Sensurround

m4rky_m4rk

Well-known Member
I am not sure if this best place to start this thread but I hope sub woofer fans will enjoy the topic.

Sensurround is a process developed in the 1970s by Universal Studios to enhance the audio experience during the presentation of theatrical movies. Specifically developed to showcase the 1974 film Earthquake

Extracts from Wiki:

Sensurround Mod-II and Mod-III boxes are extremely common and relatively easy to find from old theater equipment dealers and can be bought for $50 or so.

Not so expensive considerinq what it can do:

Sensurround involved the installation of large, low frequency, horn-loaded speakers which contained specially designed 18-inch Cerwin-Vega Model 189E drivers in custom black wood cabinets.

When triggered by control tones on the film's soundtrack, the system generated a pseudorandom noise between 17 and 120 Hertz at sound pressures ranging from 110 dB at the center of the theater to a maximum of 120 dB 4 feet in front of any horn.[4] The resulting rumble could be felt by audience members as well as heard.

The system was improved upon over the years following its debut in 1974 with the film Earthquake. They refined it and added infrasound which could only be felt and not heard. :devil:

Mod-III Sensurround was a further refinement of the system to allow much more subtle and impressive effects. It was only used for Battlestar Galactica. Instead of the Sensurround effect being a rumble that could be felt and heard, MOD-III used infrasonic effects that could be felt but NOT heard. Thus, scenes could have dialogue and other audio at standard levels while accompanied by the effect of movement. Or, the infrasonic sounds could be combined with higher frequency sounds to create the effect of wind; this was used in Battlestar Galactica when the Atlantia explodes. And as the Clonial Vipers took off, the infrasonic waves were quickly 'panned' from the back to the front of the theater, creating the sensation of "launching" in the audience. Battlestar Galactica used the Sensurround system in innovative ways.

The use of Sensurround created some controversy as theaters were damaged, theater-adjacent businesses disrupted, patrons became sick and in one documented case, a moviegoer suffered cracked ribs

Has any ever bought one and used it :eek: I doubt it but there are some crazzies about :smashin:

House still standing?

I guess most of the younger guys will not know what I am talking about!

The full Wiki article is below:

Sensurround - Wikipedia, the free encyclopedia

and there is already a post on the thread below for any comments on the 1974 film called Earthquake which featured sensurround p.37

http://www.avforums.com/forums/subwoofers/251297-best-movies-subwoofer-moment-37.html
 
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AngelEyes

Distinguished Member
My assumption (not having read the Wiki, so feel free to shoot me down) is that the audio source would need to be specially encoded with a Sensurround track. Of the few films made with Sensuround tracks, what are the chances that these tracks would be encoded on the DVD versions, if that was even possible?

It would seem a bit of a waste of time installing such a system domestically. :)

I also have a slight issue with the theory that infrasonics can be panned as the whole point is you can't hear them, so why bother?

Having said that I would like to have watched BG in the Cinema in such a Cinema! :)

Adam
 

m4rky_m4rk

Well-known Member
I think your are basically correct. The system relied on special encoding in the films but I beleive the encoding was left in on the DVD's because the control tones were just a rumbles anyway. What they didn't do was remaster the sound track to try to replicate the sensuround effect with todays HC setups ie they didn't do anything fancy on the LFE channel other than to copy over the control tones. So in theory sensuround for the home could be done because the controls tones are still there. I know there are some crayzzy bass nuts about but even they are not that insane.

The relevant bit from wiki:

Remastering for DVD
DVD prints of Earthquake from Universal Home Video, released after May 9, 2006, feature the Sensurround track (described as "Sensurround 3.1" which is an update to "Sensurround III"). In this case, the Sensurround 3.1 soundtrack is just the mono soundtrack fed to the 3 front speakers and the subwoofer; it is not a duplication of the Sensurround system, and neither is the 5.1 soundtrack. Furthermore, the DVDs of Battlestar Galactica, Midway and Rollercoaster aren't authentic as the 'rumble' on their tracks is that of the control tones. Because they had no control over the sound system equipment used by home viewers, no attempt was made by Universal to properly reproduce the surround sound effect that was such an integral part of the Sensurround experience

I have never heard one of those films outside of the cinema so I have no idea what they now sound like on DVD. I was hoping someone has though. I did see Earthquake when it was released and the shocking rumble effect is still the only thing I can remember about the film. Not bad really considering most films are very forgetable and quite quickly too.

I like the idea that audience actually felt like they were 'being launched ' in Battlestar Galactica. I also like the idea that there are some 'interesting people' mad enough to have a go just for fun. Sort of thing you might see as a Top Gear stunt. Pity there are no caravans in any of the films :rolleyes:
 
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cribeiro

Well-known Member
According to the technical specifications quoted, it is nothing special for a modern 5.1 system with a capable subwoofer (like reaching 16Hz flat). And if you take a modern soundtrack with serious bass peaks in the subsonic region, you will have the same effect.

As Adam said, the panning effect has nothing to do with the devices itself, it is just psychoacustics (your brain puts together high and low frequency sounds that seem to belong to the same object and assigns them the same origin).

I think the most interesting point of this is its existence already over 30 years ago. Finally, home cinema is catching up!
 

m4rky_m4rk

Well-known Member
I found an excellent review of the DVD of Earthquake. The guy is an expert on Sensurround.

Amazon.com: P. T. Chamberlain's review of Earthquake

I also noticed that cinema fans ocassionally organise a viewing of this film complete with Sensurround. All seem to agree the film is basically rubbish but the sound effects were revolutionary.... if you ever come across such a showing please let us all know. Its a lot of fun and should'nt be missed.

http://www.in70mm.com/news/2004/recreating_sensurround/index.htm

Here's a link to a guy who sold on the gear when it was all done and paid his college fees with the proceeds.....

http://www.in70mm.com/news/2007/sensurround/clearance/index.htm
 
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cribeiro

Well-known Member
The cut-off frequency that was designed for Sensurround was 16Hz. The bass should be played at a level of 110-120db at those frequencies!
That means that any dvd with today's technology and with today's hardware should be able to deliver the same effects/performance.
 

m4rky_m4rk

Well-known Member
I saw the 1974 Earthquake showing with Sensurround and I never experinced such shaking since...... maybe over the mist of time my memories of it are now somewhat rosier than actual reality! Maybe I will buy the DVD to see if it can shake my counch like I remember. Will first install a tactile sound unit and a net to catch the falling plaster!!
 

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