In 144,000 simulated voices, tuning a vocal tract resonance to a nearby harmonic added 6-9 dB to the vocal tract’s contribution to loudness at higher pitches, but only 1-3 dB at low pitches (Zhang, Journal of the Acoustical Society of America 2025). That single result helps explain why sopranos and belters reshape their vowels as they climb, while low voices rely more on firmer vocal fold closure. The classical “singer’s formant”, a spectral peak near 3 kHz, has a center that moves from 3092 Hz in sopranos to 2384 Hz in basses across 1,723 operatic recordings (Müller et al., Scientific Reports 2022). On the belting side, trained belters differed from untrained shouters on 18 measured parameters in men and 9 in women (Ikävalko and Laukkanen, Journal of Voice 2025). We aggregated data from the Journal of Voice, the Journal of the Acoustical Society of America (JASA), Logopedics Phoniatrics Vocology, Scientific Reports, Frontiers in Public Health and more than 30 individual peer-reviewed studies. If formants are new to you, our plain-language guide to how formant shifting changes a voice covers the basics.
TL;DR
- The singer’s formant is a spectrum peak near 3 kHz built mainly from formants 3, 4 and 5 clustering together (Sundberg, Journal of Voice 2001).
- Singer’s formant center frequency: 3092 Hz in sopranos vs 2384 Hz in basses, across 1,723 opera recordings (Müller et al., Scientific Reports 2022).
- Overall sound pressure level varied by more than 30 dB, while the singer’s formant level varied only 4 dB between male singers (Bloothooft and Plomp, JASA 1986).
- Formant tuning adds 1-3 dB at low pitch but 6-9 dB at higher pitch (Zhang, JASA 2025).
- In 10 advanced and professional sopranos, the results did not support the presence of a singer’s formant (Weiss et al., Journal of Voice 2001).
- Five premier male country singers had no strong spectral peak near 2.8 kHz (Cleveland et al., Journal of Voice 2001).
- Sopranos tune their first resonance to the pitch up to about C6 to D6 (about 1000-1200 Hz), some as far as E6 to F#6 (Garnier et al., JASA 2010).
- In belt qualities, 6 musical theatre singers tuned the first resonance to the second harmonic up to C5 (Bourne and Garnier, JASA 2012).
- Trained belters vs untrained shouters: 18 parameters in men and 9 in women differed significantly (Ikävalko and Laukkanen, Journal of Voice 2025).
- Second-harmonic-dominant belting works over only about a musical fifth of pitch for most vowels, in 12,987 simulations (Herbst et al., Journal of Voice 2025).
- Larynx height was elevated in all belting styles but not in classical-style “legit” singing, in 7 professional singers scanned by real-time MRI (Rudisch et al., Journal of Voice 2025).
1. Where the Singer’s Formant Sits: Frequencies by Voice Type
A formant is a resonance of the vocal tract, the air space from the vocal folds to the lips. The singer’s formant is the classical singer’s signature: several upper resonances crowd together near 3 kHz and act as one strong peak. The numbers below show it is not one fixed frequency but a sliding band that tracks voice type. Across 1,723 operatic sound examples, the singer’s formant center fell from 3092 Hz in sopranos to 2384 Hz in basses (Müller et al., Scientific Reports 2022).
The gap is uneven. Tenors and baritones are 251 Hz apart, while baritones and basses are only 70 Hz apart, which suggests this timbre measure separates the two lowest male voice types less clearly. The modelling work explains the mechanism: a narrow tube just above the vocal folds (the epilarynx) relative to a wide pharynx boosts the cluster, and the best ratio depends on the vowel.
