Here's an enviable paragraph from The New Yorker's music critic Alex Ross on Joaquin Phoenix's performance as Johnny Cash in Walk the Line:
'How the erstwhile Leaf got his voice so close to Cash's in timbre and heft is hard to know; it's kind of devilish. There's a good moment early on when Cash, stationed with the Army in Germany, is writing "Folsom Prison Blues." He starts out pitching his voice high, presumably in imitation of crooners on the radio. His voice flickers toward the lower register for a second, but he suppresses the impulse. He keeps working on the song, and, eventually, lets his voice slide all the way down the octave, into the black canyon of Cashitude (I think it happens on "hang my head and cry"). This gave me chills, as abrupt changes of register in music often do. Compare the moment in Schubert's B-flat Sonata when the main theme floats up an octave, into a luminous upper region that's just as heartbreaking in the end — it's blue sky out the prison window. Anyhow, the movie's great.'
Makes you want to see it just for that moment.