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Kim Hyuk Gun's Research on Vocal Technique 16/24 · Vibrato Practice and Dollyeonaegi (Turning the Sound)

Without the right control of force, vibrato turns stiff and the beat is hard to divide smoothly — so the sound is turned round.

2026-10-30 · 4 min read

▶ This part's vocal lesson

Cross Kim Hyuk Gun Vocal Lessons, How to Sing Well Season 2 Ep. 8: Vibration · 뮤토리 (Mutory)

Part 16 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) presents practice for when vibrato does not come: adjusting loud and soft in time with the beat, or moving the larynx and diaphragm.
  • Vibrato without the right control of force can sound very stiff, and the beat is hard to divide smoothly, the dissertation writes.
  • Girare means "to turn"; it is turning the sound from back to front.
  • Open the roof of the mouth at the soft palate so it rises, turn the sound and send it to the hard palate, and gather the sound round.
  • The dissertation also places singing with the feeling of turning the sound back as one step of its resonance method, in order to use several resonating spaces.

Quick AnswerKim Hyuk Gun's (김혁건) 2019 doctoral dissertation sees vibrato as learned through loud and soft on the beat and larynx and diaphragm practice, though stiff force stiffens the beat, and presents girare: opening the soft palate and turning the sound from back to front to the hard palate.

Diagram of the sound turning round from back to front and sent to the hard palate

Contents

  1. 01Where Vibrato Practice Starts
  2. 02When Force Stiffens, Vibrato Stiffens
  3. 03Girare: Turning the Sound
  4. 04Girare Within the Resonance Method
  5. 05Today's Practice
  6. 06Where to Go Next

In 2019, in the experimental lessons of his doctoral dissertation, Kim Hyuk Gun (김혁건), the vocalist of THE CROSS (더크로스), made the sixth session "learning vocal technique" and covered lessons 1-7 "Support vocal technique, tone control" and 2-8 "How to do vibrato, how to practice vibration well" together. It was a session that treated vibrato not as a principle but as something to practice.

This is the sixteenth part of the series. Following the principle in Part 15, it sets out how to practice vibrato, and girare (돌려내기, dollyeonaegi) — turning the sound round.

01.Where Vibrato Practice Starts

The dissertation's conclusion in Part 15 was that vibrato comes on its own as the result of steady vocal practice. Still, for when it does not come, the dissertation gives two kinds of practice.

When vibrato does not comePractice
First check whether the breathing muscles are too tense① Adjust loud and soft in time with the beat
② Move the larynx and diaphragm

The description of the lesson paired with this part lists dividing the beat and holding the same note as its points. It is practice in dividing the tremble in time with the beat while keeping the pitch.

02.When Force Stiffens, Vibrato Stiffens

The dissertation mentions vibrato again in its "muscle relaxation" item: in phonation, tensing, concentrating and applying force matter, but settling and releasing tension also matter a great deal.

The dissertation's explanation
Muscles around the neckYou must know how to relax them very comfortably
Control of forceNot releasing all force and tension, but keeping an appropriate state
Vibrato without that controlCan sound very stiff, and the beat is hard to divide smoothly
Too much forceApplying excess force while lowering the tongue root and larynx puts force into the throat and the sound can turn stiff. Excessive force always makes the sound unnatural

Not applying force is a problem, but applying too much force is also a problem, the dissertation concludes. And it writes that you must sing turning the sound round, with the muscles of the whole body relaxed. That sentence is why vibrato practice and turning the sound are tied together in one part. Muscle relaxation continues in Part 23.

03.Girare: Turning the Sound

Girare means "to turn," and refers to turning the sound from back to front. The dissertation writes the method like this.

  1. Open the roof of the mouth at the soft palate well, so it rises.
  2. Turn the sound and send it to the hard palate.
  3. Gather the sound round.

And it adds an image for the feeling: sing the sound richly, like a marble rolling across marble.

