A movie theater or movie theatre (also called a cinema, movie house, film house, film theater or picture house) is a venue, usually a building, that contains an auditorium for viewing movies (films) for entertainment. Most, but not all, movie theaters are commercial operations catering to the general public, who attend by purchasing a ticket. Some movie theaters are operated by non-profit organizations or societies which charge members a membership fee to view films. The movie is projected with a movie projector onto a large projection screen at the front of the auditorium while the dialogue, sounds and music are played through a number of wall-mounted speakers. Since the 1970s, subwoofers have been used for low-pitched sounds. In the 2010s, most movie theaters are equipped for digital cinema projection, removing the need to create and transport a physical film print on a heavy reel. A great variety of films are shown at movie theaters, ranging from animated films for children, blockbusters for general audiences and documentaries for patrons who are interested in non-fiction topics. The smallest movie theaters have a single viewing room with a single screen. Most movie theaters have multiple screens. The largest theater complexes, which are called multiplexes, have up to 25 screens. The audience members typically sit on padded seats which in most theaters are set up on a sloped floor, with the highest part at the rear of the theater. Movie theaters typically sell soft drinks, popcorn and candy and some theaters also sell hot fast food. In some jurisdictions, movie theaters are licensed to sell alcoholic drinks.