Building Your Own Home Theater
Evan Powell



Choosing the Right Screen Size, Part 2

So...how big should your screen be?

Well, let's answer this by first asking "where do you like to sit in a commercial movie theater?" Some people like to sit as far back as possible. Some prefer the middle. Some even like to sit in the front row. In choosing how far back you sit, you are really choosing how wide you want the screen to appear from your viewing position. That choice is a personal preference, so there is no ideal solution for everyone. The same is true in your own home theater--your perfect screen size depends on how wide you want it to look from your viewing position.

If you don't have a good feel for your ideal screen size and viewing distance, go watch a movie in a commercial theater. Before the movie starts, pace off the width of the screen, then count the paces from the screen to the row you want to sit in. Let's say the screen is 16 paces from side to side, and when you walk from the screen into the seating area you pace off 24 steps to the row you prefer. You have just selected a viewing distance of 1.5x the screen width, since 16 x 1.5 = 24.

Now sit back and watch the movie. It is important at this point to pay specific attention to the aspect ratio of the image on the screen. It will most likely be either 2.4 or something close to 16:9. As previously discussed, a 2.4 image will always create less eyestrain from any given distance. As you watch, ask yourself whether you would prefer to be sitting closer or farther away. At the end of the film, do your eyes feel good, or are they tired and strained?

Since you will be spending many hours in your home theater, it pays to watch several films from different locations in a commercial theater, so you can calibrate your ideal comfort zone when it comes to image size and aspect ratio versus viewing distance.

If you find that you are most comfortable sitting 24 steps back from a screen that is 16 steps wide, that viewing distance of 1.5x the screen width will hold in your home theater as well. If your room's depth allows you to place the seats 12 feet from the screen, you would want a screen that is 8 feet wide (8 x 1.5 = 12), in order to replicate the same viewing geometry you prefer in a commercial theater.

While a viewing distance of 1.5x the screen width is comfortable for many people, some want to sit closer, say at about 1.3x, or even 1.2x the screen width. Others might feel more comfortable with a screen that takes up a smaller angle of view, and sit back at 1.75x, or even 2.0x the screen width. The farther back you sit, the less work your eyes must do to absorb the entire screen image. That means less eyestrain over a long period of viewing time. On the other hand, the picture will appear smaller and less dramatic. The ideal solution is to find the happy trade-off point where the picture is as large as it can be without inducing eyestrain.

The Next Step: Mark it Off with Tape

Once you think you have determined the ideal screen size and aspect ratio for your viewing distance, use some black electrician's tape and a tape measure to locate and mark the corners of the proposed screen on the wall. Create an "L" with the tape at each corner so it is easy to see from a distance. By the way, make sure the screen position on the wall is as close to eye level as you can make it. Placing a screen too high will cause you to tilt your head upward to look at it--not good! It will create neck strain in the long run and interfere with your enjoyment of the theater.

As you locate the four corners of your proposed screen, make sure the corners precisely describe the aspect ratio you want to install. You can use the Projection Calculator for width and height dimensions. For example, if you want an 8-foot (96 inch) wide screen, the Calculator tells you that the height of the 16:9 image will be 54 inches, and the height of a 2.39 image will be 40 inches. You can move the screen width slider back and forth, and the height numbers will change automatically.

Once you mark the outside corners of the screen, you should also mark within that frame where the other common video formats will appear. On a 2.4 screen, put tape marks where the smaller 16:9 and 4:3 images will appear, and on a 16:9 screen you can mark where the 2.4 and 4:3 images will appear. This will help you previsualize how you will see 2.4 movies, 1.85 movies or 16:9 HD football, and 4:3 classic films and traditional television.

Your Final Sanity Check

Once you have marked off the size and aspect ratio of your intended screen, sit at the planned viewing distance and examine it for a while to verify you have made the right choice. Think carefully about the types of material that are most important to you. Are you going to be watching primarily HD sports broadcasts? If so, does the 16:9 image size that you have marked on the wall look like the size you want sports events shown in? Are you a fan of classic films? If so, are Bogart films in 4:3 going to be displayed in a size you are satisfied with?

How about super widescreen movies in 2.4? If the best display of movies in this format is your primary concern, does the 2.4 block you have marked out look the way you want it?

After thinking all of this through, you should have a settled feeling that your choice to go with either a 2.4 or 16:9 screen is the right one, and that the size you have chosen is correct.

If your room is quite deep, you may be able to move the seating up or back. This will give you some flexibility to make adjustments to your viewing distance, if necessary, after the screen is installed. But if your seating is back as far as the room will allow, getting the screen size right for comfortable long term viewing is vitally important.

This may sound like more preparatory work than you'd expect. But the objective of this article is to encourage you to think seriously about aspect ratio, size, and viewing distance before you make any purchase decisions. Taking the time to think through all aspects of screen shape and size will pay off in the long term enjoyment of your theater.

Once you've identified the aspect ratio and size of screen you want, the next step is to either build or acquire that screen. This will be the subject of the next article in this series.


