Comments on: Home Theater Calculator: Viewing Distance, Screen Size

By: Carlton Bale

Carlton Bale — Fri, 03 Feb 2012 16:59:19 +0000

Sam, lens shift should move the picture up and down without creating any keystone. It sounds like your projector is not level. The lens should be perfectly perpendicular with the screen. You needed to adjust the up/down rotation of the projector mount and also the left/right rotation. Once that is right, lens shift should allow your to fine tune. Depending on the projector capabilities and screen, you may need a longer extension pole between the ceiling and projector, to move the projector closer to the center of the screen. Good luck!

By: Sam

Sam — Thu, 02 Feb 2012 19:29:42 +0000

Carlton, this is very insightful indeed. I have a question about my setup. I have a room that is 18ft (L) x 11ft (W) and 8ft (H). The problem with this room is that near the entrance of the room the height is 8ft and the end of the room the height is approx. 7.5ft (it’s located under the garage). It’s the only space I have. I already have a 106″ fixed screen that is installed which is centered and levelled. I have a Sony VPL-HW30ESB projector mounted from the ceiling appox 13 ft back. I have a sectional in there that is approx 12-13ft from the screen. The setup of the room is great for sound and brightness.

Here is my issue, I am getting a lot of keystone issues. The projector is approx. 6″ from the ceiling (the lens). I need to check if its completely centered but it’s really close if anything. Is there anything you can suggest? I don’t want to do any lens shift and even if I do the keystone effect is still there.

Appreciate any assistance.

Thank you!

By: Frank

Frank — Mon, 16 Jan 2012 19:50:10 +0000

Carlton,
From what i read your the guy to ask. Im undecided on two areas of the home theatre project. 1. enclosed or open. 2.size and distance of screen. I have a room i can dedicate to a HT rough dimensions of 12’8″ wide
x 17′ with 7′ high finished cieling. I want to accomodate four or five viewers comfortably. i would like to use a 120″ screen with a 16:9 ratio most likely an epson 8350 projector.
Any thoughtss would be . Thank you

By: Rick

Rick — Thu, 12 Jan 2012 22:47:15 +0000

Thanks, Carlton – yes it definitely helps as you have confirmed my preliminary conclusions. Rick

By: Carlton Bale

Carlton Bale — Tue, 10 Jan 2012 09:12:22 +0000

Rick, I’m unaware of any projectors capable of this short of a throw ratio for home theater. I’ve seen some, but as you say, I don’t think the primary intent was picture quality. The only likely downside to a projector like this would be uniformity of image brightness, especially on high gain screen, with tends to be pretty directional with light return. The edges might not be quite as bright, but this is probably only a minor concern.

I think you’d be better off looking for a projector that has a flexible enough vertical optical shift. That way, you could mount it on the beam and have it lower than the top of screen, nearer the center. I’m pretty sure there are projectors that have flexible enough vertical offset to do this. I recommend to start searching on projectorcentral.com and go from there. You may need to find the manuals for a few different models to confirm. Hope this helps.

By: Rick

Rick — Mon, 09 Jan 2012 23:36:17 +0000

Carlton – thanks for the website – lots of good information. I am planning to put a home theater in my basement and have a question about the throw distance and throw ratios. The room size will be approx 20′L x 13′W x 8′H and I am looking at putting in two rows of seating. My problem is that there is a center beam about 5′ back from the screen running across the room (parallel to the screen). This beam extends down to about 7′ from the floor. So if I follow the advice I’ve seen to have the bottom of the screen about 3′ off the bottom of the floor, this would effectively limit my screen size to 4′ high. This is assuming I lower the projector to a height of 7′ to clear the beam. I’d like to put in a larger screen than that. So I was considering the idea of a short throw projector mounted on the “screen side” of the beam. This would enable me to put the projector tight up against the ceiling and take advantage of the full height of the wall for the screen. Assuming it is back 5′ from an 8′ wide screen, that would put the throw ratio at about .625. I’ve seen some ads for short throw projectors but they seem to be more geared towards presentations or special situations, not for home theater use. Is that true or am I wrong on that? Are there good home theater projectors available with throw ratios in the .6 range and if so – do you sacrifice anything in terms of quality of the picture? Thanks in advance for your advice! Rick

By: Alan Brown

Alan Brown — Wed, 21 Dec 2011 15:47:58 +0000

I was emphasizing those points for Norm. Your work is impressive. In my experience, fundamental principles may not be grasped by many readers until they are presented a number of times, and stated a variety of ways. Thanks for the resource your site provides.

