A movie theater (American English) or cinema (Commonwealth English), also known as a movie house, cinema hall, picture house, picture theater, the pictures, or simply theater, is a business that contains auditoriums for viewing films for public entertainment. Most are commercial operations catering to the general public, who attend by purchasing tickets. The film 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. Since the 2010s, the majority of movie theaters have been 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 cinemas, ranging from animated films to blockbusters to documentaries. The smallest movie theaters have a single viewing room with a single screen. In the 2010s, most movie theaters had multiple screens. The largest theater complexes, which are called multiplexes—a concept developed in Canada in the 1950s—have up to thirty screens. The audience members often sit on padded seats, which in most theaters are set on a sloped floor, with the highest part at the rear of the theater. Movie theaters often sell soft drinks, popcorn and candy, and some theaters sell hot fast food. In some jurisdictions, movie theaters can be licensed to sell alcoholic drinks.