The Scientist’s Perspective on Brass Instrument Behaviour

Abstract

This chapter discusses the application of the classic scientific method to observe, measure and record the behaviour of brass instruments and develops a simple theory (or “model”) to explain the main features of this behaviour. The sound pressure levels inside the player’s mouth and the instrument mouthpiece are related to the radiated sounds. The approximations and simplifications which are needed for basic modelling of the complexities of brass instrument playing are justified. Scientific terms and concepts commonly used in brass instrument studies are explained: these include acoustic pressure, waveform, mean flow of air, optimisation, nonlinear sound generation, Fourier analysis, frequency spectrum, spectral envelope, cutoff frequency, oscillation regime, sound reflection and sound transmission. The Bouasse-Benade prescription is formulated and the phenomenon of the trombone pedal note addressed. The chapter concludes with a discussion of the wind instrument paradox.