How a Physicist Would Make the Recorder Easier to Play

(Inside Science) -- The recorder is a near-perfect instrument for beginning musicians. It’s cheap -- often just a few dollars -- and easy to hold and play with small fingers. That’s one reason why groups of elementary students playing “Hot Cross Buns” have dominated music education, said Susan Burns, a longtime recorder player who works as the administrative director of the American Recorder Society. “It’s the ultimate democratic instrument -- anyone can play it.”

But one reason people cringe when thinking about recorder songs is the propensity of new players to blow too hard and hit a note an octave higher than where they aimed.

New physics research now proposes a tweak to the instrument that could reduce the likelihood of the painful overblowing problem. The researchers got there by modeling the way air flows through the recorder.

Nick Giordano, a physicist at Auburn University in Alabama, became interested in the physics of musical instruments three decades ago. He started studying the physics of the piano, creating a full computational model that produced calculated sounds based on Newton’s laws of physics. Then, in 2010, he heard another researcher talk about modeling the physics of wind instruments using the Navier-Stokes equations, which are complex calculations that describe fluid flow and can be used to explain smoke rings, curveballs and air turbulence around planes.

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Giordano was inspired: With enough computing power, he thought it would be possible to solve the equations in musical instruments. And the simplest instrument to look at, he said, is the recorder. “In a trumpet, your lips are vibrating, or in a clarinet there’s a vibrating reed. For a flute, you have to find the right angle for your lips,” said Giordano. “But the recorder is sort of the fruit fly for us, in terms of things to study.”

A friend of Giordano’s told him about the problem of overblowing, when the instrument’s pitch would jump an octave with hard breath. The problem was especially prevalent in larger bass recorders. Giordano and a student decided to attack the problem with their computational tools. They made maps of the air coming in the mouthpiece and noticed ways they could change the sounds that come out. The team discovered they could carve off a little bit of extra room in the cavity for air, just in the mouthpiece region, and that made all the difference in the behavior. The redesigned instrument should tolerate changes in blowing force more readily without switching tones, said Girodano. “This could be a better instrument.”

In a paper published this month in the Journal of the Acoustical Society of America, Giordano describes the calculations and design of the better recorder. His student, Jared Thacker, created the recorders using a 3D printer and analyzed the sounds coming from them -- confirming that they were indeed more forgiving to a player.

The researchers have yet to pass their redesigned instruments to musician friends, but they hope to do so later this year. Susan Burns at the recorder society thinks it’s an intriguing idea. “People think it’s like a trumpet -- like, ‘Let me blow my brains out,’” she said. “But it’s very much to be treated similar to the human voice, the way you articulate. It doesn’t have to sound like a shrieking plastic toy.”

Giordano hopes to extend the method to the trumpet or clarinet, including a model of the player’s lips or reed motion. Another goal is to model recorders of different sizes, from sopranino (about the size of a mechanical pencil) to bass (many times larger), and the sounds they would create if tweaked one way or another. Looking at physics through musical instruments also just brings a lot of joy: “Sometimes experiments are just neat,” he said. “Science can and should be beautiful in some ways.”