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Hypno89
Joined: 06 Aug 2020 Posts: 10 Location: Czech Republic, Prague
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Link Posted: Sun Nov 22, 2020 9:57 am Post subject: Custom table for Barco 1209s |
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Hello guys,
I have beginner question considering mount for CRT projector (Barco 1209s, HD120 lenses).
In my flat is not possible to mount projector in the ceiling, so I want to make custom wooden table for it.
Width of room is 368 cm, lengt of projector from back till "feets" is 90 cm, so PD should be 278 cm.
I counted with this formula from install manual:
PD = 1.311 x SW + 0.33
that screen width will be 247 cm. Diagonal should be then +- 111″, if I count right with ratio 16:9.
The questions are:
1) do I need to care about A - correction value from install manual?
2) and mainly - does projector need to be in specific height from floor (according to other values), or it doesnt matter?
Thank you
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kal Forum Administrator
Joined: 06 Mar 2006 Posts: 17850 Location: Ottawa, Canada
TV/Projector: JVC DLA-NZ7
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Link Posted: Sun Nov 22, 2020 2:33 pm Post subject: |
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Don't go by the manual. It's way too conservative. If you want the best results with ANY crt projector (not just Barco) here's how to figure out the throw distance to maximize tube life and light output:
Put the projector on the cart or simply leave it on the floor so that you can move it.
Display something that fills the screen entirely (like a grid test pattern).
Using only the green (middle) tube, look into the tube and increase the image width on the tube face until it is around 1/8" to 1/4" from the edge of the white phosphor. Under no circumstances should you allow the image to go off of the white phosphor surface!
Move the projector back and forth until the image fits your screen.
THAT is the correct throw distance for optimal phosphor usage.
It'll usually be 5-8% closer than what the manual tell you because the manual throw instructions are conservative since they make you install blindly without even looking in the tubes at all.
Ideal install will also have the projector installed half way up (or down) the screen so that you have zero keystone required. That is the ideal setup. Everything else is a compromise. Obviously that isn't possible in most setups so put the projector as close to the middle of the screen in height as possible and square out the sides with keystone. The projector maybe tilted slightly to optimize this (i.e. back end up if floor mounted, back end down if ceiling mounted).
Kal
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My basement/HT/bar/brewery build 2.0
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Hypno89
Joined: 06 Aug 2020 Posts: 10 Location: Czech Republic, Prague
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Link Posted: Tue Nov 24, 2020 9:31 am Post subject: |
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kal wrote: | Don't go by the manual. It's way too conservative. If you want the best results with ANY crt projector (not just Barco) here's how to figure out the throw distance to maximize tube life and light output:
Put the projector on the cart or simply leave it on the floor so that you can move it.
Display something that fills the screen entirely (like a grid test pattern).
Using only the green (middle) tube, look into the tube and increase the image width on the tube face until it is around 1/8" to 1/4" from the edge of the white phosphor. Under no circumstances should you allow the image to go off of the white phosphor surface!
Move the projector back and forth until the image fits your screen.
THAT is the correct throw distance for optimal phosphor usage.
It'll usually be 5-8% closer than what the manual tell you because the manual throw instructions are conservative since they make you install blindly without even looking in the tubes at all.
Ideal install will also have the projector installed half way up (or down) the screen so that you have zero keystone required. That is the ideal setup. Everything else is a compromise. Obviously that isn't possible in most setups so put the projector as close to the middle of the screen in height as possible and square out the sides with keystone. The projector maybe tilted slightly to optimize this (i.e. back end up if floor mounted, back end down if ceiling mounted).
Kal |
Kal, thank you for the help, I will follow that. You seem to have deep knowledge, hat down.
I plan to get some wheels on the table too, so I can later adjust the position easily.
As for the height - "half way up the screen" means in middle by which part of projector? That in middle of screen should be the upper part of projector, upper part of lenses, middle part of lenses, or lower part of projector? I just need that to count right, what should be the optimal total height of the table.
And the other thing - what should be the angle of the tilt? Is there a specific value for the angle of the tilt when floor mounted, or it is dependant on other factors too?
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kal Forum Administrator
Joined: 06 Mar 2006 Posts: 17850 Location: Ottawa, Canada
TV/Projector: JVC DLA-NZ7
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Link Posted: Tue Nov 24, 2020 1:00 pm Post subject: |
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Hypno89 wrote: | As for the height - "half way up the screen" means in middle by which part of projector? That in middle of screen should be the upper part of projector, upper part of lenses, middle part of lenses, or lower part of projector? I just need that to count right, what should be the optimal total height of the table. |
In an ideal situation the pictures on the tube faces should be half way up the screen. Now that said, basically nobody does this as normally the best throw distance for CRT projector places it right at about the best seating position (which is why most people will try and ceiling mount first otherwise they're giving up the best seat in the house).
Quote: | And the other thing - what should be the angle of the tilt? Is there a specific value for the angle of the tilt when floor mounted, or it is dependant on other factors too? |
Don't calculate this.
Display something that fills the screen entirely (like a grid test pattern) like mentioned above. Perfectly rectangular with zero keystone, centered perfectly on the tube faces. Now tilt up or down until you get the right angle to display it centered on the screen.
Kal
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My basement/HT/bar/brewery build 2.0
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