Every Catholic who cares about upgrading music in parish life should be happy about this article that appears in Pastoral Liturgy. It has some funny understatements ("Chants have been a part of our Catholic faith for centuries") but it is really very good on the essentials. See "Learning the Chants: Singing with a Unified Voice" by Fr. John Mark Klaus.
We might be working toward a national singing voice at long last. Next step: a universal one.