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Kim Hyuk Gun's Research on Vocal Technique 12/24 · Chest Voice: Lower the Tongue Root, Lift the Soft Palate

Chest voice is not a sound that rings in the chest — it is the sound of the mouth and throat widened by lowering the tongue root and lifting the soft palate.

2026-10-30 · 5 min read

▶ This part's vocal lesson

Cross Kim Hyuk Gun Vocal Lessons, How to Sing Well Season 2 Ep. 1: Chest Voice · 뮤토리 (Mutory)

Part 12 of 24Kim Hyuk Gun's Research on Vocal Technique (24 parts)

This series reads Kim Hyuk Gun's doctoral dissertation, 「횡격막 마비군과 비마비군을 통한 복식호흡과 발성법 연구」 ("A Study of Abdominal Breathing and Vocal Technique in Groups With and Without Diaphragmatic Paralysis," Kyung Hee University, 2019), in 24 parts for popular-music vocal students, pairing each part with one of the vocal lessons he taught. The study was approved by the Kyung Hee University Institutional Review Board (IRB; project no. KHSIRB-17-047) and was carried out as a human-subjects experiment with the informed consent of its participants.

At a Glance

  • Kim Hyuk Gun's doctoral dissertation (2019) explains that in popular music, resonating the pharynx and mouth is called chest voice, and sets low notes = chest voice = full voice.
  • Lowering the tongue root creates a resonating cavity in the mouth and lowers the larynx, making a deeper, more resonant low range possible.
  • Lifting the soft palate and widening the mouth makes it possible to sing the overtones of a deep, resonant low range together with high notes.
  • The dissertation gives "eo" (어) as a vowel suited to lifting the soft palate, and writes that the mouth's space is used as widely as possible, with the feeling of the cheeks expanding left and right.
  • If the tongue root and larynx rise in the low range, or the tongue root drops too far in the high range, the strengths of the sound are lost, so finding a natural position for the tongue and larynx is important.

Quick AnswerKim Hyuk Gun's (김혁건) 2019 doctoral dissertation sees chest voice as sound that resonates the pharynx and mouth, and explains that lowering the tongue root to lower the larynx and lifting the soft palate to widen the mouth make a deeper, more resonant low range possible.

Diagram of lifting the soft palate and lowering the tongue root to widen the resonating space in the mouth

Contents

  1. 01Chest Voice Is Not a Sound That Rings in the Chest
  2. 02Lowering the Tongue Root: Space for Deep Low Notes
  3. 03Lifting the Soft Palate: Widening the Mouth with "Eo"
  4. 04Tongue and Larynx: Finding the Natural Position
  5. 05The Lesson's Chest-Voice Steps and the Dissertation
  6. 06Today's Practice
  7. 07Where to Go Next

In 2019, Kim Hyuk Gun (김혁건), the vocalist of THE CROSS (더크로스), named "lowering the tongue root and lifting the soft palate" in his doctoral dissertation as one of the exercises for scientific vocal technique. It is an exercise that moves two places inside the mouth — the root of the tongue and the soft part at the back of the roof of the mouth — to create resonating space.

This is the twelfth part of the series. It sets out in detail, from the point of view of chest voice, steps 1 and 2 of the resonance method in Part 11 (lifting the soft palate, lowering the tongue root).

01.Chest Voice Is Not a Sound That Rings in the Chest

Because of the name, it is easy to think of chest voice (흉성, literally "chest sound") as a sound that rings in the chest. Gathering several passages of the dissertation, the place of chest voice lies elsewhere.

Passage in the dissertationOn chest voice
Resonance methods (p.163)In popular music, resonating the pharynx and mouth is called chest voice
Using nasal resonance (p.162)If the nose is blocked and the exhale cannot get out through it, the sound comes only from the mouth, so it is closer to chest voice (oral resonance) than to nasal resonance (head resonance)
Range (p.174)Low notes = chest voice = full voice

The dissertation also explains the bel canto register name "chest register" seen in Part 8 as "a range that seems to resonate in the chest." It is a sound that seems to ring in the chest, and the dissertation explains chest voice in popular music as sound that resonates the pharynx and mouth. The lesson paired with this part also lists "chest voice is not the chest ringing" as the first point in its description.

02.Lowering the Tongue Root: Space for Deep Low Notes

"By lowering the tongue root, a resonating cavity is created in the mouth and the larynx is lowered, so a deeper, more resonant low range can be expressed." The dissertation's explanation holds two things in one sentence.

Lowering the tongue rootResult
Creates a resonating cavity in the mouthThe space for resonance widens
Lowers the larynxA deeper, more resonant low range

The height of the larynx also came up in Part 5. The dissertation states that the position of the larynx changes the texture and size of the sound and the length of the vocal tract, and introduces a study in which phonating with the larynx lowered increased loudness and the vocal-fold contact rate. Lowering the tongue root is also a way of lowering that larynx.

03.Lifting the Soft Palate: Widening the Mouth with "Eo"

The dissertation writes about lifting the soft palate in more detail.

  1. Lifting the soft palate and widening the mouth makes it possible to sing the overtones of a deeper, more resonant low range together with high notes.
  2. Lifting the soft palate high while widening the mouth and turning the sound so that it reaches the hard palate carries the resonance through the bone up to the frontal sinus.
  3. Practice on "eo" (어), a vowel suited to lifting the soft palate.
  4. When the sound is turned, the mouth widens, so the vowel "ah" sounds close to "eo."
  5. Use the space of the mouth as widely as possible, with the feeling of the cheeks expanding left and right too.

