Divided or .... separated?

In general, if the language is very contrapuntal and various crossings of the divided parts occur, it is certainly advisable to dedicate one staff for the 2 parts.

If the 2 parts are independent and often become the melody or counter-melody of one another, a separation makes sense. For example, you would have a choir with Sopranos I and II, Altos, Tenors, and Basses. Practically 5 parts.

In the case of chords, even if frequent, I would keep the divisi on a single staff.

In the case of triads for a single section (you are talking about Basses), watch out for the balance of the choir in relation to the dynamics. Divisi reduce sound power. Three sounds divide the basses into 3. On average, it is already quite a lot if a choir has 4 basses, say 6? Practically you have 2 singers for every note. Each note of the three parts could be supported by 6 singers. A choice to be used judiciously.

I forgot, I don't think the "a capocchia" [random/at random] case is contemplated

Eagle wrote:

In the case of chords, although frequent, I would keep the divisi on a single staff.

In the case of Trichords for a single section (you are talking about Basses), watch out for the balance of the choir in relation to the dynamics. Divisi reduce sound power. Three sounds divide the basses into 3. On average, it is already a lot if a choir has 4 basses, let's say 6? Practically you have 2 singers for every note. Each note of the three parts could be supported by 6 singers. A choice to be used judiciously.

thanks Eagle.

Well, I also wanted to mention this problem. In effect, it's not that trichords might be too frequent, but even bicords have an impact on sound power, which in the case of the basses is an additional problem. In general, is there a criterion to say what the proportions should be, for example between Sop. I and Sop. II? I mean, a priori I don't know how many elements the choir sections will consist of, but I imagine that in a divisi it is split in half. If I deemed it appropriate to indicate, for example, that for the low note of a Sop. divisi I want to assign 2/3 of the elements (for example to give it greater dynamics compared to the high note), is there a criterion for doing so or must I write it explicitly?

If the parts are not balanced, write the desiderata in the title page, which is to say the precise instrumentation of the choir, including the proportions or the number of choristers.

Of course, if you already know that the piece is heavy on the basses, it is better to write it for 5 parts: S C T BI and BII, a bit like what is done in an orchestra where the violin lines are typically 2.

I think it is a choice; once made, one acts accordingly. After all, the instrumentation is one of the first choices.

regarding the balance of sections, if we are talking about an a cappella piece, the ideal is that there is always the same number of voices for each section. Accompanied pieces allow for greater freedom to decrease the number of bass and inner voices, which consequently means that, generally, the section in which one is authorized to increase voices is always the melodic section, which in the repertoire is the treble section 99% of the time.

The division of parts should also follow some of these logics. If I write a piece for SATB, I take for granted that the number of voices per section is equal. If I divide the basses into 3, first of all, I am saying that I would want a choir of at least 36 people (...). Since this number is not low, then much more often that division into 3 is done considering basses and tenors as a single section to be divided into 4, so that there are first tenors, second tenors/baritones, first basses, and second basses. Let's hypothesize having 5 tenors and 5 basses; it could be divided with 3 first tenors, 2 second tenors + 1 baritone, two first basses, two second basses. Everything would have to be adapted to the voices available, but generally, the second bass parts can be sung by fewer voices.

I add a possibility that is by no means rare: if the internal division within the section corresponds to a VERY different text articulation, then it would be good practice to divide the staves...

Thanks also to Dante and Thallo.

Distributing among the parts seems right to me, but there are cases that are somewhat borderline.
For example, let's say I have an F trichord in the bass; I can divide F and A to the basses, but the C is a bit borderline for the tenors. So I imagine that the specific situation must be evaluated.

Let's say we have a solo passage, without the upper parts. In itself, even just the divided basses could sing it, even if they are few in number (obviously there must be at least 3).

The issue for me becomes complicated here regarding how to define the dynamics relative to the rest of the piece. I mean, if I write a pp on the bass part, how much do they sing together? This will not be the same pp as when they sing divided, and even less so when they sing a trichord divided (moreover, a pp is not simply an f with a lower volume). It's not that I can call another choir to have additional basses sing for 3 measures, just as I don't know if it is appropriate in the text to indicate a separate part that only has a few measures.

Is this something that takes care of itself, or must it be managed somehow?
All this might be an exaggeration, but since I am constantly being prompted regarding the intelligibility of the text, I am trying to do my best.

Is there the possibility of writing "Only".

First of all, I would keep in mind the fact that unlike orchestral instrumentalists, choristers do not have parts but rather the full score. Therefore, the more intricate the score is, the more difficult its eventual reading will be.

An agreement divided into 3 voices has never killed anyone, especially in pp; furthermore, in Bianca's example, no one knows if they will sing alone (these 3 basses) or if they will have to support another 9 voices. More than anything, however, it is necessary to understand which note an eventual ff reaches. To be clear, a Eb two octaves below middle C is a bass on 100 and cannot sing f.

There is cooperation between sections; if the soprano does not have a B in their range, they can be paired with the contraltos (the same for tenors with basses), etc.

The important thing is to respect the balances

Returning to the score, there may also be graphic requirements, for which one opts for an additional staff despite a divisi being helpful. As Faria reminds us, to reduce the "volume" to the absolute minimum, there is the ppp of the solo.

3 solos in ppp form an agreement in ppp. Can it be done? Of course, if they are alone; if the text requires this sonority, yes, so it is a desired and achievable effect, yes. Etc.

That being said, following general guidelines is always fine, but there cannot be a precise rule that always applies. Talking about dynamics is already a small step towards obtaining a more carefully crafted score; it contributes to clarifying the musical design.

My experience as a choir conductor teaches me that it is better for the parts to be divided even if they sing the same notes for certain passages.

For a choir member, always reading on their own staff is much easier than reading on different staves or reading "THEIR" part in the middle of two others on the same staff.

With current notation programs, it is very easy and fast, and it guarantees evident advantages for the choir.

rstrauss wrote:

My experience as a choir director teaches me that it is better for the parts to be divided even if they sing the same notes for certain passages. For a chorister, always reading on their own staff is much easier than reading on different staves or reading "THEIR" part in the middle of two others on the same staff. With current notation software, it is very easy and fast, and it guarantees evident advantages for the choir.

in effect, that was also somewhat the idea I was forming myself.

Besides Bianca's example, no one knows if they will sing alone (these 3 basses) or if they will have to support another 9 voices.

in my example I was saying basses alone, just to simplify things, but it is only an example

it is an example that holds up, however. If you then have a need for timbre texture, and we are still talking about a piano dynamic, then the tenors can even sing a low C for you. In general, consider one thing, though: if you find a good solution yourself and write it in the score, then you have the certainty of having checked the rendering to the last detail; if you don't find the solution yourself, and therefore write nothing in the score except the triad in the bass, then that problem will be resolved somehow by the choir director who will have that score in hand. How should I put it, one way or another, the problem gets resolved