The Jerusalem Quartet believes in the power of the standard repertoire

Before Ori Kam joined the Jerusalem Quartet, he spent two years in the viola section of the Berlin Philharmonic. Ask him about the differences, and the first thing he mentions is the travel.

“A quartet spends almost all its time on the road,” he said recently from his home in Israel (the Jerusalem Quartet’s visit April 30 to Symphony Center will be part of a two-week North American tour). “A symphony orchestra gets to live where they work, and we can only dream about that.” Further, he added, “A string quartet is kind of a business. We don’t get a salary, and everything we do we’re responsible for.”

But to invert Spider-Man’s motto, with great responsibility comes great power. As a section string player in an orchestra, “you don’t make the schedule, you don’t make musical decisions, you definitely don’t choose repertoire. We’re really in the helm on a lot of those things.”

At chamber rehearsals, without a conductor to make decisions, “the only way things can go forward is by unanimous consent, so a quartet is about building consensus,” Kam said. But although the four members are equal, “that doesn’t mean that in the hierarchy of voicing, every part is the most important,” he said. “When two violins are playing in octaves, the bottom octave should be more dominant. There’s an ever-changing equilibrium between the four, which is fascinating to observe, this four-headed animal constantly morphing.”

As the violist, Kam is usually in the middle of the texture, but he compares his role to a character actor. “The viola plays a lot of different roles,” he said. “Melody, countermelody, harmony, bass line. Of all the string instruments, it’s the only one that reaches into all those roles. You might not notice it’s there, but if you take it out, everything just collapses.”

For its concert in Chicago, the quartet will actually be a sextet, as the members will be joined by Pinchas Zukerman on violin and viola and Amanda Forsyth on cello for works by Bruckner, Dvořák and Brahms. Kam estimates that 20 percent of the quartet’s concerts use a guest musician apart from the core four, and Zukerman and Forsyth “are like extended family — or repeat offenders.”

The evening will follow the usual chamber pattern of three pieces that have both enough similarities and enough differences to hold the audience’s interest. In this case, the entire program is by Central European composers from the second half of the 19th century. The Brahms, from the composer’s youth, is “full of beautiful melodies and a lot of nice licks for each of the six members of the group,” Kam said. And the Dvořák “leaves you with a smile. Even when it’s dark, it’s never sarcastic or hopeless.”

Zukerman is also an Israeli native and Kam’s former teacher, part of the deep-rooted tradition of classical music in Israel. Kam speculates that the small country’s vibrant classical scene owes a lot to the influx of refugees from Europe in the 1930s, when the Israel Philharmonic was founded. “At the end of the world, you had this world-class orchestra with Toscanini as the music director,” he said. “There was already musical activity and an audience for it, and I’m happy to say you can still see that today.”

Kam is the ensemble’s only non-charter member, joining violinists Alexander Pavlovsky and Sergei Bresler and cellist Kyril Zlotnikov in 2011. But he had played as a substitute or guest with the quartet almost since its founding in 1996. “We never really specialized in any repertoire,” he said. “A lot of quartets start with Haydn and build up, but it was a stroke of genius that already in their first year they were playing Beethoven, Dvořák, Bartók, Kurtág.”

Reviewing a Bartók concert by the quartet in 2016, the New York Times praised its “glossy and generous” sound and concluded, “Like a great actor, the ensemble managed to imbue each moment with tragedy and comedy at once.”

Although the quartet has released a CD of Yiddish cabaret music from the interwar period, they do not venture into klezmer. “It’s not really what we do,” Kam said. “We’re a very traditional quartet. We love the standard repertoire and we believe in the power of it — not just artistically, but for entertainment and the enjoyment of the audience.”