CHICAGO (Reuters) - Jazz legend John Coltrane routinely pushed his tenor saxophone into the altissimo range, notes far above the instrument’s normal range, and now Australian scientists know how he did it.

A man plays the saxophone in New York's Central Park October 12, 2007. Physicists at the University of New South Wales in Sydney said professional saxophone players can tune their vocal tract -- the tube formed by the lips, mouth, tongue, throat and vocal folds or cords -- to produce extremely high notes. REUTERS/Shannon Stapleton

Physicists at the University of New South Wales in Sydney said professional saxophone players can tune their vocal tract -- the tube formed by the lips, mouth, tongue, throat and vocal folds or cords -- to produce those extremely high notes.

Their research may solve a long-standing debate among scientists and musicians about how much of the player’s own vocal instrument contributes to the sound, said Joe Wolfe, a physics professor who supervised the research.

As in speech, changes in the shape of the mouth and tongue and vibrations in the air in the vocal tract can be enhanced or inhibited at different frequency. But scientists and musicians have differed about how this was applied to reed instruments like the saxophone.

“No one really knew: it is difficult for players to be quantitative or even explicit about what they do with their vocal tracts, and it is difficult to make precise measurements inside the vocal tract during playing,” Wolfe said in an e-mail.

To study this, Wolfe and colleagues attached a thin probe to the mouthpiece of a tenor saxophone that measured acoustics inside the vocal tract while the saxophone was being played by both professionals and amateurs.

Professional players tuned the resonance in their vocal tracts slightly higher when they played these ultra-high notes, they report in Friday’s issue of the journal Science.

Adjusting the muscles and shape of their vocal tracts allowed them to play notes higher than those they were actually fingering on the instrument.

Amateur saxophonists did not make those adjustments and were unable to play above the instrument’s normal range.

“You have to hear the sound in your head before you can produce it,” said Linda Van Dyke of Oak Park, Illinois, who has taught saxophone and clarinet for the past 25 years.

“I ask my kids to sing through their horns a lot.”

Hitting those high notes is not something she attempts to teach. “Those students who have done it have experimented on their own and figured other ways to get there,” she said.

Wolfe said it usually takes saxophone players years to learn how to modify the vocal tract appropriately.

“We cannot say whether anyone can learn it. However, nearly everyone learns, at an early age, how to produce, reliably, the dozens of different vocal tract configurations required to speak one or more languages,” he said.