A lot of choirs always stand in the same way, lining up from highest to lowest voice. However, this is not always the ideal formation. Other positions may be preferred for acoustic reasons or because they will make it easier for the singers to hear each other well.
The standard formation for classical choirs is from high to low. The highest soprano is standing on the far left and the lowest bass on the far right:
This formation is convenient in a lot of ways. It is easy to remember and the conductor will find the voice groups without effort. Furthermore, the female voice groups will hear each other well, and the same goes for the male voice groups.
However, this formation is not always ideal for a performance. In a concert hall, the high and low notes carry in different ways. High tones can be more easily placed by the audience than lower ones. (That’s why a sound system might have a single bass speaker in the middle and several small speakers surrounding the listener.) Thus, if you strive for a good stereo effect in the concert hall, it is better to put the higher voice groups at the side:
This setup has advantages in the rehearsals as well. All singers are able to hear the basses fairly well, and because they form the fundament of the harmonies, that is important for good intonation. Especially when there is a lack of men, this formation is a good idea.
Mixed
As soon as the singers know their parts, they don’t need the support of their voice group any more. The choir could then be positioned mixed:
In this formation, the choir members will be able to hear all parts equally well. This will make working on balance, blend and intonation easier. An extra advantage is that singers like to sing in this position.
The singers will hear each other even better, when standing in a full circle:
Two rows
Big choirs are mostly positioned in two or more rows, with the men behind the women, so all singers have a good view on the conductor:
A mixed formation for such a choir might be:
Fresh
Changing the positioning of a choir is refreshing. The choir members will hear different singers for a change, and they will hear a different balance in the harmonies. As a conductor, try to be creative in the formation of your choir!