At the 2004 world premiere of Peter Sculthorpe's Requiem for choir and orchestra in Adelaide, the audience was respectfully poised for what was expected to be a masterwork from this father of modern Australian composition. What began to issue from the stage was suitably piquant, with cello passages that seemed to weep in waterfalls of sound. Then, in the second movement, something miraculous occurred. Walking slowly from the back of the hall toward the stage came a gentle giant of a man, his 1.9-m bulk wrapped around a hollowed tree trunk into which he breathed. Sculthorpe's music at once expanded, evoking the spaciousness and soaring skies of the Australian Outback; William Barton's didgeridoo was the heartbeat. Barton says walking through the audience to the stage "adds something new." But what he brings to the world of classical music is both something new and something ancient: encoded in the 25-year-old's commanding frame is the gravitas of tradition. Considered by many to be the world's oldest wind instrument, the didgeridoo has been played at Aboriginal ceremonies for thousands of years. But what Barton calls "the most simple instrument in the worldjust a branch of tree minus termites," is radically new to the classical stage. "It's one of those things where, if you put something out in the universe and you really, really want it, it eventually comes back," says the northwest-Queensland-born, Brisbane-based Barton. "I remember sitting in the old car in Mount Isa and listening to my AC/DC but also my classical music and just thinking, It would be so great to have the didgeridoo with that." For his debut with the London Philharmonic last year, Barton recalls, his approach from the back of the Royal Festival Hall had the audience flummoxed. It wasn't until he was on stage, with his hand tapping the side of the didgeridoo, that they realized he wasn't a recording. But it's what Barton does with his buzzing mouth and lips that is revolutionizing the instrument. Barton has developed a fast-tongued technique that is taking the didgeridoo into new sonic realms, conjuring the spirit of a dingo or a crow with the brilliance of free-form jazz. He can also shift seamlessly between four different one-note instruments, all powered by his Herculean circular breathing (meaning he rarely needs to come up for air). "He's constantly inventing new ways of playing the instrument," says Liza Lim, composer in residence at the Sydney Symphony. "It's such a great signal of Aboriginal culture not being static; of renewing, innovating and transforming." This week sees the Sydney Opera House world premiere of Lim's new work for didgeridoo, flute and orchestra, and the SSO may never sound the same again. The Perth-born composer was interested in how Barton could reconfigure the symphonic frequencies of the orchestra, and The Compass is about "tilting the horizon point," she says. "In a way, the didgeridoo collects all the low instruments around it." The piece also brings Barton back to his roots. He begins with a chant in his native Kalkadunga tongue, since "the voice is absolutely the heart of what the didgeridoo's about," the composer says. What makes Barton a master is his prodigious musical talent, coupled with cultural insight. The son of well-known "Dream-time Opera Diva" Delmae, Barton was taught the didgeridoo from the age of seven by his uncle Arthur Petersen, a tribal elder. "I remember the first dayactually, when I got circular breathingliterally jumping for joy," he says. "Yeah, that was a good day." Barton never forgets the good fortune that has helped shape his career. After his uncle's death, Barton inherited Petersen's didgeridoo, and not long after, the teenager was invited to join an Aboriginal dance troupe which later toured the world. "I had my 16th birthday in Canada," he recalls, "but by that point I just wanted to go home and reconnect." That happened musically at Townsville's Australian Festival of Chamber Music in 2001, when Barton premiered Sculthorpe's revised (Ubirr) String Quartet No. 12. The composer was so impressed he went on to write other new works for Barton, whose playing he described as "summoning up the whole landscape." The musical chemistry was palpable, and the classical world soon came courting. A slew of commissions, CDs and concert tours has bulked up Barton's impressive c.v., culminating in a performance at the Cité de la Musique in Paris last November. "I tell you, he was a superstar," reports composer Lim, who was on hand. And refreshingly down-to-earth. While taking a break from recording in Sydney earlier this year, Barton sipped chai tea while reminiscing about his newfound love of Guinness-drinking in Ireland. "Sweet like nectar," he says. The same could be said of the sublime sounds from this new branch of an old musical tree.