stockhausen and John Cage. Stockhausen was also a favourite of Lennon, and was one of the people included on the Sgt. Pepper album cover. Music critic Ian MacDonald wrote that "Revolution 9" may have been influenced by Stockhausen's Hymnen in particular. Another influence on Lennon was his relationship with Yoko Ono. Lennon and Ono had recently recorded their own avant-garde album, Unfinished Music No. 1: Two Virgins. Lennon said: "Once I heard her stuff – not just the screeching and howling but her sort of word pieces and talking and breathing and all this strange stuff ... I got intrigued, so I wanted to do one." Ono attended the recording sessions and, according to Lennon, helped him select which tape loops to use. In a 1992 interview for Musician magazine, George Harrison said that it was he and Ringo Starr who selected the sounds, sourced from EMI's tape library, including the "Number nine, number nine" dialogue. Authors Chip Madinger and Mark Easter write that the content of Harrison's lesser-known experimental piece "Dream Scene", recorded between November 1967 and February 1968 for his Wonderwall Music album, suggests that Harrison had a greater influence on "Revolution 9"