For as long as Missouri Western State University has had a campus, throngs of barbershop quartets have gathered there to hone their singing skills.

Harmony University has no physical campus, but the Nashville-based barbershop society has for more than 30 years put its members up in the dorms at Western during the weeklong summer sessions. About 600 singers are on campus this week.

Meeting in the Fulkerson Center after breakfast Wednesday morning, the entire group, which includes members from as far away as New Zealand, Sweden, United Kingdom, Australia, Finland, followed a music director through singing exercises. The body of sound that 600 motivated barbershoppers can generate brings the phrase "raise the roof" to mind.

The average age of the participants at Harmony University is 63. But mixed within the grey and balding heads in the Fulkerson Center Wednesday was a spiky-haired blond fellow, probably in his early 20s, and preteen enthusiasts sitting alongside bass, baritones and tenors in their 80s.

Rex Winget, a 66-year old cost estimator for a steel fabrication company in Fulton, Ill., has made the trek to Harmony University for the last 18 years. He's found camaraderie as well as new tunes to add to his repertoire. His singing friends are from all walks of life - janitors, educators, lawyers.

"In this hobby we don't care what you do for a living," he said, "as long as you come and sing."

Mr. Winget fits the profile of the typical barbershopper. But he's there chasing the same thing that the 10-year old boy and the 52-year old woman (not every barbershopper is male) is chasing, and that's the overtone created when several voices hitting the right notes come together. In a quartet, the overtone or acoustic effect is referred to as the fifth voice. A physics class offered at Harmony University covers the phenomena.

Another commonality is the ubiquitous bottle of water on the hip of most singers. Sean Mulligan, 20, from Erie, Pa., said drinking water keeps the voice from giving out over a long day of singing. The tenor in Mr. Mulligan's group "Universal" said he downed nine bottles in his first day at Harmony University.

"We're definitely a minority," Mr. Mulligan said of his group's age. The three other members haven't quite reached their 20th birthdays. But he said singing eliminates the age factor. "Barbershop keeps you young."

Rick Spencer, director of music and education for Harmony University, said the 120 classes are offered during the weeklong event. The week ends with a special performance on Saturday by international barbershop champions, "Max Q" at Wyatt Park Baptist Church. College champions "Road Trip" also will perform. Tickets are $25 for general admission and $15 for students. They can be purchased by calling (816) 383-7150, or online at tinyurl.com/backinmyday.

Jimmy Myers can be reached

at jimmym@npgco.com