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Live Opera Judges Favored Heart Over Hitting Every Note
In A Nutshell
- Judges’ ratings of emotion, rich sound, and vibrato rose with overall scores, but pitch accuracy showed no meaningful link.
- Male singers with a faster vibrato, the gentle rise and fall in pitch of a held note, tended to score lower.
- Female singers tended to score higher when their vibrato swung wider, a pattern not seen in men.
- Findings from 22 singers and five judges cannot show that judges treat men and women differently, only that the patterns differ.
Hitting every note showed little connection to scores from live judges. Pitch accuracy ratings failed to predict them, while emotion and a richer sound did. Vibrato, the gentle rise and fall in pitch of a held note, told a split story: men with a faster one tended to score lower, while women showed no clear link, and women tended to score higher when theirs swung wider, a pattern that did not appear for men.
Researchers in Japan put 22 classically trained singers on a concert hall stage, with five professional voice teachers judging live. Earlier studies mostly used recordings and rarely compared men with women. Results appear in the Journal of Voice.
Careers ride on these scores. Rankings, admissions, and casting often come down to a small panel boiling a performance into one number, and score sheets seldom spell out what drove it. A judge might praise a singer’s vibrato without ever saying what that means.
Opera Singers’ Scores Tracked Vibrato, Resonance, and Expressiveness
Ten men and 12 women, ages 19 to 34, took part. All were Japanese singers enrolled in, or graduated from, a music university. Each sang Caro mio ben, a short, easy Italian song, with no backing, in a large concert hall at Keio University. Each singer got one take.
Five judges, four women and one man, sat in the audience seats. All were professional singers with 11 to 34 years of teaching experience. After every performance, they gave an overall score out of 100 and rated six qualities from 1 to 7: vibrato, resonance (how rich and well projected the voice sounded), expressiveness (how well emotion and phrasing came across), timbre (the brightness or warmth of the tone), diction (clarity of pronunciation), and intonation (pitch accuracy).
A microphone about eight inches from each singer’s mouth let researchers measure four sound features without anyone’s opinion involved: how fast the voice pulses (vibrato rate), how wide the pulse swings (vibrato extent), how much energy the voice carries in the pitch range that helps it reach the back of a hall, and overall loudness. Statistical models tested which ratings and features lined up with scores.
Scores ranged widely, from a perfect 100 from all five judges for one man to an average of 54 for the lowest-scoring singer. Ratings of vibrato, resonance, and expressiveness each rose with overall scores for both sexes. Timbre, diction, and intonation showed no meaningful connection. Researchers noted that an easy song left little room to stand out on pronunciation and pitch, and timbre describes a type of voice, not its quality. As the authors put it, “A dark voice is not a worse voice than a bright one.” Voices with more energy in that back-of-the-hall range scored higher, for men and women alike, but loudness showed no clear link.
Resonance and expressiveness counted for more here than in the team’s earlier study, which used recordings in a soundproof booth. Researchers floated a reason: live judges hear a voice fill a room and can see posture and facial expression. The acoustics of the two spaces were never compared, so that explanation remains tentative.
Faster Vibrato Tracked With Lower Scores Among Male Opera Singers
Most singers‘ vibratos pulsed about six times a second, a typical speed for professional classical singers, but men whose vibrato ran faster tended to score lower.
Speed alone may not tell the story. The two fastest vibratos in the group, one from a man and one from a woman, also had the narrowest swings, and judges rated both singers low on vibrato. Researchers said a rapid rate in such cases may signal a vibrato that has not fully developed rather than a stylistic choice. But those two singers’ vibrato measurements rested on nine and eleven vowel samples, so their influence on the results cannot be ruled out.
Wider Vibrato Tracked With Higher Scores Among Female Opera Singers
Vibrato extent, how far the pitch swings up and down, is the other half of the story, since wider swings went with higher scores among women but not clearly among men. Men’s and women’s average widths were similar, so the pattern is unlikely to come from the sexes simply vibrating at different widths.
Why women’s scores tracked width more closely remains unclear. One possibility is that tastes about vibrato depth differ between voice types, which a study of men and women together cannot separate from sex.
Vibrato and Judges’ Scores May Work Differently for Men and Women
Findings come from one song, 22 singers, and five judges, and whether harder arias or different judges would produce the same patterns is unknown. The study cannot establish that judges marked men down for fast vibrato or rewarded women for wide vibrato, or that they hold the sexes to different rules.
Live concert hall numbers show that the link between vibrato and expert scores may differ for male and female singers. Whether that reflects vocal technique, expectations for different voice types, or how judges listen is still open. For singers, teachers, and judges, that is worth taking seriously.
Paper Notes
Limitations
Each of the 22 singers performed once, singing a single short, technically modest song, so it is unclear whether the same patterns would hold with demanding repertoire such as full arias. The study shows associations only, and its design could not separate singer sex from voice type. Models built on the sound measurements explained a smaller share of the variation in scores (33 to 40 percent) than models built on the judges’ own ratings (85 to 90 percent), so the measured features captured only part of what drove the scores. Two singers with unusually fast vibrato and low scores had their vibrato measured from a small number of vowel samples, so those cases could carry outsized weight. Loudness and the other sound features were measured from a microphone near each singer’s mouth rather than from the judges’ seats, and the acoustics of the hall were not measured or compared with the soundproof booth used in the team’s earlier study, which makes comparisons between the two studies tentative.
Funding and Disclosures
The work was supported by several Japanese funding sources, including the Taikichiro Mori Memorial Research Fund of Keio University, the Keio University Doctorate Student Grant-in-Aid Program from the Ushioda Memorial Fund, JST SPRING, the Ishii-Ishibashi Fund, JST COI-NEXT, JST PRESTO, and JSPS KAKENHI grants, awarded to various combinations of the authors. The funders had no role in designing the study, collecting or analyzing data, writing the report, or deciding to publish it. The authors declared no known competing financial or personal interests. They also disclosed using the AI tool Claude to improve the fluency of the manuscript’s language, and stated that they reviewed and edited the content and take full responsibility for it.
Publication Details
The study, titled “Vocal Evaluation of Classical Singing in a Concert Hall: Perceptual and Acoustic Associations with Overall Scores in Male and Female Singers,” was written by Haruka Kondo, Sotaro Kondoh, and Shinya Fujii of Keio University and the Japan Society for the Promotion of Science in Japan. It was accepted for publication on September 25, 2026, in the Journal of Voice, published by Elsevier Inc. on behalf of The Voice Foundation, and is open access under the CC BY license. DOI: https://doi.org/10.1016/j.jvoice.2026.09.070
