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Topic: Projector mount setup
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Joined: Sep 30, 2020
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I have the Ricoh PJWX4241N projectors and I would like to use a Short Throw Mount like UST Mount, Extension:12.80"-29.13" with Universal Mounting Plate found on amazon. The classrooms have pull-down screens that are about 8 inches from the wall. Can someone tell me what screen size I will get if I extend the mount to about 29 inches?

That would set the I guess throw distance of 21
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Joined: Mar 28, 2005
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I don't think this will work.

Throw distance is measured from the front of the projection lens to the screen, not from the center.

So, with the center of the projector at 21" and a distance to lens about half the depth of the projector, you only have 16" or 17" from the lens to the screen.

While that would be a 43" to 45" diagonal, about the same size as a cheap flat panel television, it is outside the range of what that projector is designed to handle.

https://www.projectorcentral.com/Ricoh-PJ_WX4241N.htm

Ultra short throw projectors, unless they use extremely high end optics, are extremely size limited with poor focus outside that range. The Ricoh you have calls for a size between 60" and 400" diagonal. So, it can go big, but it can't go that small with the optics which are in use. Typically closer to 100" to 120" diagonal would be common in a classroom/business environment.

Using the calculator: https://www.projectorcentral.com/Ricoh-PJ_WX4241N-projection-calculator-pro.htm

It would really call for the projector to be about 3'4" lens to screen, or about 4'5" off the wall to the center of the projector for a proper 100" diagonal.

I would look for a different mount which has more reach, or mount directly to the ceiling using a Chief CMA440 and a RPMAU mount.

For short throw, you can also look at the Chief WP23US. This model is pretty much right on target with a 56" wall to center distance. My calculations above shoot for 53" for a 100" diagonal, so this would be perfect.

Be aware, many Amazon mounts are not UL listed and may not be used in commercial applications. Chief stuff is pretty much the gold standard in the commercial space for hanging projectors.
[Edited by AV_Integrated on Sep 30, 2020 at 1:03 PM]
AV Integrated - Theater, whole house audio, and technology consultation during the build and installation process in the Washington, DC metropolitan area.
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Thanks for all that info. You provided a wealth of info. Since the ceiling is low 8ft, I don't want an arm that sticks out too far so I will have to sacrifice the screen size to about 60". From that calculator that would be about 2ft from the wall. I was looking at that chief mount but I don't want the kids to do pullups on that long extension.

Do you know what the recommended height from the top of the screen the mount should be installed?
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From page 31 of the manual:
https://www.projectorcentral.com/pdf/projector_manual_8923.pdf

It looks like the center of the lens to the top of the screen needs to be 2" for a 60" diagonal image.
AV Integrated - Theater, whole house audio, and technology consultation during the build and installation process in the Washington, DC metropolitan area.