The sound track book of the theatre (undated)

408 SOUND TRACK THEATRE BOOK proaches the screen so as to permit each patron the best possible view of the screen. The best way to determine the necessary grades for each ramp is to secure a large scale elevation drawing of the entire theatre area and then plot the sight lines from the various ramp positions to the screen. Such a drawing is also useful in determining the maximum allowable heights of such obstructions as projection and concession buildings. Semi-circular construction of the ramps permits patrons located near the ends of the ramps to be close to the screen, and partially compensates for the poor viewing angles. Ramps should allow at least 9 feet of space for each car. This amount permits easy access to the junction boxes of the InCar Speaker Systems and helps to prevent collisions between cars and junction boxes. This spacing also allows accerj to each car by car hops and other theatre attendants. The number of ramps required depends upon the number of cars intended to be served. After grading has been done, ramps constructed, and junction box supports, wiring, sewage and water lines have been placed, the theatre area should be paved, preferably with a hard surfacing material. It is recommended that lighted parking facilities immediately within the entrance to the Drive-in Area be provided to handle incoming cars in the period just before the early show nears its end. tion more damage and weatherproof and imparting a better appearance to the theatre area. Pipe should be purchased 48 inches in length so that 40 inches of the length will be above the ground and 8 inches imbedded in a concrete base. The pipe should preferably be set in a suitable concrete base so that the support may better resist collisions and save damage to the junction box and speakers. Much cost and trouble may be saved in installation if the junction box selected is provided with a pipe connection fitting that does not require threading of the pipe. Many junction boxes are designed for installation on a wooden post or upon a 2 inch diameter pipe and thus require the purchase of a pipe flange. As 2 inch pipe is not always available, Motiograph designed its junction box to mount on any sized pipe or tubing from 2 in. to 3/2 in. outside diameter without the necessity for threading pipe or tubing or purchasing pipe flanges. If the pipe support or junction box is provided with a lamp to illuminate the base of the speaker standard, it will enable the drivers more easily to guide their cars to the correct position on the ramps. This eliminates much damage to speaker equipment and automobiles and also permits use of a lighter block of concrete at each pipe support. Bases so illuminated may be numbered to assist patrons to find their cars, should they leave them. Locating the Junction Boxes All in-car speaker systems require a junction box located between each two car positions along the ramps. These should be spaced 18 feet apart, about 5 feet back of the highest point of the ramp. Each junction box should be located on a wooden post or a pipe 40 inches above the ground, so that a car occupant can take an in-car speaker off the junction box without getting out of his car. The pipe mounting is more satisfactory, as the cables can be placed inside the pipe, making the installa Wiring System Wiring costs in Drive-In Theatres using in-car speakers are relatively high because of the large amount of cable required to bring the sound circuits to each junction box. If lighting circuits are also provided to each junction point, still more cable is necessary, and it is hence desirable to use the type of cable which is least expensive to purchase and install. Experience indicates that two-conductor insulated underground cable of the "Parkway" type, buried approximately one foot below