. SAB is a common combination for smaller choirs, who'll typically have many more women than men. Usually found on choir
music, indicating which voices the piece is arranged for. (cf: SSA
) Commonly a piece will have multiple arrangements appropriate for different groups - sometimes in different keys and with the melody in different voices to accommodate the different vocal ranges of the four voices, so choosing the correct one is very important.
Not to be confused with S/A/B, of course...