In 2019, Kim Hyuk Gun (김혁건), the vocalist of THE CROSS (더크로스), explained resonance in his doctoral dissertation like this: the sound made in the larynx is too weak on its own to travel far, so resonance amplifies it "just like a megaphone."
This is the ninth part of the series. From the dissertation's section on "the resonators," it sets out the mouth, soft palate and pharynx — where in the body the sound of the vocal folds seen in Parts 5–8 grows. The nasal cavity and sinuses continue in Part 10, and the order of making resonance in Part 11.
01.Resonance: Sound That Grows by Sounding Together
The dissertation defines resonance in two ways.
| Point of view | Definition |
|---|---|
| Physics | A vibrating system periodically receiving an outside force at the same frequency as its own natural frequency, so that its amplitude grows markedly |
| Phonation | "Sounding together" — one sounding body absorbing the force another sounding body produces, so that the resonance is amplified |
The sound made by the vibration of the vocal folds is very small and has almost no color. As it passes through the resonating cavities, its resonance is amplified and overtones are added, so it becomes beautiful and large. The dissertation calls the resonators involved the "sound boxes" people are born with, and refers to the related organs together as resonating cavities or resonating bodies. Tone and volume change with where resonance happens and how much.
Citing García's teaching — "the singer's true mouth is the pharynx" — the dissertation writes that the small sound made at the vocal folds is amplified in the resonating cavities of each part as it passes through the organs, so the sound grows louder and its color richer.
02.Your Body Is the Instrument
The dissertation gives the violin and guitar as examples. The sound made by drawing a bow across a string or plucking it by hand is not heard as it is; it resonates in the sound box and is heard louder and more beautiful. The human voice is the same: the sound made at the vocal folds resonates according to the shape of the vocal tract as it passes through, and comes out through the lips and nostrils. That is why the dissertation writes that "the singer's own body is the instrument."
| Instrument | Where the sound is made | Where the sound grows |
|---|---|---|
| Violin, guitar | Strings | Sound box |
| Human voice | Vocal folds | The resonating cavities of the vocal tract — out through the mouth and nose |
There are many resonating spaces in the head. The dissertation lists the orbital cavity, nasal cavity, oral cavity, pharyngeal cavity, cranial cavity, maxillary sinus and frontal sinus, and calls resonating the spaces of the head "head voice."
03.Hard Sound Boxes and Soft Sound Boxes
For resonance to happen, air has to be able to vibrate, and for air to vibrate there has to be empty space. The organs of the body that act as resonating cavities are very complex and varied, and the dissertation explains that the sound differs with their material.
| Resonator | Examples | What it gives the sound |
|---|---|---|
| Hard parts | Teeth, hard palate | Make the tone brilliant |
| Soft parts | — | Absorb short, fast vibrations, making the quality of the sound softer |
The dissertation writes that even acousticians disagree on whether all the empty spaces in the body act as resonating cavities. It adds that it has not been clearly established whether a place where you feel resonance while singing actually functions as a resonating cavity. Even so, the generally recognized main resonating cavities are the mouth and the throat (pharynx), and their shape and size are adjusted by the lips and tongue, the jaw and the soft palate. That is why the dissertation concludes that to make the most of resonance you need to be able to adjust these organs freely while singing. The shape and size of the resonators differ from person to person.
04.The Mouth: Make the Space, Then Make It Resonate
The oral cavity is the space inside the mouth. It is bounded above by the palate, at the sides by the palatoglossal arches and below by the tongue, and divided into the vestibule, surrounded by the lips, gums and teeth, and the oral cavity proper inside it. The mouth makes it possible to tell vowels apart and is used to form consonants. In the dissertation's words, the mouth is where sound is turned into words.
| In the mouth | The dissertation's explanation |
|---|---|
| Making space | Lowering the larynx and lifting the soft palate, as in a natural yawn, creates space and forms a resonating cavity |
| Size | Together with the pharynx it is the largest resonating cavity, and its shape changes with the width and shape of the tongue and the movement of the lower jaw |
| High notes | The mouth must be opened as fully as possible; the wider the mouth opens and the greater its resonance, the easier |
| Caution | Opening too far can tense or strain the pharynx and larynx, so the throat must be in the right position when the mouth opens |
And the dissertation makes one point clear. However wide you make the inside of your mouth while singing, if the air pushed out of the lungs by the work of the diaphragm escapes straight out of the mouth, the result is a sound with no focus. Making the space and making that space resonate are different things.
