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How Sensurround put me through College

The 70mm Newsletter
Written by: Greg Battas Date: 15 April 2007
Illustration from Audio magazine, April 1975

I was in college in the mid 80's and I heard that Universal was trying to get rid of their old Sensurround equipment. I found a VP at Universal (in finance I think) named Clark Stewart who told me that they had leased the equipment to the theaters and after the 4 movies had pulled it out and put it in moving and storage companies in each city. Clark was trying to sell them to theaters and that was a dead end. I got an inventory list from him and I went to my college library (before the days of the internet) and got yellow pages for each city. I started cold calling pro audio companies in each city and sold about 600 speakers and 200 amplifiers all over the US. In the beginning I was paying $75 per speaker and 200 per amplifier and in the end I was down to $25 and 150. Some of the amps were BGW750s and some were Cerwin Vegas - the CV's didn't sell for as much. The speakers should have been worth 500 each but since the buyer had to do a lot of the work I sold them for 175 each and 300 for the amps. The buyer would go to a moving and storage location who would uncrate them and the buyer could pop them with an ohmmeter to see if they still worked then he would take them home. There were typically sheets of plywood for the mouth extensions and control boxes that the buyer would scrap. They would pay the storage company who would pay all the back storage, send the rest to Clark and he would cut me a check. Funny thing is that Universal thought this stuff was gone. Clark had been selling a handful of them each year and using the money to keep the storage bills paid. I paid for college, bought a car and took a trip to Europe with all this!
More in 70mm reading:


Recreating Sensurround in England 2004

Recreating Sensurround in San Francisco 2006

Sensurround @ the Schauburg

Internet link:
Illustration from Audio magazine, April 1975

There were 3 speaker designs. In the beginning there was a W cabinet and a scoop design for corners. I never saw a scoop - I think only a few were built. The W was a huge double 18" folded horn. I only saw a handful of these but I had one pair that we put them into a theater here in Indianapolis and they did put out a lot of sound. Soon they found that the w was too big to fit though some doors so they designed the M which stood for modular. Funny that I see people calling them E's. I wonder if they saw the M on it's side or something. In the beginning they had a Cerwin Vega 189 driver then they went to the 189E (for "Earthquake") so maybe that was it. All my inventory sheets called it an M.

The M was 48" x 48" x 20". It was a folded horn with a single 189E mounted in a sealed doghouse (their term) firing backwards. It was build out of 13 ply Baltic birch (they consumed so much that Universals purchasing dept had to help Vega buy it I was told. They were painted dark grey or near black. The later ones had an extra brace between the doghouse and the outside of the cabinet as you looked at the front of the box.

The M had too small a mouth to go down deep. It had to be stacked. A single M really sounded awful (I had a dozen or so of these that I used in a PA I owned). In a large theater install they would use 12 M cabinets and 3 amplifiers (2 cabs per channel to create a 4 ohm load). They would stack 2 in each back corner with a triangular sheet of plywood on top to create a corner horn. In front they would stack 2 high by 2 wide (40" by 8 ft mouth) on each side of the screen then put a mouth extension on those using 2 sheets of plywood and 2 end pieces. The drivers were only rated for 100 watts or so but in the sealed M cabinet they could handle many times that. When you removed the side of the doghouse to access the driver you had to make sure you got all zillon screws good and tight to seal it back up. If there was an air leak into the doghouse you would blow the driver in no time.
Illustration from Audio magazine, April 1975

There is some urban legend about Sensurround - broken bones, falling ceilings, etc. A little bit is true. They did have some older theaters complain of plaster cracking and the Sensurround manual had instructions in it for how to put a piece of masking tape on the wall next to an existing crack with an arrow drawn on it for the end of the crack so you could see if it was growing. Kind of comical. Clark told me once that they had to get a theater opened on very short notice so they shipped a whole setup by UPS overnight which cost a fortune.

I have seen on the web people claiming that they put out ludicrous amounts of sound. By todays standards they are probably not that amazing. You could do the same thing with something like Tom Danley's horns. He is kind of the current king of folded horns.

So that is what I know. Haven't thought of this stuff in 20 years when it occurred to me last night to do a web search to see what was out there. When I finished college Clark wrote me a great letter of recommendation and I got a very good job at a computer maker calling my Sensurround sales as an "MBA or work equivalent" and now I work for HP. None of this would have ever happened without Sensurround. I am building a home theater now and really wish I had kept some of the memorabilia like the Sensurround stickers and manuals.
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Updated 07-01-23