Marco Beltrami replaced John Powell on Jonah Hex.

Now, back to the age of Mastodon: The The band had been brought in by Hayward to collaborate on the score with Horton's composer John Powell back in September 2009. However, the reshoots and subsequent reediting meant Powell, who was already booked for Tom Cruise's Knight and Day and Doug Liman's Valerie Plame pic Fair Game, had to leave. "There was no animosity," says Hinds. "He was just like, 'If you haven’t figured out what you’re doing cinematically, I gotta go.'"

In his place, composer Marco Beltrami (Repo Men) was hired to work with Mastodon. (A spokesman for Warner Records said the label would not comment on the soundtrack nor Mastodon’s role in it.) “All of a sudden, there’s this new guy, who went in a different direction," continues Hinds, who by that point was on a world tour with the band. "And there was no way he could connect with me: They brought all the new scenes to us, but I was on tour this entire time, so I had no time to preconceive what I wanted the movie to sound like. Being so busy ... it's hard to be creative when you're going through the same motions every day [onstage]."

Hinds says that Beltrami wanted a more restrained, subtle approach than the vigorous shredding Mastodon recorded for Hex in L.A. last fall. "I totally had to go back and start over again," says Hinds, reached in Atlanta as he prepped for the band’s 37-date spring tour of North America, which begins in Charleston, South Carolina, tonight. "We’re still working on it. We wrapped a little of it today; we’re doing a little more tomorrow. Tomorrow is enough for me. I was finished months ago. We had such short notice to work on the thing."

Though constant last-minute change isn't a new phenomenon in Hollywood, Hinds, a first-time movie composer, has found the process frustrating. "I blew my wad over there," he says of the time Mastodon spent recording and composing in L.A. last fall. "It was some of the best shit I’ve ever written in my life. Now I’m just trying to finish with as much patience as possible."

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