Reduce the sound of rock ‘n’ roll to its essential elements and one of them will undoubtedly be the voice of Tom Petty — an instrument capable of expressing anger, lust, compassion, despair, bitterness, joy, and all the emotional subtleties that live between them. That voice, and the always-disarming urgency that arrived with it, was silenced when Petty died at the age of 66 from cardiac arrest on Monday October 2, but its impact, made throughout the last four decades with his band the Heartbreakers, on solo albums, and with the all-star outfit the Traveling Wilburys, will resound forever.

In the early ’70s, when a teenaged Petty joined the Gainesville, FL band Mudcrutch, Southern rock was defined by a mix of Lynyrd Skynyrd and The Allman Brothers Band. But Petty, who idolized Elvis Presley and grew up on the glory of ’60s Top 40 radio, eschewed epic guitar solos and Dixie pride for three-minute explosions of energy and hooks, the kind soaked up from the rock, pop, and soul hits he revered as a boy, be it The Animals’ “Don’t Bring Me Down,” The Isley Brothers’ “Shout,” or Van Morrison & Them’s “Mystic Eyes (all of which he and the Heartbreakers covered in concert).

By the time Mudcrutch morphed into The Heartbreakers in the mid-’70s, the rebel spirit of the ’60s was dissolving into something a bit more bland, and rock needed a hero to champion the punch that had long marked the music’s center. Petty and pals arrived just in time — their self-titled ’76 debut album brimmed with concise tracks like the brooding “Breakdown” and the breathless “American Girl.” It had both a tough physicality and a soulful abandon, and it was clear that an important new voice had entered the rock ‘n’ roll conversation.

Today we think of Petty as a face on classic rock’s Mt. Rushmore, but the fact is that all the way into the early ’80s, he was often lumped in with the punk/new wave movement that started picking up steam around the same time the Heartbreakers were making their initial mark. The band’s long-haired, denim-clad image was at odds with punk’s fashion choices, but its take-no-prisoners attitude, combined with the songs’ unwavering catchiness and the bandleader’s no-BS approach to record making and stardom, had deep parallels.

Though Petty was frequently channeling the influence of The Byrds and Bob Dylan, evergreens like “I Need to Know” and “Listen to Her Heart” were fierce power-pop pieces as au courant as anything coming out of the post-punk underground. And when all the stars aligned for the game-changing phenomenon that was his multi-Platinum 1979 milestone Damn the Torpedoes, the band entered into the pantheon of rock royalty on the strength of indelible tunes like the anthem of defiance “Refugee,” the hard-luck hopeful “Even the Losers,” and the jolting “Don’t Do Me Like That.”

But for all Petty’s personal dynamism, rock ‘n’ roll heart and sterling songwriting chops, one of his key assets was his bandleading skills. Like Bruce Springsteen and Bob Seger, the other “heartland rock” heroes and peers, Petty based his sound around the singular noise he and his pals made together, and without question it was their collective effort — onstage and in the studio — that gave their performances so much lift-off. Guitarist Mike Campbell, keyboardist Benmont Tench, bassist Ron Blair (replaced by Howie Epstein for several years before his return), and drummer Stan Lynch (eventually replaced by Steve Ferrone) perfected a balance of energy and understatement that frequently earned them the appellation of “America’s greatest rock ‘n’ roll band.”

Campbell’s swooping licks on “The Waiting,” Blair’s graceful flurries in “American Girl,” and Tench’s angry organ blasts on “Refugee” had as much to do with the songs’ appeal as the ache and snarl coming from their boss. Petty was the instinctualy gifted bandleader who knew exactly how to harness his cohorts’ talents, and wherever he led, they followed, even into the stylistic experimentation of the loosely conceptual Southern Accents, complete with the neo-psychedelic nova “Don’t Come Around Here No More.”

Eventually, Petty felt the need to step outside the circled wagons of The Heartbreakers for a bit. And when he did, he often ended up making history all over again, and discovering new sides of himself in the process. Whether he was joining pals George Harrison, Bob Dylan, Jeff Lynne and Roy Orbison for the offhand ebullience of The Traveling Wilburys or making his first solo foray with 1989’s epochal Full Moon Fever, he delivered timeless hits like the transcendent “Free Fallin'” and the beloved supergroup’s worldly-wise “End of the Line.” They extended his legacy even further.

From their ’70s classics to ’90s singles like the appropriately airborne “Learning to Fly” and the gritty “Mary Jane’s Last Dance,” Tom Petty & The Heartbreakers created the kind of music that made the radio sound better whenever they came on (which was a lot). The reason they were still able to fill stadiums four decades down the line was that they crossed boundaries in a way few other artists ever have. The songs reached across stylistic, generational, and social borders; they were well-crafted enough for aesthetes, hooky enough for pop addicts, and hard-hitting enough for rockers of every stripe. In this sense, Petty was the Great Unifier, capable of playing the 2008 Super Bowl halftime show without damaging his cool cred.

The band spent the spring and summer of 2017 on the road, celebrating 40 years together (November 2016 was the official 40th birthday of their debut album) — they wrapped up the tour a week before Petty’s death. And though Tom had made statements to the press about scaling down the touring in favor of familial pleasures like spending more time with his granddaughter, there seemed to be no lack of energy onstage in him or his bandmates. They tackled everything from their earliest material to tunes from their most recent album, 2014’s Hypnotic Eye, with equal intensity.

Even at 66, Petty’s was a fire that seemed unlikely to be extinguished soon. So it was all the more shocking when the news of his passing arrived — the guy had just roared through America pleasing the faithful and reminding fans that focus and commitment were two of his bedrock concerns. One of rock ‘n’ roll’s staunchest champions is gone from our world, but the pleasure and power of what he left behind can never be diminished.

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