The projection booth is located on the second floor of the Concession Stand. The booth has two Century 35mm Projectors (one for each screen). Screen 1 utilizes a 5000 watt Xenon lamp for illumination. Screen 2's lamp was upgraded from 5000 to 7000 watts in 2002. Both projectors use RCA optical stereo sound heads. The sound heads were upgraded in 2002 to the new "red laser" type to accommodate the new environmentally friendly film that is supposed to be used within the next two years. The sound is transmitted to your car radio over both AM and FM-Stereo transmitters, eliminating the need for pole mounted speakers.
New in 2003, we now use a CD player in addition to our tape player for the before the show and Intermission music. We subscribe to Drive-In Radio, which provides us with updated music on 2 CD's every 2 weeks. With the addition of a Mixer, we have the ability to make live or taped announcements to both screens simultaneously, or separately.
Unfortunately, we don't offer Projection Booth Tours anymore due to insurance requirements.
Screen 1 Projector and Platters on the left, Screen 2 Projector and Platters on the right.
Each projector is equipped with an automation controller (A) that monitors film travel speed, film breakage detection (B) and controls the Xenon lamp (C), the projector motor (D), the changeover douser (E), the sound output (F) and the exterior floodlights. (G) is the hand douser, which blocks the intense light from the xenon lamp from entering the shutter and film gate areas of the projector. It is used to primarily to prevent damage to the shutter and changeover douser, if the projector is not running and the lamp is lit. We use the hand douser when we make lens changes between the intermission film and the feature, if it's in scope.
Not shown in the picture is the new film cleaner that was installed in 2002. The purpose of the film cleaner is to remove the oil, wax and dust that often accompanies the film as it passes through the projector. Because we require more light (which makes the projector run much hotter), some of the dust and oil can create deposits in the film gate along the tension bars. This can cause the film to buckle and make the picture go in and out of focus. The film cleaner uses a special media (looks similar to gauze) that removes most of the foreign material from both sides of the film.
35mm film runs through the projector at the rate of 24 frames per second and 1 1/2 feet per second. A 100 minute movie normally arrives from the film distribution house on 5 to 6 1800 foot reels of film. Modern 35 mm movies are normally produced in two formats (aspect ratios), Flat or Scope (sometimes called Anamorphic, CinemaScope, Panavision). The format determines which lens to use in the projector. The Scope lens produces the wide screen picture, whereas the Flat lens produces a narrower picture. To learn more about aspect ratios, click here. Prior to CinemaScope being created in the early 50's, the projector had a single blade shutter. Each picture was flashed on the screen for 1/24th of a second. To show CinemaScope movies, the shutter had to be changed to a two blade shutter, which flashes each picture on the screen twice for 1/48th of a second. This provided a smoother image transition and less "flicker". For you camera buffs, it also required an increase in illumination.
When the Milford Drive-In operated as a single screen drive-in, they used two projectors for one screen. Approximately every 20 minutes, the projectionist would change from one projector to the other, allowing for a non-stop show. Perhaps you have noticed the little circles or ovals that appear in the upper right corner of the screen. These were the changeover signals. When the projectionist saw the first set of marks, he would start the projector running and open the hand douser (a metal plate that prevented the lamp from burning the shutter and changeover douser - G in picture above). When the second set of marks were seen approximately 7 seconds later, the projectionist would step on a floor pedal that opened the changeover douser (E) on the projector that he just started and simultaneously closed the changeover douser on the projector that was to be shut down. He would also flip a switch that would start the sound on the full reel projector and stop the sound on the empty projector. If all went well, the changeover would normally not be seen by the viewer. Film producers usually will schedule changeovers in scenes with action so that they are less noticeable to the viewer. The projectionist would then close the hand douser on the projector being shutdown, shut off the lamp house and would then stop the projector motor and ready the projector for reloading.
Between changeovers, the projectionist would rewind the reel that just ended, reloads the projector with the next reel, and adjusts or replaces the carbon rods that provided the light. The carbon rods functioned much like an arc welder. The lamp was started approximately 3 minutes prior to starting the projector to allow the light color and the illumination to stabilize. The carbon rods were momentarily touched together and then separated approximately 1/2 inch. The electricity would start to arc, burning the carbon and creating a white-hot plasma gas, which provided the very high intensity light, and a lot of heat. The aperture plates of the projectors that used the high powered arc lamps had to be water cooled to prevent film damage.
