Chances are, while you may not have known what it’s called, you’ve almost certainly experienced polyphony. It’s a type of singing that consists of two or more simultaneous lines of independent melody. Polyphony becomes “sacred” when what’s being sung are hymns of praise to God. Monday, Jerry and Debbie will be joined by Chris Mueller, whose ensemble, Ars Mueller, produces exceptionally beautiful sacred polyphony. In a world where so much music has little or no characteristics of beauty, you’ll be inspired by this conversation.