These principals from the Catechism are applied in the following way at choral Masses at St. Anselm Abbey
A choir of voices or instruments has two roles in a Catholic Mass.
To lead the congregation in song during "the designated moments" of the Mass, which are the following:
the Opening Hymn or song, the Gloria, the Psalm Response, the Alleluia, the Holy, Holy, Holy, the Memorial Acclamation, the Amen, the Lamb of God. Note that full participation in music and spoken responses is everyone's responsibility, and we are encouraged to support and encourage one another by our own presence, attentiveness and good spirit. While the music for these parts of the Mass is generally contemporary in nature, care must be given not to remain "stuck" in any one small period of time (such as the 60's and 70's) in the Church's musical heritage which spans almost two millennia of history. The Saint Anselm College Choir continually updates its service music with an aim to expanding the musical horizons of our literate, educated congregations at St. Anselm. All the music meant to be sung is provided in printed format at each Mass, and there is frequent repetition to allow for greater familiarity with the music as the school year progresses.
The second role of a choir or organ or instruments is an offering to God of first-fruits of time and talents, and a ministry to the congregation seeking to provide appropriate music for prayer, reflection and meditation. The liturgy allows for such music before Mass, during the Offertory, during Communion and after the Dismissal (in place of a closing hymn). These musical offerings draw from the Church's rich musical heritage and ministers of music are encourage by the Church to develop their talents in the service of the liturgy. Organ music, instrumental music and choral works are offered not as mere entertainment or performances, but as a form of prayer which hopefully can move others to pray as well.
Song and music fulfill their function as signs in a manner all the more significant when they are "more closely connected...with the liturgical action," according to three principal criteria: beauty expressive of prayer, the unanimous participation of the assembly at the designated moments, and the solemn character of the celebration. In this way they participate in the purpose of the liturgical words and actions: the glory of God and the sanctification of the faithful:
How I wept, deeply moved by your hymns, songs, and the voices that echoed through your Church! What emotion I experienced in them! Those sounds flowed into my ears, distilling the truth in my heart. A feeling of devotion surged within me, and tears streamed down my face -- tears that did me good. (St. Augustine, Convessions 9:6, 14)
from the Catechism of the Catholic Church, # 1157: