In 2019, in the "experiment and results" chapter of his doctoral dissertation, Kim Hyuk Gun (김혁건), the vocalist of THE CROSS (더크로스), reported in numbers the change left by ten sessions of singing and breathing training. The basis for the conclusion summarized in Part 1 — that abdominal breathing is an important factor in crossing the passaggio — is in this chapter.
This is the last part of the series. It restates the experimental results as group values, and bundles what you have read through Part 23 into a ten-session practice routine.
01.How the Experiment Measured
| Item | Details |
|---|---|
| Participants | Diaphragmatic-paralysis group of 4 (2 trained singers · 2 non-majors), non-paralysis group of 4 (2 trained singers · 2 non-majors) |
| Singing and breathing training | Only the four non-majors (two from each group). The trained singers, who had already completed singing education, did not take part |
| When | October 2017 – May 2018, ten sessions. Measured in session 1 and session 10 with the same tools |
| Breath | Exhale with a peak flow meter (L/min), inhale with an inspiratory meter (cc) |
| Range | Measured with a tuner and converted into scores for comparison. Measured separately with active abdominal breathing (on one's own) and passive abdominal breathing (produced by pressing on the belly) |
| Statistics | Paired t-test (comparing group means) |
Range was scored like this. In the dissertation's notation, "1-octave C" is C3 and "2-octave C" is middle C, C4. Each semitone up from C3 counts as 1 point, so one octave is 12 points and a two-octave range is 24 points.
02.Results ① How Much Breath Increased
| Mean of four non-majors | Before | After | Change | Statistics (paired t-test) |
|---|---|---|---|---|
| Inhaled volume | 1100cc | 1775cc | +675cc | t(3)=3.756, p=.033 |
| Exhaled flow | 260L/min | 407.5L/min | +147.5L/min | t(3)=3.865, p=.031 |
Source: only the group means from Kim Hyuk Gun (2019), Table 22, "t-test results before/after singing and breathing training."
For reference, the dissertation gives the average inhaled volume of the general population as 1300–1900cc or more and the average exhaled flow as 350–700L/min or more, and reports that the difference in breathing volume before and after training was highly statistically significant. Because Ambu bag breathing training and singing education were done together, these numbers should be read as the result of the whole experimental program in Part 1, section 05.
03.Results ② How Much Range Widened
| Comparison | Participants | Mean score | Difference | Statistics |
|---|---|---|---|---|
| Before training: active abdominal breathing vs passive abdominal breathing (produced by pressing on the belly) | Four in the diaphragmatic-paralysis group | 11.5 → 14.0 | +2.5 points | t(3)=5.000, p=.015 |
| Active range before training vs passive range after training (maximum difference) | Four non-majors | 13.5 → 16.25 | +2.75 points | t(3)=−11.000, p=.002 |
Source: only the group means from Kim Hyuk Gun (2019), Tables 33 and 35.
Here are the conditions of the two comparisons, as they are.
- The first row compares, before training, the range the same paralysis-group participants sang breathing on their own with the range they sang when the belly was pressed to push the diaphragm up. Pressing on the belly widened the range by two to three semitones.
- The second row compares, as in the title of the dissertation's Table 35, the "active range before training" with the "passive range after training (maximum difference)." Because the non-paralysis group's abdominal muscles resisted by reflex and they could not do passive abdominal breathing, the after-training value includes the range paralysis-group participants sang with the belly pressed. It is not a value measuring the effect of training alone, but the difference in maximum range after both training and abdominal compression.
The four trained singers had a wider range than the non-majors and showed no meaningful change in range before and after training. The dissertation explains this by their having already internalized singing through abdominal breathing.
The dissertation also reported voice breaks: when the belly was pressed to make participants exhale, if the exhaling force was too strong and the force closing the vocal folds too weak, the forces fell out of balance and the note broke (Part 6).
04.What Else Was Measured, and the Limits
With these results, the dissertation concluded that it had verified abdominal breathing as an important factor in crossing the passaggio: passive abdominal breathing using abdominal compression, together with singing and breathing training, had a positive effect on crossing the passaggio (Part 17 and Part 18).
The dissertation built this singing program as a music-intervention program of musical activity, and also measured everyday indicators such as quality of life, depression, coughing, phlegm and dizziness. This series covers only the breathing and range results that singing practice needs.
And the dissertation states its own limit: with only eight participants, it is limited in how far its results can be generalized.
05.Today's Practice — Ten Sessions as One Cycle
Pairing the ten-session program of the dissertation's experiment (its Table 5) with the parts of the series turns the whole series into a ten-session practice routine.
| Session | Goal in Table 5 | Lessons in that session | Parts of the series to read |
|---|---|---|---|
| 1 | Understanding the basics of vocalizing · pre-measurement | 1-1 Breathing, 2-4 Vocal Exercises | Parts 2 and 3, this article |
| 2 | Head voice and chest voice | 1-2 Head Voice, 1-3 Resonance Spaces, 1-6 Chest-Voice Technique | Parts 5, 9 and 4 |
| 3 | Vocal technique | 1-4 Vibrato, 1-5 Singing Technique | Parts 15 and 1 |
| 4 | Nasal resonance · pronunciation | 2-3 Nasal Resonance, 2-5 Correcting Pronunciation | Parts 10 and 22 |
| 5 | The next step in vocalizing and breathing | 1-8 Connecting Head and Chest Voice, 2-6 Abdominal Breathing | Parts 14 and 3 |
| 6 | Vocal technique | 1-7 Support and Tone Control, 2-8 Vibrato | Parts 20 and 16 |
| 7 | Vocal technique | 2-9 Chest (Full) Voice, 2-10 Falsetto, 2-11 Half-Falsetto | Parts 7, 8 and 17 |
| 8 | Understanding singing styles | 2-12 Resonance, 2-13 Low Notes, 2-14 Low-Mid Notes | Parts 11, 21 and 19 |
| 9 | Raising the range | 2-15 High Notes, 2-16 Shout | Parts 18 and 23 |
| 10 | Review · post-measurement | 2-4, 2-11, 2-15 | Measure again the range you noted in Part 1 |
The three lessons not named in the sessions of Table 5 — 2-1 Chest Voice, 2-2 Head Voice and 2-7 Releasing Throat Tension — were covered in Parts 12, 13 and 6.
- Measure at the start and the end — In session 1, note your range and the note where your voice breaks; in session 10, measure again the same way. The dissertation's experiment also measured in session 1 and session 10 with the same tools (the dissertation's Table 5).
- The start of every session — Begin with posture and correct breathing (Part 19) and a warm-up chosen from the singing practice table (Part 21).
- Log it — Keep recordings and feelings in your vocal diary (Part 21, section 03; dissertation pp.164–165).
Ambu bag breathing training and forced abdominal compression were carried out as experimental procedures reviewed by a research ethics board. Do not turn them into exercises to try on your own.
The lesson to watch with this part is Season 2, Episode 4, "Vocal Exercises" — the lesson (2-4) used in both session 1 and session 10 of the dissertation's experiment. Its description lists crescendo and decrescendo, staccato and legato with the vocal folds together, fifth and third scales, and oral resonance practice.
06.All 24 Parts
The voice and repertoire of the singer who wrote this study are in Kim Hyuk Gun's Voice: Three-Octave High Notes and Hard Rock Roots, and the song, book and talk that share one title in "You Can Do It": The Song, the Book, and the Talk. Inquiries for concerts and talks go to Booking inquiry. Lesson videos are in Korean.
Start from posture and sing on the exhale — that is the one sentence 24 parts leave in the practice room.