Sing to the Lord: Music in Divine Worship (US Bishops, 2007) treats “Who Prepares the Music for the Liturgy?” at nos. 119-121, quoted below. The pastor or priest has ultimate responsibility, but he is to work with others and may well designate others to carry out the work of music preparation.
What do you think? Who should pick the music? How widespread should the consultation be? How do we best select music that meets the ritual, musical, and pastoral requirements of the liturgy?
Who Prepares the Music for the Liturgy?
119. Preparation for the celebration of the Sacred Liturgy, and particularly for the selection of what is to be sung at the Liturgy is ultimately the responsibility of the pastor and of the priest who will celebrate the Mass [See GIRM, no. 111]. At the same time, “in planning the celebration of Mass, [the priest] should have in mind the common spiritual good of the people of God, rather than his own inclinations.” [GIRM, no. 352]
120. In order that there “be harmony and diligence in the effective preparation of each liturgical celebration in accord with the Missal and other liturgical books,” [GIRM, no. 111] the pastor may designate that the director of music or a Liturgy or music committee meet regularly to make the preparations necessary for a good use of the available liturgical and musical options.
121. When a Liturgy or music committee is chosen to prepare music for the Liturgy, it should include persons with the knowledge and artistic skills needed in celebration: men and women trained in Catholic theology, Liturgy, and liturgical music and familiar with current resources in these areas. It is always good to include as consultants some members of the worshiping assembly so that their perspective is represented.