| Metric | Value | Source |
|---|---|---|
| Location and origin of the singer’s formant in classical singing | Spectrum envelope peak near 3 kHz, mainly from a clustering of formants 3, 4 and 5 | Sundberg, Journal of Voice 2001 |
| Operatic sound examples analysed for singer’s formant timbre | 1,723 (774 sopranos, 389 tenors, 343 baritones, 217 basses) | Müller et al., Scientific Reports 2022 |
| Singer’s formant center frequency (frequency of half energy in the band), sopranos vs tenors | 3092 ± 284 Hz vs 2705 ± 221 Hz | Müller et al., Scientific Reports 2022 |
| Singer’s formant center frequency, baritones vs basses | 2454 ± 206 Hz vs 2384 ± 164 Hz (70 Hz apart, against 251 Hz between tenors and baritones) | Müller et al., Scientific Reports 2022 |
| Energy concentration in trained singers’ head-register singing, compared with 15 untrained men and 15 untrained women | Significant concentration at 2.2-3.4 kHz and at 7.5-8.4 kHz | Lee et al., Clinical and Experimental Otorhinolaryngology 2008 |
| Pharynx-to-epilarynx cross-sectional area ratio that maximised the singer’s formant cluster (2-3.5 kHz) in a 3D model of one female vocal tract | 11.4:1 for the vowel [a:] and 25:1 for the vowel [i:] | Vampola et al., Journal of Voice 2024 |
| Resonance peak clustering in growl, an extreme rock vocal style, in one professional singer scanned by MRI | Around 2000-4000 Hz, the singer’s formant region | Traser et al., JASA 2026 |
Context note: the band itself is defined differently across studies (near 3 kHz, 2-3.5 kHz, 2-4 kHz). Most recent available data for the untrained-versus-trained comparison: Lee et al., 2008.
2. Level and Loudness: What the Resonances Are Worth in Decibels
Singers do not get louder by pushing harder alone. The decibel figures below show that the vocal tract shape decides how much of the source energy reaches the listener, and that its payoff depends heavily on pitch. Strong formant tuning added 6-9 dB to the vocal tract’s contribution to intensity at higher pitches, against only 1-3 dB at low pitch (Zhang, JASA 2025). At low pitch, firmer closure of the vocal folds (adduction) was the main lever instead.
The older measurement data point the same way. In professional singers, the singer’s formant level barely differed between men (4 dB) but swung 23 dB with vocal effort, so it behaves more like a technique dial than a fixed trait. A computer study using source spectral slopes of -6, -12 and -18 dB per octave also found that at low pitches the source slope, not resonance tuning, drove sound level gains (Herbst and Story, JASA 2022). This resonance-and-harmonic arithmetic is also part of what singing voice synthesis systems have to reproduce.
| Metric | Value | Source |
|---|---|---|
| Variation in singer’s formant level due to differences among male singers (14 professional singers) | 4 dB | Bloothooft and Plomp, JASA 1986 |
| Variation in singer’s formant level due to vowel and due to fundamental frequency | 16 dB (vowels) and 9-14 dB (fundamental frequency) | Bloothooft and Plomp, JASA 1986 |
| Variation in singer’s formant level among female singers and between modes of vocal effort | 24 dB (female singers) and 23 dB (vocal effort) | Bloothooft and Plomp, JASA 1986 |
| Variation in overall sound pressure level in the same 14-singer data set | More than 30 dB | Bloothooft and Plomp, JASA 1986 |
| Increase in the vocal tract’s contribution to intensity from strong formant tuning, low pitch vs higher pitch | 1-3 dB vs 6-9 dB | Zhang, JASA 2025 |
| Vocal conditions simulated in the formant tuning model | 144,000 | Zhang, JASA 2025 |
| Fado-canção from Coimbra, 16 professional singers: equivalent sound level (Leq) and formant cluster prominence (FCP) | Leq 86.4 dB; FCP about 10 dB, smaller than in two opera baritone examples (14.8 and 20 dB) | Lã et al., Journal of Voice 2023 |
| Effect of raising the first resonance with louder dynamics in classically trained men | May strengthen the singer’s formant by several dB | Vurma, Journal of Voice 2022 |
Context note: Most recent available data for singer’s formant level variation: Bloothooft and Plomp, JASA 1986. No newer study of comparable design (14 singers, nine vowels, nine modes of singing, fundamental frequencies from 98 to 880 Hz) was found.
3. Who Has It and Who Does Not: Sopranos, Lieder, Country, Musical Theatre and Other Traditions
The singer’s formant is often taught as a universal marker of good singing. The data say it is a style choice tied to classical male and lower voices. In 10 advanced and professional sopranos, the resonance bands were usually at least 2 kHz wide, against under 1 kHz in tenors, and the results did not support a singer’s formant (Weiss et al., Journal of Voice 2001).
