Home Theater » Home Theater Calculator: Viewing Distance, Screen Size

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1. Carlton Bale dot com » Blog Archive » 1080p Does Matter - Here’s When (Screen Size vs. Viewing Distance vs. Resolution)
   

   18 years ago

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2. 

   Great tool. It looks though that you have diagonal misspelled though in the dropdown menu in cell e7 (diagional). It makes it useless as the rest of your cells look to key off the proper spelling.

3. Thanks Frank. I noticed the same problem over the weekend. I’ve posted a new version (3.0) with this problem corrected as well as many other feature additions.

4. Terrific tool. I see only one cell with strange results. It is the “Field of View Width (second row center).” Is this the width of vision at that distance from an object, or is this supposed to be the subtended viewing angle as in the cell above it for the first row?

5. Randy: Thanks for the feedback; the second row field-of-view width calculation was supposed to be the same as the first row. The unit conversion for “Field of View Width (second row center)” was not calculating properly. Version 3.1 fixes that problem.

6. Hello!
   I got through your website when I searched on Hometheater calculator. So far your calculator has the most info to it; But I am still getting confused about certain specs/info. Are there any similar calculator out there, that would give the option of what screen size(diag,W,L)if you want to use front projection or Rear or Direct view Dispaly, seating distance, if you want to add additional rows? All would have to be based on actual room dimensions. It has been so confusing on the ‘rule of thumb’ for screens size (i.e 3 to 5 times of the seating distance). Are they talking about diagonal or Width and Length? how would you decide of the actual height of platform if you’d like to add a 2nd row etc…Basically all the info/detail that you have on you calculator but by just inputting the actual dimenssions of the room?
   thanks for your help!
   Sidney

7. Sidney, I haven’t seen a calculator that starts with a room dimension and gives you possible layouts, but I think that is a great idea. I’d see if I can add that capability at some point to my spreadsheet. My spreadsheet can currently answer your questions, but you’ll have to enter different screen sizes and then see what the “maximum recommended seating distance” is for each screen size. The smallest screen size that gives a viewing distance equivalent to your back row distance from the screen is the screen size you should choose. (In other words, don’t use the rule-of-thumb you mentioned, use the THX / SMPTE recommended values in the spreadsheet.)

   There is really no way to recommend the type of display based on room layout. The general guideline is to get a front projector if you have complete light control (zero visible sunlight) and want a giant screen (larger than 60 inches). If you don’t have complete light control, get a flat panel or rear projection unit that fits your budget and aesthetic requirements.

   The second (or third) row seating height is dependent on two factors: the height of the screen and the height of the the head of the someone sitting in the front row. Basically, you don’t want to have the screen blocked by someone’s head when you’re in the second row. My calculator will currently perform that calculation; just enter the info for screen height and first row head height in the appropriate cells.

   As for number or rows, Allow enough room for a reclined chair (66 inches) and a walkway in between rows (12 inches minimum; 18-24 inches recommended). Then look at the spreadsheet for min/max seating distances. For a room 21′ deep, 3 rows would put the front row too close to the screen. I’d stick with two rows.

8. I am trying to determine the proper height for mounting a tv on a wall. Is there a formula that will calculate this by knowing the viewing distance, nominal height of eye level and using recommended viewing angle of 20 degrees.

9. Lawrence: The formula would be (ArcTAN of 20 degrees)*(distance to screen) + height of viewers head from = height of screen from floor. (If you enter this into Microsoft Excel, you’ll first have to convert degrees to radians for the ATAN (ArcTan) function to work. I’m assuming you’re measuring to the middle of the TV screen, not the bottom.

   As a simple rule of thumb, I’d suggest picking a point 1/3 (or up to 1/2) of the way up from the bottom of the screen and mounting that at eye level. Mount it higher only if you are worried about blocking viewers behind you.

10. Dear Carlton,

    This is brilliant. your calculator is of immense value, especially for computer unsavvy people like me.
    for this very reason i would appreciate if you could send me te exact typed code for the screen height that you mention above as i am quite sure that i cannot define this myself.

    best reagrds
    aditya

11. Aditya: To tell you the truth, I’m not sure what the “recommended viewing angle of 20 degrees” means in terms of screen height. I have a hard time recommending it or including it in my spreadsheet because I don’t even know if it is above or below horizontal, plus I’m not sure it’s valid either way.

    For screen height from the floor, the nominal eyeball height from the floor is 40 inches. The bottom of the screen should be no more than 40 inches from the floor. Ideally, the center of the screen would be 40 inches off the floor if you have one row only.

    If you have two rows, my spreadsheet has the calculations (near the bottom) to determine screen height based on the first and second row seat heights and distances from the screen. This is to prevent the first row from blocking the second row.

12. Hi,

    You may want to add 2.37:1 to the drop down list of allowed AR’s in your excellent spreadsheet as all the anamorphic horizontal expansion lenses are 1.33. 1.33 X 1.78 gives 2.37:1, not 2.35:1.

    We sell 2.37:1 screens to allow for this.

    Just a thought

13. Carlton:

    I have been reading the AVS thread on the Mits 46231 and found a link to your very helpful website here. Thanks for taking the time to put this together. I have found it to be very useful.

    One small nitpick. On your Theatre Calculator spreadsheet, in the tab named Sheet 2, the word “noticeable” has been spelled incorrectly in cells 2C, 2E and 2G.

14. Darrin and John: Thanks for the feedback. Changes implemented.

15. Hi,

    I would like to know how to determine the best height to put my screen on a wall and why it’s not part of your calculator ?

