The key to singing well is understanding register function. No matter if the music is classical or some style of CCM, if you do not understand registers, you will not get good vowel sounds (resonance) and you will be limited in what you can do with your body and breathing.
Why is this so? Because the vocal folds are responsible for both pitch and register quality. When you are vibrating the full length and depth of the folds, you are using the vocalis or thyro-arytenoid muscle, and the sound is chest register dominant (meaning it is full-bodied). If you are contracting the crico-thyroid muscle, tilting the thyroid cartilege, you are stretching and thinning the vocal folds, tightening them, and pulling them to vibrate only on their upper edges, which gives the sound a lighter quality and is called head register. You can label these vocal qualities any way you like (chest resonance, chest voice, chest mechanism, heavy mechanism, lower mechanism, modal, etc.) and you can say that either or both are good or bad (depending upon your pedagogical point of view). You can even say they don’t matter or aren’t there, but that won’t change the FACT that they exist and, in normal voices, they function.
The vocal folds are in the larynx (the above mentioned thyroid and cricoid cartileges together, as a joint), and the larynx can go up (for swallowing) and down (for yawning) by virtue of the contraction of the constrictors (upper, middle and lower). Theoretically, you can have thick folds (chest) or thin folds (head) in a larynx that is down low at the bottom of the throat, in the middle of the throat or up high near the soft palate, as there is a lot of variability here. One thing you CANNOT do, however, is by-pass the larynx. Any sound that is voiced comes from there, no matter where you feel it vibrating in the bones of your face and head, or kneecaps!
The key to developing the voice is developing control over registers for their own sake which, for the vast majority of human beings, is a deliberately learned behavior. Rarely is a voice perfectly cultivated and balanced through life experience without any kind of training. Breathing is a factor in singing, but it is most important in classical singing for the sake of generating sufficient levels of volume (high decibels or high sound pressure level), called “good breath support” by most teachers, and in other styles that require a belt sound. Soft easy production as used in many styles of CCM need conversational level volume or something close, but are electronically amplified when more volume is necessary.
No one really knows or understands why it is that the mechanism wants to change from chest to head at approximately the same place in everyone (give or take about a major third) which is approximately at or near E/F above middle C. There have been studies for a long time but no one has really explained why we have these two different sound qualities and why they want to adjust where they do. (Ask Dr. Titze about this if you don’t agree). It is pretty much decided, however, that we do have these registers and they do function differently. The behavior of the vocal folds effects the parameters of the air that flows between the vibrating folds (the vocal folds control the airflow, NOT the other way around. The wind moves the sail, but the sail doesn’t make the wind blow). The vocal folds do not make the air move, but they control how much gets out and how fast, no matter what goes on with the abs and ribs.
If you do not learn to control the transition between the two registers, you don’t really have “good” vocal technique. If you control everything by manipulating the shape of the vowel and the volume, good for you, but that’s not all there is to know or do. If you have one register developed and the other is latent, you don’t even know what balanced singing is. If you confuse one parameter with another, you are confusing what is cause with what is effect….a good recipe for poor control if ever there was one.
Many people teach effects as if they were cause. What does that mean?
It means that they want to change the basic color or tone of the sound by manipulating the breath or the shape of the mouth. Those are not causes, they are effects. The vocal folds are the source (cause) and the vowel sounds are effected by the position of the larynx and the behavior of the vocal folds. The shape of the vocal tract (resonant space) is very variable. Not all shapes are equal. Some are more accurate for bouncing the vibrating patterns of each vowel sound around in the vocal tract, therefore producing resonance (effects) or less accurate and don’t produce much resonance. Without a good deal of pressure (strength) from the exhale, and without the ability for the vocal folds (larynx) to receive this strong exhale in a viable manner, you don’t get real “resonance”. Therefore, a hard driving exhale does not good singing make. A yell has high sound pressure levels, but you know it is a yell and not singing, so the idea that “breathing” does it all is just WRONG.
Understanding registers or registration takes time and developing them takes more time. There is, however, NO SUBSTITUTE for this in vocal training. I repeat, NO SUBSTITUTE. Only register development is register development. If you do not have this figured out, keep working on it, as everything else will get better as you do, especially in your middle voice, which is where the vocal function (the mechanics of singing) matters. You CANNOT skip over this in terms of skill development. You can try, but if you were to ask the people who have done so for years, and who are well aware of the fact that their singing has always been “flawed” even though it was good enough to get them high-level work, they would tell you, it’s worth doing it right in the first place. It’s better than not figuring it out all at or figuring it out after 20, 25 or 30 years of being a singer.