The music of Beethoven and Bach gets a lot of attention in the Berkshires every summer. But amid the more august offerings, there is a musical collective that wants to rip the powdered wig off traditional classical music. Playing the work of living composers, and using unconventional methods, they are interested in anything but a musical history lesson.

Leading a string ensemble of about twenty musicians an hour before their public recital, conductor Brad Lubman gives his players an unusual criticism—they sound too polished, clean, locked in with each other…