Flute acoustics: measurement, modelling and design - School of ...

338 APPENDIX C. QUANTIFYING MUSIC
spectral content is far from the only determinant of timbre. The initial transients in a musical
note are also very important in distinguishing between, say, a note played on a flute and the
same note played on a clarinet. In this work we make some predictions about aspects of the
timbre of notes based on mathematical modelling of flutes, but it is impossible to convey the
richness of a concept such as timbre in a single numerical prediction.
Musical instruments may all be thought of as devices that convert one form of energy to
another. Energy is supplied to the instrument in a variety of forms, and some of it is converted
into sound waves. As energy converters (or transducers), musical instruments are extremely
inefficient, typically converting only 1% of input energy into sound (the remainder is lost as
heat, or converted into a constant flow of air, which we do not perceive as sound). The input
energy of a guitar, for instance, is supplied by the guitarist plucking a string; this is then transferred
from the string to the soundboard and from the soundboard to the surrounding air. In
woodwind instruments, the input energy is carried by air, either as a flow or pressure. To sound
a flute the flautist blows a stream of air across the embouchure and to sound a clarinet, the
player supplies a pressure at the embouchure end.