A big band is a type of musical ensemble associated with playing jazz music and which became popular during the Swing Era from the early 1930s until the late 1940s. A big band typically consists of approximately 12 to 25 musicians and contains saxophones, trumpets, trombones, and a rhythm section. The terms jazz band, jazz ensemble, stage band, jazz orchestra, and dance band are also used to refer to this type of ensemble. This does not, however, mean that each one of these names is technically correct for naming a 'big band" specifically.
In contrast to smaller jazz combos, in which most of the music is improvised, or created spontaneously, music played by big bands is highly "arranged", or prepared in advance and notated on sheet music. The music is traditionally called 'charts'. Improvised solos may be played only when called for by the arranger.
