When the first drive-in opened in Camden NJ, a company by the name of RCA Victor designed the sound system. They called it "Directional Sound". Using 3 main speakers mounted next to the screen, they tried to blast the volume so that even the cars in the back could hear.
There were 2 major problems with this type of sound system. Since light travels faster than sound, the sound arrived at the back rows late, i.e out of sync with the picture. the second problem was that while everyone in the entire drive-in could hear the sound, but so could the neighbors, passing cars, and overhead planes. Some complaints stated that farm animals were disturbed miles away. This system was replaced with the individual window-speakers most movie goers are familiar with.
It was in the early 70's that AM radio sound came into practical use at the Drive in. Although the idea had been kicking around since the 1950's, with some systems even calling for a separate box the patron would purchase and reuse, it was made practical by Cinema Radio, a company started by Fred J. Schwartz after experiencing what he felt was poor sound quality at a drive-in.
The big change since 1950 was the number of cars that had radios, by 1970 the number was up to an estimated 97%. The timing was perfect. Normally transmitting a radio signal would require a facility license. For no reason clear to me, the drive-ins were given the wave by the FCC. They passed on licensing these Low Power stations as long as they kept it under 50 milliwatts. [Closed cable FM was also exempt.] These broadcasts usually could be received via your car radio, or by a transistor radio which you could borrow from the snack bar.
Initially these were AM stations but the policy spread to FM licenses as that became adopted as the standard. FM is what remains in use to this day at most drive-ins. read more here: http://www.capridrive-in.com/dih.php
RELATED DRIVE IN RADIO FIRSTS:
In 1986 FM stereo sound was introduced via FM broadcast at broadcasting is introduced at Shankweiler's in Orefield, PA. This is also America's oldest, continually running Drive in. http://www.shankweilers.com/
In 1999 The Boulevard Drive in was the first drive in theater in the world to install digital sound. They broadcast at 89.7 FM in Kansas City. I am told that their fixation on high quality audio has made it superior to that of many indoor theaters. http://www.boulevarddrivein.com/
There is now even a company trying to buy time before, between and after the movies run on the radio signals at the drive ins! They distribute content via CD-R mailed weekly. It's an interesting niche service. http://www.driveinradio.com/
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ReplyDeleteGreat article, enjoyed it. I realize you posted it 15 years ago, but would like to comment on something you said..
You said:
"..For no reason clear to me, the drive-ins were given the wave by the FCC.. ..as long as they kept it under 50 Milliwatts..."
Breifly, the "waver" you refer to already existed in the FCC's Part 15 rules; the whole concept of which is restricting reception of a signal to a limited area. Any individual or business may broadcast to the public in a clear band without notification or prior application to the FCC. The only stipulation is that you conform to the limiting specifications of the established Part 15 rules that apply to the frequencies and bands you wish to broadcast in.
Schwartz, who already owned a chain theaters, received assistance from William Halsted (famous for the George Washington Bridge part 15 install in the 1940s, as well as LAX Airport transmitter system in the 1970s.. Not to mention his invention of FM Stereo)...
But anyway, Schartz got together with Halstead and perfected an induction cable transmission system (buried underground) for his drive-ins that would not require a licence, and few years later Schwarts started his 'Cinema Radio" company which employed the same method. It was FCC Compliant for licence-free AM broadcasting, so the FCC did not interfere. The rest is history.
That is one of the first posts I ever wrote. And I've been unable to to find a start date for the part 25 rules. Anecdotally I was told the drive-in exemption predates the Part-15 rules... but I've made no progress there.
ReplyDeleteThe part 15 rules began in 1938, Halstead came out with his part 15 cable, originally used for traffic control in 1939, the most famous use was on the George Washighton Bridge for the duration of the World's Fair in 1940 and than later in 1971 for Cinama Radio.
DeleteI need to google Halstead
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