    Thanks

16. Thank you for the great spreadsheet. I have one question. In the cell for projector brightness, should I enter the rated brightness or the brightness measured while playing from reviews.
    Thanks

17. Jack: Definitely use the measured / calibrated brightness. The inflated manufacturer specification figures do not represent real world performance.

18. The 4:3 aspectratio won’t work? Spreadsheet gives no value ex. fo Screen Brightness1 (projectors only) #! foot-Lamberts #! cd/m2

19. Tjm: The 1.33:1 (4:3) aspect ratio is working fine for me. You probably have a blank cell cell or missing input. You can’t leave any of the input boxes blank. Try re-downloading the spreadsheet if you can’t get yours corrected.

20. Just wanted to add my thanks for a great resource in the spreadsheet. Any chance of adding a 1.33 anamorphic lens option (eg ISCO III) to the sheet?

    Cheers,

    Mark

21. Mark_H: That capability is already there (indirectly). Enter the native resolution of your 16:9 projector and then select 2.37:1 as the aspect ratio. The only thing it will not do is compute the new throw ratios (with the lens) based on the original projector throw ratios.

22. The most recent changes in the revision history say “16-Feb-2006”, but it should be “2007”.

23. Atamido: Thanks, fixed!

24. good tool,but may you please give a Chinese edition?

    B’rgds
    Bill

25. Sorry, no plans for a Chinese edition. I don’t speak Mandarin and can’t enter pinyin characters. Additionally, maintaining two versions is more than I’d want to take-on.

26. Thanks, I was wondering how to negotiate a maze of facors as I try and setup a media room for the viewing of my photography – this is perfect! You’re a practical genious, thanks for distributing it.

27. The 4:3 aspect setting does not work correctly for me either. I just downloaded the spreadheet. Choosing 4:3 aspect ratio, screen height is calculated as zero. It will stay at zero even if you change the aspect ratio back to the original or another value. And some other values in the spreadsheet are #VALUE! when changing to other aspect ratio’s after chosing 4:3.

28. Great Job!!! I Just wanted to say thanks. Your calculator was very helpful!!

29. Very good stuff! It’s exactly what I was looking for… Let me see if I get it: for a 37” TV HDMI, my actual viewing distance (9-10 feet) is a few longer? Thanks!

30. Hey!

    I just looked at your calculator, and it’s a great tool. Made me realize I can use it to persuade the wife we need to move our 40″LCD ALOT closer, as I’ve been arguing for a year now!
    Anyways, some of the aspect ratios don’t work for me, and I think it’s because we here use a ‘,’ as decimal delimiter, and your sheet seem to use ‘.’. I’ll work on it a little and try to come up with a clever solution. :o)

31. I had to say thanks for creating by far the best single resource for home theater design that I can find. And being an Excel geek myself I can appreciate the thought and effort that went into creating the spreadsheet. Thanks for sharing with everyone!

32. A new version of the calculator has been posted; here are the details:

    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.

33. Tested it, and it seems to be working flawlessly now. Thanks alot! :o)

34. I just updated the Home Theater Calculator to estimate visual acuity viewing distances based on the eyesight of the viewer:

    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.

35. Carlton,

    I am looking to build a high end home theater with a room 31 feet deep by 21 feet wide by 13 feet tall. I will have three rows of seating. The 1st will be sofa seating, the 2nd will be recliners and the 3rd will be bar seating.

    I am looking to have as wide a screen as possible so that I can have complete immerserion when viewing film. I am looking to use four way masking with a 2 to 1 aspect ratio.

    The projector would be would be mounted in a projection room and be a top of the line unit budgeted at $50,000+.

    What would be the largest size screen you
    think the room can handle.

    Thanks for you time and help.

36. That’s a big room and it needs a big screen. It somewhat depends on which row is your primary row and how close it is to the screen. If you want to use all 3 row and have it be as immersive as possible, you need a very big screen (133+ inches). I think it really comes down to what your projector is capable of handling — it will need to be very bright for a screen this large.

    I’d suggest a 2.35:1 screen. This is also known as a constant height setup. This, combined with a lens that converts a 16:9 (1.78:1) projector into a 2.35:1 projector is the way to go. The setup is becoming very popular in high-end home theaters and many projectors / image processors are now supporting it.

    I don’t have masking on my screen. I was initially going to add it but found I didn’t really need it; the extra screen space was barely noticeable. If you do decide on masking, with a 2.35:1 screen, you would side-masking only. Thus the name “constant height.” Good luck!

37. We are looking to buy a wall-mounted HD TV for an 11′ x 14′ bedroom that we are converting into a TV watching room. What is the best size for the TV knowing that we are probably 9′ away and the room is only 14′ in length?

    Do 1080s or 720s come into play then?

38. Dave S: My best advise is to enter your room info into the spreadsheet. It will answer all of your questions.

39. Hi
    I am planning to have a 110″ wide 2.35 screen. But there are no 2.35 projectors. Only 16:9 projectors are available and ProjectorCentral.com website provides manufacturers projection calculator based on 16:9 projectors. So will the amount of brigtness (in lumens) recommended for a 110″ wide 16:9 screen be the same for 110″ wide 2.35 screen. Please let me know.

    -Venkat

40. Venkat: If you want to you a 2.35:1 screen, you’ll have to use a 16:9 (1.78:1) projector and an anamorphic lens to stretch the image sideways. You’ll need to make sure the video processor (either internal to the projector or an external processor) can handle the required format conversion.

    Brightness is brightness. The light output of the projector divided by the area of the screen being illuminated gives screen brightness. Use the spreadsheet, enter your screen dimensions, and see what your required brightness is. Then go out and find a projector that has the required brightness and can handle a 2.35:1 converter lens.