A jazz club is a venue where the primary entertainment is the performance of live jazz music, although some jazz clubs primarily focus on the study and/or promotion of jazz-music. Jazz clubs are usually a type of nightclub or bar, which is licensed to sell alcoholic beverages. Jazz clubs were in large rooms in the eras of Orchestral jazz and big band jazz, when bands were large and often augmented by a string section. Large rooms were also more common in the Swing era, because at that time, jazz was popular as a dance music, so the dancers needed space to move. With the transition to 1940s-era styles like Bebop and later styles such as soul jazz, small combos of musicians such as quartets and trios were mostly used, and the music became more of a music to listen to, rather than a form of d