Lip constriction lowers the frequencies of all vocal tract formants
Evidence
In order to produce different sounds, the shape of the vocal tract is altered by means of the articulators to change its acoustic properties. The perturbation theory principles explored in the context of woodwind reed instruments (see Figure 4.23) can be employed here also (Kent and Read, 1992). Figure 4.38 shows the velocity nodes and antinode positions for the first three formants of the vocal tract during a neutral nonnasalized vowel, which can be confirmed with reference to the upper-right-hand part of Figure 4.23. Following the same line of reasoning as that presented in the context of Figure 4.23, the effect of constrictions (and therefore enlargements) on the first three formants of the vocal tract can be predicted as shown in Figure 4.39. For example, all formants have a volume velocity antinode at the lips, and a lip constriction therefore lowers the frequencies of all formants. — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1347
Categorization
Category: Causal Relationships
- XREF: Perturbation theory bridges woodwind acoustics and speech science — a cross-domain parallel to Chapter 4’s instrument model.
Related
- Vowel production shifts formants by perturbing vocal tract geometry like a woodwind instrument (similarity 0.86)
- Tongue and lip constrictions shift vocal resonances mostly near their nodes, not antinodes. (similarity 0.86)
- Tongue and lip constriction locations systematically shift formant frequencies from neutral values (similarity 0.84)
- Vowel formant frequencies are predictable from the location of vocal tract constrictions (similarity 0.81)
- Vowels are distinguished by formant frequencies controlled by tongue, jaw, and lips (similarity 0.79)
- The vocal tract behaves acoustically like a stopped tube of constant diameter (similarity 0.79)