There has seemingly been quite a bit of confusion concerning all these different terms we use to describe the voice – how it works and what we are feeling. Let us go on a clarification adventure for a moment.
There are two main muscle systems that bring the vocal cords into a state of work, whether healthy or unhealthy. These two muscle systems are called the arytenoid muscle system and the crico-thyroid muscle system.
The arytenoid muscle system closes the cords and produces a texture of sound when isolated called “Chest.”
The crico-thyroid muscle system stretches the cords and produces a texture of sound when isolated called “Falsetto.”
These two muscles coordinate in different ways; producing many awesome textures and sounds. These two muscles can also get mad and fight one another; producing textures of sound that are decidedly not awesome.
Yet, when these two muscles are equally strong and doing their right jobs, when they are perfectly balanced or in equilibrium with neither muscle system dominant but rather in a hospitable sharing on all pitches, they produce a texture of sound called “Full Voice.” This texture of sound extends to the bottom and all the way to the top! What some may call “Middle” is simply “Full Voice.” What some may call “Head” is simply “Upper Full Voice.”
One does feel differences as one moves up and down the scale, but it feels more like one holds the end of a rubber band with a smooth stretch as one goes up the scale while holding the other end of the rubber band stationary with a smooth return to the beginning position of less stretch as one comes down the scale.
The idea of full voice accurately describes the different feelings we have as well as pointing to the balanced unity of the two muscle systems as they work together. If we watch the muscles and cords on a special camera, then this description makes even more sense. Hopefully, this bit of an adventure in terminology has been useful.