DULUTH — Once a month, typically on a Sunday afternoon, the Friends Meeting House is filled with voices singing together. It's not a performance because everyone present is involved in the singing.

Groups of Sacred Harp singers are working together to revise their hymnal The a capella tradition uses shape-note music to sight-read songs from the hymnal's 554 options Families pass the musical ...

Sacred Harp or shape note singing is a communal form of singing that arrived in the U.S. from England, became popular in the early 1800s and spread across the country largely in religious communities.