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1947-48 Theatre Catalog, 6th Edition, Page 360 (346)

1947-48 Theatre Catalog, 6th Edition
1947-48 Theatre Catalog
1947-48 Theatre Catalog, 6th Edition, Page 360
Page 360

1947-48 Theatre Catalog, 6th Edition, Page 360

matched to the acoustical characteristics of the speaker housing resulting in exceptionally good tone quality.

The SEE-7535 in-car speaker shelter and junction box is designed on the same principle as rural mail boxes. It has a flanged metal base section which may be mounted either on a 2-inch pipe post or on a standard wooden fence post. The ends are slotted to permit the speaker cords to hang downward. Terminal blocks are provided near the center for the speaker and feed cables, and the impedance matching transformer for two speakers is adjacent to them. Transformers are available with any desired primary impedance up to 14,000 ohms.

Speaker shelter compartments and a center transformer compartment are provided by the formed metal cover for the base section. It has flanged and hinged doors at either end, and fits snugly down over the base section to provide entirely adequate weather protection for two SE-7530 in-car speakers. With the supporting posts properly located between each two car positions, the speakers may be taken out of or be placed in the shelter compartments without the necessity for getting out of the cars. Provision is also made for clamping two speakers to the sides of the shelter box to give the patron even quicker access to the in-car speaker.

Theymetal parts are fabricated from heavy gauge galvanized sheet steel finished in light grey weather resistant paint. This basic design permits the shelters to be repainted to any desired color after installation and to be re finished easily during seasonal theatre overhauls. The transformer circuit is so arranged as to prevent accidental speaker cord shorts from disturbing other speaker pairs on the same ramp feed line.

The Motiograph in-car speakers may be expected to last for a long time so long as they are properly sheltered when not in use.

Unsheltered speakers may hold up for a season or two in mild climates, but best professional opinion among competent quality speaker designers is that replacement costs will be very heavy thereafter due to cone failures, to corroded metal parts, particularly the iron and steel components in the speaker unit magnetic structure, and to general deterioration caused by exposure to the elements.


A weather-proof and fool-proof in-car speaker, terminal box, and speaker-receptacle unit for drive-in theatres, designed for permanent location on the parking ramps, is now in production and ready for distribution, the RCA Engineering Products Department has announced.

Rugged, compact, and designed to withstand all kinds of weather, the new speakers are mounted in brackets, one at either end of a terminal box to be installed between two ramps, within easy reach of patrons from their car windows. This eliminates excessive handling and delays involved under the old system used by some drive-in theatres, where a speaker was passed out to each car as it drove in, plugged into a terminal at the pump by an attendant, and turned in at the exit as the patron left.

One feature of the new speaker is the use of a new type of coiled speaker cord which enables the patron to place the speaker anywhere within the car without the tangling and dragging of a long straight cord.

The individual in-car speaker eliminates many problems inherent in centralized speaker systems. It permits use of the speaker with the car windows closed in cold weather, thus extending the length of the regular operating season. The in-car speaker also has an adjustable volume control, enabling patrons to adjust the sound level to their own satisfaction. The speaker itself is of special design for acoustically correct operation inside a car. An attached bracket makes it easy for the patron to attach the speaker to the car window or any convenient support inside the car.

RCA,s combined terminal box and speaker receptacle unit has been so designed that a short circuit in the speaker unit or cord can affect no more than the two speakers connected to any one terminal box. This permits all other speakers to continue normal operation in case of trouble in any one unit, and facilitates location of the trouble. Formerly, a short circuit in even one speaker could put a whole line of speakers out of operation until the trouble could be located and corrected.

Built to take a lot of hard handling,

the new speaker has been tested under extremely adverse conditions and found to be able to withstand greater variation in temperature and humidity than would ever be encountered in actual operation.

The new type neoprene-covered extension cord is sixteen inches long in its retracted form, and can be stretched to about four and one-half feet with a pull on the speaker unit of only one and a half pounds. If neccessary, this cord can be stretched to a miximum of approximately seven times its retracted length, or about nine feet. Since the cord covering is treated with a sunproofing wax, it can be exposed to the hot sun over long periods of time without deterioration.

The new in-car speaker and receptacle are part of a complete new line of drivein theatre equipment. One of the features of the new sound system is an arrangement for keeping the sound level constant regardless of the number of speakers in use, once the line volume has been adjusted.

The tubes used in the new amplifier system cost less than one-half as much per watt output as tubes used in prewar systems. This sound system reduces materially the cost of operation and brings to the drive-in theatre the high quality and dependable performance.

THE RCA SPEAKER is a weather-prod, fool-proof in-car device, with a terminal box and speaker receptacle unit, designed for permanent location on the parking ramps. The new type neoprenecovered extension cord is coiled and 16 inches in its retracted form, but can be six-etched to 45 feel with a pull on the speaker unit of only 1; pounds.

If necessary, the cord can be stretched to 5 feel.

1947-48 Theatre Catalog, 6th Edition, Page 360