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Discussion Starter #1
Hello all,

I'm having my basement finished and I would like to create a home theatre room in the process. I would like to go over what I have planned and see if anyone can confirm I'm on the right track and if I've missed something along the way.

The home theatre room will be 18' long, and 14' wide, with 7' high ceilings. I plan on using the wall at one end of the room to be the projection screen. It will be painted white. The wall will be 7' high, and 14' wide. The room will have no windows so I can have it completely dark while viewing. Room lighting will be halogen pot lights with dimmer switches so I can control light levels. I also plan to house all A/V equipment in a recessed cabinet somewhere in the room, but I haven't decided if it's going to be at the back or on the side near the screen. Seating area will likely be 12' from the screen wall.

My friend recommended I go with the Optoma HD-20 projector which has good reviews and is within my budget (around $1000). It will be mounted on the ceiling. I will have the contractor put an electrical wall socket and HDMI cable wall plate on the ceiling near the location of the projector. I haven't looked into what to use to mount the projector to the ceiling, so any suggestions would be appreciated. The mount can be installed prior to the basement reno work if that makes it easier.

According to the distance caculator on Optoma's website, I can achieve a 130" image dialgonal if I mount it at 15'-5" from the screen. Image brightness is 17 fL. Zoom at 1.1x. The top of the projection will be 10.2" from the height of the lens. I'm not sure how close to the ceiling I can mount the projector, so I've allowed 6" from ceiling to the height of the lens for now in my calculations. Based on this, the image will be 4" off the floor, 5'-4" in height, and approx. 16" from the ceiling. there will be 2'-3.5" of space on both sides of the image to the edges of the wall. The recommended seating, based on Optoma's website is 13' to 21' from screen. I'd like to have my sofa placed 12' from screen so that I have approx. 6' of open space behind the sofa for other activities (like playing the Wii/Kinect). I'd imagine I cannot play Wii/Kinect in front of the sofa as the body will obstruct the projection.

So that's what I have so far in terms of planning. Is there anything that you can think of that I should also consider or watch out for? Any other suggestions on projector choice? Even if I have a wall that I can use, are there any advantages of considering a projection screen? I've just begun my research on front projectors so any pointers would be much appreciated.

Thanks.
 

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rvs007 said:
Seating area will likely be 12' from the screen wall.

According to the distance caculator on Optoma's website, I can achieve a 130" image dialgonal if I mount it at 15'-5" from the screen. ... Based on this, the image will be 4" off the floor ...
In my opinion, 4" off the floor is too low:
- It will cause you to have to look down, rather than straight ahead.
- You won't have room for a center channel speaker. (The bottom of my screen is ~24" off the floor.)

Also, keep in mind that 12' from 130" means that DVD-quality video or poorer is going to look like crap. I sit 13' from my screen and, while DVD-quality video is fine, I wouldn't want to be sitting any closer.
 

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Discussion Starter #3
Thanks for the quick response Eljay!

Do these projectors allow vertical adjustment of the image so that I can shift the image higher (closer to the ceiling) and gain for more space below the image?

As for viewing distance... I can definitely move the seats back further (it just reduces the amount of usable space behind the sofa). But I don't intend to watch TV (not SD content anyway) with this set up and it will be primarily used for BR and DVD movies.

However, if I were to keep the viewing distance at 12' from the screen, what would be the ideal screen size? Since the mounting location for the projector is flexible at the moment, I could also move the projector closer and reduce the screen size a bit.
 

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Do these projectors allow vertical adjustment of the image so that I can shift the image higher (closer to the ceiling) and gain for more space below the image?
Depending on the projector, you can get horizontal and vertical lens shift, and keystone adjustment capabilities. (You want to avoid keystone adjustment as much as possible.) See what the specs for your projector say. A good site for info. is ProjectorCentral.com.

(Edit: According to the site, the Optoma HD20 has vertical keystone adjustment capabilities only.)

However, if I were to keep the viewing distance at 12' from the screen, what would be the ideal screen size?
That's too subjective a question to answer definitively. At 13', I think 100" is great. 106" might be just a little bit better. 120" would be too much, especially for DVD-or-poorer video quality. At 12'? I wouldn't go over 100". YMMV.

Since the mounting location for the projector is flexible at the moment, I could also move the projector closer and reduce the screen size a bit.
Use the Projection Calculator on ProjectorCentral.com to help you find the mounting point.
 

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Discussion Starter #5
Any recommendations on good projectors that have vertical lens shift adjustment that are in a similar price range?
 

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I don't think you'll find many (any?) 1080p projectors with lens shift at the ~$1K mark.

But, do you need lens shift? I just ran the calculator and, if you mount the HD20 at 13' (lens to screen), you can get a 100" image (87" (w) x 49" (h)).

Middle of lens to top of screen is 7.8". You are planning to mount 6" down from the ceiling, so that's 13.8". Add the distance from top of mount to middle of lens - say, 4" - and you're at 17.8". So, 17.8" (ceiling to top of screen) + 49" (height of screen) = 66.8".

You have 7' ceilings = 84", which leaves you just under 18" of space for a center channel speaker.

