Throaty voice quality: subglottal pressure, voice source, and formant characteristics

"Throaty" voice quality has been regarded by voice pedagogues as undesired and even harmful. This study attempts to identify acoustic and physiological correlates of this quality. One male and one female subject read a text habitually and with a throaty voice quality. Oral pressure during p-occlusion was measured as an estimate of subglottal pressure. Long-term average spectrum analysis described the average spectrum characteristics. Sixteen syllables, perceptually evaluated with regard to throaty quality by five experts, were selected for analysis. Formant frequencies and voice source characteristics were measured by means of inverse filtering, and the vocal tract shape of the throaty and normal versions of the vowels [a,u,i,ae] of the male subject were recorded by magnetic resonance imaging. From this material, area functions were derived and their resonance frequencies were determined. The throaty versions of these four vowels all showed a pharynx that was narrower than in the habitually produced versions. To test the relevance of formant frequencies to perceived throaty quality, experts rated degree of throatiness in synthetic vowel samples, in which the measured formant frequency values of the subject were used. The main acoustic correlates of throatiness seemed to be an increase of F1, a decrease of F4, and in front vowels a decrease of F2, which presumably results from a narrowing of the pharynx. In the male subject, voice source parameters suggested a more hyperfunctional voice in throaty samples.