Sensurround for Earthquake Commemoration
Meyer Sound Helps Pacific Film Archive Resurrect Sensurround for Earthquake Commemoration
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The 70mm Newsletter
|Written by: Larry the O, Meyer Sound||Date: 15 April 2007|
|"I called Meyer Sound not knowing anybody there and expecting I would have to write letters upon letters to get anywhere, but they put me through to (Executive Vice President) Helen Meyer who quickly agreed to help with the project."|
- Video Curator,
Pacific Film Archive, University of California Berkeley
Through the years, Hollywood has tried just about everything to supplement the usual film experience in order to create more excitement in moviegoers, including some things perhaps best left to the history books. Everyone has seen footage of audiences wearing 3D glasses, and who can forget Smell-O-Vision? It seemed to Steve Seid, video curator of the Pacific Film Archive (PFA) at the University of California Berkeley, that it might be fun to resurrect some of these stunts. Accordingly, in 2004 Seid planned a retrospective film series highlighting various gimmicks the film industry has dabbled with. He soon involved Meyer Sound to help bring back one of these ploys.
One of the attention-grabbers Seid wanted to revive was Sensurround, a system developed by MCA Universal in the early 1970s to add very low-frequency effects to movies, especially the blockbuster disaster movies popular at the time. This crude but pioneering system foreshadowed the dedicated low-frequency effects channel in today's digital 5.1 surround sound decades before 5.1 came into widespread use. However, a Sensurround screening carried an implicit requirement for loudspeakers capable of reproducing the very low frequencies the system generated at sufficient levels to create the desired sensations in the audience. In the '70s, producing this amount of very low frequencies was not easy. Fortunately for Seid, subwoofer technology had improved hugely in the intervening 30 years since Sensurround's brief existence, in part due to the development efforts of Meyer Sound.
Conveniently for Seid, the Meyer Sound factory is located in West Berkeley, only a few miles from PFA. "I called Meyer Sound not knowing anybody there and expecting I would have to write letters upon letters to get anywhere," says Seid, "but they put me through to (Executive Vice President) Helen Meyer who quickly agreed to help with the project." Meyer Sound loaned PFA the subwoofers it needed, and the showing of 1977's "Rollercoaster" was happily accompanied by the desired rumble.
In the fall of 2005 Seid again contacted Meyer Sound to see if there was interest in taking a second shot at Sensurround. This time, the occasion was a film series being planned as part of the San Francisco Bay Area's commemoration of the 100th Anniversary of the great 1906 earthquake and fire. Company founders and owners John and Helen Meyer were both enthusiastic about the idea and turned the project over to Design Associate Brian Long in the company's Design Services department. Long had an interest in film technology, having spent time at Universal Pictures Post Production Sound Department as part of his thesis work at the University of Southern California.
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|The subwoofers on the floor. Image by Brian Long.|
"We were fortunate to have the time to research the technology thoroughly and devise the most accurate method of recreating it, so that the technology would integrate well with modern film projection systems" Long says. Between the different versions of the technology and the way its information was stored, research was very much in order just to understand the system enough to recreate it.
Long found out that Sensurround's extended low-frequency content came from a noise source triggered by control tones on an audio track. Depending on the film format (of which there are a great many), the control information was stored on either the optical track or one of the magnetic tracks. In the original, Mark I version of the system, the noise source was a noise generator card in the controller unit, but the Mark II version recorded the noise directly onto a track on the film. However the noise and control signals were stored, the resulting signal was sent on to amplifiers that drove custom-built subwoofers.
Sensurround was utilized for only 5 films: "Earthquake" (1974), "Midway" (1976), "Rollercoaster" (1977), "Battlestar Galactica" (1978), and "Zoot Suit" (1981). Despite its short life, Sensurround was quite effective, and the lore is filled with tales of people running in fear and plaster falling from theatre ceilings the night "Earthquake" opened.
Long's research led him to Thomas Hauerslev of www.in70mm.com, a website containing extensive documentation of Sensurround's technology and history. Hauerslev knew of multiple Sensurround systems in active use at 70mm cinemas in Europe, which was a good start, but, unsurprisingly, there were complications. To start, there were several flavors of controller boxes (to accommodate Mark 1 and Mark 2 formats, and optical or magnetic storage for the control information), but the other conundrum was that the "Earthquake" print was in the Mark I optical format and the only known extant 35mm Sensurround controllers were Mark II boxes, without the Mark I controller's noise generator card.
|The Sensurround control box (grey box) in the projection room. Image by Brian Long.|
Over the course of the next few months, help came from Darren Briggs, Thomas Hauerslev, Jeff Taylor at Universal Pictures, Ron Surbuts at Dolby Laboratories, and the late R.J. Stumpf (one of the original Sensurround patent holders). Finally, a working 35mm Sensurround Mark 2 control box — modified to be compatible with Mark 1 prints — was found and loaned to PFA. Surbuts provided extensive technical support in interfacing the box to a current Dolby film processor.
The one-of-a-kind controller was integrated into the PFA theatre's playback system in combination with a mixing console and a Meyer Sound CP-10 complementary phase parametric equalizer to alleviate grounding and gain issues. A Meyer Sound UPM-1P ultra-compact wide coverage loudspeaker and M1D ultra-compact subwoofer enhanced the projection booth monitoring system, while six 700-HP ultrahigh-power subwoofers were deployed at the front of the theatre. Sensurround's original specification for locating the low-frequency loudspeakers were different than this, but current fire codes did not allow the original locations. However, the modified placement did little to affect the performance.
San Francisco's earthquake centennial proved to be a series of events stretching out over weeks and spanning the entire Bay Area, from an earthquake photo exhibit at the city's Museum of Modern Art ("SOMA MOMA," as it is known) to an exhibit about the earthquake's effect on San Jose at Silicon Valley's California History Center, and, of course, the actual commemoration event at Lotta's Fountain in San Francisco at 5:12 AM on April 18, the day and time that marked 100 years since the city shook. PFA made their whimsical and successful contribution to the affair a week and a half before that day, presenting a screening of "Earthquake" with, well, earth-shaking results.
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