The open-air Cavea, named after the great Maestro Luciano Berio, is the heart of the Auditorium's architectural complex, with the dual function of a piazza, a meeting place and an amphitheater for outdoor performances. It is shaped as a semicircle and is divided into two parts: a lower paved part giving access to the foyers, and an upper tiered part for the audience.

The theatre square, entirely paved in travertine marble, is the Auditorium's most versatile space, as it has a dual function: an exhibition area covering 560 square metres, suitable for presenting new products, or an arena for 3,737 seated people, or 5,128 standing. Its semi-elliptical configuration on two levels takes advantage of the natural height difference of 10 metres to provide an unsurpassed example of acoustics. The Cavea of the Auditorium can easily adapt its configuration to any requirement: Festa del Cinema di Roma (Rome Film Festival) it hosts the Red Carpet, while during the summer season it is the stage for the Roma Summer Fest, a two-month concert series featuring leading rock, jazz and pop musicians and exponents of the Italian and international art music scene take to the stage.