Portland-based Capella Romana is a world-class male vocal group specializing in Greek Orthodox and Slavic church music. If that’s outside your normal sphere of activity, you have a good reason to hear this group. The music is often similar in effect from plainchant and early Western polyphony, with which Anonymous 4 made its reputation. And the contemporary compositions that Capella Romana feature also stem from that religious tradition, so you’re likely to find a whole intriguing world in this concert. Of course, since the event is at the new Bing Concert Hall at Stanford, the likelihood is that it’s nearly sold-out. But you might want to call in a favor to catch this concert.