Mastodon Credit: Jimmy Hubbard

As Mastodon worked their way from the underground into the realm of radio metal over the past decade or so, the evolution of their expansive, florid sound never felt painfully labored—rather it’s been more gradual and predictable. Since their record of record Leviathan, the Atlanta band’s forceful, heavy dual-guitar sludge riffing has been a bit buried beneath heady noodling and, at times, a vocal sheen that sounds ripped straight from an Incubus album. Still, on their newest, Emperor of Sand (Reprise), Mastodon, ever the consummate metal pros, undergird even their poppiest tracks (like “Show Yourself”) with tunneling, thick riffs that seem almost sneaky in how they snake through ornate prog noodling and busy rhythms. On a triumphant behemoth like “Roots Remain” they shift from torpedoing time-signatured accents to pensive moments of added percussion to guitar-rocketing solo overdubs in a way that should sound contrived but comes off as wholly natural. Seven full-length albums deep and with nary a notable lineup change, Mastodon are so comfortable with their celestial-metal supersound that, short of reanimating Ronnie James Dio to come out onstage and duet with guitarist-vocalist Brent Hinds, nothing ever feels off-limits.   v