In my column on Renaissance polyphony in this week's New Yorker, I mention in passing the Flemish group Capilla Flamenca. The delightful video above comes from their well-stocked website. Another group with a potent web presence is Cappella Pratensis, which not only has its own site but also participates in Jennifer Bloxam's remarkable multimedia study of Obrecht's Saint Donatian Mass. The latter allows you to follow along in the score and observe how the contrapuntal technique meshes with the religious texts. (Thanks to Matthew Westphal for the tips.) Blue Heron, the main focus of my piece, have their own richly informative site. They'll be back in NYC for a Victoria program on March 13. Pomerium, longtime New York mainstays, appear in the invaluable Music Before 1800 series on Feb. 13. And the Tallis Scholars remain the heavyweights of the polyphonic arena, offering highest-quality downloads through their in-house label, Gimell Records.