George Clooney is not the only one whose singing did not make the final cut of “O Brother, Where Art Thou?” and the film's best-selling soundtrack, which helped turn old-time music into hit pop tunes again. Clooney's stab at singing the film's signature song still remains in the vaults, but an expanded version of the soundtrack, in US stores Tuesday, packs 14 extra tracks, including 12 previously unreleased cuts from music producer T Bone Burnett's “O Brother” sessions. The two-CD set, which also includes the 19 tunes from the original soundtrack, helps celebrate the 10th anniversary of the “O Brother” triumph at the 2001 Grammys, where it was picked as album of the year. The film's $45 million haul at the domestic box-office was at the time the biggest success yet for filmmakers Joel and Ethan Coen, but it was a pittance compared to Hollywood blockbusters. The album, though, was a runaway hit, selling 9 million copies, ranking as one of the 10 top-selling soundtracks ever and inspiring renewed interest in long-neglected music that continues today. As the studio engineer tells Clooney's gang in the film, “people can't seem to get enough” of that old-time stuff. “That type of music had been around my whole life. There was a time in the late 1950s and early '60s where it was actually popular music, and I knew there hadn't been a light shone on it for some number of years,” Burnett said. “We knew we were getting ready to shine a very bright light on it with a George Clooney movie and a George Clooney video, for that matter. I thought there was a very good chance that it would penetrate the zeitgeist, these singers and musicians; for a lot of people to hear them and think this was good music. The thing I didn't foresee was all the banjo sales increasing by 7,000 percent.” The expanded soundtrack features more songs by performers who were on the original album, among them Norman Blake, the Fairfield Four and the Peasall Sisters, and others who did not make it on the initial release, including Van Dyke Parks, Colin Linden and Alan O'Bryant. The double album features two previously unreleased tracks by the late John Hartford, a banjo player and music folklorist who wrote “Gentle on My Mind.” Burnett recalls that Hartford recorded 30 or 40 songs in a single day as they were working on the “O Brother” soundtrack. Clooney, nephew of singer Rosemary Clooney, recorded a version that “sounded great ... he does have those genes, and he is Irish,” Burnett said. “If George wanted to, he could be a singer.” As it happened, Clooney had only a brief time to prepare for his studio session. Burnett said that for the film to work, the song had to sound timeless, the sort of tune that could sweep the airwaves and become the salvation for Clooney and his “Soggy Bottom Boys.”