Vocal resonance is the process by which sound is intensified or “colored” after leaving the vocal cords, but before leaving the body. Our unique voices are not only a product of the thickness and length of our vocal cords, but also, the size and shape of surrounding structures around the vocal tract. There are a number of structures in your body that resonate when you sing, including your chest, larynx, pharynx, oral cavity, nasal cavity, and sinuses.
Notice that these structures range as low as your ribcage, and as high as the top of your face. The only structures you can actually consciously manipulate are your throat, mouth, and diaphragm, and this transitively affects the rest of the resonators. Head voice, chest voice, and middle voice simply refer to where you feel the majority of resonance when you sing.
When you sing in your “head voice” it means you should feel vibration around the upper half of your face, because, at that moment, the predominant resonator is your sinuses. This doesn’t mean the other vocal structures aren’t resonating. It means that more resonance is occurring in your sinuses than anywhere else.
When you sing in your “middle voice” you should feel more vibration around the lower half of your face, chin, and upper neck. What you are primarily feeling is your hard palate resonating, but again, this doesn’t mean the remaining structures, including your chest and sinuses aren’t vibrating sympathetically.
When you sing in your “chest voice” you should feel more vibration around your lower neck, and sternum. If you want to know what this feels like, talk in your regular speaking voice, and put your hand in the middle of your chest. It’s vibrating.
The Continuum of your Voice
From the above explanation, you should be able to glean that your three “voices” form more of a spectrum than they do discrete vocal modes. Your voice should almost always mix the three resonance areas, with one area predominating over the others. So that’s why you’ll hear me say “sing with more chest voice,” but you’ll never hear me say, “switch into your chest register.” And great news! Your voice as a spectrum means that you can eliminate your “vocal breaks” with practice, by working to seamlessly mix your resonance zones (but more about that later).
Play With It!
There is no better way to get familiar with your voice than to experiment. I could tell you what to do a thousand times, but if you can’t feel what you are doing to reproduce it, you’re wasting your time. Your vocal tract is an incredibly complicated place, with almost endless ways to sing any given pitch. Here are a few fun exercises to get you started:
Hum a note, and siren it up and down in pitch. Close your eyes. Do you feel the vibration moving up and down the front of your body? Try doing the same thing on different vowel sounds. Does “ee” resonate differently than “oo” or “ah”? What happens if you pretend to yawn while singing a note? What happens if you try to buzz like a bee while singing a note? Try playing around with releasing a lot of air as you sing, and then a little. Almost everything is fair game—just be sure not to overtly shout, and if something hurts your voice, stop.