Film-Tech Forum ARCHIVE: Drive-In Projector Height

This is topic Drive-In Projector Height in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Justin West (Member # 920) on 01-04-2003, 07:53 PM:

I would like to know how far off the floor is the optical center line of projection in a typical drive-in projection set-up? Is 42" a standard height? The how far from the wall (to the portholes) should the projector sit? Thanks. [Confused]

Posted by Gordon McLeod (Member # 33) on 01-04-2003, 08:17 PM:

Depends on the amount of upward angle and the base
Simplex made a low pedastal to allow for an upward angle through the standard port heigth. Century made a casting that raised the heigth o the pivot on the base to allow for upward angles on there base

Posted by Adam Martin (Member # 641) on 01-04-2003, 09:07 PM:

It also depends on where you're installing the projector. In one place, I had to build a platform (think stadium seating) so the projector could effectively shoot over a driveway to the screen from the ground floor.

Posted by Tim Reed (Member # 137) on 01-05-2003, 12:19 AM:

Guys, he's talking about a standard projector pedestal, the optical height remains a constant, 12" or so above the pedestal pivot point. Elevation doesn't matter. Justin asked me this question on the phone tonight, but I couldn't remember. I don't recall if it's 42" or 48"... I think 48" was the height with those Century extensions, but I'm not sure. He needs to know the standard height for sure.

If anyone has an old elevation chart, for spotting port hole height, it should be on there, and coincide with the 0 degree position.

And, I always put the front of the pedestal foot 36" away from the wall, but that was just me -- primarily to allow the operator to walk around the front of the machine, if the platter happened to be located on the gear side.

Thanks,
Tim

Posted by Gordon McLeod (Member # 33) on 01-05-2003, 01:01 AM:

From Centurys drawings it lists
for 0 projection angle 48" optical centreline
distance from front wall to centre of base 54"

Posted by Ken Layton (Member # 133) on 01-05-2003, 01:30 AM:

There is a porthole locator/projection angle tech article on film-center.com under "quick tips".

Posted by Tim Reed (Member # 137) on 01-05-2003, 02:02 AM:

48"! Thanks, Gordon! I knew it was one or the other; couldn't remember, and I don't have access to my tech info anymore. The Century "drive-in" extensions must've put them up to 52", then.

Posted by Jack Ondracek (Member # 1466) on 01-05-2003, 02:08 AM:

quote:
I always put the front of the pedestal foot 36" away from the wall, but that was just me

Wow... I couldn't do that with the ports Tom Moyer installed in his builds. Even the flat image would be hitting the walls!

Fortunately, our drive-in has pretty good sized ports... but even at that, I don't think I've ever seen a machine that far back. Maybe that's a good thing. If I started walking around the front of a machine, I'd eventually kill myself on the conduits!

Posted by Tim Reed (Member # 137) on 01-05-2003, 03:58 AM:

Jack, that was borne of new multiplex construction for GCC, where economy of motion was a concern, and the ports could be sized accordingly, if necessary. Worked great in practice. If it were my booth I was designing, I don't know that I would necessarily put them quite that far back, although it did make it nice if you ever had to remove a projector head.
[thumbsup]

Posted by Justin West (Member # 920) on 01-05-2003, 10:45 AM:

Thank you all, for your input. Until Tim and I spoke, I was not aware there was a standard height or distance from the ports. All info very interesting.

Posted by Gordon McLeod (Member # 33) on 01-05-2003, 11:31 AM:

The older SMPTE manual has a good drawing of the Century A and JJ with dimensions and a porthole locator table for angle

Posted by Barry Floyd (Member # 385) on 07-02-2003, 01:09 PM:

I, like Justin have to ask this same question. My Simplex XL and SH1012 soundhead are hanging on a standard Simplex pedestal.

My contractor is going to start laying the block for our building next week, and he wanted me to verify the height of the porthole.

The chart over on film-center is now only offered on CD Rom.
(If somebody downloaded it before, please email it to me.

The center-line of my screen is at at elevation of 138.50, the finished floor of my booth is at elevation 108.80 (a difference of 29.70 feet). The distance from the face of the screen to the outside edge of the block on the building is 348.53 feet.

And like Adam mentioned above, I too have to shoot over a driveway about 12 feet from the outsidewall of the booth.