Over the past several years, I've slowly constructed a spreadsheet to meet all of my home theater design needs. I noticed on various forums that others could probably benefit from this spreadsheet, so I cleaned it up and I'm now making it available to the public. Please download it and put it to good use!
The spreadsheet contains calculations for the following:
- recommended viewing distances for a given screen size – for both flat panels and projectors (based on THX and SMPTE standards)
- recommended viewing distances for a given display resolution – 480p, 720p, 1080p/1080i, 1440p, etc (based on Visual Acuity standards)
- various screen aspect ratios (4:3, 16:9, 1.85:1, 2.35:1, custom ratios, etc.)
- projector screen size & screen brightness with guidelines for recommended values (based on projector brightness and screen gain)
- projector screen size & projector mounting location (based on min/max projector throw distances)
- seat locations, a second row stadium seating platform height calculation, and a few other goodies.
theater_calculator_v4.0.xlsPlease report any problems or suggestions via e-mail or the comments form below.
Revision history:
- Version 4.0 – 26-August-2008: Added Anamorphic (horizontal expansion) front projector lens option, which adjusts projector brightness and throw ratios when selected.
- Version 3.7 – 14-June-2008: Clarified back row platform height input fields, modified formulas to prevent negative platform heights (user info message instead), changed spreadsheet defaults to better fit a typical home theater.
- Version 3.6 – 21-July-2007: Added feature to allow calculation of Visual Acuity Viewing Distance based on eyesight of the viewer. The default is 20/20 vision; changing the input to 20/10 vision with show that the viewer will be able to spot resolution deficiencies at much greater distances due to more acute eyesight.
- Version 3.5 – 20-July-2007: Fixed bug in the aspect ratio input that caused international users to have problems (problem was related to using "," as decimal delimiter instead of ".") Added cells to the far right of the spreadsheet to allow changing and adding custom screen aspect ratios.
- Version 3.4 – 27-June-2007: Widened columns that were causing being truncated for international users.
- Version 3.3 – 16-Feb-2007: Added 2.35:1 aspect ratio back.
- Version 3.2 – 13-Feb-2007: Changed anamorphic aspect ratio from 2.35:1 to 2.370370:1, which is the correct value for a 16:9 projector with a 4:3 anamorphic lens. Corrected spelling mistakes on one of the extra tabs within the spreadsheet.
- Version 3.1 – 15-Dec-2006: Fixed unit conversion formula that was causing "Second Row Field-of-View Width" to not calculate when any unit besides "inches" was selected.
- Version 3.0 – 13-Dec-2006: Added minimum viewing distance calculation, added conditional feedback on seating distance for each specification (seating distance too far, etc.), added first row and second row seating distances (for conditional feedback on seating distances), added field-of-view results (in degrees), added ability to calculate projector throw distances for any screen size (just enter the throw information for one screen and it will interpolate for other screen sizes), fixed mis-spelling that was causing formulas to break.
- Version 2.9 – 01-Dec-2006: Added 2.40:1, 2.70:1 screen aspect ratios, added 'hover' comments to better explain the different seating distances; added conditional formatting on the screen brightness result cell (red if brightness is too low, yellow if it is close to being too low).
- Version 2.8 – 20-Nov-2006: Added charts for "seating distance vs. screen size based on screen resolution" and "seating distance vs. screen size based on published standards."
- Version 2.7 – 29-Sept-2006: Edited notes fields to improve clarity for data entry fields.
- Version 2.6 – 09-May-2006: Added LCD/Plasma support. Added 16:10 aspect ratios for LCD monitors. Added hints to help enter panel resolutions (hint lists commons resolutions). Added pixel density calculation (useful when using as a PC monitor). Added dot pitch (in mm – millimeters). Added total pixel count. Fixed spelling errors.
- Version 2.5 – 27-Nov-2004: Updated screen brightness calculation to adapt to entering screen width vs. height vs. diagonal measurement. Thanks Brad for finding the problem.
- Version 2.4 – 01-Nov-2004: First Public Release. Uses both metric and English units. Converts between many units. Gives hints for some common input values such as aspect ratio. Seating distance. Platform height. Viewing angle. Screen brightness. Many other features.
You might want to add these viewing distance standards, too:
Reference Viewing Distance specified by SMPTE (3 Picture Heights and AR=16:9 or lower)
Minimum Viewing Distance recommended to hide the "Screen Door Effect" where PPD=30
Maximum Viewing Distance recommended by THX for CinemaScope (HVA=36° and AR=2.39:1 letterboxed)
Ideal Viewing Distance specified by 20th Century Fox for CinemaScope (HVA=45° and AR=2.39:1 letterboxed)
Minimum Viewing Distance specified by SMPTE (2 Picture Heights and AR=16:9 or lower)
Source:
http://home1.gte.net/res18h39/calculator.htm
This diagram shows nicely, as well:
http://home1.gte.net/res18h39/allscope.gif
This tends to jive with what most people find an ideal seating distance (1.2x-1.3x 2.35 width) for maximum involvement and immersion when it comes to dedicated home theaters with 2.35 screens – based on what I've witnessed on AVS Forums over a period of quite some time.
