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Why you can't make out what the fat lady sings

New measurements show that a soprano distorts her pronunciation when she opens her mouth wide and adjusts her vocal tract to hit the highest, loudest notes.
Spanish soprano Maria Bayo interprets Margarita during the rehearsal of the Gounod opera "Fausto" in Seville. Scientists say the vocal tracts of sopranos are optimized for musicality and volume rather than intelligibility.Marcelo Del Pozo / Reuters file
/ Source: The Associated Press

Even opera buffs peek at the electronic subtitles when a diva rattles the chandelier with a soaring aria. It may sound beautiful. But what exactly is she singing?

Scientists say you shouldn’t blame your uncultured ears for not being able to understand the lyrics, even when they are in English.

New measurements show that a soprano distorts her pronunciation when she opens her mouth wide and adjusts her vocal tract to hit the highest, loudest notes.

“It’s not our ears,” said Australian physicist Joe Wolfe. “In some cases, the information simply is not there.”

Scientific conundrum
Until now, scientists had difficulty measuring and explaining the effect, which is most pronounced in sopranos, who have the highest voices.

When an opera singer’s voice fills the concert hall, the lungs push a prodigious amount of air through the larynx, vibrating the vocal folds. At 220 times per second, a woman’s vocal cords vibrate almost twice as fast as a man’s, and that is what creates her higher pitch.

The sound waves are shaped as they move through the vocal tract; that is the soft, fleshy tunnel through which sound resonates as it passes through the mouth and past the lips, adding brilliance, fullness and power.

The best sopranos can sing nearly as loud as the roar of a jet engine. That not only helps them to be heard above a large orchestra; it also conveys the dark emotions that composers like Verdi and Wagner intended.

If the composer pushes hard and high enough, singers must sacrifice intelligibility to make the music.

Studying the sopranos
Wolfe and others at the University of South Wales developed a method to measure this “soprano’s effect,” which they described in a brief paper published in Thursday’s issue of the journal Nature.

The researchers used eight classically trained sopranos. A researcher struck an ascending scale of notes on a glockenspiel. The sopranos sang into a microphone to match the scales. They sang four words that emphasized different vowel sounds — “hard,” “hoard,” “who’d” and “heard.”

The sopranos usually lowered their jaws and opened their mouths in wide grimaces to hit the highest, loudest notes. Soon, the actual words they were singing became muddied.

“When you round your lips to say ‘oo,’ it is difficult to open your mouth wide enough to generate a loud sound,” Wolfe said. “That’s when ‘oo’ begins to sound like ‘ah.”’

“They put their vocal tracts in a shape that is right musically rather than right for speech,” Wolfe said.

So what’s a diva to do? Amplification will not enhance the performance, he said. For one thing, it sounds unnatural. And in concert halls where singers use microphones, people rustle, sneeze and chat as the singer tries to sing louder over the noise. Soon everybody is shouting.

“And people often wonder why they have sore throats in the morning,” Wolfe said.