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Screen illumination
For 35 mm presentations, screen luminance at the center of the screen should be 16 fL +2 fL. Screen luminance at the edges of the screen (5 percent in from each edge) should not be less than 75 percent of the center. The distribution of the screen illumination should be evenly dispersed and symmetrical about the geometric center of the screen, and no portion of the illuminated area should be less than 10 fL. The white point image on the screen should be 5,400 degrees Kelvin, +600 degrees, –200 degrees. (Reference: SMPTE RP 98-1995, ANSI/SMPTE 196M-1995)
Server
See Digital cinema playback system.
Show
A term referring to a complete digital cinema presentation. This could include movie trailers, cinema advertising, and feature films. A show is assembled on the digital cinema playback system by selecting the desired pieces of content, called “clips,” and setting the running order. On some systems, shows can be scheduled for automatic playback at specific times, or can be triggered externally by an existing automation system.
SMPTE
Society of Motion Picture and Television Engineers. An international body creating standards for the motion picture and television industries.
Speaker
A device that converts electrical signals to sound. Not the same as a channel; a channel may have any number of speakers, all receiving the same signal.
SPL (sound pressure level)
A measure of the loudness of sound at a particular point in an auditorium. All cinemas and mixing studios are aligned to the same SPL to ensure the audience hears the film soundtrack at the level the director intended.
Stems
Final-stage premixes, fully balanced and positioned, which still contain the individual elements (music, dialogue, and effects) separately. Stems are combined to produce the final printing master and other delivery requirements.
Stereo
Sound recording and reproduction by more than one (mono) channel. In home music reproduction, "stereo" came to mean two channels (left and right), while in the film industry, "stereo" is understood to include surround and center channels in addition to left and right. To avoid confusion, multichannel stereo is often referred to as "surround sound."
Stereo variable area (SVA)
A matrixed stereo optical soundtrack used in the Dolby analog formats. The variable area for each matrixed track is used to change the amount of light passing through the film to the soundhead on the projector. Two independent variable tracks are used for the Lt and Rt signals, which are then decoded to become Left, Center, Right, and Surround channels.
Subwoofer
A loudspeaker dedicated to reproducing very low bass. Dolby Digital soundtracks provide a separate low-frequency effects (LFE) channel specifically for playback over subwoofers.
Surround Sound
The key home theater technology. Surround sound consists of four to eight channels, with the speakers surrounding the listening area.
Surround sound
The reproduction of ambience, atmospheres, and occasional special effects that are recorded on one or more dedicated channels, and played through speakers placed along the sides and rear of the auditorium to surround the audience.
Surround Speakers
Side and back speakers that create the depth and ambience of a soundtrack or recording. These are the speakers that put you in the middle of the action.
THX
A technical specification for the entire playback environment (picture and sound) regardless of film format.
Terminal Adapter (TA)
The Terminal Adapter is a device or modem which connects to the ISDN lines. The TA formats the data into the correct format and originates the dialing and signaling required by the ISDN network
THX
A trademark identifying compliance with the playback performance parameters of Lucasfilm THX for commercial and home theatre sound systems. THX develops standards for the playback environment, regardless of film format. THX-certified theatres use professional Dolby cinema processors for playing Dolby soundtracks (which is why both logos can appear on the same cinema marquee), and THX-licensed home theater systems are based on Dolby Surround Pro Logic and Dolby Digital decoding.
UPS
Uninterruptible power supply. A power conditioning device that is required for digital cinema playback systems with insufficient onboard electrical protection.
User interface
The way in which a user can control a device. Digital cinema playback systems sometimes offer different controls optimized for different uses (for example, illuminated keys for use by the projectionist during a show, or a screen and mouse for show setup).
Variable area
The technical term for the analog optical soundtrack whose width varies with the sound. A Dolby analog optical soundtrack sometimes is referred to as an SVA track, for "stereo variable area." An earlier type of optical track, variable density, varied the track's photographic shading (rather than its width) with the sound.
X-curve
A standard replay characteristic that makes it possible for cinemas of different sizes to sound similar by compensating for the different reverberation characteristics.
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