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Vintage Balcony Delay from the 1950’s

Posted by jdbsound on November 25, 2017

This is a vintage passive Analog delay. Most likely installed in this 1800 seat church in the late 1940s or early 1950s. When this delay was installed, there were no electronic devices invented yet to give a long enough delay that this church needed. This delay was used to manage sound under and above a balcony for around 700 seats. It is a 2-inch conduit pipe with a high-frequency horn driver at one end and a quality microphone on the other. The length of the pipe is about 25% longer than the distance between the pulpit to the front face of the balcony. Whoever designed this understood very well about the HASS effect. This system was working very well into the 1990s where it was upgraded to a digital delay and new speaker system to accommodate the transition to a contemporary worship service.

Vintage passive delay

If you look closely you can see the wire for the microphone on top and the Green Altec high-frequency compression horn at the bottom. The microphone was moved back and forth in the pipe until they got the best delay setting. Then the pipe was sealed. The frequency response of this setup was very good. It was +/- 2dB from 1800 to 6000 Hertz. If this church continued with their traditional worship service, this delay could have continued to serve the church.

For most under balcony installations, you don’t need full range boxes. All you need is sound from 1200 Hertz and up as the low-frequency information will go around objects and under the balcony. If you ever walk into a church and hear great sound under the balcony and don’t see any speaker boxes and grills, if you look closer, you will most likely see just tweeters mounted with or without a small baffle about 6 x 3 inches. Using this approach means that a budget limited church can afford a very high-end quality sound under the balcony with better, even sound distribution. This also allows you to use a lower cost 25-volt distribution system for each delay line and you can tap off each tweeter at 1 watt as that is all you will need.

Oddly enough, today, a digital delay is often included in Digital mixers and speaker processors. To build this passive today would cost as much or more than a 16 channel digital mixer (as of 2017). Historically, this church could have used a reel to reel tape recorder on a loop to create the right delay. In those days this passive system may have cost around $500.00, whereas a reel to reel system would have cost around $2,500.00. And consider this, the tape would have had to be replaced often, the belts inside of the recorder would have to be replaced often and delay drift would require readjusting as belts would stretch over time. A reel to reel loop system would have been an ongoing expense that most churches would want to avoid.

I don’t know who coined the phrase, “set it and forget it” (Ron Popeil is credited for using that phrase in infomercials of the 1980s.) but this passive delay system was just that. Once set, you could forget about it and it would last forever. This is an excellent example of high-quality sound churches can afford. Whoever designed all of this did an excellent job.

(This is information is not yet in Wikipedia. Nov 2017)

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