After years of delay, Metallica's new album is in the mixing stage with the hopes of a fall release. And while drummer Lars Ulrich admits he doesn't fully know what it sounds like, he was able to describe how it contrasts with their previous effort, 2008's Death Magnetic, in a new interview.

"It’s probably a little less frenetic than the last record," he told Citizens of Humanity. "It’s probably a bit more of a diverse record than the last one. It’s exciting, but I don’t have quite the perspective yet."

One of the reasons for the change in sound, he believes, is a change in producer. The return to their thrash metal roots on Death Magnetic was the work of Rick Rubin, and with a new man behind the boards, they can look in other directions.

"Rick Rubin really encouraged us to, for the first time, be inspired by our past," Ulrich explained in the new interview. "It was the first time we sort of looked in the rearview mirror. This time around it’s a little bit of a different thing. We’re not working with Rick, we’re working with the engineer from the last record, who’s producing, Greg Fidelman. So there’s some of the same production elements at play, but we’re expanding a little bit on the sonics."

Three weeks ago, Ulrich said that the group was going to spend this month putting the finishing touches on the record, with the intention of having it out by the end of 2016. “If the record doesn’t come out this year, then it won’t be because it’s not done," he remarked. "It will be because there’s some sort of cosmic reason that it would be smarter to hold onto it until next year. But the record will be done this summer."

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