The debate here is between my strongly-held belief in what the assembly must sing and those who believe these parts may be sung by the schola on behalf of the congregation.
NorthernTenor wrote:Clearly, the Church is directing us to a middle ground, in which the polyphonic repertoire is upheld by choirs capable of it, so long as there are sufficient occasions for the rest of the parish to sing and know the chant.
It is not a case of "sufficient occasions" but "specific occasions". Consider these:
GIRM 1975 [¶55b]: "Joining with the angels,
the congregation sings or recites the Sanctus. This acclamation is an intrinsic part of the eucharistic prayer and
all the people join with the priest in
singing or reciting it."
GIRM 1975 [¶169]: "The preface is said by the principal celebrant alone;
the Sanctus is sung or recited by all the concelebrants
with the congregation and the choir."
Celebrating the Mass[¶192]: “In this acclamation
the assembly joins its voice to that of all creation in giving glory to God, with words inspired by the vision of Isaiah (6:3).
Celebrating the Mass[¶192]: Settings of the Sanctus Acclamation, together with Memorial Acclamations and Amen should form a unity which reflects the unity of the whole Eucharistic Prayer.
Take away this bedrock of practice, and suddenly you don't have to sing
Hosanna on Passion Sunday,
Venite adoremus at the procession of the Cross on Good Friday or
Alleluia at the Easter Vigil. These are cultic items with a specific functionality – give these items to the choir and you change that functionality and, arguably, the whole nature of the rite.
NT suggests that these instructions leave room for manoeuvre. If so, where does that leave us with instructions on maintaining Gregorian Chant?
But it's about more than following rules. A good liturgical musician can
feel why certain texts should be sung by the assembly. A poor one will simply hand things over to the choir when the going gets tough.
And, please, note, I am not discussing or favouring specific genres or styles here: I am simply explaining the philosophy with which we old gits grew up.
NorthernTenor wrote:if the setting goes with other elements of the sung Ordinary, it's a reasonable choice.
No it isn't. The item in question is the
Agnus Dei. Its specific function is to accompany the breaking of the bread. This rite has become so short these days that the litany has been reduced to two or three invocations ending have
mercy on us and
grant us peace. To shift the
Agnus Dei to communion because, to quote NT, it "goes with other elements of the sung Ordinary" is an example of rite serving music rather than music serving rite.
One final point before my next coffee – because I am not yet quite awake – given how many thousands of items of polyphony there are available for the choir, and given that there are five or six opportunities to sing from this repertoire in any Mass, why would you want to take from the assembly those three or four items which
Sacrosanctum Concilium describes as "rightly theirs".