Shaping new sounds

Abstract

MRI experiments have revealed how throat singers from Tuva produce their characteristic sound.

Keywords: acoustic phonetics; biphonation; human; physics of living systems; speech biomechanics; tuvan throat singing.

Figure 1.. Normal and overtone singing.

The output of a Tuvan throat singer as a function of time (horizontal axis) and frequency (vertical axis), as measured by Bergevin et al.; colour is used to represent the intensity of the output, with red being high and blue being low (see colour bar). For the first two seconds we hear a single low pitch (at a frequency of roughly 100 Hz, which is close to the musical note G2): this corresponds to the harmonics that can be seen at multiples of this frequency. After two seconds (to the right of the red arrow), the singer alters the vocal tract to emphasise a narrow band of harmonics between 1 kHz and 2 kHz (shown in red): this emerges as a second higher pitch (which is higher than the musical note B5) that adds a whistle-like sound to the low pitch. It can be seen that the singer is also able to vary the frequency range (and associated pitch) of this band of higher harmonics. Bergevin et al. used MRI to show the changes in the vocal tract that are responsible for the emergence of the frequency band and associated pitch. CREDIT: Bergevin et al., 2020.