How far from celing to mount a fixed screen for a Mitsubishi HC3000U?

[heebsk]

I think I've finally decided on which projector I want. After much research I've decided to go with the Mits HC3000U (close call with Optoma HD72). Now, I have some basement framing starting and I need to know approximately where my screen will go. I have 9 foot ceilings, and the overall width of my screen must be less than 85". I was looking at the Carada Presision 92" diag, which is just over 84" with a 2 inch black border.

Question is how high from the ceiling/ground will this picture be? I've tried to calculate the offset but an example I saw was using 100" screen. Based on the projector calculator, the throw distance is between 10.9 to 13.2'. I'd probably split the difference and mount it around 12' since the ceiling is also not finished yet and I can mount it basically anywhere I want. One thing that is confusing me though is that the calculator shows the image height to be 47", but the fixed screen height for a 92" diag is 45.1". I'm not sure but I think the differences in my image/screen size are due to the Mits HC3000U being a 15x9 native resolution projector.

Is this going to cause me problems with a 1.78 fixed screen, or since I have 2 inches all the way around in black frame will I be okay?

Thanks to all in advance.

 

[heebsk]

Also, I won't have the ability to get the projector first to see where it will throw the picture. So I have to have a rough idea ahead of time and then be able to have it match up when I finally do mount the projector.

Any ideas?

 

[mtrycrafts]

Also, I won't have the ability to get the projector first to see where it will throw the picture. So I have to have a rough idea ahead of time and then be able to have it match up when I finally do mount the projector.

Any ideas?

Yes, your eye height during watching should be about the bottom 1/3 of the screen for best viewing.

Projectors lens center line usually don't like to be above the top of the screen's white section. You will have to have the projector dropped, extended down enough, or you need a lift to lower it into place when in use.
Then, you have other issues for wiring.

 

[Johnd]

Projectors lens center line usually don't like to be above the top of the screen's white section.

Ditto to everything mtry has written, except I would mount the centerline of the lens at the exact same height as the center of the [usable] screen. Avoid keystoning at all costs. Only hacks compensate by keystoning.

 

[heebsk]

Johnd,

Can you explain what you mean by keystoning? I am not familiar with that term. And I don't think I understand when you say to have the lens at the same height as the center of the screen. Wouldn't that mean that the lens would need to be around around 4 feet from the ceiling? I would think that you could only achieve that with a shelf mount, not a ceiling mount.

What am I missing here?

Thanks.

 

[heebsk]

Ok, I did some quick research and figured out what keystoning was. I guess I had always heard about the trapezoid effect instead. Anyway, I still don't see how I could have the lens at the same height as the middle of the screen without it sitting on a stand/shelf or hanging 4 feet down from the ceiling.

 

[mtrycrafts]

Ditto to everything mtry has written, except I would mount the centerline of the lens at the exact same height as the center of the [usable] screen. Avoid keystoning at all costs. Only hacks compensate by keystoning.

Some projectors have an area of operation, without having to resort to keystone adjustments even though it is not at the center of the screen. My pj is at the top and the test pattern it projects shows no keystone effect trapezoid that I can detect by my biased eyes
If you place it at the center, your head is at the bottom 1/3, something will not feel right. You will see the pj if you sit behind it, or stand up into it if it happens to be right overhead and if it is behind you, well, that may work but..

 

[Johnd]

Ok, I did some quick research and figured out what keystoning was. I guess I had always heard about the trapezoid effect instead. Anyway, I still don't see how I could have the lens at the same height as the middle of the screen without it sitting on a stand/shelf or hanging 4 feet down from the ceiling.

The 3000's manual itself states that the lens center should be centered with the sceen center. The projector also ought to be perpendicular to the screen. If the product manual directs this type of installation, I would do it. Without following these simple instructions, you will experience distortion.

The only workaround to this that I know of is to slightly angle both screen and projector (if you can) so that they remain perpendicular to one another. That is, if your proj. is too high, tilt the top of the screen away, if the proj. is too low, tip the top of the screen forward.

And, finally, yes, if the center of your screen is 40" from the ceiling, by deduction, so would you proj. (if you install it properly). Which means you replace the standard 12" (or whatever) length of pipe from the mount, and replace with a correctly sized one. Or you fabricate a shelf on the back wall at the appropriate height. These things are understood to achieve a proper installation.

 

[mpompey]

You could always contact that manufacturer and see what they recommend. I have an Optoma projector. I mounted it with the center of the lens along an axis that projected (no pun intended) from the center of my screen and the top of the white area, at the recommended distance, and everything worked out fine.

 

[Johnd]

This is a direct quote from page 10 of the HC3000u owners manual (italics added):

Setting up your projector

Setting up the screen
Install the screen perpendicularly to the projector. If the screen can not be installed in such a way, adjust the projection angle of the projector. (See below.)
• Install the screen and projector so that the projector’s lens is placed at the same height and horizontal position of the screen center.

It is projector 101 to do these simple steps, else the trapezoid effect occurs, which can then be nulled by keystoning, which only distorts the picture further. Set it up properly...don't be a hack.