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Riser Height Calculator

post #1 of 152
Thread Starter 
Every now and again, there's a thread about what is an appropriate riser height. Unfortunately, there is no one answer that covers all situations. Everyone's setup is different, and requires a different answer depending on many different variables. Here's a fairly easy formula to figure the exact minimum riser height for your setup.

Riser Calculator
Courtesy of trunks in Post #2

First, take the following measurements in the same increment (e.g. inches):

S=Floor to screen bottom
H1=Height of seated front row viewers top of head
E1=Height of seated rear row viewers eyes (no riser)
D1=Screen to front row viewers eyes
D2=Screen to back row viewers eyes

Then, plug them into these calculations:

H1-S=V1
V1/D1=R
R*D2=V2
V2+S=E2
E2-E1=Riser height

V1=Vertical 1, V2=Vertical 2, E2=Back row eye level (with riser).

This formula uses a single height viewer in both rows. If you think you'll have taller people in front and shorter people in back, you might want to adjust the numbers slightly to compensate. You will probably come up with a number that seems too high. It is not. This number is the minimum riser height that will allow a person seated in the back row to see the entire screen, over the head of a person seated directly in front of them. Anything less, and some of the screen will be blocked.

Happy Building!

Rob
post #2 of 152

Rob -
I made a simple script based on this forumla.. I hope you don't mind.

thanks,
jake

Sorry, I didn't notice this domain had expired. Here's a new link:

 

http://calc.xn--f5a.net/


Edited by trunks - 10/8/12 at 5:42pm
post #3 of 152
Nice job, guys.
post #4 of 152
Thread Starter 
Jake,

Great job! That is absolutely fantastic! Anyone else think that this should be a sticky? Moderators?

Rob
post #5 of 152
I stuck it before I posted previously. Even added a lightbulb !
post #6 of 152
That is definitely a keeper if it works! Hall of famer.
post #7 of 152
Thread Starter 
Sorry, didn't see it. This is kind of exciting...contributing to a sticky. Woo Hoo!

Rob
post #8 of 152
Since I originated the particular discussion which resulted in showing the basic math followed by the helpful Riser Calculator, I'd like to see further adjustments, such as:
1. A variable number for the height of the seated rear row viewers eye
2. The picture actually changes as different variables are put into the calculator.
3. Assuming the height of the seated front row viewers eye is supposed to be 1/3 to 1/6 of the screen height, somehow add that.

Not being a programmer, it's easy for me to ask for something as complicated as this might become. In any event, nice work.

Sincerely, Take Aim
post #9 of 152
Thread Starter 
Take Aim,

Regarding 1. above, you can use any height you want in the "front row viewers eye" space. It's actually the rear eye height that you need . I simply called it that because I used the same seats for both, and used the front seats to figure the eye height, before I actually had the rear seats. As for the other two, that's all Jake!

Rob
post #10 of 152
Thread Starter 
Jake,

I realize now that my wording of the original formula might be confusing. If you agree, and would like to change the third line of your script to read "Height of rear row viewers eyes", with the tan line connecting the rear heads eyes to the top of the riser, I would change my original post as well. If not, I think people can figure it out.

Rob
post #11 of 152
Quote:
Originally posted by robbyc30
Jake,

I realize now that my wording of the original formula might be confusing. If you agree, and would like to change the third line of your script to read "Height of rear row viewers eyes", with the tan line connecting the rear heads eyes to the top of the riser, I would change my original post as well. If not, I think people can figure it out.

Rob

Done

Quote:

2. The picture actually changes as different variables are put into the calculator.
3. Assuming the height of the seated front row viewers eye is supposed to be 1/3 to 1/6 of the screen height, somehow add that.

I thought about this a little more, and since the room isn't drawn to scale, the second request doesn't do a whole lot for us. Now the third option is a good idea, but I would also need the screen height (and probably the room height) to make it work.
What I would like to do is make a new calculator, this will be much more complex and take some time, but here are my ideas:

this will require room height, width, length. It will make a recommendation for number of riser levels, but allow the user to select how many they actually want (IE room size will allow for 3 riser levels, which script recommends, but user only actually wants 2 in room...) it will have defaults for several items, but all of course are user changeable: 4' riser for standard theater seats, 5' for nonreclining chairs/sofa, 6' for recliners (In my experience these approximate numbers usually work pretty good).
It will then give recommendations for riser height/placement, screen placement and maximum size (limited by riser visibility, or SMPTE/THX viewing angle for closest row)
Any recommendations? Hopefully I can have this done in a week or two (don't have a lot of free time)
post #12 of 152
Quote:
Originally posted by trunks
Rob -
I made a simple script based on this forumla.. I hope you don't mind.

thanks,
jake

Riser Calculator

Very nice guys!

Just one comment.

The brown dimension line associated with the text "Height of rear row viewers eyes " are drawn showing the height of the FRONT row viewers eyes.

Larry
post #13 of 152
Quote:
Originally posted by LarryChanin
Very nice guys!

Just one comment.

The brown dimension line associated with the text "Height of rear row viewers eyes " are drawn showing the height of the FRONT row viewers eyes.

Larry

Sorry, you must've been using it right as I was making the change. Should be fixed now.

