Jo Estill was a professional singer for almost fifty years. Singing always came naturally to her but she didn’t enjoy performing. She decided to retire from singing and study the science of the voice and how it works to see if she could determine what made her singing so beautiful and thus be able to teach it to others. At the age of 48, Jo Estill got her BA and went on to get her master’s in education, along with 30 credit hours in speech pathology elective classes. In the early 1970’s, after she finished her degrees, Jo Estill worked as a research associate and lab technician at the Department of Otolaryngology at the Upstate Medical Center of the State University of New York in Syracuse. She worked with a voice scientist, a speech pathologist and an otolaryngologist (ENT) on a study of laryngeal cancer. During this time Jo investigated aspects of vocal quality through acoustic analyses, perception studies, x-ray, high speed film, and inverse filtering analyses. Jo hypothesized that the average person could identify different speech qualities---speech, sob, twang, and opera. After she proved this, she set about researching how people manipulated the different structures in their larynx to arrive at these different voice qualities.
Jo Estill developed the model of Power-Source-Filter. Power refers to the lungs that create breath flow. Source refers to the true vocal folds---part of the body that creates the sound when air passes through. Filter refers to the space and structures in the vocal tract above the true vocal folds that change the vocal quality. Jo also established that this system was not a linear system, meaning that one completely determined the others. The system is non-linear because the vocal tract (filter) is able to affect the true vocal folds (source) and the true vocal folds (source) are able to affect the breath coming from the lungs (power) and vice versa.
Thirteen Structures and six vocal qualities
Estill identified thirteen structures that affect vocal quality and showed that people could be taught to control these individual structures independently from the others. The thirteen structures are the head and neck, the velum (soft palate), the lips, the tongue, the jaw, the aryepiglottic sphincter, the false vocal folds, the true vocal folds body cover, the true vocal folds onset and offset, the thyroid cartilage, the larynx, the cricoid cartilage, and the torso. Estill went on to develop exercises that train and test the independent control of each of these thirteen different structures. She called these exercises the Compulsory Figures for voice. These figures were named after the figures that ice skaters used to have to do.
In the following video I give an overview of the thirteen structures along with an anatomy lesson.
By going to the vocal gym and practicing the Figures for Voice Control, singers develop the ability to control their voices and create the sound that they want when they are singing and speaking. In Estill’s model, one vocal quality isn’t placed over the others as the best or most beautiful. Different vocal qualities are appropriate for different situations and students can be taught to move from one vocal quality to another. Today, there are six vocal qualities that are taught along with the Figures for voice control. The original four are still used----speech, sob, twang, and opera---along with belt and falsetto.
Attractor States & Effort number
Each person has an attractor state for each of the structures when they are speaking or singing. An attractor state refers to the natural state that each of the the 11 body parts is in. This is generally influenced by what we have grown up hearing in our environment. Also, if my attractor state when singing is a wide AES, I’m going to have to use a high effort number to narrow my AES. But if my attractor state when singing is a narrow AES, it is the opposite situation, and I will need to use a high effort number to sing with a wide AES. Effort numbers will change based on practice, and whether you are healthy or sick.
The Estill Voice Model and chanting
This vocal model has so much to offer us as chanters. It trains our perception and sensitivity to sound as it teaches us what we are hearing and how the sound is being produced biomechanically. We can analyze the vocal quality of respected chanters and through the Figures for voice control, we can learn how to produce that vocal quality with our own voice. We can learn how to have more power with seemingly less effort, how to develop more stamina and healthy singing habits, and how to explain all of these things in a biomechanical way. Many non-Estill voice teachers use imagery to get a student to do these things, but oftentimes the student doesn’t understand what they are doing or why.
In this class we will focus on learning the figures for about half of the structures. Learning to control these structures will help you if you would like to chant with a more traditional sounding vocal quality or develop power and stamina. If you are practicing a figure and you feel a scratch, tickle, or pain, you should stop your practice. You are doing something that doesn’t go well with something else, like using too much air with thick vocal folds, or you are doing something for a long period of time which you should try to minimize, like constricting your false vocal folds.
The best way to learn the figures is in person, but these audio lessons and videos will be a good start. For each structure, there are different positions. As we learn to control each structure, there is another important thing to be aware of---effort number. So for the Torso, the options are to be anchored or not anchored. We could be slightly anchored with an effort number of 2, or we could be putting a lot of effort into our anchor with an effort number of 10.