Glottal waves obtained via inverse filtering vowel sounds may contain residual vocal-tract resonances due to incomplete glottal closures. This paper investigates the effect of incomplete glottal closures on the estimates of the glottal waves via inverse filtering. It shows that such a residual resonance appears as stationary ripples superimposed on the derivatives of the original glottal wave over a whole glottal cycle. Knowing this, one can determine if there are significant resonances of vocal tracts in the obtained glottal waves. It also shows that given an incomplete glottal closure, better estimates of glottal waves can be obtained from large lip-opening vowel sounds than from other sounds. The glottal waves obtained from /scripta/ produced by male and female subjects are presented. The obtained glottal waves during rapid vocal-fold collisions exhibit transient positive derivatives, which are explained by the air squeezed by the colliding vocal folds and the air from the glottal chink.
Bibliographic reference. Deng, Huiqun / O'Shaughnessy, Douglas (2007): "Effect of incomplete glottal closures on estimates of glottal waves via inverse filtering of vowel sounds", In INTERSPEECH-2007, 546-549.