If you're not sure what to expect from a string quartet that calls itself Ethel, the most sensible advice is simply to expect the unexpected. From one track to the next on Light, the group's second album for the wonderfully eclectic Cantaloupe Music label, you'll encounter Brazilian dance rhythms and Finnish fiddling, jazz licks and blues cadences, and a flawless classical technique in the service of rock 'n' roll energy. Like another of today's adventurous chamber ensembles, the Imani Winds, Ethel's musicians are not only performers but composers and arrangers as well: Their own work accounts for half of the music on Light. But as on their self-titled debut, Ethel also collaborates here with some of the boldest composers on the avant-garde scene. The album's furthest-out experiment, "Ethel Dreams of Temporal Disturbances," is full of electronic effects, samples of an Irving Berlin song, and the vocals -- reminiscent of Laurie Anderson's wry observations -- of composer Pamela Z. In contrast, the hauntingly melodic minimalism of Mary Ellen Childs's "After Dust" provides a relatively tranquil respite from the more exuberant goings-on. The quartet's jazz leanings are also brought to the foreground, with Ethel violinist Mary Rowell's arrangement of Lennie Tristano's "Requiem" providing one of the album's most powerfully emotive moments, and one of Don Byron's "Four Thoughts on Marvin Gaye" offering a more abstract, but no less intriguing, synthesis of jazz, soul, and the avant-garde. And then, just when you think you've mapped out the limits of Ethel's influences and experiments, you encounter the "vocals" of Einstein -- an African gray parrot -- on the spirited final track, Rowell's "Also Sprach Einstein." Light may not suit those who want their music to fit neatly into one predictable category or another, but for the rest of us, it contains an album's worth of invigorating musical fun.