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

2pMU3. Experimental determination of the stiffness of a saxophone reed by means of the evaluation of the reactive power.

Vincent Gibiat

Lab. Ondes et Acoust., ESPCI, 10 rue Vauquelin, F75005 Paris, France

Xavier Boutillon

Univ. Paris 6, F75005 Paris, France

A simple model for a saxophone or a clarinet reed---one pure spring with stiffness k---is acceptable for frequencies beneath the resonance frequency of the reed. When the instrument sustains a harmonic tone, Eq. (1) of the previous paper holds and the right-hand side quantities can be experimentally determined in order to evaluate k or k/S[sup 2]. Experiments were driven on a saxophone so as not to encounter large uncertainties due to the weakness of even harmonics and corresponding minima of the input impedance of a cylindrical pipe. The reed stiffness is derived from separate measurements of the input impedance (TMTC method) and of the internal pressure spectrum when the saxophone is played by a musician or blown by an artificial system. Combined with an evaluation of the reed area, results on reed stiffness under playing conditions are in good agreement with compliance values measured on isolated reeds by other authors. The reactive power balance between the reed and the pipe also sheds a new light on the playing frequency changes that are observed when the saxophone is played softly or loudly without any mouth correction. A link with the anharmonicity of the pipe resonances will be shown.