Genres that put the text first tend to drop it. Country singers, musical theatre singers and lieder (German art song) singers all show a weaker or absent cluster, and in a small listening test musical theatre singers, who lack a strong singer’s formant, were slightly more intelligible than opera singers (Sundberg and Romedahl, Journal of Voice 2009). Non-Western traditions split by sex: in Chinese National Singing, tenors showed the singer’s formant in sung vowels and songs, while sopranos showed it only in specific songs (Liu and Wang, Journal of Voice 2025).
| Metric | Value | Source |
|---|---|---|
| Sopranos tested for a singer’s formant at 932, 622 and 261 Hz | 10; presence not supported; bands usually at least 2 kHz wide vs under 1 kHz in tenors | Weiss et al., Journal of Voice 2001 |
| Premier male country singers analysed with long-term average spectrum (LTAS) | 5; the strong spectral peak near 2.8 kHz of classical singers was not found | Cleveland et al., Journal of Voice 2001 |
| Musical theatre vs opera singers (5 per group) | Musical theatre singers showed higher formant frequencies and no clustering of formants 3, 4 and 5 | Björkner, Journal of Voice 2008 |
| Singer’s formant in lieder vs opera recordings (18 lieder notes vs 20 opera notes) | Present at times in lieder, at significantly weaker intensity than in opera | Johnson-Read et al., Journal of Voice 2015 |
| Vibrato rate and vibrato extent, lieder vs opera | Rate about 6.4 Hz in both; extent about 112 cents (lieder) vs about 138 cents (opera) | Johnson-Read et al., Journal of Voice 2015 |
| Modern Chinese folk singing, 7 tenors and 7 sopranos: maximum gain factor at 3 kHz | 1.85 for men, 1.68 for women; female singers had no singer’s formant | Wang and Zhao, Journal of Voice 2024 |
| Countertenors (one student, one amateur, two professionals) | Singer’s formant not observed | Cruz et al., Journal of Voice 2026 |
| Singers versed in both early music and Romantic opera (5 women, 5 men) | Romantic opera: more prominent singer’s formant; early music: higher vibrato rate and smaller vibrato extent | Capobianco et al., Journal of Voice 2025 |
Context note: the soprano, country and opera-versus-musical-theatre comparisons are older studies. Most recent available data for these three: Weiss et al., 2001; Cleveland et al., 2001; Björkner, 2008.
4. Formant Tuning: How Sopranos and Other Voices Track Their Own Pitch
High voices face a physical problem: the pitch (the fundamental frequency, f0) can rise to or above the first resonance a vowel has in speech, leaving the pitch without reinforcement. Over roughly C5 to C6, sopranos usually answer by tuning the first resonance (R1) to the pitch (Jeanneteau et al., 2022), and the vowels converge and overlap as a result (Joliveau et al., JASA 2004). Sopranos keep the first resonance on the pitch up to about C6 to D6 (about 1000-1200 Hz), and some extend it to E6 to F#6 (about 1300-1500 Hz) (Garnier et al., JASA 2010). Note names here assume standard concert pitch; see our A=440 concert pitch statistics for how that reference was set.
Lower voices tune differently, to the second or third harmonic (the multiples of the pitch frequency), and individual strategies vary widely. A 2026 study of six professionally trained sopranos (three in Chinese National Singing, three in Bel Canto) found that for the vowel /a/, the study stimulus, tuning of the first formant to the pitch emerged in the high pitch range (Wang and Liu, Journal of Voice 2026).
