Figure 5.

(a) Phonation threshold pressure P_th and (b) phonation onset frequency F₀ as a function of the resting glottal half-width g₀. In (a) and (b), the symbol ○ denotes results obtained when Eq. 6 was solved with two modes only and no damping; ◻ denotes results obtained when Eq. 2 was solved with the first ten modes included and with a structural loss factor σ=0.4. (c) Natural frequencies of the first five modes (in ascending order) of the vocal fold structure as a function of the resting glottal half-width g₀. (d) Coupling strength between the first and second modes (○), second and third modes (◻), and fourth and fifth modes (+) as a function of the glottal half-width g₀. A convergent geometry was used with α=−5° and T=0.5. Coupling strengths for other pairs of modes were either negative or complex and are not shown.