The acoustics of the shakuhachi---and of the shakuhachi player's face

The expressiveness and flexibility of the shakuhachi---the end-blown Japanese flute---has made it popular in the Western phenomenon of "world music". Its flexibility in pitch and timbre are achieved in large part by varying the angle between the instrument and the player's face. Like other flutes, it is open to the air at both ends, and so plays at minima in the acoustic impedance. The player's face, especially the upper lip, acts as a variable baffle at the blowing end.

Measuring the acoustics of the instrument was almost routine for our lab, but measuring the acoustic response of the player's face was not. For this, we mounted our measurement head inside the bore of a shakuhachi. The head comprises a source of carefully calibrated acoustic current with several hundred different frequencies, and a microphone.

Riley Lee, a grand master of the classical shakuhachi, international soloist and recording star, came to the lab. As he demonstrated some of the embouchure effects, we measured the acoustic response of his face, as 'seen' (heard?) by the shakuhachi.

The frequency-dependent end effects for the different embouchures explain not only the large variations in pitch achieved in playing, but also some of the timbre changes. They also contribute to the harmonic tuning of the instrument itself.

Joe Wolfe, John Smith and John Tann