Your death metal vocals might be great, but maybe consider taking a look at how bats do theirs. Yes, seriously. In a new study titled Bats expand their vocal range by recruiting different laryngeal structures for echolocation and social communication published in PLOS Biology, authors Jonas Håkansson, Cathrine Mikkelsen, Lasse Jakobsen, and Coen P. H. Elemans compared the lower range of bat vocals (and their technique) to that of death metal vocalists.
In the abstract of the study, the authors points out "that bats extend their lower vocal range by recruiting their ventricular folds—as in death metal growls—that vibrate at distinctly lower frequencies of 1 to 5 kHz for producing agonistic social calls." The study later elaborates on the technique, comparing it to the multi-tonal Tuvan throat singing. Which if you've ever seen that performed, is insanely impressive.
"In humans, ventricular folds play a role in several low-frequency forms of singing, such as death metal grunting and Tuvan throat singing, where they can touch the vocal fold and increase the mass of the oscillating structures," said the authors. And don't worry, this isn't just some rough comparison – the authors actually cite a separate study from 2009 explicitly dedicated to figuring out how death metal vocalists do what they do.
Turns out the metal vocals aren't just intuitive for bats, but also for babies! In a 2017 study by Krzysztof Izdebski, he points out that babies innate ability to scream at high pitches for long periods of time is roughly the same technique used by metal vocalists to accomplish some of their harsher vocals.
"So a growl is, is one of the most aggressive sounds that heavy metalers do; it sounds something like 'Rahhhh!!!' said Izdebski. "Okay. So, a growl is produced — and they can do it over and over and over, hour after hour … The images that we recorded clearly show that it’s produced predominately, predominately by structures above the glottis.
"So, the vocal folds do open and vibrate but actually don’t collide, and the entire sick area above — aryepiglottic folds, arachnoids, epiglottis — everything claps and dances, basically, and creates vibrations and creates acoustic orchestration."