A brief primer on how to sing the psalms:
356. Since the psalms are songs, whenever possible, they should be sung. The manner of singing them may be:
1. antiphonal, that is, two groups alternate singing the stanzas; the last stanza, the doxology is sung by both groups.
2. responsorial, that is, the antiphon is sung by all before and after each stanza and the stanzas are sung by a cantor.
3. direct, that is, the stanzas are sung without interruption by all, by a choir, or by a cantor.
The rubrics for each psalm in morning and evening prayer indicate a way for singing it; other ways may be used.
And indeed, as we get to the psalms in OCF 376ff, we’ll see that the psalms each have an indication, but that this indication is not required.
In the discussion on the propers at Pray Tell, the Chant Cafe and elsewhere, I think many musicians are missing the point. The focus is on singing the psalms as a primary repertoire of Christian worship. How psalms are sung: this is not an issue the liturgy needs to settle. Particular antiphons may or may not focus these musical pieces. In the Liturgy of the Hours, certainly, the psalms themselves are of primary importance. Whether the antiphon attached to Psalm 23 is “The Lord is my shepherd …” or “Remember me in your kingdom, Lord” doesn’t strike me as something as important as the Scriptural repertoire itself. The post-conciliar emphasis has been to sing Scriptures, especially the psalms–not to continue one particular way of rendering them or one particular repertoire at the expense of other alternatives.
If the Office of the Dead provides options for rendering the psalms, it would seem that the celebration of the Eucharist, too, can and should be open to alternate ways of rendering the psalms, be they sung at entrance, after the first reading, during Communion, or at other places.
Note that direct singing is a possibility, either by everyone or by a choir or by a solo voice. It’s good that a variety of approaches is provided for the many pastoral situations of the funeral rites. My own sense is that if people are accustomed to singing the psalms, they should do so. And if they are not, then they need not. But if people don’t sing the psalms or are unaccustomed to them, it is a point of formation for the Sunday and daily assemblies of worshipers.