William Barton practices on the didgeridoo with the Charlottesville High School String Ensemble. He’ll play at the Phillips Collection on Sunday. (T.R. Goldman)

Sound is generally invisible, but when William Barton plays the didgeridoo, producing a low moaning note that is unearthly and ethereal, you can practically see the long vibrations leave the end of his lacquered, wooden tube and slide their way across the floor. And that’s just the drone note.

Barton, who is 6-foot-3 with a linebacker’s girth, is at the same time tapping his five-foot long didgeridoo with his right index finger — hard — and making a series of yelps, barks, squawks and at times a loud whooshing sound, like a flying owl flapping his wings. This occurs with no break in the sound, since Barton is practicing what is known as circular breathing — maintaining enough air in his diaphragm to continue to blow while he is taking in air through his nose.

“You don’t actually need much air to make the sound of the didgeridoo,” he explains. “Once your lips and embouchure are strong enough, it’s like blowing on fairy floss” — the Australian name for cotton candy.

Nobody knows when Australian aborigines discovered that blowing through a termite-hollowed length of eucalyptus wood could produce a sound so powerful and otherworldly, a sound that can be pitched to one key or another depending on the length and bore size of the instrument. Didgeridoos show up in 1,500-year-old rock art from northern Australia, where the instrument has traditionally been used for religious and spiritual ceremonies, so it’s at least that old, and possibly a lot older.

But while some of the earliest Western music, like plainchant, also started roughly 1,500 years ago, the didgeridoo, for obvious geographic reasons, had virtually no place in the Western musical canon. Until very recently.

Barton is here, in Washington, to further that aim, playing a solo recital Sunday at the Phillips Collection. Indeed, Barton has been playing didgeridoo with orchestras all over the world for about half his 32 years. He’s a big deal in Australia, the winner of the 2012 ARIA — the Australian equivalent of a Grammy — for best classical album. He has played Carnegie Hall, the Amsterdam’s Concertgebouw, the Pompidou Center in Paris, the Sydney Opera House and dozens of other halls worldwide.

All this in the service of something Peter Sculthorpe, at 84 the dean of contemporary Australian composers, calls a “quintessentially Australian instrument.” The sound of the didgeridoo, he said, mirrors the flatness of the country. “Therefore I love working with it — I’m Australian.”

Barton’s big break came after he played Sculthorpe’s haunting orchestral work, “Earth Cry,” in 2002, a piece Sculthorpe had written 16 years earlier without the didgeridoo part.

“One day, I had a phone call from a young man called William Barton,” recalled Sculthorpe, reached at his home in the Sydney suburb of Woollahra. “He was in his early 20s, and he’d just played my String Quartet No. 12 at the Townsville Festival in Queensland. He told me it was his ambition to play the didgeridoo with classical music. I was delighted. I’d never come across a player with that ambition.”

In 2004, Sculthorpe wrote his Requiem with Barton in mind, reportedly the first time a didgeridoo had been featured in a full-scale symphonic piece. “We became good friends,” said Sculthorpe, “and we’ve been good friends and fellow travelers ever since.”

On this trip to the Washington area, Barton is traveling with his mother, Delmae, 70, who often sings with her son, an experience that, up close, can be even more intense than hearing the didgeridoo for the first time. Slipping off her shoes, Delmae, who is a good foot shorter than her son, closes her eyes, places her hands in front of her, palms up, and let’s loose with a searing, mezzo-soprano-ish round of long notes, a style she says she learned as a child while walking alone in central Queensland singing with the birds and her own echo. “It was like a natural amphitheater,” she says.

Barton grew up in Mount Isa, a mining town and administrative capital in the middle of the outback in northwest Queensland, home to his Kalkadungu aborigine tribe. He learned to play the didgeridoo when he was 8, from his uncle. When his uncle died three years later, rather than bury the didgeridoo with him, as was the custom, the tribal elders allowed Barton to keep it.

Barton started traveling internationally at 15. Like any musician, his instrument has always been central to his life. “I remember the day I got the circular breathing,” he said, referring to the physically tricky technique of continuous breathing that is essential to master the didgeridoo and that is part of the technical repertoire of many jazz and classical brass and wind players as well. “I was at home lying down on the bed on my side,” he recounted during an interview at the University of Virginia’s Kluge-Ruhe Aboriginal Art Collection, where he is staying this month while rehearsing for concerts he will play with the university’s string quartet and the Charlottesville High School string ensemble. “It was the first part of a long journey.”

To practice, Barton would take an old Yamaha four-track recorder and put in a tape of “If You Want Blood, You’ve Got It,” an album by Australian hard rock band AC/DC. He played the tape at different speeds so he could improvise along on his didgeridoo in different keys.

“People always ask me: ‘How long does it take to [learn to] play the didgeridoo?’ And I tell them anyone can play the guitar with three chords,” says Barton, whose second instrument is the guitar, “but if you want to tell a story, that’s a different matter.”

“The hardest part is learning the language. And every culture has a song line,” he said. “Just like every society has seasons, every society has its musical version of [Vivaldi’s] ‘Four Seasons.’ ”

Barton jammed with Canadian classical violinist Lara St. John on the famous chaconne from Bach’s second partita. “It was a totally last-minute thing,” St. John said, “but it’s an incredible sort of sensation when you’re in the same room.”

Barton is not classically trained; he learned to notate music about 10 years ago with a private tutor he had after winning a year-long fellowship to Griffiths University in Queensland. Like many composers, he finds inspiration anywhere, “from a pedestrian crossing, or blinkers in a car. They start off in time, then swing out.”

On rare occasion, he has encountered opposition to taking the didgeridoo out of its traditional aboriginal context and using it in the service of Western music.

“People say it’s sacrilege,” he says. “I say: ‘Mate, it’s from your culture. Get over it.’ ”