Early in their document, Sing to the Lord, the US bishops review the various ministerial roles within liturgical music. Writing of any instrumentalists, the bishops remind us of their purpose with regard to the song of the assembly: “lead and sustain … without dominating or overpowering.”
The bishops praise the addition of variety, color, and especially harmony to the singing (42). They write to encourage improvisation (43), especially when prepared music ends before the ritual action, but caution against “mere background sound.” If instrumentalists can’t improvise, then “published literature” is recommended.
Instrumental music may serve “as a prelude before the Mass, an instrumental piece during the Preparation of the Gifts, a recessional if there is no closing song, or a postlude following a closing song.” (44)
There’s not a lot of depth here. Not mentioned is the value of coordinating instrumental music among two or more players. Ensembles of musicians provide an opportunity to model the ideals of Christian community: sharing prepared arrangements, coordinating improvisation, and most of all, practicing the discipline of listening.
Another bit to mention is the importance of attuning one’s musical repertoire to the liturgical season or feast. Otherwise, any comments from the readers?