Woodwind design uses microwave theory

Woodwind musical instruments consist of holes and tubes that enable a musician to play different notes. Woodwinds can be modeled with open holes as short circuits and tubes as transmission lines. An instrument can be designed by modeling all of the sections and fingering configurations. Transmission-line approximations and cascaded transmission-line theory can be used to model woodwind instruments, such as the flute, crumhorn and cornetto. In fact, the same transmission-line equations and approach of breaking a circuit into small sections are used for microwave circuit design. In this article, this approach is applied to design a crumhorn using commercially available Lucite tubing. After fabrication, good agreement is obtained between the measured performance and the theoretical predictions.