How to indicate divisi with specific uneven players

Question

My prior understanding was that when writing divisi with strings, the number you specified with “a[x]” indicated the number of players per divisi section; i.e., “div. a8” = 8 players on this line, etc. Example (two-staff 24-player Vln. I section):

Since then I’ve learned this is woefully incorrect, and that the a[x] simply specifies how many different subsections to divide the main section into. In that case, how do you write it if you want a specific number of musicians to play each line (such as 16/8 as in the above example)? Is there a particular convention, or would you just write “div. (16 players)” or similar?

EDIT: Searching through my scores collection more, I found this (excerpt from “9M49-Fawlkes 20j”, Harry Potter and the Half-Blood Prince, by Nicholas Hooper):

This is a two-staff Violin I section; as you can see, it starts with all 24 players playing unisoni on the first staff, then splits into a2 with each section receiving 12 players, and the player numbers are clearly marked. This way makes it easy to identify how many players you want per staff, so I could just write “16 players” and “8 players” on each respective divisi staff.

Anyone have any thoughts, objections, or better ideas?

Answer 1

As Kilan points out, absolute numbers are not used for good reason - no ensemble will exactly match the requirements. I see two possible solutions, since what you attempt is a sort of dynamic balancing:

1. You divide into three groups and give two of them the identical first voice.
2. You keep the two groups and adjust the dynamic specifications, so the second is always a step below the first (mf instead of f, p instead of mp)

Answer 2

In your comment you said this was for the entire piece. Just write a note on the first page saying "Violin 1 should have twice as many players as Violin 2". There is no need to say "approximately twice as many". If a small orchestra has 10 violinists they will figure out whether the piece works best for them if they split 6:4 or 7:3.

Actually it's an unusual request, since there is not much difference in sound level between say 6 violins and 12 violins. The performers and conductor might end up wondering why the composer wanted this.

A more common request is to split off a specified number of players from a larger group, which is shown by "1 solo", "4 soli", etc. Note the "1" in "1 solo" is required - just writing "solo" means "everybody plays this as if it was a solo part." If the group divides into "soloists" and the "everybody else" the part for "everybody else" is labeled "gli altri" (which is Italian for "everybody else", amazingly enough).

Writing double note heads is wrong. It means each player should play the two unison notes as a double stop on two strings at once. That is very rare except when one of the strings is an open string, simply because it is hard to play.

If you want a good collection of examples of how to notate this sort of thing, get a score of Stravinsky's "Rite of Spring" which is notorious for having the string section divided up every which way at different times.

Answer 3

@Walter If you want to divide the 1st violin section in two groups of 16 and 8 violin players then you have indirectly said that it is a prerequisite for this piecec to be played that the orchestra has 24 violin players in the 1st violin group. That is a lot.

Well, if that is what you want then it is what you want, but it means that your music can only be played by an orchestra of that size. So in this case you just write a note that you want 16 players to play one part of the divisi and 8 players to play the other part.

But if the music can be played by orchestras of different sizes you could write a note that you want 2/3 of the 1st violin group to play one part of the divisi and 1/3 to play the other part.

EDIT: The suggestion in your edit looks fine.