I’ll explain how to make an edge voice and a death voice.
To make the edge voice, the arytenoid cartilage on the cricoid cartilage moves. This movement is a slide and tilt to the side, and the vocal folds bend down to make a space between the glottis.
Furthermore, if you exhale stronger when extending the vocal cords (causing the mucosa) downward, from the status of making the edge voice, then the death voice will be made.
Note1:The vocal folds move downward when letting out both the edge voice and death voice. If you exhale to vibrate the vocal folds when the vocal folds are downward, the vibration increases making the edge or the death voice.
This is same as with a guitar, if the strings are thin it makes high-pitched sounds, and if strings are thick it makes low-pitched sounds. If you tighten the strings the guitar will make a high-pitched sound, and if you loosen the strings, it will make a low-pitched sound.
Similarly, the vocal folds’ pitch is controlled by (1)opening and closing (2)expansion and contraction (3)hardness and softness (4)thickness and thinness.
Note2:In the case of human beings, structural composition is always different and depends on the person’s (1)angle (2)size(3)speed(4)asymmetry
In conclusion that is why everybody has different abilities and every individual’s voice is unique.