By: Carlton Bale

Carlton Bale — Wed, 21 Dec 2011 14:58:34 +0000

Alan: All of the factors you mention are in included in the spreadsheet.

By: Alan Brown

Alan Brown — Wed, 21 Dec 2011 03:14:37 +0000

You may be missing an important fundamental in determining screen size. Image size should be evaluated based upon the primary seating position and the capabilities of your projector. These factors are limited by the fact that your projector will likely be producing a 1920 x 1080 resolution image. If you sit too close, you will see the pixel grid in the picture. Faces, etc., will have a regular texture, which is not natural. Sit too far away and image size will occupy a smaller field of view and limit a sense of envelopment.

THX image width is typically based upon film presentation. Video is not film. Film has an amorphous image structure, while digital video has a grid-like structure. Sit closer to film and the image just gets softer and less sharp/crisp/natural in character. The THX recommendations for image width are for a 36 to 40 degree field of view. The digital video recommendation is for a 30 degree field of view for average 20/20 vision. That is intended to provide the sharpest image short of recognizing the pixel grid. If your vision is better than 20/20 you will need to sit a bit farther from the screen. If you have less visual acuity, you can sit a bit closer to the screen.

If you reduce the size of your screen and place the front row at 3 times the screen height, or 1.5 times the screen diagonal, this will fulfill the digital video industry recommendation. By reducing the screen size appropriately, you can move your seating closer to the screen wall and allow the space you need for the second row for occasional guests.

Some viewers don’t seem to mind watching video programs with the pixel grid visible in the image. I find this distracting and annoying while watching movies. In my mind, envelopment in the program consists of more than sheer panorama. It includes image quality as well. In the end, you get to decide how to view movies in your home theater. I find a smooth, sharp, natural image much more enjoyable than just the image size factor.

By: Carlton Bale

Carlton Bale — Wed, 21 Dec 2011 01:23:35 +0000

Design around your first row as it will always be occupied. Occasional second row guests won’t notice or care.

By: Norm

Norm — Wed, 21 Dec 2011 00:58:11 +0000

Thank-you Gary B.

As the calculations demonstrate, it is almost impossible to have two rows (6 feet apart meet the “perfect world” calculations.

A compromise between the two seems to be the only option.

By: Gary B

Gary B — Mon, 19 Dec 2011 21:54:50 +0000

Well, according to the calculators (either the spreadsheet or the link I gave above), with a 14′ wide screen (16′ diagonal) you’d want eye distance between 21-30 feet. There’s not really an “optimal” front row position; you need to make all the rows fit into this range as best you can. And really, it’s all a tradeoff between seating and screen size.

Here’s another simplified calculator that has a “wizard” format that might be easier for you to use:

http://www.hdhes.com/tv/hdtvviewdistance.aspx

By: Norm

Norm — Sat, 17 Dec 2011 21:50:29 +0000

need help. Have a projected home theatre room (25’4″ x 15’8″)basement…no windows can be totally dark.

figuring a max of 4 oversized seats per row based on advertised “home theatre furniture (11 feetwide /4 seats), and a wall that could hold a (14′ wide screen x 8 or 9 feet in height), what would be the optimal distance from the screen for the first row? Should the screen be somewhat smaller in width and height?

Thanks

By: Panasonic TX-P37X10. HDReady (720p) versus FullHD (1080p). « Nauscopio Scipiorum

Sat, 17 Dec 2011 11:12:46 +0000

[...] CarltonBale.com Home Theater Calculator: Viewing Distance, Screen Size [...]