Reader Comments(15 comments)

Posted Nov 11, 2013 12:33:24 AM

By bob

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just making these decisions but building my own block out cloth screen and simply thought that I'd get the maximum cloth height which is 150 cm, make it 2.4 times as long and erect a simple curtain on each end to open or close to switch between 2.4 and 16.9. the cloth height is the deciding factor as 2.4x for width fits the room and seating position. the height I can't make bigger for 16.9 anyway and will just adjust zoom to match height. still figuring out but just thought might work and make it easy. what do you think?

Posted Jun 29, 2013 8:07:42 PM

By Morgan Talley

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I have been planning a home theater for quite some time and I read many articles and posts about seating distance. However, what I want to know is why the local cineplex doesn't use the same seating distance criteria? The front row seats are way closer than 1.5x screen size ratio. The answer to that question would go a long way in how I want my home theater seating. Keep in mind, I'm very much aware of why these calculations exist for home theaters (eye strain, sensory overload etc...). However, the room I'm planning to use is 30 x 48 and 25' Stewart Director's choice 2 screen and I don't want to have just one row of seating fifty feet away.

Posted Jul 24, 2012 2:38:23 AM

By Matthew O'Sullivan

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As a matter of Interest I have multifocals glasses and my pet (but very good) optical shop did high quality glass lenses with my script for movie only and at a distance of 5 metres ( the distance from my mian viewing seat to my screen) I have a curved Screen Research ISF 2.9m wide 2.4. The curve I think helps. I am not cetain how - but I think the picture is more cohesive to the viewer - this holds for action sequences I think - and I've asked a few people to comment on and confirm that "feeling" about that feature (pre install and post).

3D is another whole different discussion - I think it would be interesting to start this discussion again and reference how the immersion in 3D might potentially change view distances for some.

Posted Dec 31, 2011 9:55:53 AM

By Tony Jones

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Thanks, that was a very informative series of articles. It has given me much to think of in planning my Home Cinema. I have a large DVD and Blu Ray Collection of early and modern film giving the full range of ratios. Most are around the 16:9 mark, including my favourite 70's car films so I may put up with the black bars for the newest 2.4:1 Blu Rays as they are much fewer in number.

Cheers for taking the time and effort to explain the fundamentals of what to plan before spending money unduly on unsuitable kit.

Posted Feb 4, 2011 3:05:42 PM

By Glen

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Everyone has a "formula", and most seem to be based on a variation of "1.5x width". However, projector images have dramatically improved since that rule of thumb first came out.

There is one simple solution. Do not buy your screen until AFTER your projector. Go to JoAnn's fabrics and buy "blackout cloth" (pure white, blocks light completely, about $5/sq yard).

Put it on your wall and project your image. Watch a few movies, varying the size & location. NEVER MEASURE -- please do not have any preconceived notions!

I did this in 2004 when building my theater (panny AE700) http://goglen.com/post/theater/front%20wall,%20textured.jpg

When I'd settled, I measured and it was 130" - so I bought a 133" screen. My wife thought it was a bit too big, and sat in the 2nd row of the theater... for maybe a couple months. Now, she loves the front row! Our eyeballs are 11' back - or 1.1x

Make your OWN judgement this way...

Posted Dec 28, 2010 2:29:46 PM

By Matt Gholston

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Well I almost did go with a screen that was too big, I bought a 120" screen, which left 6" on each side of my room before the walls... In that room it worked great. Then we moved to a new house, and it was almost too big for my new media room!

I would suggest that if you ever think that you will be moving that you keep screen size within reason so that you don't have to chuck it and buy another one down the road.

I have found that my 120" 16:9 screen is very comfortable to view from 10-15' back from the screen, at 8' back it is starting to get fatiguing.

I am lighting it up with a Panasonic AE-200U 720P Projector. When I get my new 1080P unit viewing characteristics may be slightly different.

RMG

Posted Nov 24, 2010 5:02:24 AM

By mike

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much have been said about 16:9 and 2.4:1 cinemascope... my question is, if the native resolution of the projector is 16:9, will there be video quality reduction if i change the setting to 2.4:1? if so, then i suppose the way to go is to use 16:9. in addition, using 2.4:1 will have larger black top and bottom margins on your screen... these considerations may offset the benefits on your viewing distance when using 2.4:1

Posted Nov 16, 2010 2:55:52 AM

By Michael Rudd

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Rather than screen width, it is sometimes helpful to think about screen height. A good viewing distance is often about 3 screen heights back. This is 1.2 screen widths for a 2.4 screen and 1.7 screen widths for a 16/9 screen. The projector operator then has to zoom out the image when changing from 16.9 to 2.4 image. Accordingly the pixels appear larger on the 2.4 image. However, even in this case, most people will not notice the pixels. Remember that a digital movie theater projector usually only has 2048 pixels horizontally, compared with 1920 for HDTV. Not a big difference. (In a movie theater, 2K refers to the number of horizontal pixels; in the home, 1080 refers to the number of vertical pixels! However 4k, horizontal, movie theater projectors are on their way.)