As seen in Part 9, the soft palate is the soft part of the roof of the mouth that separates the nasal cavity from the mouth, and in ordinary phonation it is raised. The dissertation also writes that lowering the larynx and lifting the soft palate as in a natural yawn creates a resonating cavity in the mouth. The depth of low notes (tongue root) and the overtones within high notes (soft palate) — the two movements are used together.

04.Tongue and Larynx: Finding the Natural Position

In its "tongue and larynx" item, the dissertation separates two things about sound: pitch is determined by the vocal folds and the diaphragm, and pronunciation by the tongue and the structure of the mouth. It then writes about what happens when the tongue and larynx are in the wrong place.

RangeThe tongue root and larynxResult
Low rangeRiseThe richness of the low notes is lost
High rangeThe tongue root drops too farThe edge of the high notes is lost

So the dissertation's conclusion is that "it is important to find a natural position for the tongue and larynx and sing." It means not lowering the tongue root at all costs, but finding the position that suits the range.

05.The Lesson's Chest-Voice Steps and the Dissertation

Season 1, Episode 6, "Chest-Voice Technique," seen in Part 4, lists four steps of chest-voice singing in its description. Pairing the steps that have a matching passage in the dissertation gives this.

Lesson step (video description)Passage in the dissertationIn this series
Breathe in through the noseThe short inhale; the inhale that comes in through the nasal cavityParts 4 and 9
Keep the shoulders and chest stillIn chest breathing, when the shoulders and collarbones rise, the larynx rises with themPart 3
Tongue root and soft palateLowering the tongue root, lifting the soft palateThis article
Gathering the mouth— (no passage of the same name in the dissertation)—

06.Today's Practice

Turned into points to check while you practice, what the dissertation and the lesson highlight looks like this.

  1. Lift the soft palate on "eo" — Sing on "eo" (어), a vowel suited to lifting the soft palate. When you turn the sound, "ah" sounds close to "eo" (section 03; dissertation p.175).
  2. Widen to the cheeks — Use the space of the mouth as widely as possible, with the feeling of the cheeks expanding left and right (section 03; dissertation p.175).
  3. Tongue root and larynx on low notes — On low notes, check that the tongue root and larynx do not rise. If they rise, the richness of the low notes is lost (section 04; dissertation p.177).
  4. Lift the soft palate with a yawn — Lesson Season 2 Ep. 1 (Chest Voice) covers widening the mouth and lifting the soft palate with a yawn (video description).

The lesson to watch with this part is Season 2, Episode 1, "Chest Voice." Its description lists that chest voice is not the chest ringing, widening the mouth, and lifting the soft palate with a yawn.

07.Where to Go Next

The five steps of making resonance are in Part 11 · Resonance Methods, and head voice, chest voice's partner, continues in Part 13 · Head Voice — a Bright "E" and the Maschera. A rock vocalist moving between deep low notes and high notes can be heard in THE CROSS Band's Rock Covers. Lesson videos are in Korean.

Lower the tongue root and lift the soft palate — a deep sound comes from a widened mouth.

← Previous partKim Hyuk Gun's Research on Vocal Technique 11/24 · Resonance Methods: Five Steps to Making ResonanceNext part →Kim Hyuk Gun's Research on Vocal Technique 13/24 · Head Voice: Ringing the Front of the Head with a Bright "E"

Frequently asked questions

Is chest voice a sound that rings in the chest?

Kim Hyuk Gun's doctoral dissertation explains that in popular music, resonating the pharynx and mouth is called chest voice. It also describes bel canto's chest register as "a range that seems to resonate in the chest."

How does lowering the tongue root change the sound?

The dissertation explains that lowering the tongue root creates a resonating cavity in the mouth and lowers the larynx, making a deeper, more resonant low range possible.

What does lifting the soft palate do?

Lifting the soft palate and widening the mouth makes it possible to sing the overtones of a deep, resonant low range together with high notes. The dissertation writes that turning the sound so it reaches the hard palate carries the resonance through the bone up to the frontal sinus.

Why practice lifting the soft palate on the vowel "eo"?

The dissertation gives "eo" (어) as a vowel suited to lifting the soft palate, and explains that when the sound is turned the mouth widens, so the vowel "ah" sounds close to "eo."

Should the tongue root always be lowered?

No. The dissertation writes that if the tongue root drops too far in the high range, the edge of the high notes is lost, and concludes that it is important to find a natural position for the tongue and larynx and sing.

What determines pitch and pronunciation?

The dissertation explains that pitch is determined by the vocal folds and the diaphragm, and pronunciation by the tongue and the structure of the mouth.

Sources

  1. RISS — 횡격막 마비군과 비마비군을 통한 복식호흡과 발성법 연구 (Ph.D. dissertation, Kyung Hee University)“혀뿌리 내리기를 통해 구강 속의 공명강을 만들고 후두를 내려 더 깊고 울림 있는 저음역을 표현할 수 있다" ("By lowering the tongue root, a resonating cavity is created in the mouth and the larynx is lowered, so a deeper, more resonant low range can be expressed.")” · 2019
  2. 뮤토리 (Mutory) — Cross Kim Hyuk Gun Vocal Lessons, Season 2 Ep. 1: Chest Voice“instructor Kim Hyuk Gun” · 2012.03.02

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