Courtesy of Ian Fry The So Percussion ensemble will team up with the group Nexus on June 8 to perform "Ionisation," a complex piece featuring military snare drum riffs and bursts of gongs, anvils and temple blocks.

When it rains, it pours.

In the case of this year's Ojai Music Festival, that means a hailstorm of percussionists required to play Steve Reich's "Drumming."

But it also means a rare opportunity to stage "Ionisation," Edgard Varèse's seminal percussion work and a first for Ojai in the festival's 62-year history.

Scored for 13 percussionists, "Ionisation" still wows audiences with its blend of delicate military snare drum riffs and cacophonous bursts of gongs, anvils, temple blocks, sirens and lion's roar.

The Nexus and So Percussion ensembles — along with four additional percussionists and a pianist — will perform the Varèse piece June 8 at Libbey Bowl.

Staging "Ionisation" (1929-31) is usually a tough sell because it's hard to justify hiring 13 players for a six-minute piece, said Thomas Morris, festival artistic director and one of the additional percussionists in the morning concert.

But with nine players already on hand for "Drumming," it was easy to make the case.

Also, Morris and David Robertson, festival music director, needed a significant 20th-century work to round out the first half of the program.

"So since we had them around, we thought, Let's make "Ionisation" the capstone of the first half,'" Morris said.

"Ionisation" is often mistakenly cited as the first piece written exclusively for percussion ensemble. However, the fifth and sixth movements of Amodeo Roldan's "Ritmicas," composed in 1930, predate Varèse's piece by a year.

Born in Paris in 1883, Varèse was an eccentric maverick who hobnobbed with futurist and dada artists and spent the greater part of his career in the United States. He preferred the term "organized sound" over music and burned all but 12 of his compositions before he died in 1965.

"Ionisation" was first performed at Carnegie Hall in 1933 and conducted by Nicolas Slonimsky, to whom it was dedicated. In the liner notes for the debut recording, Sidney Finkelstein wrote that the piece was "built on a most sensitive handling and contrast of different kinds of percussion sounds. There are suggestions of the characteristics of city life."

"Ionisation," however, is no dated warhorse trotted out for novelty purposes. It's as relevant today as when it was first performed, Morris said.

"Percussion, of course, is much more accepted today than it was way back then," Morris noted. "It's just a great, exciting piece that thrills people. And if you look at it historically, it's one of the most unique pieces of music in the context of the time in which it was written."

At that time, percussion writing was just coming into its own, said Jason Treuting, a member of So Percussion who grew up in Westlake Village.

"The tradition of percussion in other cultures from many different parts of the world was richer, and this was one of the first instances where it stood on its own," Treuting, 31, said in an e-mail.

But you don't need a degree in music history to enjoy the piece, he added.

"If you sit back, relax and take in the many different sounds as a collage and a unique listening experience, you're not going to hear the history and why the piece is important to us," Treuting wrote. "You are only going to hear a brilliantly organized cacophony. I love that about it."

Treuting has played "Ionisation" three times. But he admits not quite getting it the first time around, when he was a student at the Eastman School of Music in Rochester, N.Y.

"It was fun to play with so many percussionists, and it was cool to mix the sounds of the sirens with the drums and metals and crashing piano," he wrote. "But it didn't really click with me until years later."

That wasn't the case for late rock guitarist and composer Frank Zappa, who would eventually claim Varèse as a critical influence. (Varèse's quote, "The present day composer refuses to die," graces the cover of "Freak Out," the first Mothers of Invention record released in 1966.)

As a teenager growing up near San Diego, Zappa first read about "Ionisation" in a magazine article.

When he spotted a copy of an LP recording in a music store, he was enthralled with the photo of the frizzy-haired Varèse, whom he likened to a mad scientist.

Zappa's first attempt to play the recording on the family Victrola got the record and turntable banned from the living room.

He would eventually wear it out and later persuaded his parents to let him call Varèse in New York, in lieu of a $5 birthday gift. Varèse was not in that day, but the two later spoke on the phone and exchanged letters.

"All through high school, whenever people came over, I would force them to listen to Varèse — because I thought it was the ultimate test of their intelligence," Zappa wrote in his 1989 autobiography, "The Real Frank Zappa Book." "They thought I was out of my (expletive) mind."

Ojai's audience is likely to be more receptive, although what you see is not what you get.

"It looks like you're going to be hit with an onslaught of loud percussion, given everything that's on stage and all the players," Morris said. "But what comes out is this very quiet, very delicately scored, very alive piece.

"I love pieces which aren't what they seem to be and, in many ways, that whole concert is not what it seems to be."