Layout on stage of Choir

Layout on stage
There are various schools of thought regarding how the various sections should be arranged on stage. In symphonic choirs it is common (though by no means universal) to order the choir behind the orchestra from highest to lowest voices from left to right, corresponding to the typical string layout. Since 2000 several choirs introduced the historic layout of the 17th –19th century with the choir in front of the orchestra, so the American North Penn High School Concert Choir [1], the Canadian Tafelmusik Chamber Choir, the German Kreuznacher-Diakonie-Kantorei and the French Chapelle Rhénane. In a cappella or piano-accompanied situations it is not unusual for the men to be in the back and the women in front; some conductors prefer to place the basses behind the sopranos, arguing that the outer voices need to tune to each other.
More experienced choirs often sing with the voices all mixed together. Proponents of this method argue that it makes it easier for each individual singer to hear and tune to the other parts, but it requires more independence from each singer. Opponents argue that this method loses the spatial separation of individual voice lines, an otherwise valuable feature for the audience, and that it eliminates sectional resonance, which lessens the effective volume of the chorus.
For music with double (or multiple) choirs, usually the members of each choir are together, sometimes significantly separated, especially in performances of 16th-century music. Some composers actually specify that choirs should be separated, such as in Benjamin Britten's War Requiem.
Consideration is also given to the spacing of the singers. Studies have found that not only the actual formation, but the amount of space (both laterally and circumambiently) affect the perception of sound by choristers and auditors.[2]

Refer to http://en.wikipedia.org/wiki/Choir