| Metric | Value | Source |
|---|---|---|
| Classically trained sopranos, altos, tenors and baritones measured directly | 22; sopranos tuned R1 close to f0 over at least part of their upper range for all vowels studied | Henrich et al., JASA 2011 |
| Sopranos in the high-range tuning study, by expertise | 12 (4 nonexperts, 4 advanced, 4 professionals), from A4 (about 440 Hz) to their highest pitch | Garnier et al., JASA 2010 |
| Upper limit of first-resonance-to-pitch tuning | Below C6 to D6 (about 1000-1200 Hz); some singers to E6 to F#6 (about 1300-1500 Hz) | Garnier et al., JASA 2010 |
| Sopranos who learned to tune the second resonance (R2) with visual feedback in a one-hour session | 6 of 8, over a range of several semitones | Jeanneteau et al., Logopedics Phoniatrics Vocology 2022 |
| Pitch interval of the single laryngeal transition on glissandi, 12 sopranos | Gradual, over several tones within D#5-D6 | Garnier et al., JASA 2012 |
| Professional operatic tenors from C3 (131 Hz) to C5 (523 Hz) | 5 tenors; R1 tuned to the second harmonic and R2 to the fourth in some vowels; no systematic tuning on high notes | Ambros and Andrada e Silva, Journal of Voice 2025 |
| Male operatic singers in falsetto vs chest register at the same pitch and vowel | 7 singers; glottal contact quotient typically lower by 0.27; R1 lower by 65 Hz and R2 by 90 Hz | Henrich Bernardoni et al., JASA 2014 |
Context note: one hour of feedback training did not immediately extend the sopranos’ singing range (Jeanneteau et al., 2022). Most recent available data for the core soprano tuning limits: Garnier et al., 2010.
5. Belting Physiology: Closed Quotient, Subglottal Pressure and Larynx Height
Belting is the loud, speech-like, chest-dominant style of musical theatre and pop, as opposed to “legit”, the classical-style sound used in older musical theatre. The physiology tables point to one profile: longer vocal fold contact per cycle, a raised larynx and a narrowed throat. The closed quotient is the share of each vibration cycle in which the vocal folds touch; subglottal pressure is the air pressure just below them. In real-time MRI of 7 professional musical theatre singers, the larynx sat higher in every belting style but not in legit, with no significant differences between men and women (Rudisch et al., Journal of Voice 2025).
Belting is also not shouting with training on top. Trained belters reached similar acoustic output to untrained shouters with less subglottal power (Ikävalko and Laukkanen, Journal of Voice 2025). This section is about acoustics and physiology only; the clinical side of high-voice-use professions is covered in our vocal fold nodules statistics for teachers and singers.
| Metric | Value | Source |
|---|---|---|
| Scientific belting studies reporting a closed quotient above 50% | 27 of 58 | Kervin et al., Journal of Voice 2026 |
| Scientific belting studies reporting pharyngeal narrowing / an elevated larynx / high subglottal pressure | 26 / 24 / 10 of 58 | Kervin et al., Journal of Voice 2026 |
| Female musical theatre singers, chest vs head register at about 11 cm H2O subglottal pressure | 7 singers; maximum flow declination rate and closed quotient significantly greater in chest | Björkner et al., Journal of Voice 2006 |
| Female musical theatre singers, chesty belt vs legit at F#4-D5 (about 370-600 Hz) | 6 singers; closed quotient, EGG waveform symmetry and sound pressure level significantly greater in chesty belt | Bourne and Garnier, JASA 2012 |
| Trained belters vs untrained shouters (10 vs 10): parameters that differed significantly (P < 0.05) | 18 in men, 9 in women | Ikävalko and Laukkanen, Journal of Voice 2025 |
| Vocal efficiency in dB (re 1 W), belters vs shouters | Higher in belting in both sexes | Ikävalko and Laukkanen, Journal of Voice 2025 |
| Real-time MRI of 7 musical theatre singers (4 women, 3 men) in 5 vocal qualities | Larynx elevated in all belting styles, not in legit; rock belt had the largest lip and jaw openings | Rudisch et al., Journal of Voice 2025 |
Context note: in the belters-vs-shouters comparison the direction differed by sex. Male belters had higher closed quotient than shouters, while female belters had lower subglottal pressure and lower closed quotient (Ikävalko and Laukkanen, 2025).
6. Belting Acoustics: Harmonics, the First Formant and the Pitch Ceiling
The belt sound depends on one alignment: the first formant sits on the second harmonic (twice the pitch frequency), so the second harmonic outweighs the fundamental. That alignment only works over a narrow window, which is why belters modify vowels as they go up. In 12,987 simulations, second-harmonic-dominant belting could be produced over only about a musical fifth of pitch, extended to an octave for the vowels [ɔ] and [ɑ] (Herbst et al., Journal of Voice 2025). The two vowel symbols are the International Phonetic Alphabet symbols used as the study stimuli.
