A Bit of Vocal Science
So much of what we do as singers and voice teachers is about balancing and controlling resonance. In fact, many of the problems people blame on the vocal cords or breathing are primarily resonance issues.
Some will argue the best way to fix resonance is by using proper “placement,” or putting the resonance forward, back, higher, lower, etc., until it is “correct.” The problem with this approach is that feelings of placement are resulting sensations and not actual controllers of resonance.
The best way I have found to control and balance resonance is through vowels. Making changes to the vowel makes direct changes to the resonance chambers and, when done correctly, will produce the sensations of proper placement.
What Vowels Do
It is obvious that we need to make physical changes with our mouths to go from an AH vowel to an OO. But there are also less obvious changes that happen in our throats. If you put your finger on your larynx (Adam’s apple) you should feel it slightly change position, higher for AH and lower for OO.
So these two areas, the throat and mouth, have to make changes for different vowels – but why do these changes produce these specific sounds? Why do round lips sound like OO and wide lips make an AH?
Form – What?
The answer is – formants. What the heck is that? Well I will tell you.
Every acoustic space acts as an amplifier. The body of an acoustic guitar, the wooden shell of a drum and even your throat and mouth are all amplifiers. These spaces take the sound wave and intensify the energy as the waves bounce off one wall and into another, picking up energy the whole time.
However, the size of the acoustic space will dictate how the sound waves will be affected. Smaller spaces will give more amplification to higher pitched sounds, bigger spaces will boost lower pitched sounds.
This is why high pitched drums have smaller shells than low pitched drums.
Changing the shape of a resonator will also have an effect on identical pitches on the same instrument.
If you play the same note on an acoustic guitar with a large body and then the same note on one with a smaller body, they will sound different. The pitch will be the same but the color and quality of the note will have changed. That’s because the resonators are amplifying different parts of the sound wave.
Different parts? Yes. Every sound wave has many pitches in it. These many pitches are called “harmonics” and are what gives the note being played tone and color. Harmonics make up the spectrum of sound your voice produces on any given pitch.
If you have a bigger resonance space, the lower or darker sounding harmonics will be amplified and brought out. If you have a smaller resonance space, the higher or brighter harmonics will dominate.
This is why if you make a dark, dopey sounding voice, your larynx goes down and if you make a bright witchy sounding voice, your larynx goes up. You are changing which harmonics are dominant and therefore the vocal color or quality.
The name for what you are changing in your resonator is a “formant.”
A formant is a way to measure an acoustic space. When we see a spike of energy in a harmonic is because the resonator has aligned its value or formant to that harmonic.
A smaller space has a higher formant value, which aligns with higher harmonics. A larger space has a lower formant value, so it brings out the lower harmonics.
When you move your lips, tongue, larynx or jaw, you are changing the formants, which change the boosted harmonics, which gives us different tone quality and even different vowels.
Formants are why we have vowels and instruments don’t. A guitar’s resonator has formants, but they can’t be changed. This gives the guitar a consistent sound.
The voice has moveable, very agile resonators that can assume different shapes and sizes. This means we can change the formant value quickly, giving us a huge range of sounds.
Change the resonators, or formants enough and we now hear a different vowel.
A Singer’s Best Friend
We can adjust formants to accurately pinpoint certain harmonics. Align the formants with the right harmonics and you can achieve a glorious, powerful vocal sound with little physical effort.
Misalign the formants and harmonics and you get all kinds of vocal issues from straining to flipping to poor tone quality.