Glottal Voice Distortions: Nasolaryngoscopic and Spectral Analysis of Anatomophysiologic Changes in Singing Voice

The distorted voices, commonly called vocal drives in Brazil and in some other South American countries, are vocal ornaments belonging to the aesthetics of popular singing and desired by singers of different styles. The advances in vocal sciences have allowed the demystification of this type of technique in the last four decades, classifying them as glottal, supraglottic or mixed distortions/drives. The interdisciplinary approach in the evaluation of singers who use glottal distortions is fundamental for a broad understanding of the particularities of each case. The present study has as main objective to describe the anatomophysiological and spectral findings of the glottal distortions, identified in the practice of many singers. A sample of three singers in a sung emission with and without vocal distortions was collected. PreSonus® AudioBox Studio One kit was used to record the voice during the nasolaryngoscopic evaluation. The singers underwent vocal warm-up and functional evaluation of the larynx based on two studies on contemporary singers. The singers performed the Snarl Voice and Phaser distortions and both showed particular anatomophysiological behaviors. The larynx was low in the first distortion and the level of the clean voice in the second, with the posterior opening of the glottis in both distortions being observed, with opening of the middle third of the glottis for the first as well. Formants vary according to the vocal tract settings used for the distortions. The glottic distortions present a complex anatomophysiological behavior in their composition, with fundamental participation of the transverse interarytenoid muscle and lateral cricoarytenoids, as well as the the participation of the vocal fold in the frequency break. F3 varied according to the longitudinal length and F4 with the diameter, both being related to the three-dimensional adjustments of the vocal tract.