Unlike amateurs, professional sax players can play notes in the very high altissimo sound register by tuning their vocal tract to assist the instrument, new research in the journal Science reveals.
The finding resolves a 25 year-old debate among scientists and players of reed instruments, such as the saxophone and clarinet.
It means that a player's vocal tract is sometimes more important than the instrument itself.
The longevity of the debate is due to the technical difficulty of making non-perturbing, precise, acoustical measurements inside the mouth during playing - that is, in a variable, humid environment with very high sound levels.
Australian scientists at the University of New South Wales demonstrated that professional players achieve this effect by systematically tuning their vocal tracts to resonate at a frequency close to that of the desired note. This tuning adds the tract's resonance to that of the saxophone, which allows the instrument to play above its normal range.
The research reveals that amateur players, who were unable to play notes in the altissimo range, did not tune a strong vocal tract resonance.
The standard range of the saxophone that is taught in elementary and intermediate stages of learning is a little over two and a half octaves. The altissimo range, used by experienced players, extends another octave or two above this.
"Acousticians have long debated whether and how the resonances of the vocal tract are involved in the playing of clarinet and saxophone," says Chen Jer-Ming, a UNSW PhD student. "We measured the resonances of saxophonists' vocal tracts directly, while they played. Over the standard range, there is no simple relation between tract resonances and notes played.
"However, in the altissimo range, the second resonance of the tracts of professional saxophonists was systematically tuned slightly above the desired note," says Mr Chen. "The players who couldn't achieve this effect were also those who couldn't play in the high range."
"Over the standard range, a resonance of the air within the saxophone determines the note played: you press the right keys and the right note (usually) comes out. But for the altissimo range, the sax's own resonances are weak, and to play up there you need to make the resonances of your own vocal tract stronger so they can assist those of the instrument to produce the desired note."
Although the effect was shown in the saxophone, similar effects are likely to be important in other single and double reed instruments, whose players also report the importance of the tract for special effects, including high register playing.
Editor's Note: Original news release can be found here.