Ah, GIRM 313 -- Don't put the organ in the hallway.

To the OP, yes, absolutely. Especially in the Magisterium of Pius XII and beyond.

the pipes may be in the main body of the church

...along with the other "lawfully approved instruments" such as the tambourines, guitars, kazoos, snare drums, and crows, in the mind of the Church.

Let’s not forget the cymbals. They’re in the Bible, after all.

ryand - Indeed 'Praise the Lord with the clashing of cymbals'. But probably not while the priest was in the Holy of Holies. I don't know of any detailed description, but Luke 1:10&21 don't suggest that the crowd was tired of singing, rather of attentive waiting. I would welcome cymbals, in some outdoor processions.

I figured "crow" was the singer whose voice resembles a crow.

I figured "crow" was the singer whose voice resembles a crow.

DING DING DING.....winner winner chicken dinner!!

whether the expectation is that the organ will play its own part, or that it will merely function as an accompaniment for voices. I think the expectation is different in the praxis of the OF and the praxis of the EF

When I was trained ('63-'69) in 'church organ,' it was understood that the organ could be played independent of singing--thus such pieces titled "Preludium", "Offertorium", "Communio", and "Postludium" were part and parcel of organ-music collections. (NOT true for Advent and Lent, of course.)

That was true for Missa Cantata and Missa Lecta. By praxis in this area, that hasn't changed--except for the compulsive ORGAN IS GOOD!!! playing during Lent at OF Masses.

Accompaniment in Church documents doesn't necessarily mean what we musicians think of. I would refer you to nos. 15-18 of Tra le sollecitudini, where it should be clear that voluntaries, improvisations, or interludes are referred to, and alternatim practice elsewhere in the documents. Note that these have a permissive rather than prescriptive character, but I believe there is actually a rubric requiring the playing of the organ at the intonation of the Gloria on Holy Thursday and at the Easter Vigil.

Feria V in Cena Domini, Missale romanum, 1960:

incipit solemniter Gloria in excelsis, et pulsantur campanae et organum, quae, expleto hymno, silent usque ad Vigiliam paschalem.

I use the organ for accompaniment, only, during OF masses for most of Lent. On the infamous "Pink Sunday," I will play interludes during communion, maybe offertory. Postludes return at the Easter Vigil. A bit of silence is a good thing.

My experience with the EF folks is that they do as they please, make up all kinds of reasons to justify it, then criticize the OF folks for not following the rules.

None whatsoever. Just observation and experience.

You realize I am only referring the nuts in my area, not the nuts in yours. I have no idea what yours do.

They make their own enemies.

No, I just hope those nuts never unite. Ecumenism would be the death of us all.

Credo, which must be entirely sung

True I think, but a counterreformation novelty, to judge by Cavazzoni's organ verses and alternatim polyphony such as Isaac's.

The rubrics AFAIK never say the organ must be played, it is always potest pulsari - it is possible/allowed to be played. In Chapter 28 of the Ceremoniale Episcoporum(1948) it sometimes says it is customary at certain times to play the organ, and modern texts continue to emphasise that the organ is to be held in high esteem.
In the rubrics one never sees the solecism "the organ will play".

...until everything was thrown into confusion in a major way circa 1969 but brewing since the late 1940s.

Hence, we MUST refer back as the errors of modernism were subtly weaved into the newer documents on music, and then we see that the later give way to unabashed novelty.

I see the Motu of 1904 as one of the most significant and clearly stated guidelines on Musica Sacra. Correct me if I am wrong, but what moving forward from there brings any more clarity to the pursuit of the craft?

The Missal rubrics are concerned almost exclusively with instructions for the ministers. The music gets little more than a passing mention. Nearly all the customs of the church are set out in these other books. Fortescue said -

OBVIOUSLY the first source of all for a book on Ceremonies is the liturgical books themselves, the rubrics of the Missal, Breviary, Pontifical, Ritual and Caerimoniale Episcoporum, then the Memoriale Rituum of Benedict XIII, the Instructio Clementina, for the Forty Hours, our own Ritus Servandus for Benediction and Exposition of the Blessed Sacrament.

