Spectral composition—the focus of the JACK Quartet’s upcoming Vancouver New Music appearance—is more properly the stuff of doctoral dissertations than brief magazine features, but don’t let that scare you off. Ari Streisfeld is perfectly happy to talk prospective listeners through the basics of the latest compositional trend.

“What spectral composers have done is basically break down the components of sound,” the violinist explains by cellphone, en route from a concert in Washington, D.C., to his New York City home. “From there, they write for these different components using different aspects of sound. So that might include noise; that might include the harmonic series—the naturally occurring harmonic series. I always like to think of the harmonic series as like when you shine white light through a prism and you get the rainbow. With the harmonic series, you have a single pitch, and that single pitch is made up of an infinite number of pitches—very specific pitches, but an infinite number of them going up higher and higher.”

It’s heady stuff: the pieces that Streisfeld, violinist Christopher Otto, violist John Pickford Richards, and cellist Kevin McFarland will play in Vancouver involve arcane tunings, microtonal pitch shifts, and unconventional bowing techniques, all the better to bring out these evanescent partials. Yet this music can also be appreciated with little theoretical understanding: because composers like Georg Friedrich Haas, Taylor Brook, and the late Horaţiu Rădulescu are dealing with the physical properties of sound, their work often incorporates a gloriously sensual component.

“This is especially apparent in the music of Haas,” Streisfeld says. “He likes to take partials low on the harmonic series, which to a layman’s ear sound like beautiful major thirds and pure sevenths, which our ears are kind of used to hearing. These are harmonies that make up tonal harmony; the only difference is that they’re tuned in a pure way rather than in an equal-tempered way, from a piano.”

There are more than theoretical links between Haas’s String Quartet No. 8, Rădulescu’s String Quartet No. 5, and Brook’s El jardin de senderos que se bifurcan. Although stylistically distinct, all three are derived in some way from literary sources.

“Haas and Taylor’s quartets are very exact in their notes and rhythms, in terms of what’s written out, while in Rădulescu’s quartet there’s actually an improvisational element to it,” Streisfeld explains. “Each page is about a minute of music, and we have very specific techniques that we’re supposed to use, but then while we’re doing those techniques we also have a text at the top of each page that’s from the writings of Lao-tzu, from the Tao, and we’re incanting the rhythms of the text through our bows.…It creates a really interesting texture on top of all these otherworldly sounds.”

Haas, in turn, draws on German poetry, while El jardin takes its title from a Jorge Luis Borges short story. Perhaps the most important through-line, though, is that the JACK players will approach each piece with their singular combination of rigorous analysis and focused musicality—qualities that make them among the most exciting string quartets working today.

Vancouver New Music presents the JACK Quartet at the Orpheum Annex on Saturday (March 14).