Extensive soundproofing With the advent of electric lights, enclosed stages were built in Hollywood and rapidly converted to sound stages with many
mattresses placed on the walls. With the coming of the
talkies in the late 1920s, it became necessary to enclose and fully
soundproof these stages to eliminate noise and distractions from outside, including limiting access. The
ceilings and
walls of the building containing the sound stage must be heavily soundproofed, so the structure must be sturdy and capable of accepting such additional features and loads, or a new building specifically designed with the features and to bear the loads is required, which often is the less expensive alternative to retrofitting an existing structure because of
engineering issues. Buildings without soundproofing still are referred to as silent stages and may be used where the dialogue and other sounds are recorded as a separate operation. This separate operation usually involves the principal actors doing synchronized
dialogue replacement voice recordings over a working cut of the film, specialized language actors doing a secondary language
dubbing or for the filming of special effects. A sound stage, unlike a silent stage, requires caution to avoid making noise anywhere within range of the audio recording equipment. Sound stages make filmmaking more efficient because they are less vulnerable to external noises which often interfere with
filming on location: car horns, aircraft, and emergency vehicle sirens. A sound stage traditionally has a large red light above or next to each exterior door. When the light starts blinking, it means
shooting is in progress. Anyone who opens the door at that point will introduce external sound and light and ruin the
take in progress. When a studio is home to multiple sound stages, they tend to all look alike from the outside: giant beige box-shaped buildings. Sound stages are marked on the exterior with large numbers to help distinguish them.
Enclosed stage An enclosed stage makes it easier for the crew of a production to design and build the
sets to exact specifications, precise scale, and detail. The art director of a production makes an
architectural plan and carpenters build it. On a film, the head
electrician is credited as the
gaffer and the assistant as the
best boy, regardless of gender. After a set is painted, the
set dresser furnishes it with everything that the
set designer, under the direction of the
art director, has selected for the interior. Another benefit of sound stages is that they can be rented on a long-term basis for television production. Permanent sets can be installed, properly lit, and used again and again. Filming on location means having to build or dress temporary sets and then strike them later.
Cameras, lights, catwalks, and walls On a sound stage, the camera may be placed exactly where the director wants it. Set walls can be easily moved as needed to get them out of the camera's way. This flexibility allows for a wide range of shots, such as graceful
tracking shots. Achieving the desired lighting is much easier because each stage has a metal framework with
catwalks and lights suspended from the
ceiling. This makes it easier for the
cinematographer to have the
grips position each flag or bounce and the
lighting technicians to position each light to get exactly the correct lighting for every shot. Sound stages allow for complete control over lighting, to the extent of filming nighttime scenes during the day and vice versa. In contrast, when filming on location in real-world buildings, professional lighting equipment must be placed on the floor where it will radiate heat energy and constantly get in the way, ceilings are short, and walls cannot be removed. As a practical matter, filming inside real buildings often means that multiple cast and crew members and a lot of expensive filmmaking equipment are all jammed together inside a tiny, hot and cluttered space. This may severely limit artistic choices.
Other benefits Filming on a sound stage offers several additional benefits over filming on location. At a well-run studio, the sound stage interior will have comfortable air conditioning and heating, and restrooms which are convenient and well maintained. If the sound stage is close to where most of the cast and crew already live, then their commute will be short and convenient. If the sound stage is also close to the
production company's office, then executives can easily visit the set to monitor the progress of production. ==Cameras, rentals, and special techniques==