Don't worry, Metallica fans! Lars Ulrich has promised he's "not going to start playing Metallica songs with mallets" after achieving the "thunderous" sounds director JC Chandor enlisted of the drummer for Netflix's new military thriller Triple Frontier. However, he does want to someday compose a soundtrack made entirely of drums and other rhythmic instruments.

"I started thinking what it would be like one day to make a score for a film only out of drums and rhythmic instruments," Ulrich recently told Rolling Stone. “It would not have a score or any kind of melodic instruments — just rhythms and pulses and beats. You can go so many places in how you manipulate the sound. It would be super fun.”

That's the drummer's wavelength, anyway, after helping the Triple Frontier team morph floor toms into timpanis and otherwise "embellish, elevate or add another layer" to the film's incidental music from composer Disasterpeace.

“For the score I wrote a lot of rhythmically diverse music," the Metallica member explained of the soundtrack collaboration. "But what we found we needed at times was a strong, steady pulse to glue things together better."

Those rhythms and pulses were first discussed after Ulrich met Triple Frontier director JC Chandor at a 2013 screening of the filmmaker's All Is Lost. There, the drummer asked the director a question during an open-audience Q&A, getting the ball rolling on a creative partnership that eventually led to Chandor's stormy drum entreaty.

"I think the word he kept using was 'thunder,'" Ulrich recalled of Chandor's instructions for the movie's music. "'I feel that your drumming has this thunder to it, and I would love to add some thunderous drums to the score.'"

While the Metallica drummer recorded the rolling rhythms for the film that stars Ben Affleck and Oscar Isaac, he got a chance to appreciate the movie's story of five former special forces operatives reuniting to steal a drug lord's fortune.

"I can be a little bit of a film snob,” Ulrich admitted. “But this film had a depth to it, and a couple of what I’d call ‘unconventional layers,’ such as the dialogue. It had a different kind of creative energy flowing through it. I started talking to Rich about it, and I knew it was going to be different. That’s what why I wanted to do it. To me, just repeating anything that I’ve done with Metallica or whatever would not be that interesting."

To the last point, Ulrich uncovered a deeper understanding of his role as the world-famous drummer of what is perhaps the world's most visible metal band. Rather than stretching the Metallica formula too thin, the drummer said his outside soundtrack work only imbues his main act with a better overview of the music world at large.

"I have no interest in playing with anybody else other than Metallica,” Ulrich contended. “But occasionally when there’s an opportunity to do something that’s just out of the wheelhouse, for me, I guess subconsciously, I always think, ‘If I go do this, it’ll be an experience that will be interesting and then I’ll have another point of view to give to Metallica.'"

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