For many filmmakers, music is often the last element in the post-production process. But Darren Aronofsky, director of "Requiem for a Dream," believes in involving his composer early.

"You want them to see the development, to witness the whole process," says Aronofsky. "The score is an element of the storytelling, and you have to spend time on that."

"I just handed Clint (Mansell) a script and said I won't film this for a year," adds the director. "I treat the composer as I would a d.p. or a production designer.

That Aronofsky tapped Mansell should come as no surprise to anyone familar with their long association. Mansell, once a member of the band Pop Will Eat Itself, scored Aronofsky's breakout film, "Pi." And in the days before "Pi's" success, they were briefly roommates.

"One of the things Darren and I share is a belief that directors and musicians can work particularly well when they partner for the long haul," says the British-born Mansell. "Look at Sergio Leone and Ennio Morricone, for instance."

In the case of "Requiem," a harrowing look at the perils of addiction, Aronofsky wanted music that would drive home the film's tough message. Mansell believes he achieved that goal.

"Darren wanted the score not placed in any particular period," says Mansell. "The movie is really a fable, and he wanted the music to transcend time and place. We had to think about what would do that for us, and it was tough working it out. Eventually, we found one cue that fit nearly every pivotal scene, and that became the main theme, though originally I wrote it in a minor key, and to begin the film with it, we had to change it to a major key."

There was, however, another obstacle, and surmounting it involved drafting the Kronos Quartet, long associated with classical music's avant garde.

"Once we settled on the main theme," Mansell says, "we realized that the music needed to be played on real strings rather than produced electronically."

Mansell and Aronofsky praise the ensemble's easy-going manner and strong work ethic, and the composer insists they enhanced his score.

"They brought it to life," he says.

Mansell calls this amalgam of synthesized and acoustic sounds "modern scoring." And Aronofsky couldn't be more pleased.

"I'd be happy to work with Kronos again, if they'll have me," he says.

With regard to Mansell, the sentiment is implicit.