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Topic: Largest screen possible for inside
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Joined: Mar 17, 2019
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Greetings, this is my first post, and even though I am on this site often, I am a novice to projectors, and the only one I have used is a Yankyo 510, so basic, its not even in the database.

So my big silly question, is it possible to have a 300 inch screen inside?

I see just about all the projectors on the top ten lists say they max out at 300 inches, but is it possible to achieve this?

Just from the screen alone, and say 3 feet extra below the screen for speakers, and 2 feet on both sides so its not wall to wall screen, then the throw distance of 30 feet, with the zoom turn all the way up. The room for this would be close to 26 ft wide, 30-35 length, and ceilings 15 ft tall.

When I play with these measurements on the projection calculator, it seems to work, but based on the viewing distances, I would be sitting much closer than any practical viewing distances, like 20 feet from the screen.

On my beginners screen I have now, I'm sitting about 10 feet away to a 150 inch screen. Mainly only playing games and watching quality produced BR's, its nice, and after the dizzy spells went away, I'm enjoying it, even though I know I'm not at the best viewing distance, but that is where my crazy idea of doubling the effect, another 10 feet away, and a 300 inch screen.
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Joined: Mar 28, 2005
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300" is a 'max size while retaining focus' number, it's not a real number for a usable image.

The big limiting factor is brightness.

A projector, for home theater use, in a DARK room, needs no less than about 15 lumens per square foot of screen space.

Doing math (height times width in inches divided by 144 to get square footage)...

So, a 300" screen is 147"x262" or 38,514 square inches.
That's 267 square feet (rounded).

267 square feet, at 15 lumens per square foot, needs at least 4,005 lumens from the projector AFTER CALIBRATION to have minimal acceptable quality in a completely dark environment.

There is really not a list of home theater models which can deliver this level of brightness, and realistically, you want about 20% more light on screen for acceptable results. You can get there with some models, but it starts costing exponentially more to do so.

Home theater projectors, after calibration, tend to be closer to 800 to 1,400 lumens. The Epson LCD models can reach about 2,000 lumens and can do quite well on larger screens or with some ambient light.

If you have the space, you can move your projector back twice as far and get a screen four times the size of what you currently have... Sure, it won't fit on your screen, but it will be about 300 inches diagonal. You will see how bright (dim) the image is.

I run a 161" screen, and I wouldn't go much larger for fear of just losing too much brightness. I have a 1.3 gain screen which helps.

Home theater projectors, especially the inexpensive models (under $3,000) are designed around the typical home theater. The typical home. This means 8' ceilings and a typical image diagonal between 100" and 140". Going larger is definitely possible with the newer, brighter projectors. Like you have at 150" or my 161" diagonal. Especially with a bit of gain to the screen.

But, realistically, to keep the same quality of brightness you have right now, you would need a screen with about 4.0-5.0 gain to get there, and that will significantly impact the image quality.

Oh, and at that point you might want to consider an acoustically transparent screen, like theaters use, and put your speakers behind the screen.
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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I really appreciate such a detailed response.

Even when I played with the projection calculator, all the setups had the position of the projector deep into the red on brightness.

Whenever I get a real projector, I will be able to see the difference, for now, my only experience is with something teachers or business meeting use for presentations.

Thanks again for all the information.
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Projectors from major manufacturers are still very similar across different types. Presentation projectors tend to have lower contrast and a brighter image with weaker colors. So, a 'real' home theater projector tends to be dimmer than these models, but with better color and much better contrast.

So, if at 150" you are happy now, then you can expect it to be dimmer with a home theater model, and 300" will likely look very poor.

Large image sizes like that are achieved with far more expensive projectors most often.
AV Integrated - Theater, whole house audio, and technology consultation during the build and installation process in the Washington, DC metropolitan area.