At the time that St. Augustine wrote "Qui cantat, bis orat" -- he who sings prays twice, one could easily recognize how much the character itself of sacred music made it essentially different from a simple group singing or an elegant performance by an expert musician of the secular realm.
The conviction of the fact that prayer is doubled if sung instead of being recited was not based so much on the merits of human effort, but rather on the need to describe the numinous dimension within sacred music, its emotive and artistic aspects, inasmuch as it is an exchange between God, the Giver of every gift, and the response of love of the human being to the Lord's omnipotent love.A greater love will seek a higher quality and not just more abundant quantity, and this happens when the perseverance of an individual or a group has made progress in the musical realm and has experienced the beauty of its spiritual consolations.
...[SC] No. 10 clarifies that "the liturgy is the summit toward which the activity of the Church is directed." Hence the liturgy is precisely the source of the necessary strength for every apostolic work. Wherever the liturgy of the Church is left to chance, the lack of coherence in its fruits becomes evident.
...Beyond the challenges represented by personal or cultural preferences, the purpose of sacred music is always praise of God. The active participation of the assembly must be ordered to this end, so that the dignity of the liturgy is not compromised and the possibilities for an effective participation in divine worship are not darkened. Active participation does not exclude different levels of participation that, of themselves, indicate that "participation in the act" is not diminished by the fact that one might not be singing everything at every moment. Sacred music must be conformed to the liturgical texts and devotional music must be inspired in biblical or liturgical texts, taking care in every case not to hide the ecclesiological reality of the Church.
[JPII said] "The liturgy, like the Church, is intended to be hierarchical and polyphonic, respecting the different roles assigned by Christ and allowing all the different voices to blend in one great hymn of praise." Hence, in its expressions of religious faith, textual fidelity and measured dignity, sacred music must become a symbol of ecclesial communion.
...The character of sacred music is not diminished when it is simple, to the degree that its simplicity is noble rather than banal. The widespread use, though prohibited, of secular recorded music and "pop" songs in funerals justifies the distancing of many faithful, who feel themselves foreign to the musical life of the Church. "Cult" songs, doctrinally insipid, often take the place of liturgical treasures with catechetical value, with the effect that the culture of ecclesial music in many parishes has been "led down a blind alley in which one can say always less about its quo vadis" -- this is the way in which J. Ratzinger describes the separation of modern culture from its religious matrix
...It would be sad, however, if, because of the desire to understand everything, the use of Gregorian chant in the parishes were to be limited to the celebration in the "extraordinary form," thus relegating the ancient language of this chant to the history of the Church and to a symbol of polarization. Among the pastoral opportunities, it's not too much to ask that persons might have the experience of the universality of the Church at the local level, being able to sing the parts that correspond to them in Latin (cf. SC 54). This was the intention of the Fathers of the Council. With due moderation and pastoral sensitivity, this practice would be united harmonically to the rich expressions of the Catholic faith in the vernacular.
There's a lot there for church musicians and their pastors to think about.