<P> The soundtrack was originally conceived as a major component of the film, not merely as a background or support . For this reason it was decided to record a soundtrack before filming . T Bone Burnett was invited to design collections of music . One member of The Stanley Brothers, Ralph Stanley, personally took part in recording the music for O Brother, Where Art Thou?, singing a cappella folk song O Death . </P> <P> There is a notable use of dirges and other macabre songs, a theme often recurring in Appalachian music, such as in "O Death," "Lonesome Valley," "Angel Band," and "I Am Weary", in contrast to the bright, cheerful songs, like "Keep On the Sunnyside" and "In the Highways", in other parts of the film . </P> <P> "I Am a Man of Constant Sorrow" has five variations: two are used in the film, one in the music video, and two in the soundtrack . Two of the variations feature the verses being sung back - to - back, and the other three variations feature additional music between each verse . The voices of the Soggy Bottom Boys were provided by Dan Tyminski (lead vocal on "I Am a Man of Constant Sorrow"), Nashville songwriter Harley Allen, and the Nashville Bluegrass Band's Pat Enright . </P> <Table> <Tr> <Th_colspan="2"> Professional ratings </Th> </Tr> <Tr> <Th_colspan="2"> Review scores </Th> </Tr> <Tr> <Th> Source </Th> <Th> Rating </Th> </Tr> <Tr> <Td> AllMusic </Td> <Td> </Td> </Tr> </Table>

Who sings man of constant sorrow o brother where art thou
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