@dad29 - To my knowledge the CE is the only liturgical book that spends any time dealing with the use of the organ. The rest - like a great deal of the liturgy - is the work of commentators and rubricists, whose directions are worth whatever they are worth - a whole subject in itself, much like the "common opinion of theologians" vis-a-vis the wholly separate subject of dogmatic theology. Thanks to @a_f_hawkins for the reference here implying, I think, the foregoing.

@francis - agree wholeheartedly with the authority of the 1903 motu - hard to imagine that anything subsequent added much more. Interesting tidbit - when the 1958 instruction permits the use of women singers it cites two SRC decrees as authority for its decision that decided precisely the opposite. Such a glaring error raises questions about the whole document.

Disclaimer: I don't want to fight with anyone about this particular point, or about the 1958 document. The observation is offered as food for thought, and an interest item. I have had enough flack over other posts elsewhere in this forum! (And I'm saving my energy to keep my immune system up to dealing with COVID!)

@Richard Mix - I have no knowledge of the organ composition (and concede the point, if there is evidence extant of alternating organ compositions as was envisioned for the gloria, etc.), but could not the polyphony have been intended to alternate with the Gregorian, like so many settings of the magnificat and benedictus deus?

@CharlesW - fair enough, but I wonder if the diversity to which you refer, which I acknowledge, is so diverse as to make pre-Trent practice not useful as a tool of legislative interpretation. Example: (and I don't want to fight about this either: it's an academic point, not [yet] a critical one) in many instances over the years, the SRC expressly provided, consistently with Pius X's motu, that the Sanctus was to be sung before the consecration, exclusive of the Benedictus, which was to be sung after the elevation. In 1961 (if not before - I haven't checked; perhaps it was 1958) the rubrics were changed to mandate that the Sanctus and Benedictus be sung together, unless the lengthy polyphony required them to be split (again, this may be from 1958). Why, I wonder, would the SRC have been so consistent and definitive in holding the line in the face of several rescripts submitted from various places and at various times? What could the pre-Trent practice, in basically the first millennium of Christian worship, tell us that would explain why this decision was adhered to so consistently? (And how, then, would / could we evaluate the change - in other words, following standard canons of statutory construction / interpretation, if we knew the "why" for the original law, we could understand if or why that original "why" no longer applied, and thus better appreciate the legitimacy of what might otherwise seem [as - full disclosure - it seems to me] a purely arbitrary change for the sake of change).

I note that the Messe Greque de Saint Denis has organ/choir alternatim throughout except for the Symbolum where they split into two choirs. (Several copies on the internet here for example.) I don't know whether it is a guide to typical usage, of course, but because it is an oddity it is carefully recorded. And because it is an oddity, it would probably not have been altered to conform to later usage.

SRC Dubium 2682 ad 31.

31. Ubi cantus Chori non producitur usque ad elevationem Hostiae, Benedictus qui venit etc. cantarine debet post elevationem; an immediate post primum Hosanna in excelsis?
cantari debet post calicis elevationem

That suggests to me that the choir could sing the Benedictus beofre the Elevation, if they have time.

I should have added the date, Dubium 2682 was answered on 12 Nov 1831. I was not looking for the change, but to find the long established custom.

Also the Pustet 1871 Gradual, which had official force.

Finita Præfatione chorus prosequitur Sanctus etc. usque ad Benedictus exclusive.

I wonder why this clear rule was omitted from the 1908 Gradual. Perhaps Solesmes wanted to change the rule, but were just trying to slip it past SRC unmentioned. They did not even put a double bar before 'Benedictus ', whereas Pustet starts a new line.
No doubt there is at least one treatise on the subject.

Why, I wonder, would the SRC have been so consistent and definitive in holding the line in the face ..., if we knew the "why" for the original law, we could understand if or why that original "why" no longer applied, and thus better appreciate the legitimacy of ...

Holding the line was what SRC did, that was why the Pian Commission was set up to work in complete secrecy, Pius XII wanted to present SRC with Papal fait accompli.
Perhaps Solesmes thought the practice of splitting was an unwarrented post-medieval imposition of polyphonic practice on the chant, and were eventually shown to be right?
I have been trying to recall what we did at school 1949-1955, I think we carried straight on from Sanctus to Benedictus, but then - it was a Benedictine school.

that was why the Pian Commission was set up to work in complete secrecy, Pius XII wanted to present SRC with Papal fait accompli.

elaborate, please.