New chamber groups spring up all the time, usually without fanfare. But the new Eidolon String Quartet deserves attention because its founder is Franklyn D’Antonio, concertmaster of the Berkeley Symphony, and former member of the Chicago Symphony and the Los Angeles Philharmonic. The second violinist, Noah Strick, is a recent graduate of the San Francisco Conservatory and the Oberlin Conservatory and is assistant concertmaster of the Berkeley Symphony. Clare Twohy, on viola, is also a recent SFCM graduate teaching at the Crowden School. Cellist Gianna Abandolo is on the faculty at UC Berkeley and Mills College. In their inaugural concert, the group plays music of local composers, including Twohy and Clark Suprynowicz, former composer in residence at the Berkeley Symphony Orchestra.