The relation between tongue shape and pitch in clarinet playing using ultrasound measurements

Tongue shapes during clarinet performances of chromatic scale, portamento and pitch bending exercises were imaged using an ultrasound machine while audio and video were recorded synchronously. Analysis of the data from four participants revealed that tongue position varies non-monotically with note frequency in the lowest register (up to ≈ 440 Hz) and then descends monotonically as note frequencies rise through the upper registers. The descent of the tongue results in an expansion of the vocal tract's posterior oral cavity, resulting in a vocal tract input impedance maximum tuned to high frequency. Portamento and pitch bending were found to involve a raising of the tongue and concomitant contraction of the posterior oral cavity. The degree of contraction was similar in both portamento and pitch bending, suggesting a common acoustic mechanism.