ASA 127th Meeting M.I.T. 1994 June 6-10

2pMU2. Applying the reactive power approach to the woodwind instruments.

Xavier Boutillon

Lab. d'Acoust. Musicale, Univ. Paris 6, Case 161, 4 place Jussieu, F75005 Paris, France

The time-domain approach of self-sustained instruments such as the violin or the clarinet has sometimes revealed a marked hysteresis between force or pressure and velocity or flow. Formally defined by analogy with the active power, the reactive power Q[sub n]=n(pi)p[sub n]f[sub n] sin((cursive phi)[sub n]) injected by a component into a pipe is highly sensitive to phase differences between pressure and flow components. The reed dynamics is one major cause for hysteresis; under various assumptions, the reed stiffness will be expressed as