There is a passage that connects to lifting the soft palate in Part 12 too. Lifting the soft palate high to widen the mouth and turning the sound so it reaches the hard palate carries the resonance through the bone up to the frontal sinus, and turning the sound widens the mouth so the vowel "ah" sounds close to "eo," the dissertation writes.

04.Girare Within the Resonance Method

Girare also appears in the five steps of resonance in Part 11. The fourth step is "sing with the feeling of turning the sound back (Girare)," and the reason is to use several resonating spaces.

Passage in the dissertationGirare
Resonance method d (p.164)The feeling of turning the sound back — to use several resonating spaces
Turning the sound (p.176)Turn the sound from back to front, to the hard palate, gathered round
Lifting the soft palate (p.174)Turn the sound to reach the hard palate → resonance up to the frontal sinus
Experimental lessons (Tables 4 and 5)Lesson 1-5, "Passaggio, support, pitch, resonance, girare," was covered in session 3

Girare is not a separate technique standing apart; it sits where resonance, the soft palate and relaxation meet.

05.Today's Practice

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

  1. Loud and soft in time with the beat — Adjust the loudness of one note in time with the beat (section 01; dissertation p.113).
  2. Divide the beat, keep the same note — Lesson Season 2 Ep. 8 covers dividing the beat and holding the same note (video description). If the beat divides stiffly, check that force has not gone into the muscles around your neck (section 02; dissertation p.172).
  3. Open the soft palate and turn the sound to the hard palate — Open the roof of the mouth at the soft palate so it rises, turn the sound and send it to the hard palate, and gather it round (section 03; dissertation p.176).

The lesson to watch with this part is Season 2, Episode 8, "Vibration." Its description lists that "vibrato" is a more accurate term than "vibration," dividing the beat, and holding the same note.

06.Where to Go Next

The principle of vibrato is in Part 15 · How Vibrato Works, and the five steps of resonance in Part 11 · Resonance Methods. The next part covers the zone where registers change, Part 17 · Passaggio. THE CROSS's recent stage can be seen in THE CROSS's Open Concert Finale: "Poem of the Wind" and "Don't Cry". Lesson videos are in Korean.

Like a marble rolling across marble — a sound turned round trembles smoothly.

← Previous partKim Hyuk Gun's Research on Vocal Technique 15/24 · Vibrato: A Tremble That Comes from PracticeNext part →Kim Hyuk Gun's Research on Vocal Technique 17/24 · Passaggio: The Path That Joins the Registers

Frequently asked questions

How do you practice vibrato?

Kim Hyuk Gun's doctoral dissertation, for when vibrato does not come, first checks whether the breathing muscles are too tense, then presents practice in adjusting loud and soft in time with the beat or moving the larynx and diaphragm.

Why does vibrato sound stiff?

The dissertation explains that vibrato without the right control of force can sound very stiff, and the beat is hard to divide smoothly. You must not release all force, but keep an appropriate state.

What is girare?

It means "to turn"; it is turning the sound from back to front. Open the roof of the mouth at the soft palate so it rises, turn the sound and send it to the hard palate, and gather the sound round.

How is girare related to resonance?

The dissertation places singing with the feeling of turning the sound back as the fourth step of its resonance method, and writes that the reason is to use several resonating spaces.

Should I just relax my throat completely?

The dissertation explains that you should not release all force and tension, but keep an appropriate state. Not applying force is a problem, and so is applying too much.

How do vowels sound when the sound is turned?

The dissertation writes that turning the sound widens the mouth, so the vowel "ah" sounds close to "eo."

Sources

  1. RISS — 횡격막 마비군과 비마비군을 통한 복식호흡과 발성법 연구 (Ph.D. dissertation, Kyung Hee University)“지라레(Girare)란 돌려낸다는 뜻으로 소리를 뒤에서 앞으로 돌려내는 것을 뜻한다" ("Girare means to turn — turning the sound from back to front.")” · 2019
  2. 뮤토리 (Mutory) — Cross Kim Hyuk Gun Vocal Lessons, Season 2 Ep. 8: Vibration“instructor Kim Hyuk Gun” · 2012.03.02

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