Antoine Lefebvre: Methods for the Design of Woodwind Instruments

Antoine Lefebvre is a PhD Candidate in the Computational Acoustic Modeling Laboratory (CAML) and the Centre for Interdisciplinary Research in Music Media and Technology (CIRMMT) at the Schulich School of Music of McGill University. His research focuses on the development of computer-aided methods for the design of woodwind instruments. He studied mechanical/aerospace engineering at the Montreal Polytechnic School and graduated with distinction after which he completed a masters degree in applied science in computer engineering, developing a system for the measurement of the acoustic impedance of wind instruments.

The design of a woodwind instrument is a difficult engineering problem because of the high precision required to satisfy the exacting standards that professional musicians demand.  As well, there are many, often contradictory, geometric and acoustic constraints that need to be satisfied. In this talk, an overview of the acoustics of woodwind instruments is presented with an emphasis on the factors that influence the playing frequency of an instrument, including the excitation mechanism and the geometry of the air-column. Then, the transmission-matrix method (TMM) for the calculation of the input impedance of an instrument is presented, along with work using the Finite Element Method (FEM) to develop refined tonehole models and to validate the results of the TMM with the simulation of complete instruments.  Finally, using the TMM to calculate the input impedance of hypothetical instruments, an optimization method is developed to calculate the best position and dimension of each tonehole on a given bore, which minimizes the tuning error for each requested fingerings. Examples for simple instruments are shown.