High female Broadway belting goes further than the textbook picture. At C5 to D#5, five female belters amplified up to four harmonics, with balanced reinforcement of the 2nd to 4th harmonics rather than one dominant one (Zuim and Titze, Logopedics Phoniatrics Vocology 2026). That fits the Broadway recordings below, where the higher belt range showed less variability between harmonic peaks than the lower, more traditional belt.
| Metric | Value | Source |
|---|---|---|
| Scientific belting studies reporting the first formant tuned to the second harmonic | 16 of 58 | Kervin et al., Journal of Voice 2026 |
| Belting simulations of the dominant harmonic | 12,987, covering 37 fundamental frequencies (C3 to C6), 27 source spectral slopes (-4 to -30 dB per octave) and 13 vowels | Herbst et al., Journal of Voice 2025 |
| Pitch span where second-harmonic-dominant belting is possible | About a musical fifth, centered where the pitch is about half the first resonance frequency; an octave for [ɔ] and [ɑ] | Herbst et al., Journal of Voice 2025 |
| Female Broadway belters at C5 to D#5 (5 singers, 3 phrases, 3 vowels, 2 pitches) | Up to four harmonics amplified; balanced reinforcement of the 2nd to 4th harmonics | Zuim and Titze, Logopedics Phoniatrics Vocology 2026 |
| First resonance tuning in belt qualities, 6 musical theatre singers | R1 tuned to the second harmonic up to C5; R1 stayed lower in legit | Bourne and Garnier, JASA 2012 |
| Professional Broadway actresses, lower vs higher belt range | 10 women; peaks near the 2nd and 3rd harmonics were higher; the gap between peaks was greater in the lower belt | Flynn et al., Journal of Voice 2020 |
| Vibrato use, belt vs legit performances by 5 professional female musical theatre performers | Belt had a smaller share of notes with vibrato, and shorter vibrato within a note | Becker and Watson, Journal of Voice 2025 |
Context note: the singer studies in this section tested 5 to 10 singers each, and the Broadway data cover women only. Section 7 shows how typical that is.
7. The Evidence Base: Small Samples, Many Terms, Mostly Women
The belting literature is young and thin, and the numbers here are the caveat behind every figure in sections 5 and 6. The 2026 scoping review screened 2,018 publications from January 1978 to November 2025 and kept 112, of which only 58 were scientific studies (Kervin et al., Journal of Voice 2026). The other 54 were pedagogical writing, mostly expert commentary.
Samples are small and skewed toward women, and the field has not agreed on what to call the thing it studies. The survey data on who belts is also dated: the professional belter survey published in 2024 collected its data in 2019.
| Metric | Value | Source |
|---|---|---|
| Median sample size of multi-participant belting studies | 14 participants (range 2 to 100) | Kervin et al., Journal of Voice 2026 |
| Scientific belting studies with female-only vs male-only participants | 27 of 58 (46.6%) female-only vs 7 of 58 (12.1%) male-only | Kervin et al., Journal of Voice 2026 |
| Different words and phrases used to describe belting | Over 100 | Kervin et al., Journal of Voice 2026 |
| Professional singers who consider themselves belters responding to a demographic survey | 238 responses (data collected February 1 to July 31, 2019) | LoVetri et al., Journal of Voice 2024 |
| Polish contemporary commercial music (CCM) singers surveyed | 412 (310 women, 102 men); 283 had vocal training; singing was the primary income for 11.4% | Morawska et al., Frontiers in Public Health 2024 |
| Time dose (share of time spent phonating) during musical theatre rehearsals, 5 student singers over four three-hour rehearsals | 4% to 7% of rehearsal time | Zuim, Stewart and Titze, Journal of Voice 2026 |
Context note: the LoVetri survey is a self-selected online sample, mostly female and US-based by the authors’ own description, so it describes respondents, not all belters.
