The New York string quartet Ethel isn’t like most other classical groups: their name sounds better suited to a rock band, their repertoire includes improvised material, they amplify instruments, and their performances feature customized lighting and choreography. They may like to have fun now and again—Kronos Quartet is the model—but the members are all serious, Juilliard-trained players. Last year they released two fine albums with new violinist Cornelius Dufallo, who replaced founding member Todd Reynolds. AllSteel (Tzadik), a bracing collection of new music by John King, is filled with prickly dissonance and wild, hard-driving rhythms, with an emotional range that regularly jumps from melancholia to agitation to celebration. King started the album’s titular eight-movement centerpiece on September 10, 2001, and you can clearly hear a dramatic shift in tone through later movements. 

Light (released by Cantaloupe, the label run by the affiliated Bang on a Can crew) is typically eclectic, but in comparison to the group’s self-titled debut there’s a much greater emphasis on works written by ensemble members, which fit right alongside pieces by clarinetist Don Byron, new-music vocalist Pamela Z, the great jazz pianist Lennie Tristano, and the young Brazilian composer Marcelo Zarvos. Mary Rowell’s ebullient, almost manic “Sambula” has the postexotica haze of kitschy Hawaiian music, juggling the rhythms of bebop and samba while drawing on percussive effects, whistling, and loads of shape-shifting. Dufallo’s “Lighthouse” applies classical rigor to a lovely pop-worthy melody that just happens to run through constant permutations.

Ethel performs in Evanston at Pick-Staiger on Thursday, April 5, as part of Northwestern University’s QuadroMania Festival. They’ll be joined by the local harmonica virtuoso Howard Levy, better known to jam-band lunkheads as a collaborator of Bela Fleck & the Flecktones. While Ethel regularly collaborates with musicians from diverse backgrounds—Light includes contributions from the great jazz pianist Vijay Iyer—I have a hard time imagining them playing with Levy. Maybe because I loathe jazz harmonica.