Growl, Scream, Distortion: What MRI and High-Speed Imaging Reveal About Rough Vocals!

The terminology used to describe rough vocal qualities remains far less standardized and considerably less researched than the concepts established in Western classical singing pedagogy. Terms such as vocal fry, fry scream, grunt, death growl, distortion, rattle, and undertone are widely used in contemporary and extreme vocal styles, yet their underlying physiological mechanisms are often inconsistently defined in both pedagogical and scientific contexts.

From an acoustic and voice-physiological perspective, the voice production mechanisms grouped under the umbrella term rough vocals represent a particularly fascinating field of study. Many of these vocal qualities involve double oscillation mechanisms, in which the true vocal folds oscillate in interaction with additional anatomical structures of the vocal tract, such as the ventricular folds or aryepiglottic tissues. These interactions result in complex vibratory patterns that strongly influence perceived sound quality.

This course examines a range of rough vocal mechanisms from a scientific yet practice-oriented perspective. The analysis is based on data from high-speed videoendoscopy as well as three-dimensional vocal tract configurations obtained through magnetic resonance imaging (MRI). By integrating physiological imaging with acoustic analysis, the course provides insight into how different rough vocal qualities are produced and how they differ in terms of vibratory behavior, laryngeal configuration, and vocal tract shaping.

Based on these data, a functional classification of rough vocal mechanisms into distinct groups is proposed. Particular emphasis is placed on distinguishing mechanisms that allow for efficient and sustainable voice production from those that may increase vocal load if applied without appropriate technical control.

Throughout the course, scientific findings are directly linked to vocal pedagogy and clinical practice, supporting informed artistic expression while promoting long-term vocal health.