The organizers located some used 35mm projection equipment (Simplex XL's, RCA soundheads, 4000 watt Xenex lamphouses with rectifyers and Crown amps). Since they have no experience in projection or exhibition, my first task was to go with the organizers to look at the equipment and explain what they were buying and what might be missing from having a full booth set-up. Once that was done and the equipment was purchased, I have been working with a very experienced projectionist and a sound technician to assemble and troubleshoot the equipment to make sure everything is working up to par.

Now that I've given you all the background on the project, here's the question:

The organizers have purchased a truck with an enclosed back end and plan to use it as a mobile projection booth. I have not seen the truck yet but I believe it is similar to a Ryder truck. They want to permanently install the projection/sound equipment in the
truck so that they can drive it back and forth to the temporary film venue each week.

How should we anchor the pedestals and sound rack in order to prevent damage to equipment during transportation? We will be using two projectors and doing 2,000 foot changeovers. Each projector will be mounted on a standard booth pedestal. Can we just bolt the pedestals down? If we do so, will vibrations from potholes and such damage the projectors and soundheads? The same question goes for the amplifyer. The sound rack we are installing will contain one Crown solid state amp for mono sound through two Altec A7's which will be placed under the screen when a film is presented. Should the amp be somehow padded? What about the xenon bulb? I'm guessing that the bulbs should not be left in the lamps when the truck is driven.

I know that a number of you have been involved with film festivals and similar venues where projection and sound gear is set up temporarily. Based upon your experience, what do you think we should do?
 

Once the trailer is in place and leveled, the projectors are unbolted and the flywheels installed. You will need to unbolt the projectors to center them up on the screen. There are some bases that can handle this adjustment, but the course adjustment seems to work best just by shoving them around.
 

The outdoor film shows will be in Hagerstown, Maryland. The plans right now are to put up some sort of screen in a parking lot not too far from city hall.
 

As far as whether our mobile booth will be code compliant, I'll check into that. I think we're okay since the city is supporting us and is well aware of everything we are doing. I will make a point to check on the code issue, however.
 

Live concerts and stage shows also use them for mains power. The house electrician simply ties pigtails equipped with the connectors to the buses and he's done. The techs can connect to them at will.

I'd build the truck just like any other projection booth (except for extra mounting bolts and a padded container for lamps and flywheels). You might want to consider removing the platters from the tree during transport. I would imagine a good pot hole could send them flying.

Just remember that everything that we rely on gravity for will need to be bolted down!

Put a nice 200 amp, three phase distro-panel on the wall and throw the pigtails out the back when you arrive.

Everyone will jump on me for this one, but keep a couple of magna-coms handy for when the local police officer says that your truck is too close to a fire hydrant (after you have set up)!

This sounds like a really neat project. I'm sitting here designing a truck! (LOL) I actually starting this post about an hour ago!

Keep us posted on the progress.

Russ
 

Hmmmm...I see by your profile that Charleston now has a stadium seating theatre. I used to live in Cross Lanes (1984-1987) and used to go to the movies in downtown Charleston, Kanawha City, and at the Valley Drive-In at St. Albans (may it rest in peace). Which part of town is your theatre located in?

Take the "digital tour". The auditorium pictured is theatre one (formerly known as theatre "A").

You will need "pig-tails" for both ends of your AC connection, as well as the bolt on connectors for the bus bars at the source.

Russ

 

All of our booths passed the electrical final inspection using them on the xenon supplies.

I love taking inspectors through a theatre! It's supposed to be a formal ritual, but it always ends up more like a tour!

Inspectors were kids once too! They all wondered what was in the room where the picture came from!

So long as you use lots of "seal-tight" and have proper grounding, they are happy.

As far as I know, the traveling concert and stage play people are not having to use different power distro techniques in different areas. So long as the current ratings on the connectors are not exceeded, he should be fine.

This just came to me: Should he have some sort of cover for the port glass? I'm thinking that it could be chipped by road debris, rocks and alike while in transport.

Russ

Speaking of security issues, we initially discussed whether we should have a large glass window for a port or the standard high and low ports like in a fixed booth. Although it might have been interesting to the public to see the equipment in operation, my recommendation to the group was to go with the smaller standard type ports in order to make it difficult for someone to simply break the window and climb in when the truck is parked and unattended.

Another thing we will need to consider is winterizing during the off-season since we will pretty much operate only during the warmer months. We'll have to use some of the tricks that drive-in operators use when closed for the winter. Things like removing the bulbs from the lamphouses, keeping the insides of the lamphouses warm and dry, etc.

 

The proper name for the connectors that I described earlier is "Cam-Lock".

"Twist-Lock" is just a West Virginia term!

The connections at the bus are made by a rather large, bolt-on, allen screw. I would imagine that this would not be kosher in a permanent installation, but rock and roll does it every day.

It is a temporary connection, which when made by a qualified electrician, is safe. They "twist-connect" the ground as well.

No one is allowed to access power until the connecting electrician says he's done.

Another example (I have no clue about this) would be travelling carnivals. How do they provide AC distro? They have huge rides that are temporarily connected to AC mains.

They might offer ideas as well.

Again, I like this topic!

Russ

Most of the traveling carnivals I have seen have their own diesel powered generating systems for the rides and other things. They are pretty much self contained and self sufficient.

I don't know if this type of thing would be an option for the traveling booth. Noise is of course one problem related to this solution, so it may not be viable.

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Oscar Neundorfer
Chief Engineer
SMART Devices, Inc.

oscar@smartdev.com
 

This is always a good proposition.

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Better Projection Pays!