Eroicas stretch without straining

Although the Eroica Trio is not exactly a traditionalist’s idea of what a chamber music group should be, neither is it perpetually out on the edge like, say, the Kronos Quartet.

Rather, violinist Adela Pena, pianist Erika Nickrenz and cellist Sara Sant’Ambrogio have found a middle ground -- playing standard repertoire and stretching into new territory that doesn’t terrify the conservative core chamber audience. And while they still resemble cast members from “Sex and the City” in their publicity photos, their musicianship and teamwork are clearly built for the long haul.

In lieu of an announced but not yet completed new piece by Philippe Bodin at a Coleman concert in Caltech’s Beckman Auditorium on Sunday afternoon, the Eroicas turned to a different Los Angeles-area premiere by the protean country-jazz-rock-classical violinist and composer Mark O’Connor -- his Trio No. 1, subtitled “Poets and Prophets.” One glance at the titles of the movements reveals that the piece was meant to be a homage to the late Johnny Cash, who inspired performers and listeners all over the musical spectrum, whether they care to admit it or not.

Yet aside from the distinctive loping rhythm from the piano in the movement titled “The Tennessee Two,” O’Connor hardly ever evokes Cash’s music literally. Rather, he tries to write a fairly conventional four-movement classical trio, albeit with a few countrified portamentos and inflections along the way. Peter Schickele’s gentle fusions of Americana come immediately to mind -- and though O’Connor’s inspiration gets stuck in spots, “Poets and Prophets” went over pleasantly.

By comparison, Anne Dudley’s fanciful piano trio arrangement of J.S. Bach’s Chaconne from the Partita No. 2 for solo violin seemed more nervy and free. Dudley tosses Bach’s single line among the three instruments and conjectures all kinds of implied harmonies; at one point near the end, it sounds like Brahms! Though their playing was a bit rough at times, the Eroicas relished the opportunity to dig in and deepen the transcription’s swerving emotional states.

For the main course, the Eroicas tackled a masterpiece, Schubert’s great Trio in E flat, Opus 100 -- moving swiftly, though not quite immaculately, grappling with some of the work’s amazing spiritual depths. Godard’s Berceuse from “Jocelyn” was the encore.