Acoustic tube models of the human vocal tract for the university classroom

Abstract

Composite vessels of cylindrical tubes are often used to provide simple models of vowel formation in the human vocal tract. Already a two-tube model allows one to discuss vowel formation in the context of tube eigenmodes. In order to validate the two-tube model we use 3D printing to build a set of two single tubes and 26 two-tube composites representing different model realizations of the vocal tract. Good agreement between theory and experiment is obtained if the so-called acoustical end correction is taken into account. A better representation of human vowels requires an extension to more than two tubes; thus we took data for the construction from literature and investigate the spectra of five eight-tube models corresponding to the vowels [a:], [e:], [i:], [o:] and [u:]. The experimental work connected with the contextual applications in voice production aims to broaden the student’s conceptual understanding of tube resonances depending on the geometry in a more general manner.