Josiah Krodel, 11, sings with the Cincinnati Boychoir. (Photo courtesy Cincinnati Boychoir)

The world’s best boys’ choirs have been losing their sweetest sopranos earlier and earlier to puberty. Every choir director knows that the crack, croak or squeak from a young singer means the boy will soon have a different sound. Many boys never stick with it through this voice change to see where it takes them.

That’s why the Cincinnati Boychoir is partnering with researchers from the Cincinnati Children’s Hospital Medical Center to study the science behind boys’ changing voices and learn better ways to help them transition as singers.

“Many choral directors and voice teachers believe that the voice change is a primary reason for boys quitting singing as they enter puberty,” Christopher Eanes, Cincinnati Boychoir’s artistic director and co-author of the upcoming study, told The Washington Post in an e-mail. “Who can blame a boy who, when singing, becomes uncomfortable for a time, follows his friends to the football team, never to look back at his musical career.”

“When one thinks about the fact that boys’ voices in the 18th century changed at 17 or 18 years old, and now they change around 12 or 13 years old, one can only conclude that boychoirs are heading for extinction,” he added.

Later this month, researchers will begin to study the physiological, aerodynamic and acoustic changes that happen when boy singers hit puberty. Some 20 Cincinnati Boychoir members from ages 5 to 11 will participate in the study, which is expected to last about two years. The boys will speak and sing in a sound booth, and researchers will examine their larynxes and voice boxes to see how they change during certain tasks, co-author Alessandro de Alarcon, an ear, nose and throat doctor at the Cincinnati Children’s Hospital, told The Post.

Over time, the researchers said, they hope the study will shed more light on how the male voice changes during puberty, particularly in vocalists, so voice teachers will know how to intervene to help them move into their adult voices.

“My personal hope is that we can, on some level, anticipate voice change stages in order to assign the appropriate voice part for a boy, or to design appropriate vocal exercises to strengthen certain aspects of the singing voice,” Eanes said. “Overall, anything we can do to make the voice transition more comfortable for boys will help us as teachers and conductors.”

During puberty, a boy’s larynx and vocal cords grow quickly, causing the voice to become deeper. Scientists have compared the phenomenon to string instruments: The longer or thicker the strings, the deeper the sound. Some voice coaches refuse to train boys through this process for fear they might cause damage to the singing voice, Wendy LeBorgne, a voice pathologist and singing-voice specialist who is working on the study, told The Post in an e-mail.

“Just as many adolescents become awkward in their physical coordination as their bodies are growing and changing more rapidly than they can keep up, their voices are ‘awkward’ as well,” she said. “Depending on the boy, it has been my clinical and singing studio experience that boys who sing before puberty — and have a good understanding of their instrument — are able to adapt to the ever-changing voice as they progress through puberty. They are able to find stability in their post-puberty voice and continue singing with minimal disruption.”

Each year, Cincinnati Boychoir has about 200 boys and young men from more than 90 schools in Ohio, Kentucky and Indiana, according to its Web site. Watching the voice transformation in the choir each year, Eanes said, he became interested in how voice teachers could help boys through it. He contacted LeBorgne, an adjunct assistant professor for musical theater at the College-Conservatory of Music at the University of Cincinnati.

LeBorgne and Barbara Weinrich, a researcher in speech-language pathology at the Cincinnati Children’s Hospital, then took Eanes’s idea to de Alarcon, according to the Cincinnati Enquirer. The group will collaborate on the study.

Although there have been numerous studies on the science behind boys’ voice changes, the researchers said, not much has been done on how it happens — as it happens — particularly in dwindling boys’ choirs.

“From a singing voice pedagogy standpoint, much of the information and training techniques regarding the male singing voice through puberty is often the result of singing voice teachers’ experience and understanding of what they perceive,” LeBorgne said.

The group said they hope the study will add to the limited literature on the topic.

“It is a natural and inevitable part of a boy’s growth,” Eanes said, “and yet when it comes to the singing voice, the way we handle it has so much to do with the fulfillment that they get from making music.”