OK! We have air. We need to use it wisely. We have a system for converting the potential energy of pressure we apply to the air in our lungs. It is called the larynx.
I once upon a time had a video embedded here but it has disappeared from YouTube. The illustration of all the various parts of the vocal structure was really good. I am on the lookout for another example.
The conversion center is so complex that one could despair of ever understanding how it works. There are labs at prestigious Universities populated by hyper intelligent people seeking to nail down an explanation of how these structures really work to produce the human voice. Until they are able to formulate a real time theory of all the muscular activities as well as the air pressure being converted into sonic energy they will not be able to offer a recipe of muscular activity for any of the millions of different noises we humans are capable of making. So we might just give up thinking about this critical feature of our anatomy and get on with life. You know, go to lunch, catch up with your text messages, do your peer reviews, take in a few YouTube videos, organize the dust on your desk, memorize the music in the program you plan to do next week or struggle to keep your eyes open while your department head, voice teacher, stage director, agent or even your most dedicated fan talks at you.
There is really no value, beyond the fun of knowing things, in being aware of the structure of your larynx while you sing. The knowledge you need as a singer is quite different from putting names to every structure in the larynx. It is the sonic knowledge most everyone has, but very few acknowledge as having any value at all. What I’m talking about is best understood as an ability to hear content or meaning in the tone of voice. It is the “subtext” of our communications. Just remember the times your mother said to you something like: “Don’t you speak to me in that tone of voice!” We speak it and we hear it. All the bits and pieces of our larynx provide about half of that subtext, and the anatomy of our ears collects this toning of our words. Our brains processes what our ears collect, and it is sad to say that many of us are tone deaf. If you cannot hear the subtext, you are particularly disadvantaged at air conservation. Forget about interpretation. What you cannot hear, you cannot imitate.
The key to air conservation is your ability to recognize your tone of voice. The lock you must open with that key is maintenance of your tone of voice. If you can recognize the subtext of the sound you are making and you can maintain it as you change things like vowels or volume or registers for that matter, you will be employing everything described in the above video in a balancing act that no singer can execute as a matter of will or factual understanding.
So listen to the key. Listen to yourself. Hear the sound you make on an easy note in the middle of your voice at medium volume. I ask students, who need to be introduced to their voices, to display joy and satisfaction as they sing one note for me. Do the same for yourself. Sing one note as if you are one of the happiest people on Earth. See how long you can hold the note without losing that joyous tone of voice. That is to say, time it. Keep repeating this happy singing with your stop watch. Joy and note longevity are the goals.
For the guys, please sing in Chest Voice. You will have to explore Falsetto later, but for now it’s all Chest all the time on one note at one volume.
When you have the ability of hold your happy tone of voice in one volume on one note using every bit of air in your lungs, I believe Garcia would have moved on to making the student sing using up all available air while dividing the time in three equal parts. On third on the original note then one third on the upper neighbor then the final third back down on the original note. This subdivision would progress along the scale for as many notes as Garcia saw as necessary. In the case of our focus on air conservation, I think we can risk going straight for the jugular.
The great test for air conservation expertise is the “Messa di Voce”. Start with one of the pitches on which you have already sung and measured with your stop watch and found yourself able to hold it for a long time without producing a noise that sounds like you are getting bored or forgetful or disinterested. Start to sing on that pitch as if you were going to just do the long note again “with feeling” as you have already done successfully many times. The difference this time will be that you will make a diminuendo for half the time you know yourself able to hold that pitch in full voice, and then at the halfway point start a crescendo that will bring you back to the same pitch, sound quality and volume with which you started the exercise. The original rule to maintain your tone of voice: happy and satisfied, is to be maintained through the diminuendo and the crescendo. You will find the exercise really difficult as long as you are unable to do this tone of voice maintenance. You will find that your ability to stay with the program while doing the “Messa di Voce” will be equal to your ability to match the “Messa di Voce” length to your sustained tone singing of the same note. Guys! Guess what? When you do your diminuendo, you are going to find singing in Falsetto unavoidable and you will be forced to explore Falsetto as you sing softer and softer. Within this exploration the key is to carry your original tone of voice at the beginning of the note all the way through the exercise. Have fun.
An old friend sent Debbie, my wife, a You Tube video link for a singer who starts an aria in a concert with a long held note during which she slightly varies the volume. She presented the note as if she were doing something as difficult as a gymnast standing on his hands walking around with his feet in the air and then standing still on just one hand. After she finished her “show off” trick she acted embarrassed at having made such a display of vocal prowess which is, after all, not called for by the composer.
Yugo for you?
Ferrari for me!
I’m sorry to say that her display is more like a car salesman selling a Yugo to a guy who wants to buy a Ferrari. Now that would be a good trick. A hand standing gymnast (for the girls) would have deserved the applause that she got. The note that this soprano sang for her audience, almost anyone can do, and for far longer. I can understand how some misguided students of singing can convince themselves that if gathering applause is that easy, the road to fame must be really easy.
Do that “Messa di Voce” thing and don’t give yourself an easy time of it. Many of the secrets of singing are waiting for discovery inside this exercise. 
Every one of the muscles in your larynx has a part to play. I’ll be back to talk more specifically about them.