Screams, Growls, and Science: The Basics of Extreme Vocals – Voice Science

Behind every scream or growl is a surprisingly intricate balance of control, anatomy, and artistry.

Today on The Voice Science Podcast, we’re diving into the world of extreme vocalizations — the screams, growls, and shrieks that sit on the boundary between singing and sound design. Are they safe? How are they created? And why do they connect with listeners so powerfully?

Let’s take a closer look at one of the most misunderstood corners of vocal technique — and separate the science from the stigma.

You may be unacquainted with the term “extreme vocalizations.”  Like me, you may be more familiar with the name “vocal distortion” or “harsh vocals.” One of the most useful tools I found during my online research for this podcast was a video entitled “The Science Behind Vocal Distortion: Will Ramos of Lorna Shore” produced by the YouTube channel The Charismatic Voice in May 2024. Will is a death metal singer famous for his extensive repertoire of extreme vocalizations. The video followed Will’s journey at Utah Center for Vocology at the University of Utah, founded by the esteemed physicist and voice scientist Dr. Ingo Titze. Will underwent a battery of procedures, including an EMG and MRI, in order to collect data to help voice scientists better understand the biomechanics behind these types of vocalizations.

The video is worth a watch, apart from the annoyingly-interruptive ads. Will’s vocals are mind boggling and there’s real voice science on display. During the video, I was schooled by Dr. Amanda Stark, Research Associate at the School of Vocology, to consider the bias conveyed by the words like “distortion” and “harsh,” which casts doubt on the correctness of such singing. Dr. Stark believes:

“There is a stigma that harsh vocalizations are harmful, hurtful, cause problems and injury. We know that is simply not the case. These are not treatment-seeking artists. That’s the other thing, is why I don’t think there’s been much work in this, is these artists have not sought treatment like we see in other genres. Which has to make you question: something is safely happening. The term is not aligning with how these sounds are being produced and what the listener ultimately perceives. The term has to align with what is being done. Then, the science has to drive these terms because otherwise they become irrelevant. Misleading misnomers.” I agree with her convictions that we should avoid words and terms that relay judgment until we have a better understanding of what these types of vocalization entail.

Before moving on, a brief observation about online searching. The 21st-century ability to instantly access information is a remarkable gift, but it comes with a responsibility. The reader must test for accuracy.

Let me give you an example. As I began my research for this episode, I went to Google and typed in “vocal distortion.” As I expected, there was ample AI-generated information, and an endless stream of how-to videos. One piece of advice it offered, for creating distortion, was “tilt the epiglottis backward.” Tilt? As a newbie to the topic, I knew I had much to learn, but this information seemed specious. So, I asked Google AI if one can tilt the epiglottis backwards. The answer: “No, a person cannot voluntarily tilt the epiglottis backward because its movement is an involuntary, passive reflex that occurs during swallowing.” So, which of these AI-generated facts is correct?

We will get to that in a minute, but the point of the anecdote is not to discourage discovery, but to encourage seeing the process to the end. Test the veracity of the information before adopting it as fact and practice, particularly, in regards to today’s topic, which, in all fairness, has to be seen as a high-risk form of vocal production. Voice science is just beginning to understand what is happening in the vocal mechanism for those who practice extreme vocalizations.

What are they and where do they occur

According to Dr. Titze, who coined the word vocology as the study of vocalization, extreme vocalizations are akin to all primal vocalizations, sounds humans make by imitating birds and animals. We identify these sounds as–scream, shriek, rasp, snarl, creak, grate, rattle, growl, grunt, caw, croak, click–just to name a few.

Voice science affirms that extreme vocalizations largely occur in the supraglottic region, the area above the glottis, which is the space between the true vocal folds which are housed in the larynx. Extreme vocalizations are the result of overlaying largely-periodic (regular) oscillations produced by the true vocal folds with aperiodic (irregular) oscillations created in the supraglottic region, which lies only a few centimeters above the true vocal folds. In addition, the pharyngeal wall and members of the oral cavity, particularly the velum and tongue, can also be enlisted to modify the sound. I know that was a mouthful so allow me to put it another way. These sounds, like all vocalizations, are a combination of what’s happening at the source, at the true vocal fold level, with what’s in play in the filter, the area above the true vo cal folds all the way to the lips. What makes extreme vocalizations different, by and large, is the presence of aperiodic oscillations, commonly called noise, which radically changes the listener’s perception of the sound. The noise is the result of structures within the supraglottic region being drawn close enough together to vibrate.