By: Gary B

Gary B — Thu, 15 Dec 2011 16:08:45 +0000

I’m not Carlton, but I’ll take a shot since I’m going through the same questions right now. There’s a few different things to consider: (1) screen size, (2) dimensions for best audio and (3) seating space. Let’s start with seating space, since I’m coming to believe that’s the least flexible. (After all, you can adjust screen size or deal with viewing angles, or you can do treatments to fix the audio, but you can’t get around room for seats.) If you’re going with typical “home theater” seating like you see to the left and right of this page, 14×12 is going to be a bit tight but doable for 8 seats.

Regarding the screen size, the spreadsheet is awesome but here’s a calculator that’s a bit simpler to use: http://myhometheater.homestead.com/viewingdistancecalculator.html . According to THX (high-quality movie theater) standards, you will want to be in the 26-36 degree viewing angle range. Make sure you plug in the eye positions in both the front and back rows, using the maxim “every seat a good seat.”

One thought about a riser: you’ll have two rows regardless, and you’ll want to raise the second row. This raises the question of how to get into the room. The room will have to be arranged so the door gets around the seats, but also you don’t want the door to come into the riser area. (Think about it: open a door and you see a step.) So, the room will want to be arranged so the door comes into either the front (next to the screen) or front-half side of the room.

There’s lots more to be said, and Carlton will probably correct my blathering, but if you want to talk about this more I’ll be glad to pass on what I’ve learned.

By: Shailendra Bansal

Shailendra Bansal — Thu, 15 Dec 2011 15:19:35 +0000

Dear Carlton, I am constructing a house and want to have a home theatre in the basement. I have two room options – one measuring 17’4″x 22’4″ and the other 14′ x 12′. I want seating capacity of 6 to 8 people and want to use a LCD projector. Can you please suggest which room size would be better and other things I need to keep in mind (steps, AV system etc.)? I am a newbie so sorry for the trouble. I tried the excel sheet but couldn’t really make much out of it. Thanks…..Shailendra Bansal

By: Gary B

Gary B — Wed, 14 Dec 2011 11:00:44 +0000

Chris, can you estimate a starting guess, plug that in, and see if the results look good? Then change the input and see what happens.

By: Oldengaerde

Oldengaerde — Wed, 30 Nov 2011 17:31:45 +0000

Dear Mr. Bale,

Thank you for kindly providing this handy calculation sheet for all to use. It is a great help, and your effort is much appreciated!

Sincerely,
Oldengaerde

By: Carlton Bale

Carlton Bale — Tue, 29 Nov 2011 13:48:18 +0000

Mike, I’m afraid these are not quick, easy answers. You should enter data in the spreadsheet and play around with it. Here are some quick suggestions on where to start. Riser height depends on how close the row is to the one in front of it. 14″ is generally a minimum; someone over 6′ tall would almost be touching a 9′ ceiling when standing up in the back row, but that row isn’t designed for standing, so I wouldn’t worry about that. You will need at least a 123″ screen, maybe 133″. Plug numbers in the calculator. Screens that big need a very bright projector; you can start by looking at the Panasonic PT-AE7000. Speakers are a very personal choice; I suggest figuring if you want in-wall or on-wall or floor-standing, then listening to the options. Good luck!

By: Michael

Michael — Tue, 29 Nov 2011 09:48:08 +0000

Hey Carlton, its great reading all your material. I have some questions, I am planning a home theater room That is 20′ wide and 25′ deep, 3 rows of seats for a total of (20)seats, what size screen would you recommend for a projector?, I am looking at getting the best model projector out there for a home, looking to spend close to $5,ooo for it. How high should I make each riser for the next 2 rows. Ceiling is eiter 9′ or 10′. We are building the house next year and I am installing it in my basement, I have not decided how tall to make my foundation. What brand speakers do you recommend for something like this 7.1? Thanks, Mike