However...
- if 'top of mount to middle of lens" is less, or
- if you tilt the projector up slightly and apply a bit of keystone adjustment, or
- if you mount less than 6" down from ceiling,
...you'll have more room under the screen, or you might be able to go with a slightly larger image (106"?).

Just my 2¢... :)
 

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Another option - not my preference, and not always possible or practical - is to mount the center speaker on the wall above the screen, where you've got over 17" of usable clearance, and angle it down toward the seating area. With no speaker under the screen to worry about, you don't have to resort to any lens shifting or other adjustments, and you can go with a (slightly?) larger screen.
 

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Discussion Starter #8
I actually like this option. Since this is a brand new install, I can ask the contractor to build a 1' "ledge" along the top of the wall where I could place the centre speaker on it. I do need to evaluate whether going to a screen size larger than 100" would be too big. As you said, it's highly subjective and based on personal preference. Any stores I could check out that have these systems set up where I can sit and see what 100" would look like vs. 120"?
 

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120" screen.

6" + 4" + 9.4" = 19.4"
19.4" + 59" (height of screen") = 78.4"

This puts the bottom of the screen just under 6" off the ground. At the top, you've got 19.4" - 3" (see below) = 16.4" of space for a shelf and center speaker.

-----------------------
Assuming a fixed-frame screen, the frame is usually ~3" wide. So, while there's 19.4" of space from ceiling to top of screen, there's 16.4" from ceiling to top of frame.

In the example with the 100" screen, the amount of space at the top should actually be just over 14".
 

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Discussion Starter #13
Sorry one more question. You mentioned a fixed-frame screen. I was planning to project onto a white wall. Is there advantages of using a fixed-frame screen over a white wall?
 

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I was planning to project onto a white wall. Is there advantages of using a fixed-frame screen over a white wall?
A screen (fixed-frame or otherwise) will be designed for optimal light reflection, and it will offer a perfectly flat surface.

If your wall is perfectly flat, there's no harm in throwing an image onto it and seeing how it looks. If you decide that it doesn't look good enough, but you're still not ready to invest in a screen, you can always buy projector screen paint (such as Screen Goo) and apply it to your wall to create an "on-wall screen".
 

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apply a bit of keystone adjustment
You do not EVER want to use keystone adjustment on a theatre projector!! Power point in a convention hall is fine but the distortion and artifacts are awful!!

You are far, far better off tilting the screen forward or back a little to accommodate and, from in front, the image is perfect!
 

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You do not EVER want to use keystone adjustment on a theatre projector!! Power point in a convention hall is fine but the distortion and artifacts are awful!!
Easy there, fella! :eek: First of all, I initially stated:
(You want to avoid keystone adjustment as much as possible.)
The comment you quoted was one of THREE options to gain more room below the screen - on the assumption that a) he was going to be using a screen and b) he was going to place a center speaker below it - and I clearly said "a little bit" because, as pointed out above, I know that keystone adjustment is to be avoided.

Jeez...

You are far, far better off tilting the screen forward or back a little ...
Seeing as how the OP states that he will be projecting onto his wall, you may want to explain to him how to tilt his wall forward or back a little. ;)
 

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I clearly said "a little bit" because, as pointed out above, I know that keystone adjustment is to be avoided.
There is no such thing as a "little bit" of digital keystone adjustment. The instant it is applied, the artifacts appear. I don't view it as an available option at all.
 

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There is no such thing as a "little bit" of digital keystone adjustment. The instant it is applied, the artifacts appear.
There is such a thing as a "little bit" of digital keystone. I use a "little bit" of digital keystone. Not only did I not notice any artifacts the instant I applied it, but I haven't noticed any artifacts at any time since then.

Let me re-iterate:
eljay said:
(You want to avoid keystone adjustment as much as possible.)
 

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The following image is nothing more than concentric circles. But depending on your display, you will begin to see some other patterns appearing near the center.

A "moire pattern" is the unique pattern that is created when you merge two screenlike objects together.

In this case, one screenlike pattern is the concentric circle design and the other screenlike pattern is the layout of the pixels on your display. Where those two screenlike patterns begin to 'interfere' with one another, a moire pattern emerges.

In video displays, moire patterns are cause when certain video images interfere with the tiny pattern of pixels on your display.

Moire distortion is an immediate and unavoidable artifact created when 'keystone' correction is added !



You don't have to believe me but in 40+ years in broadcasting, I've learned a few things. Copy this image to your computer and display it on your projector. Apply ANY amount of keystone correction and watch what happens!!
 

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Apply ANY amount of keystone correction and watch what happens!!
My projector currently does apply ANY amount of keystone adjustment to the images it projects. It's just a "little bit", mind you - only 2 or 3 points out of 100 (or whatever the scale is), just enough to "square" the bottom corners with the screen - but the images I see on my screen are perfect.

I understand that keystone is to be avoided. Hell, I even STATED that keystone is to be avoided. But if it makes you happy, here goes:

To the OP: Never, ever, ever use keystone adjustment. Ever! :eek:
 
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