A - Vertical Mirror Adjustment, B - Glass/Metal Concave Mirror, C - Negative Carbon Rod Adjustment Knob, D - Negative Carbon Rod, E - Horizontal Mirror Adjustment, F - Positive Carbon Rod Adjustment Knob, G - Positive Carbon Rod, H - Hand Douser
When the new Xenon lamps came into production in the 60's, many theaters quickly changed to that method of illumination and simultaneously added film platters to be able to utilize a single projector for a single screen. This allowed for a non-stop movie utilizing the single projector and required no carbon rod changes. When the first projector automation systems hit the market, theaters owners quickly realized that more screens could be operated with less labor and machinery, making the Automation/Xenon lamps and platters very cost effective. According to one of our projectionists, Doug Toms, a good projectionist can run up to 20 screens simultaneously.
In many theater complexes, with the proper automation equipment, projectionists are eliminated altogether. The manager performs the projectionist functions as well as overseeing the concession and ticket areas. In this type of operation, the projectors are started remotely and a heavy reliance is placed upon the automation system to monitor the projectors, while the audience or theater staff is responsible for detecting focus, sound and framing problems and reporting the problems to the operator. The manager in this type of operation also has the job of making up the movie or taking it down the last night of the showing. Breaking the movie down or splicing all of the reels together and loading onto the platters normally takes about an hour for each procedure, for each movie.
Many people ask about the different sound processing systems and what the differences are. The information below was obtained from the sound system producer's web-sites and from information provided by General Cinema. The information pertains mostly to indoor theaters, but is posted here as technical content for those of you that are interested.
(Mono) sound features only one speaker, located behind the screen (which is perforated to allow the sound to pass through).
Dolby Stereo utilizes a "Dolby Processor" to create three channels of sound (left, center and right) from the two analog tracks on the film. Three different speakers are located behind the screen and depending on the visual action on screen, the sound effects will be directed more towards one speaker than another.
This system creates a fourth channel of sound from the analog soundtrack which is sent to a series of "surround " speakers placed on the sides and the back wall of the theater. Surround speakers provide environmental sounds such as thunder and rain. Often, a fifth, or sub woofer channel, is also derived from the analog soundtrack. This is used for speakers behind the screen which reinforce and add drama to the low frequency sounds/special effects like the rumbling of a passing train or an explosion.
(Spectral Recording) is an enhancement of Dolby Stereo that uses a new method of recording to achieve near digital quality in an analog format. The amount of background noise inherent to analog recording is drastically reduced, thus expanding the dynamic range.
This system features six individual digital recorded sound channels; left, center, right, left surround, right surround, and sub-woofer.
In order to record sound, sound waves must be converted from their original state, - variations in air pressure - to information on a recording medium. Two methods used to achieve this are: analog and digital.
In analog recording, sound waves are converted first into corresponding waves in another medium, then to electronic pulses for transmission to the amplification system. For example, phonographic records have grooves of varying width which are mechanically read by the phonograph needle which then transmits the vibrations to the sound system.
An analog motion picture soundtrack utilizes an area of light with varying width. Light is projected through the soundtrack on to a solar cell which then converts the light intensity into electronic pulses and then transmits them to the sound system. These variations are an "analogy" of those in the original sound wave, hence the term "analog". Limitations of analog sound reproduction are:
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a percentage of the sound can be lost in the transmission process, |
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the transmission system has its own sound (background noise), and |
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the range between the loudest and the quietest parts of the soundtrack (the dynamic range) is limited by the size of the soundtrack. |
An analog soundtrack is located between the picture and the films sprocket holes. On a standard 35mm motion picture film, there is room for two "tracks" of sound information.
In digital recording, sound waves are stored as numbers (digits). This allows more information to be stored on the soundtrack which results in:
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expanded dynamic range, |
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multiple tracks for surround sound, and |
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no background noise or loss of sound quality during transmission to the sound processing system. |
A familiar example of a digital recording is the audio CD.
Today in the film industry, there are three primary manufacturers of digital sound processing systems:
(Digital Theater System) - uses a digital soundtrack on a CD, synchronized by a time code printed on the film.
SR¤D (Dolby Spectral Recording Digital) is a digital soundtrack printed between the sprocket holes on the film.
(Sony Dynamic Digital System) is a digital soundtrack printed on both edges of the film.
A state-of-the-art sound system can sometimes be foiled by distracting elements in and around a theater. Then a theatre has THX certification or HPS-4000, the moviegoer can be assured that the sound quality is superior.
THX is a certification for an individual auditorium. Developed by Lucasfilm, THX details exact auditorium specifications in order to provide a quality sound and picture environment. An auditorium must meet a rigorous set of acoustical and sound requirements as well as geometry, screen light levels, and many other factors. Annual recertification is required.
HPS-4000 (High Performance Stereo) was designed by John F. Allen to enhance dialogue intelligibility, i.e. the clarity of speech, and to present digitally recorded soundtracks at maximum capability.
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