Effect of Wall Material on Vibration Modes of Wind Instruments

Abstract

The effect of material on the tone quality of wind instruments is a very controversial subject. At first glance it is evident, for example, that a flute made of wood has a different sound to a flute made of metal alloy. At closer observation, the influence of materials can raise multiple questions. The physics of wind musical instruments teaches us that the origin of sound production is by the open end of the waveguide. The contribution of wall vibration to sound production and to radiation of a pipe of circular section is not enough to radiate audible sound into the room. For a better understanding of the interaction between the wall vibration and the properties of materials it is necessary to describe the characteristics of wind musical instruments with impedance curves. A specific device—BIAS—was developed by the Wiener Klangstill Institute for the measurements of the impedance curve versus frequency. In this chapter the effects of wall thickness, the geometry of a tube and of wind instruments, the nature of materials, the wall surface quality and thermal losses were discussed. It is worth mentioning that the methodology developed by Tronchin and co-workers (Cocchi and Tronchin in Proc Acoust Soc Am 103:763–764, 1998; Tronchin in Non-linear convolution applied to acoustic signals, 2012; Tronchin in The emulation of non-linearity of musical instruments by means of Volterra series, 2016; Tronchin and Amendola in On the effect of material in the acoustics of flutes, 2016) allowed to notice the differences in timbre among the flutes made of copper alloy, silver and gold. This very complex methodology is based on sound vibrational behaviour of the flute and is expressed as frequency response function and intensity of acoustic radiation. Having in mind theoretical considerations and numerous experimental approaches described in this chapter, we can mention that materials have a limited effect, if any, on the sound of acoustic specimens or experimental musical instruments. On the other hand, the vibration of a wind instrument wall can influence the feeling of a player for various reasons. It is evident that different materials provide very different amounts of damping, and therefore it is also evident that this phenomenon should be taken into consideration.