Oh, I should also note that most people with 20/20 vision find visual acuity for maximum resolvable content for moving images is around 30-40 pixels per degree (approx factor of .5 to .66) – might be worthwhile to add this distance, as well.
Just to clarify, for the universal projector throw distance calculator, is the screen width horizontal or diagonal? and Thanks for this cool tool.
JJ: It's horizontal screen width for the universal throw distance calculator.
Hey
Thanks for this awesome tool.
However i want to confirm something, if you could help me out here.
My room length is only 13 FT, and i plan to get a full hd projector along 140" screen . Do you think this size will be suitable for this room, i just want the maxiumi size possible based on the 13FT length. Please advise
thanks in advance
R
Hello
i would like to know. do you have a calulator to estimate the viewing distance and resolution for a soccer field…..
Help please?
Gladys: The same calculator should work. Just enter screen size and viewing distance. The field-of-view would be much smaller because people would be farther away, but the spreadsheet will tell you if the viewer at a certain distance needs more or less resolution than what you've entered in the top section of the spreadsheet. Keep changing the resolution until you find one that is appropriate.
Carlton, Thanks for this great tool. I just have a question for you. I don't really understand the calculation in the final portion of the table for the platform height for the second row. Is the back row seated eye height supposed to be measure from the floor or from the platform level? If my first row seated eye height is 40 inches from the floor and my platform for the second row is 10" height. The back row seated eye height should be 40" + 10" for a total of 51", assuming that both seats are identical. However in the table I get a negative value for the back row platform height when I enter these values.
Pedro: I've updated the spreadsheet. It should address all of your questions. Here is a list of the changes:
Version 3.7 – 14-June-2008: Clarified back row platform height input fields, modified formulas to prevent negative platform heights (user info message instead), changed spreadsheet defaults to better fit a typical home theater.
Thanks Carlon.
Brilliant, thanks! If I can say so, I ran your calculations by a customer service rep at Panosonic and they agreed that I only needed a 42" 720p for my family room, kudos to both of you, they could have easily upsold me.
How high should I set my screen from the floor fro best viewing? Scren size 92" (45X80) viewing distance back is about 13.5ft. and my viewing hieght when sitting wil be about 40". Where should the center of the screen be located?
The middle of the screen should be near to eye level, or slight above eye level. If you have 2 rows of seating, make sure the screen is high enough for the second row to see above the front. The screen will probably look too low on the wall; building a stage above the top of the screen solves that problem.
I think what this formula needs is the ability to calculate optimal tv size based on viewing distance/seating distance, resolution, and the like…
Ecellent work,however it is unclear to me,are you talking eye-screen distance or chair front-screen distance or any other distance?Might be my stupidity,butbpls clarify.Thanks C.J.H.Potasse
Excellent work – really useful… I want to place my Sony TV – 52 inches diagonally over a fireplace – the minimum distance from the floor to the bottom of the TV would be about 60 inches – to clear the mantle.
Having a room 13 wide by 15 feet depth – how do I calculate the maximum height of my tv over the fireplace? Thanks LP.
Carlton, do you calculate the recommended screen placement (vertical), as well? Thanks so much.
Vertical placement: Start with the center of the screen at eye-level and move it up as aesthetics and any second row viewing-over-the-heads-of-front row requires.
Just wanted to say thanks, your calculator is great
answered all of the questions I had
Carlton,
Having been using your program and it is great.
Question, does a program exist that gives one the optimum drop placement from the ceiling so as to achieve the highest fL at the viewer's eye. Assuming that the distance of the viewer from the screen and the PJ are different.
Please correct me if I am wrong (most proably am geometry was never my strong point) but ideally should the viewer's angle and the PJ angle be the same?
Thank you for all your hard work on this program.
Paul: You are correct. The vertical angle between the viewers eyes up the center of the screen and the angle between the center of the screen up to the projector should be the same for maximum brightness. The difference is more apparent with higher gain screens, which are more directional. But you are likely to get more brightness gain by zooming the lens so the projector is as close as possible to the screen; the trade-off is generally slightly reduced contrast ratio.
Carlton,
One more question, in the Epson 6100 manual is written "Ideally, keep the projector and place so its lens is centered between the top and bottom of the screen.