Posted Nov 12, 2010 6:25:46 PM

By RA Moynihan

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Rather than pace out the width of a cinema, I've always used the "fist" method to compare screen sizes between venues. Hold your fists out in front of you at arms length and use them to quantify the visible width of the screen.

For example, my computer screen in front of me is about 2.5 fists wide. Another: when we watched "Avatar" in a cinema last January the cinema was quite full and we had to sit close -- 7 fists wide. After an hour I was starting to feel motion sickness, so I left my family and friends to sit near the back, in one of the few empty seats. No more problems.

I've not constructed my home theater yet, but my design is gradually settling on a width of approx. 4 fists. For my hands this works out to about 8 ft wide at 11 ft distance.

Certainly this method isn't perfectly transportable from person to person, since hand sizes vary. But it is a very easy method to quantify screen widths -- and the measurement tool is always with you.

Posted Nov 11, 2010 4:31:01 PM

By yakov kaufman - israel

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The article has not taken in consideration optometry since. Ask an optometry expert, Why a good sight is phrased in numbers 20:20 or 6:6. What does it mean the numbers in a prescription of eye sight given to you + - No. etc? Answers. A. 20:20 are foot; 6:6 are meters, pay attention to the correlation. Mending the sight, with various numbers of eye glasses is trying to reach an exact calculated point. Now ask the manufacturers of televisions or projectors Why do they express sizes with a diagonal length? Diagonal length is unique to eye sight world. Why? The other world of three dimension objects is measured by Width. Height, Depth. Well, to my poor knowledge. Diagonal X 20 (foot) or 6 (meters) is the "eye sight field". The ultimate point where you are able to see full field without moving one muscle of your eye ball.

Now you can easily calculate picture size vs. distance, or distance vs. picture size.

Posted Nov 11, 2010 1:44:57 PM

By James Quesenberry

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This might sound stupid but I would think that image quality per technology would also play a part in sitting distance. LCD TV vs LCD projection vs DLP vs plasma ect. At a certain distance, per quality of display, aren't you going to pick up on the image processing itself?

Posted Nov 11, 2010 10:58:09 AM

By Mike Knuppe

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At a charity function , meeting George Lucas he told me something I have never forgotten. "Sit in a chair, hold both hands up to the sides of your head, palms in. If your (projected)screen width extends beyond your hands, you will fatigue quickly. I find it to be a good rule of thumb."

Posted Nov 11, 2010 10:54:54 AM

By Alan Brown

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So, using such logic, IMAX must be a terrible idea? Are you also saying that film viewing equates with digital video viewing? The imaging scientists have been saying since NHK's seminal human perceptual factors research that a 1920 x 1080 HD image would be best viewed by most people no closer than a distance resulting in a 30 degree viewing angle. For humans with 20/20 average visual acuity, any closer results in the visibility of individual pixels in the picture. In other words, clouds, sky, faces, etc., start to have an unnatural texture. This can disrupt the willing suspension of disbelief for viewers. Pixels being visible in the image has also been tied to viewing fatigue and eye strain.

Other guides used by experts for recommended 1080p HD viewing distance include: three times the screen height, or 1.5 times the diagonal of 16 x 9 screens. The formulas for calculating a 30 degree viewing angle are: Viewing distance x .5359 = screen width Screen width x 1.866 = viewing distance Some projectors have featured methods to diminish pixel definition by improving fill factor. This has only been marginally effective. At a certain point, viewing these devices from much closer softens the image and diminishes perceived intra-image contrast. Film has an amorphous grain structure that allows closer seating distances, but only up to the point the picture starts to look unnaturally soft.

These are not hard and fast rules, due to variations in visual acuity from one viewer to the next. However, these principles of imaging science allow a good starting point for considering how to design an effective video system. As I have become more familiar with what constitutes a reference image, my preferred seating location in commercial cinemas has moved farther from the screen. A sharper picture looks more natural to me, and therefore more involving. Picture size is not the only factor to be considered in evaluating how immersive the viewing experience will be.

Best regards and beautiful pictures, Alan Brown, President CinemaQuest, Inc.

"Advancing the art and science of electronic imaging"

Posted Nov 11, 2010 10:18:55 AM

By Steve Atkinson

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Nice article Evan...

I think most new HT folks tend to go with a smaller screen than they can. As most are moving up from a normal television set... even saying the words 96" conjures up a screen of immense proportions compared to the 42" set they have now.

Ultimately most people I read on the forums eventually wish they had gone with a larger screen.

Personally I have never seen a HT with a screen that is too large... (and my son's is 151" 16x9 format screen), but I do not doubt it could happen so it is good to cover that eventuality.

In my experience the biggest issue in installing a large screen is that your choice of projectors to light that large of a screen is narrowed considerably.

Posted Nov 11, 2010 10:10:05 AM

By Jim Webster

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Do you have or are you referencing any published data regarding eye-strain as it relates to viewer distance and formats?

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