A cappella is big with Perpetuum Jazzile

A cappella singing has become more prominent in the last decade thanks to groups like Straight, No Chaser, movies like “Pitch Perfect” and such television series as “Glee” and the reality competition “The Sing Off.”

Perpetuum Jazzile takes a bigger approach to a cappella.

Instead of creating those harmonies and rhythms with a dozen voices or less, the Slovenian group is 50 voices strong when performing at home, and 35 members landed in the United States on Monday for a three-week U.S. tour that includes a concert Wednesday at Stambaugh Auditorium.

While the ensemble is bigger, the concept is similar to the style currently popular in the States with the group putting an all-vocal spin on contemporary music. A YouTube search of the group’s name turns up high-energy arrangements of everything from the Lady Gaga / Beyonce collaboration “Telephone” to Van Halen’s “Jump.”

Peder Karlsson, who spent 26 years as a member of the Swedish vocal act The Real Group, became the choir’s music director in 2009.

In a telephone interview from Charlotte, N.C., Karlsson said he first heard the group when it performed on the same bill as The Real Group.

“They really had the rhythm down,” he said. “They had a groove and a rhythm like a band. That’s what was unusual to me. Usually you don’t take choirs seriously when it comes to pop music, but I immediately got respect for what they were doing.”

A year later, he was offered the job of music director.

Perpetuum Jazzile is one of the most popular musical acts in its native Slovenia, and many singers audition to be in the group just because it is famous. Some change their minds once they find out everything that is required, Karlsson said. Before a singer becomes a full-time member, they spend six months in a testing period.

“They have to sacrifice a lot to be in the group,” Karlsson said. “We do 70, 75 concerts a year, and we’re not quite yet in a position where we can pay all these people what they get in their (regular) jobs … We present them with an enormous amount of work. They have to learn a lot of stuff at home.”

The singers range in age from about 21 to 33, and since most formal music education in Europe is classically focused, the group features a mix of trained and untrained singers.

“About half of the singers read music, the other half don’t,” he said. “It’s just something that I noticed that all of the successful vocal groups have a mix of people with musical education and more or less rock ‘n’ roll, pop-session singers. We look for a combination. We want people with character in their voices. They have to be able to deliver a pop song and make it sound authentic. Standard choir voices don’t have that. But we also cast them for their ability to blend in with other singers. They need to have an individual voice but also tune into the other things that are happening with the music.”

Karlsson creates the intricate vocal arrangements for the group. Part of the task is deciding whether to go “in the footsteps” of the original artist or to dramatically rework the sound of the song. Then it’s a matter of creating vocal parts that not only match the melody and lyrics but capture the instrumentation of the song, he said. While vocal percussion is relatively easy, getting the voice to emulate a guitar or a piano is much more challenging.

Without naming any titles, Karlsson said the audience at Stambaugh can expect to hear many familiar songs at Wednesday’s concert.

“We have exceptional singers who like to have fun and know how to communicate that in concert. They want to entertain, but they also get entertained themselves by singing.”