In the manual, however, the maximum lens offset A (upper half of screen) if PJ is table/bookshelf mounted is, at 11.8 to 25.2 feet distance, 27", maximum offset for B (lower half of screen) is 86". Does this mean that the strongest fL is centered 69% up on the screen, equation as follows (((1-(27/86))*100), or is this number irrelevant.
If true would it affect the measured height at which one would calculate the light bounce in a higher gain screen say 1.24 and up? Would the measure angle be taken from 69% up on the screen and not halfway up?
If it does affect where the measure is taken from would it be best to do as Epson suggests (center on the screen), or shelf mount it higher than center and offset down, or ceiling mount upside down? The only issue I see if this percentage offset does affect the maximum fL the ceiling mount upside down angle would create a smaller luminosity angle to the viewer requiring a very long drop from the ceiling, if PJ is placed at around 21 feet, the drop would be 44", a longer drop if closer, assuming persons eye level at 37".
So what I am questioning is the luminosity center on the screen different than actual center if looking at the screen, and where on the screen is it best to take the angle measurements? Roll off percentage starts to take its toll at 21 feet.
I realize that I could be over thinking this but as you can see it would change the numbers as to where the angle is calculated from, but it is bugging me not knowing.
In my own case the 16.9, 1.24 gain Wilsonart Designer White homemade screen is a 110" diagonal, the throw distance for the present will have to be 21', hope to change to 14.5 feet (under negotiation), and the screen sits 44" off the floor. I know 3-4" too high. We sit 15’6” from the screen. The arrangement cannot easily be changed because of being married to, as Rumpold of the Bailey said “She who must be obeyed”.
Thank you for a very quick reply to my last question, after this I promise no more unless I do not understand the reply.
Paul, I think you're over-thinking things. Make sure you more the projector in a way that integrates with your room. You won't notice any small performance differences between dead-center of the screen and the top edge of the screen. Figure out a range of projector locations that are acceptable to the aesthetics of the room, then within that boundary try to optimize image quality.
Carlton,
Thank you for your response. That is what I thought I was doing "over thinking" this but I wanted to be sure.
At present I have no option but to put the projector at 19'11" throw, mounted away from a back wall, fortunately I have a 10.5 ft ceiling.
The height of the projector is mounted in such a way as the angle to the screen and the returning to the viewer's eye is nearly the same and after calibration and inputting the figures into your program gives me a calculated fl of 18-19. Which as the room has little to no ambient light is perfectly satisfactory.
The PJ is installed in that manner. And while it does not have the punch that mounting it at 14.5 feet does it appears to me, and I maybe just imagining (please tell me if I am) to really bring out the various shades of grey very well. A good comparison would be this looks more like an Ansell Adams photo, versus a good advertising photo where punch is more important than shades of grey, such as Mr. Adam's photos. The "Pirates of the Caribbean 2 " Blu-ray movie with mostly dark scenes looks great.
As we really only watch DVD and Blu-ray movies I actually like less punch and more detail but I think it is a matter of personal taste. Of course at this distance it is really not able to let one view TV in the daytime, unless it is cloudy, but we do not do that in this room.
Now the half-German genes in me (it must be exactly so) can sleep at night, fortunately the other half of the genes are mostly Russian and as usual they do not care a less.
So once again,
Thank you
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I don't see a variable for projector distance form screen. Wouldn't this distance affect the ft-luimen?
Yes, projector zoom ratio does affect projector light output (as well as contrast ratio.) This variable is projector-dependent and cannot be calculated using a generic formula. Read reviews for your projector of interest, determine the brightness at a specific distance, and enter that brightness into the input field of the spreadsheet.
Thank you for that spreadsheet!
How about adding an optimal TV/Screen height calculator using the eye height and distance from TV and suggested angle (10-20 deg) as parameters.
How do I figure up the lumens for a particular projector? Is it the listed number on the particular projector shown in their specs. If so how would I figure the lumens if the lamp is turned to a lower mode? I currently have a Mits HC6000 projector.
The manufacturers specs are the best place to start. But as you probably know, the ANSI brightness spec highly inflated for most manufacturers (with the exception of JVC.) To figure out calibrated brightness, your best bet is to find a magazine/blog review or a forum thread and start reading. Real-world tests are the best source of data.
Hi, Please help!!!!I would like to hang a LCD above my fireplace. The viewing distance is 10 ft and the height of the fireplace is 35 inches. Will this work? What is the maximum TV size I can use? Thank you so much. I have been thinking about this so much – my head hurts!!!!
I can't help with your calculations, but you have to beware of heat above the fireplace. 35" base doesn't seem horrifically high off-hand, but it doesn't seem like it would be optimal.
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