How and why do vocal tract resonances and articulation change when shouting? Vocal tract resonances R1 and R2, Open quotient, Fundamental frequency, voice intensity, larynx height, lip aperture and spreading were simultaneously recorded for a female native speaker of French, on 7 French vowels and for 3 different conditions of increasing vocal effort: "normally" (S1), when keeping a pitch constant (S2) and when keeping both pitch and articulatory position constant (S3). R1 depends not only on articulation, but also on open quotient and larynx height. Results suggest that raising R1 and hyper-articulating in loud speech may serve to tune R1 to the first or the second voice harmonic, and thus help in increasing voice intensity.
Bibliographic reference. Garnier, Maeva / Wolfe, Joe / Henrich, Nathalie / Smith, John (2008): "Interrelationship between vocal effort and vocal tract acoustics: a pilot study", In INTERSPEECH-2008, 2302-2305.