Why singers use them and listeners like them

Extreme vocalizations are a definitive element in some rock, heavy metal, and death metal music. As someone who doesn’t listen to these genres, I am curious to know what attracts people to them. I informally asked a half-dozen friends and acquaintances if they listen to metal music, and if so, to tell me what is the draw. Those who did, all self-defined as occasional listeners, found the music catalyzing, cathartic, and energizing. One person found the sound highly emotive, another even described it as beautiful.

But I wanted to hear from a real devotee, and found one in Andrew Hatch, writing for the website HeavyBlogIsHeavy.com. In his post entitled, “Harsh Vocals: A History,” Andrew observes that “the chief complaint of the vast majority of metal naysayers revolves around the vocals.” He finds few people complain about the rest of the band, “but the knee-jerk reaction against harsh vocals will always remain.” Yet, Andrew acknowledges that one can, with time, acquire a taste for harsh vocals, as he himself has.

But, as with most art, humans have the capacity to use it as portals through which they can access, to whatever degree they choose, ideas and emotions they might otherwise avoid or ignore. Andrew suggests this when he writes: “But the vocals–this is something different. They’re human and yet not, festering firmly in the graves of the uncanny valley. There’s powerful effect created by the corruption of the human voice into something inhuman and bestial. Metal harnesses this to manufacture soundscapes that examine the dark and macabre, the obscene and violent, the evil and the forgotten.”

Ways to create them

For the purposes of this episode, I am only concerned with extreme vocalization physically produced by the singer. Today, thanks to electricity, microphones, computers, software plugins,  vocal effect processors (pedals), not to mention human imagination, a host of vocal effects are achievable without any physical manipulation of the vocal mechanism. 

Yet, for some singers, self-producing is a quest they are willing to take. We stated earlier, voice scientists agree that the locus of activity for extreme vocalizations is the supraglottal region. But, which structures therein are at play? Another excellent piece of research I found is a video, “Vocal Effects in Singing: A Study of Intentional Distortion” on the website cvtresearch.com, a component of the Complete Vocal Technique method out of Copenhagen. The video is a presentation of a study by otolaryngologist Dr. Julian McGlashan in 2013 at the 10th International Conference on Advances in Quantitative Laryngology.

For the study, Dr. McGlashan examined twenty singing teachers using digital videolaryngostroboscopy while using intentional distortion while singing. The following structural adjustment were observed in a majority of the subjects:

• False vocal fold vibration
• Medial-lateral constriction of false folds
• Anterior-posterior constriction of false vocal folds
• Larynx raises
• Posterior-lateral pharyngeal wall constriction
• Narrowing of piriform fossae
• Epiglottis drawn backwards
• Arytenoid complex drawn anteriorly

It is impossible for me to read this list and not draw this conclusion: extreme vocalizing requires a high degree of reduction of height, depth, and width in the supraglottic region. They stand in stark contrast to the standard operating procedures most singers use everyday. Learning how to create these conditions to produce such vocalizations will require knowledge, patience and perseverance.

Before drawing the episode to a close, I want to return to the anecdote I told earlier about “tilting the epiglottis.” Based on Dr. McGlashan’s findings, drawing the epiglottis backwards, was evidenced in some of the subjects. I only mention this to reaffirm the importance of holding everything you read online under the bright light of evidence-based voice science before accepting it as truth. We have so much more to learn.

Closing thoughts

Extreme vocalizations are one type of vocalizations in the world of vocology.

Extreme vocalizations and intentional distortion, also called vocal distortion and harsh vocals, is adding a distorted sound onto a singing tone.

My colleague Mark Yeary reminded me that they should be thought of as an extended technique, which is defined as unconventional or non-traditional methods that produce sounds and timbres outside the established norms.

True. They are quite a departure from what most singers produce on a daily basis, but are similar in that all singing is a combination of a mode of phonation at the true vocal fold level plus the organization of the filtering system rising above the glottis.

In fact, as alien as extreme vocalizations may seem, and they are, I am convinced that most of the singing we take in has, to some degree, been selectively filtered to create an emotional or aesthetic effect. We hold “pure” singing up as a standard to be met, but perhaps we are all cooperatively gaslighting each other.

According to voice scientists, extreme vocalizations, when correctly produced by a capable practitioner, are no more likely to cause vocal trauma than other types of singing. 

Thank you for listening to today’s wild ride of an episode. What a fascinating topic, one we’ve only barely begun to discover. Until next time, keep singing, and singing smart.