Tom Morello recently spoke at length about different notable aspects of the groundbreaking rock singers he's worked with, calling Rage Against the Machine bandmate Zack de la Rocha "the greatest frontman of all time" and complimenting the late Soundgarden and Audioslave frontman Chris Cornell for "his ability to craft melody, beautiful and ferocious melody out of the ether."

Of course, Morello has a rich history with both bandleaders, having made multiple albums with each. So, last week, while sitting down with Revolver for a "Fan First" interview, the RATM guitarist, Audioslave alumni and Prophets of Rage icon had no problem gushing about his work with the two frontmen.

Watch the video down toward the bottom of this post.

On de la Rocha, Morello said matter-of-factly, "In my opinion, he's the greatest frontman of all time. He's the punk-rock James Brown."

The guitarist continued, "There's no one in the history of Western music that has the sort of totality of spiritual commitment onstage and in the studio as [de la Rocha]. And it's matched with a brilliant intellect, and he's a tremendous musician as well, and it's really an unbelievable combination [and I] feel fortunate to be in a band with him." [via ThePRP]

As for Cornell, "on top of his startlingly good looks and hair and eyes," Morello remarked of the singer who died at age 52, "he had this ability to craft melody, beautiful and ferocious melody out of the ether."

The musician added, "I remember making that first [Audioslave] record with Rick Rubin. And Rick's like, 'You don't understand how lucky you got. I work with a ton of vocalists and it's difficult to make a great melody. And this guy is just throwing them right and left!' 'Like A Stone,' 'I Am the Highway,' no matter what we threw at him — the simplest chord progression, or the most complicated heavy riff, he'd just sit in a chair with a cigarette, and he's like, 'OK, that sounds like a great song right there. What's next?'"

In the same chat, Morello also talked about Soundgarden, the pioneering grunge act that first brought Cornell to the attention of most listeners.

"I love metal and I loved poetry, and Chris Cornell was one of the people that brought those things together, and in a way, it was commercially successful at the top of the chart," the Rage rocker said. "So we all owe him a grade of debt for, I think, saving metal, in a way."

Morello's new solo album, The Atlas Underground Fire, emerged last week.

Tom Morello "Fan First" With Revolver Video

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