A typical projector system. This one originally had built-in mono sound (the panel at the top of the console) but that part is no longer used. Instead, this screen now has a separate center/surround/subwoofer sound system.
Screen #1 has seven-channel digital sound (left, center, right, subwoofer, left surround, right surround, rear surround) based around a DTS 6AD Cinema Processor. These are the power amplifiers. The sound runs on CDs that are sync'd with the film by a control track that is read optically by a digital reader mounted on top of the projector.
As a backup for the digital sound, all films still have the traditional four-channel analog soundtrack, which is also read optically by an analog reader soundhead mounted beneath the projector. Digital sound effectively comes after the picture (the frame being projected is IN the projector, the digital sound code is on top ABOVE the projector), while analog sound is ahead of the picture (the frame is in the projector, the sound code is below it).
Screen #3 has six-channel digital sound based around an older DTS processor. DTS Processors are basically a PC customized to follow the film's sync code for running the (SCSI) CD drives and outputting the sound signal. I think the original released model was a 16 MHz 386-SX computer. They're much more powerful nowadays.
The projector light source is a high-pressure Xenon-filled arc lamp. The lamphouses are 3-phase with an AC-to-DC power rectifier to run the bulb. Typical bulb life is around 2000 hrs of running time. They sometimes explode if they get unstable or are pushed too far beyond reasonable/safe operating time. Bulb explosions cause damage to the mirrors and reflectors inside the lamphouse.
Film runs from outboard platters external to the projector. Films are still shipped on 2000'-capacity reels, which hold 20 minutes of film in running time. A 2-hr movie is six reels. The individual reels are loaded onto the platter when the film arrives, spliced end-to-end. Each reel includes a "head" and "tail" that identifies the reel number so they're assembled in proper order. The platter works somewhat like an 8-track tape, feeding from the middle of one disc and wrapping around the take-up ring on another. Each disc can be used for either feed-out or take-up, so the film is simply run back and forth from one disc to another. There are 3 discs so as to leave one available for making-up the next film when it arrives, or for running two films on one screen for a double- or split-feature.
This view shows another platter with the top disc for take-up and middle for feed-out. The blue table in the background is used to load the individual reels onto the platter, or to unload them when the film is ready to ship out. When loading ONTO the platter, the reel free-spins on the table and the platter pulls the film. When unloading, the platter disc is disengaged from its drive motor and the table pulls the film off onto the reel.
Here's another view. The film runs through a swing-arm in the center of the feed-out disc that controls the platter drive motor so it keeps up with how fast the projector is pulling the film through. There is NO direct tension on the film on the feed-out side. On front of the platter support post there's a carriage that rides up-down (and provides take-up tension) and is mechanically attached to a variac (speed controller) beneath the lower disc, which sync's the take-up speed with the projector. Thus, the film itself controls the platter. The platter and projector are not electrically connected to each other.
Screen #1 has seven-channel digital sound (left, center, right, subwoofer, left surround, right surround, rear surround) based around a DTS 6AD Cinema Processor. These are the power amplifiers. The sound runs on CDs that are sync'd with the film by a control track that is read optically by a digital reader mounted on top of the projector.
As a backup for the digital sound, all films still have the traditional four-channel analog soundtrack, which is also read optically by an analog reader soundhead mounted beneath the projector. Digital sound effectively comes after the picture (the frame being projected is IN the projector, the digital sound code is on top ABOVE the projector), while analog sound is ahead of the picture (the frame is in the projector, the sound code is below it).
Screen #3 has six-channel digital sound based around an older DTS processor. DTS Processors are basically a PC customized to follow the film's sync code for running the (SCSI) CD drives and outputting the sound signal. I think the original released model was a 16 MHz 386-SX computer. They're much more powerful nowadays.
The projector light source is a high-pressure Xenon-filled arc lamp. The lamphouses are 3-phase with an AC-to-DC power rectifier to run the bulb. Typical bulb life is around 2000 hrs of running time. They sometimes explode if they get unstable or are pushed too far beyond reasonable/safe operating time. Bulb explosions cause damage to the mirrors and reflectors inside the lamphouse.
Film runs from outboard platters external to the projector. Films are still shipped on 2000'-capacity reels, which hold 20 minutes of film in running time. A 2-hr movie is six reels. The individual reels are loaded onto the platter when the film arrives, spliced end-to-end. Each reel includes a "head" and "tail" that identifies the reel number so they're assembled in proper order. The platter works somewhat like an 8-track tape, feeding from the middle of one disc and wrapping around the take-up ring on another. Each disc can be used for either feed-out or take-up, so the film is simply run back and forth from one disc to another. There are 3 discs so as to leave one available for making-up the next film when it arrives, or for running two films on one screen for a double- or split-feature.
This view shows another platter with the top disc for take-up and middle for feed-out. The blue table in the background is used to load the individual reels onto the platter, or to unload them when the film is ready to ship out. When loading ONTO the platter, the reel free-spins on the table and the platter pulls the film. When unloading, the platter disc is disengaged from its drive motor and the table pulls the film off onto the reel.
Here's another view. The film runs through a swing-arm in the center of the feed-out disc that controls the platter drive motor so it keeps up with how fast the projector is pulling the film through. There is NO direct tension on the film on the feed-out side. On front of the platter support post there's a carriage that rides up-down (and provides take-up tension) and is mechanically attached to a variac (speed controller) beneath the lower disc, which sync's the take-up speed with the projector. Thus, the film itself controls the platter. The platter and projector are not electrically connected to each other.
