Keio University: in a live contest of 22 singers, vibrato, resonance and expressiveness tracked higher scores

Researchers at Keio University in Japan staged a small classical singing contest and found that higher scores went with three qualities: vibrato, resonance and expressiveness, Earth.com reports. The study was led by doctoral student Haruka Kondo with Sotaro Kondoh and Shinya Fujii and was published in the Journal of Voice earth.comEarth.comearth.comOpen source ↗. Twenty-two Japanese classical singers (10 men and 12 women, average age about 25) each sang the Italian art song "Caro mio ben" once, without accompaniment. A microphone about 8 inches (20 centimeters) from the mouth recorded every performance.

Five professional singers with 11 to 34 years of teaching experience judged live from a 720-seat hall on Keio's Shonan Fujisawa Campus. Each gave an overall score out of 100 and rated vibrato, resonance, expressiveness, timbre, diction and intonation from 1 to 7.

What the judges rewarded

A one-point rise in the vibrato, resonance or expressiveness rating went with about 3 more points overall, with the other five qualities taken into account. Together, the six ratings accounted for 85% of the differences in scores. Diction, intonation and timbre showed no clear link to the final scores. The authors note that pronunciation and pitch have fixed targets and that all participants had university training.

The top scorer, a 34-year-old baritone, received 100 from every judge. A 19-year-old soprano with two years of vocal experience came last with an average of 54 earth.comEarth.comearth.comOpen source ↗.

What the recordings showed

Singers with more energy between roughly 2,000 and 4,000 vibrations per second (the singer's formant band) relative to lower frequencies scored higher, among both men and women. Loudness showed no clear link to scores.

For vibrato, each extra pitch oscillation per second went with roughly 9 fewer points among men, while women showed no clear link. Among women, each extra 10 cents of swing went with about 1.7 more points, while men showed no clear link. The average swing across all singers was 138 cents.

The authors stress that these are associations. The judges could see the singers, so posture and facial expression may have affected the expressiveness ratings. The vibrato figures for the two singers with the fastest rate rest on only 9 and 11 usable vowels. The contest involved 22 singers, five judges and one easy song, and the authors want future studies to use several pieces from real competition repertoire earth.comEarth.comearth.comOpen source ↗.