-Jake
post #14 of 152
Thread Starter 
I changed the original post to reflect the new script. Thanks Jake.

Rob
post #15 of 152
Rob,
Thanks very much for getting the formulas to us and adding to our knowledge.
Trunks,
Thanks for making it use friendly for some of us.

Art
post #16 of 152
robbyc30
Thank you for taking the time to post the formula

trunks
Thanks to you as well for writing the script so as to input info and get dimensions on the fly.

Best regards
Don
post #17 of 152
Thread Starter 
You're very welcome. Glad to be of service. With so many people here, with so much great information, and giving such helpful advice, this makes me feel a little less like a mooch!

Rob
post #18 of 152
Ok... I'm at work and don't have exact measurements in my brain, but that is just down right cool!!! Thanks!
post #19 of 152
I spent lots of time before construction drawing sight lines etc... to be sure I got the riser height right.

I went and plugged in my numbers to compare with what I came up with in real life and your calculator was only one inch off of what I came up with for my riser.

I can see this being very helpful to everybody starting to plan their theater. Saves time.

Just make sure your eye, head height is the same as the defaults set here. Change them to be more accurate.

Very good job guys.

Jeff
post #20 of 152
Very nice. I built my riser 10" high and my second row is about 3 inches to low. Your calculator says it should be 13-1/2".
post #21 of 152
Just Wow! Thanks! I've just started building. This will surely be useful.

Nice Job! Adam.
post #22 of 152
Hi,
I just plugged my numbers into the Riser calculator and it came back with a rear riser height of 2.25 inches. Anyone else get such a low measurement?

Here are the numbers I used:
Floor to bottom of screen 26"
Height of seated front row viewers top of head 45"
Height of rear row viewers eyes 50"
Screen to front row viewers eyes 13' (feet)
Screen to back row viewers eyes 18' (feet)

Minimum riser height 2 1/4"

*I can't really put my screen any higher. Maybe 28". And the screen to front and back row eyes doesn't have much room for movement either.

My front (non-riser) row is going to be Berkline 094's and my rear (riser) row is going to be Berkline 088's.

Do any of my numbers look off?

Thanks!
post #23 of 152
Your numbers sound very similar to my room and my riser is 16" tall. A two inch riser does not sound big enough.

I put my numbers in to play around with it and I varied the front head level by 5 inches or so and got the number to lower to something like you were getting.

My advice is to not guess where the head levels will be. Go measure this if you have access or have others that own these chairs do it for you.
Second, err on the side of taller if you have the head room in your room. I would go with at least 12 to 14 inches or even up to what I have at 16 inches. I can tell you, when seated in the back row and a full theater, everybody reclined it is perfect. Any lower and I would have visability issues.

Also get some graph paper and draw it out. Put everything to scale and draw sight line diagrams and make sure they clear the head in front. I figured everything in the upright position and it worked out very good for me. Any lower and I would have problems and any higher and I would loose valuable head clearance.

My room setup is:

Berk. 090s

Front row at 12 feet
Second row on a 16 inch riser at 17 feet.
Screen at 24 inches off the floor.
Can't remember eye height but I think its right at 42 inches with my 090s. Add around 5 to 6 inches to the top of your head.

Good luck.
post #24 of 152
Thread Starter 
MoG,

According to your numbers, your rear row eye level is 5" higher than the front row top of heads height. Unless the seats on the 94"s are about a foot lower than the seats on the 88's, this isn't possible. Re-check your numbers.

Rob
post #25 of 152
Great work guys!

Thanks for your efforts

Regards

Ken L
post #26 of 152
I get a negative number on all of my results, any ideas why??

here is what I get:

Floor to bottom of screen 36"
Height of seated front row viewers top of head 42"
Height of rear row viewers eyes 52"
Screen to front row viewers eyes 9'8.5"
Screen to back row viewers eyes 14'4"
Minimum riser height -7 1/8"

Glack
post #27 of 152
Thread Starter 
Glack,

You seem to be making the same mistake MoG did. Unless your front row seats have a seat level drastically lower than you rear seats, the rear eye level should be lower than the front head level (because your eyes are lower than the top of your head). Your numbers indicate you already have about a 16" riser. If you do, and the 52" is including the riser, the calculator is telling you that it is 7 1/8" higher than it needs to be. If you go with the defaults (42" and 36"), you get 8 13/16", which is very close to 8 15/16" (16" - 7 1/8"). If you don't already have a riser, something is wrong with your measurements.

Rob
post #28 of 152
You are correct, I was placing the rear eyes where I wanted them and not at default height. I ran it again with the default settings and all is well

Thanks.
Glack
post #29 of 152
Did all the measurements this AM with wife seated staring at a level (good wife) and drew all out on graph paper. The answer I got was a 16" riser.

This afternoon I saw your sticky, pluged in the numbers and got 16 1/2".

Thanks for the very accurate caculator.
post #30 of 152
I am planning on making a 10" or 12" riser. My sealing is only 7 and half feet tall though. I would rather the backrow be looking down and over the front row. It will be 68" wide to allow full reclining. If you are going to do a riser shouldn't it be atleast a foot tall?
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