Summary: Singing Formant and Belting Voice Acoustics by the Numbers
| Metric | Value | Source |
|---|---|---|
| Location of the classical singer’s formant | Near 3 kHz, from clustering of formants 3, 4 and 5 | Sundberg, Journal of Voice 2001 |
| Singer’s formant center frequency, sopranos vs basses | 3092 ± 284 Hz vs 2384 ± 164 Hz | Müller et al., Scientific Reports 2022 |
| Operatic recordings analysed for singer’s formant timbre | 1,723 | Müller et al., Scientific Reports 2022 |
| Singer’s formant level variation between male singers vs with vocal effort | 4 dB vs 23 dB | Bloothooft and Plomp, JASA 1986 |
| Formant tuning gain, low pitch vs higher pitch | 1-3 dB vs 6-9 dB | Zhang, JASA 2025 |
| Fado-canção equivalent sound level | 86.4 dB | Lã et al., Journal of Voice 2023 |
| Singer’s formant in 10 advanced and professional sopranos | Presence not supported by the results | Weiss et al., Journal of Voice 2001 |
| Lieder vs opera vibrato extent | About 112 cents vs about 138 cents | Johnson-Read et al., Journal of Voice 2015 |
| Maximum gain factor at 3 kHz in Chinese folk singing, men vs women | 1.85 vs 1.68 | Wang and Zhao, Journal of Voice 2024 |
| Upper limit of soprano first-resonance tuning | About C6 to D6 (about 1000-1200 Hz), some to E6 to F#6 | Garnier et al., JASA 2010 |
| Sopranos who learned second-resonance tuning in one hour with feedback | 6 of 8 | Jeanneteau et al., Logopedics Phoniatrics Vocology 2022 |
| Falsetto vs chest contact quotient in male operatic singers | Lower by 0.27 in falsetto | Henrich Bernardoni et al., JASA 2014 |
| Belting studies reporting closed quotient above 50% | 27 of 58 | Kervin et al., Journal of Voice 2026 |
| Belters vs shouters, significantly different parameters | 18 in men, 9 in women | Ikävalko and Laukkanen, Journal of Voice 2025 |
| Larynx position in belting vs legit (7 singers, MRI) | Elevated in all belting styles, not in legit | Rudisch et al., Journal of Voice 2025 |
| Belting simulations run | 12,987 | Herbst et al., Journal of Voice 2025 |
| Pitch span of second-harmonic-dominant belting | About a musical fifth for most vowels | Herbst et al., Journal of Voice 2025 |
| Harmonics amplified by female Broadway belters at C5 to D#5 | Up to four | Zuim and Titze, Logopedics Phoniatrics Vocology 2026 |
Methodology and Sources
We searched the Journal of Voice, JASA, Logopedics Phoniatrics Vocology and adjacent journals through PubMed and Europe PMC, prioritising 2024-2026 papers and keeping older studies only where no newer study of comparable design exists. Every figure comes from the paper’s abstract or open full text; no figure was taken from a secondary blog. Studies are small, and results describe the singers tested, not singers in general.
- Kervin et al., Variability in Acoustic, Physiological, and Perceptual Features of Belting Among Adult Singers: A Scoping Review, Journal of Voice 2026
- Zhang, Vocal tract contribution to vocal intensity, JASA 2025
- Müller et al., New objective timbre parameters for classification of voice type and fach in professional opera singers, Scientific Reports 2022
- Sundberg, Level and center frequency of the singer’s formant, Journal of Voice 2001
- Bloothooft and Plomp, The sound level of the singer’s formant in professional singing, JASA 1986
- Lee et al., The singer’s formant and speaker’s ring resonance, Clinical and Experimental Otorhinolaryngology 2008
- Vampola et al., Three-dimensional finite element modeling of the singer’s formant cluster, Journal of Voice 2024
- Traser et al., Vocal tract configuration and acoustic transfer characteristics in extreme vocal styles, JASA 2026
- Herbst and Story, Computer simulation of vocal tract resonance tuning strategies, JASA 2022
- Lã et al., Long-term average spectrum characteristics of Portuguese fado-canção from Coimbra, Journal of Voice 2023
- Vurma, Amplitude effects of vocal tract resonance adjustments when singing louder, Journal of Voice 2022
- Weiss et al., Singer’s formant in sopranos: fact or fiction?, Journal of Voice 2001
- Cleveland et al., Long-term-average spectrum characteristics of country singers, Journal of Voice 2001
- Björkner, Musical theater and opera singing: why so different?, Journal of Voice 2008
- Johnson-Read et al., Performing lieder: comparison of vibrato and singer’s formant with opera singers, Journal of Voice 2015
