A concert is a live performance of music in front of an audience. The performance may be by a single musician, sometimes then called a recital, or by a musical ensemble, such as an orchestra, a choir, or a musical band. Concerts are held in a wide variety and size of settings, from private houses and small nightclubs, dedicated concert halls, entertainment centres and parks to large multipurpose buildings, and even sports stadiums. Indoor concerts held in the largest venues are sometimes called "arena concerts" or "amphitheatre concerts". Regardless of the venue, musicians usually perform on a stage. Concerts often require live event support with professional audio equipment. Before recorded music, concerts would provide the only opportunity one would generally have to hear musicians play. Informal names for a concert include "show" and "gig".