05.The Soft Palate: The Door Between Nose and Mouth
The soft palate is the soft part behind the hard palate, which continues from the upper teeth, and at the center of its tip is the uvula. The soft and hard palate separate the nasal cavity from the mouth and play an important role in speech sounds and resonance.
| Situation | Soft palate |
|---|---|
| Making nasal sounds; breathing in | Stays lowered |
| Making palatal vowels | Quickly closes off the nasal cavity |
| Ordinary phonation | Is raised |
There is an interesting passage too. When you breathe in, air comes in through the nasal cavity, so the nasal cavity is open and the soft palate does not rise — yet you feel as if the soft palate has been lifted, the dissertation writes. The same feeling arises during phonation as well.
06.The Pharynx: A Tube in Three Sections
The pharyngeal cavity is the empty space inside the pharynx, shaped like a long tube running from the back of the nose to the top of the vocal folds. It is the passage that sends air or food taken in through the nose and mouth to the esophagus or larynx, and the dissertation counts it among the most important spaces for resonance.
| Section | Where | In singing |
|---|---|---|
| Nasopharynx (upper pharynx) | Starts at the passage behind the nose, above the soft palate — from the base of the skull down to the soft palate | Used for high notes in head voice |
| Oropharynx | Behind the mouth, between the soft palate and the epiglottis | Used for the middle voice; with the mouth, one of the most important resonating cavities |
| Laryngopharynx (lower pharynx) | From the epiglottis to the upper surface of the vocal folds | Its size is adjusted by the narrowing of the throat and the back of the tongue |
The mouth and the oropharynx always work together when amplifying the small sound made in the larynx. The dissertation explains two sensations you feel while singing through this structure.
- A feeling that the throat is tight — when the oropharynx contracts for various reasons.
- A cool, open feeling in the throat — when the roof of the mouth rounds and the uvula and soft palate lift and close up.
As the movement of the uvula changes the direction in which air and voice go out, the tone changes too. The dissertation calls it "nasalization of the voice" when a lot of resonance is added in the nasal cavity and nasopharynx. The nasal cavity continues in Part 10.
07.Today's Practice
Turned into points to check while you practice, what the dissertation and the lesson highlight looks like this.
- The yawn space — Lower the larynx and lift the soft palate as in a yawn, and sing "ah." Even with the mouth wide inside, if the breath leaks straight out of the mouth the sound has no focus. After making the space, listen to whether that space resonates (section 04; dissertation p.97).
- Open wide, but not too wide — Open the mouth wide on high notes, but check that no tension forms in the pharynx and larynx (section 04; dissertation p.97).
- Is the throat tight, or open? — While singing, tell apart a feeling that the throat is tight from the open feeling of the roof of the mouth rounding and the uvula and soft palate lifting (section 06; dissertation p.99).
The lesson to watch with this part is Season 1, Episode 3, "Resonance Spaces and How to Use Them." Its description lists lowering the tongue root and lifting the soft palate, oral and nasal resonance, and the "three elements" of diaphragm, vocal folds and resonance. Lowering the tongue root continues in Part 12 · Chest Voice.
08.Where to Go Next
Registers and falsetto are in Part 8 · Falsetto and Registers, and the sound boxes in the nose and the bones of the face continue in Part 10 · The Nasal Cavity, Sinuses and Using Nasal Resonance. The duet Kim Hyuk Gun sang with Park Ki-young can be heard in Kim Hyuk Gun and Park Ki-young's "The Prayer": Winning the 2017 New Year Special of Immortal Songs. Lesson videos are in Korean.
If the body is the instrument, practice is finding that instrument's sound boxes.