- Wang and Zhao, Acoustic characteristics of modern Chinese folk singing at different vocal efforts, Journal of Voice 2024
- Liu and Wang, Acoustic characteristics of tenors and sopranos in Chinese National Singing and Bel Canto, Journal of Voice 2025
- Cruz et al., A comparison of countertenor singing at various professional levels, Journal of Voice 2026
- Capobianco et al., Assessing acoustic parameters in early music and Romantic operatic singing, Journal of Voice 2025
- Sundberg and Romedahl, Text intelligibility and the singer’s formant: a relationship?, Journal of Voice 2009
- Henrich et al., Vocal tract resonances in singing: strategies used by sopranos, altos, tenors, and baritones, JASA 2011
- Joliveau et al., Vocal tract resonances in singing: the soprano voice, JASA 2004
- Garnier et al., Vocal tract adjustments in the high soprano range, JASA 2010
- Garnier et al., Glottal behavior in the high soprano range and the transition to the whistle register, JASA 2012
- Jeanneteau et al., Using visual feedback to tune the second vocal tract resonance in the high soprano range, Logopedics Phoniatrics Vocology 2022
- Ambros and Andrada e Silva, Resonance strategies in the upper range of Western operatic tenors, Journal of Voice 2025
- Wang and Liu, Vocal register adjustments in sopranos, Journal of Voice 2026
- Henrich Bernardoni et al., Vocal tract resonances in singing: variation with laryngeal mechanism for male operatic singers, JASA 2014
- Björkner et al., Voice source differences between registers in female musical theater singers, Journal of Voice 2006
- Bourne and Garnier, Physiological and acoustic characteristics of the female music theater voice, JASA 2012
- Ikävalko and Laukkanen, Belting by trained singers compared with shouting by untrained nonsingers, Journal of Voice 2025
- Rudisch et al., Vocal tract configurations across belting qualities using real-time dynamic MRI, Journal of Voice 2025
- Herbst, Story and Meyer, Acoustical theory of vowel modification strategies in belting, Journal of Voice 2025
- Zuim and Titze, How trumpet-like is female Broadway belting?, Logopedics Phoniatrics Vocology 2026
- Flynn et al., Acoustic comparison of lower and higher belt ranges in professional Broadway actresses, Journal of Voice 2020
- Becker and Watson, The use of vibrato in belt and legit styles of singing, Journal of Voice 2025
- LoVetri et al., A demographic study of professional belters, Journal of Voice 2024
- Morawska et al., Population characteristics and self-assessment of speaking and singing voice in Polish CCM singers, Frontiers in Public Health 2024
- Zuim, Stewart and Titze, Vocal demands of musical theatre rehearsals: a dosimetry study, Journal of Voice 2026
- Data watch: the Kervin et al. 2026 review is internally inconsistent in places: its abstract says 472 publications had full-text review while the results say 477, and expert commentary is counted as 32 in the abstract and 33 in the tables; several study counts in its text (for example, elevated larynx 23 vs 24) differ from its tables, and we used the table values. Its statement that 53.4% of studies had “fewer than 10 participants” matches a table bin of 2-10 participants plus single-participant studies, so we did not use it. The singer’s formant band is defined differently across papers (near 3 kHz; 2-3.5 kHz; 2-4 kHz; and both about 2-3 kHz and about 3-4 kHz inside the same review), so frequency figures are comparable only within a study. The Müller et al. 2022 figures describe recordings, not singers: the paper does not state how many individual singers the 1,723 examples come from. For the 2025 belters-vs-shouters study we read the abstract only; the open-access full text was blocked to our tools, so no mean SPL, pressure or closed quotient values are quoted. Several core data sets are older than three years (Bloothooft and Plomp 1986; Weiss et al. 2001; Cleveland et al. 2001; Björkner 2006 and 2008; Garnier et al. 2010 and 2012) and are flagged in their sections as the most recent available data.
Last updated: November 8, 2026. We update this roundup quarterly, and the next refresh is expected when the Voice Foundation publishes its 2027 Annual Symposium abstracts and the first 2027 issues of the Journal of Voice appear.