A phoniatrician and 20-year metal singer shows what the larynx really does during growls and screams - and why done right, it is safer than it sounds.

Dr. Enrico Di Lorenzo is both the doctor and the growler, and he brings endoscopy, high-speed video at up to 20,000 frames per second, and spectrograms to prove his point. You will see which structures actually vibrate in a growl - false folds, arytenoid caps, aryepiglottic folds - while the true folds stay open, giving high airflow and low subglottic pressure. He contrasts that with the squeezed vocal tract of a scream, explains harsh voice and diplophonia, compares male and female growls, covers breathing demands, and finishes with starter exercises for students. For teachers and singers working in metal, rock and heavy contemporary styles.