Screen too low, how do I make it higher? - AVS Forum
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Old 05-29-2012, 07:30 AM - Thread Starter
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Hi folks,

I'm about to pull the trigger on a Mitsubishi HC7800 Projector and have encountered an issue I would like help with before I take the plunge.

My major concern is that the screen is simply too low and I want to know if it can be raised without compromising screen size or PQ?

Using the Mitsubishi Online Projector throw Distance Calculator...http://www.mitsubishielectric.com.au/2652.htm
The calculator tells me that with full lens shift it's only 19" from the floor (75.9" (Top of Screen on Wall Height)-56.9"(Screen Height)=19"), that doesn't give me enough space for a unit and centre speaker.

So I don't get my numbers wrong I've attached a screen shot which contains my room sizes etc..

Am I getting this wrong? I would love it if the screen would be at least another 12" higher. Is this possible? I've heard installing the PJ on a slight tilt and using keystone affects PQ, is this my only route?

many thanks
Dave
LL
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Old 05-29-2012, 12:58 PM
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Quote:
Originally Posted by dhodgson7 View Post

Hi folks,

I'm about to pull the trigger on a Mitsubishi HC7800 Projector and have encountered an issue I would like help with before I take the plunge.

My major concern is that the screen is simply too low and I want to know if it can be raised without compromising screen size or PQ?

Using the Mitsubishi Online Projector throw Distance Calculator...http://www.mitsubishielectric.com.au/2652.htm
The calculator tells me that with full lens shift it's only 19" from the floor (75.9" (Top of Screen on Wall Height)-56.9"(Screen Height)=19"), that doesn't give me enough space for a unit and centre speaker.

So I don't get my numbers wrong I've attached a screen shot which contains my room sizes etc..

Am I getting this wrong? I would love it if the screen would be at least another 12" higher. Is this possible? I've heard installing the PJ on a slight tilt and using keystone affects PQ, is this my only route?

many thanks
Dave

I confess I do not fully grasp your question. Perhaps because I do not own the HC7800. I gather it has to do with offset limitations.

WRT the second question. Rather than using keystone correction (usually eschewed) you can tilt the projector down a few degrees and then tilt the screen the corresponding amount by bringing the bottom edge forward. This permits you to maintain orthogonality. That is, the center-most light-ray from the projector strikes the screen perpendicularly. Overdone, it can be a problem aesthetically.

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Old 05-29-2012, 06:48 PM - Thread Starter
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Maybe I wasn't clear enough. I would like the screen to be higher on the wall so the distance between the bottom of the screen and the floor is increased so I can install my AV equipment.
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Old 05-29-2012, 07:12 PM
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Quote:
Originally Posted by dhodgson7 View Post

Maybe I wasn't clear enough. I would like the screen to be higher on the wall so the distance between the bottom of the screen and the floor is increased so I can install my AV equipment.

Have you tried using the lens shift to move the image higher?
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Old 05-29-2012, 08:05 PM
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dhodgson7

I understand your goal. From a cursory look at the manual, it appears that the projector's lens is designed such that the projector sits either above the projected image or below it. I could be wrong in this. If this is true, and if the projector cannot be raised higher because of the ceiling, then maybe you should consider a different projector. Speakers could be accommodated behind a perforated screen and the components could likely be relocated in the room. My DLP machine (Vango) is not so fussy about placement. Be aware that raising the image close to the ceiling will exacerbate any black level issues if the ceiling is a light color. Some hands-on anecdotal input from HC7800 owners would be useful.

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Old 05-29-2012, 08:17 PM - Thread Starter
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Quote:
Originally Posted by sonichart View Post

Have you tried using the lens shift to move the image higher?

Unfortunately I think the lens shift as on the attached picture is at it's max height.
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Old 05-29-2012, 08:24 PM - Thread Starter
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Originally Posted by Vlubbers View Post

dhodgson7

I understand your goal. From a cursory look at the manual, it appears that the projector's lens is designed such that the projector sits either above the projected image or below it. I could be wrong in this.

I think you are correct, it certainly seems that way from the online calculator.

Quote:
Originally Posted by Vlubbers View Post

If this is true, and if the projector cannot be raised higher because of the ceiling, then maybe you should consider a different projector.

I have looked and the mitsubishi is the only PJ I really like. Unfortunatly I can't go with any type of LCD as I see ghosting, even when in 2D. Other DLP's such as the BenQ W7000 doesn't appear to be as good and it also would only give me a 100" screen. Maybe I'm being to stuborn or fussy

Quote:
Originally Posted by Vlubbers View Post

Speakers could be accommodated behind a perforated screen and the components could likely be relocated in the room. My DLP machine (Vango) is not so fussy about placement. Be aware that raising the image close to the ceiling will exacerbate any black level issues if the ceiling is a light color. Some hands-on anecdotal input from HC7800 owners would be useful.

Unfortunatly my room size is too small to accomadate speakers behind the screen.

many thanks
Dave
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Old 05-29-2012, 09:43 PM
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Quote:
Originally Posted by dhodgson7 View Post

Maybe I wasn't clear enough. I would like the screen to be higher on the wall so the distance between the bottom of the screen and the floor is increased so I can install my AV equipment.

You can gain a few inches, by tilting the projector up slightly and then tilting the top of the screen out. By tilting the screen you will not have to use any keystone. if you would like more explanation, shoot us an email.

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Old 05-29-2012, 11:22 PM - Thread Starter
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Originally Posted by AV Science Sales 5 View Post

You can gain a few inches, by tilting the projector up slightly and then tilting the top of the screen out. By tilting the screen you will not have to use any keystone. if you would like more explanation, shoot us an email.

How many inches are possible before the screen becomes too tilted?
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Old 05-30-2012, 06:21 AM
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The Mits HC7800 has only a very limited lens shift adjustment range and that can be a real limitation. I suggest you take a look at other projectors in this price range and see if there are others that better suit your desired screen/projector geometry while providing the overall performance you are looking for. For DLP projectors the BenQ W7000 has a wider range lens shift adjustment, with LCD you have Epson and Panasonic and with LCOS you have JVC and Sony.

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