In the words of Audioslave guitarist Tom Morello, the rock and roll group's forthcoming third opus is an "ass-kicker." As fans might expect, the still-untitled LP (Morello said the band's toying with the idea of naming it Revelations) is bursting at the seams with the kind of brutal riff rock that's become Audioslave's trademark. But at the same time, they've woven deep '70s funk and soul grooves with heavy guitars, "and it's a pretty potent combination," he said. When the album drops (Morello dispelled reports that it will surface in June), expect the end result to be "really unique" and...