Choose Your Projector and Find the Best Place for It


Introduction: Choose Your Projector and Find the Best Place for It

About: PhD in microelectronics with Physics degree. Something I can break?

In this instructable I want to show how to choose a projector and find the better place for it. The most common way to choose a projector is checking how much you can afford, then you find the models and finally check some reviews to see which one is better

And of course, this steps should be done, but we haven't taken in account the most important thing: where are we going to place the projector?

Think about it: Under the same conditions one projector may be better than the other, however, your room probably has something that changes all the equation: ambien light, distance available to the screen, maximum size... In many cases it might be still the right choose but if you follow this instructable you will be sure which one to choose.

If you already have a projector, you can follow the instructable to check if you have it in the correct location. Of course you can always follow the manual, but the amount of values and parameters may discourage you to go on. I'm going to provide an easier way.

Let's get started!

Step 1: Know Your Environment

So, let's start planing: If you have looked around, some people begin with the size of the screen, but I have to disagree. The screen size is important of course but the amount of light in your room will affect drastically your image, it doesn't matter how big you want it, if you have too much light, your image will be difficult to see.

That's because the amount of light in the room affects the throw distance of your projector, in other words, if you have a very bright room, the projector needs to be closer to the screen and the image diagonal (screen size) will be smaller. On the other hand, if you don't have any light at all, you can increase it.

So, how do you know your ambient light?

Well, to be accurate you need a light meter to be able to measure the reflected light, but assuming that you don't want to spend money in something you might use only once, we can use the common values:
- 5 foot candles (fc) (~50 lux) is the light in a nighttime sidewalk or a parking lot, you can see but you don't have good perception of details
- 10 to 15 fc(~100 to 150 lux) is the light you can expect in a corridor or in a changing room.
- 20 fc (~200 lux) is the light you probably have in your dining room.
- 30 fc (~300 lux) is the light ambient you can find in a library or a teaching theater

We can go further, but when you have more ambient light you just have to place your projector in the closest position to the screen. In general, if you want to have a big screen (more than 100") you should go lower to 10fc and for really huge screens (more than 200") it's better to go below 5fc.

You can see the difference in the pictures attached to this step. In the first one just a small desk lamp is illuminating the room but the quality of the image is compromised. In the second picture not light at all is used.

Be aware of three things!
- Values depend on your projector! I will show you this in the next step.
- They also depends on what media you will display (data, pictures, movies...). If you plan to use it to play videogames or movies you have to get rid of almost all the light and get a good screen.
- These are 'reflected light' values, that is, the amount of light that goes to your screen and is reflected, not the light that is emitted from your light source.

You don't need to be extremely accurate, but these numbers will help you in the following steps to make a better decisions. For example, if you don't expect to have any light in the room, as I recommend, you probably will be fine choosing the furthest position to get the biggest screen. But if you can't avoid light, or just don't want to, you should be aware roughly about of the amount of light.

Finally, of course you should know how much space do you have. Things like the maximum distance to the screen, the location of the projector (ceiling or floor), where do you want to sit, be aware that you should be able to connect the cables... just think about it, in the next step you will take all the decisions about these things.

Remember: the projector has to be place exactly on the center of the screen. Yes, many of them has optional horizontal shifts but do not rely on them. You are working hard in finding the best place and this is the best place, exactly at the center of the screen. Only use the horizontal shift if you don't have any other option.

Step 2: Find Your Correct Values

There are two ways to proceed here: The first one is using your projectors specifications (provided by the manufacturer), this is the most accurate but takes more time and you probably want to set up everything as fast as you can.

The second one is using the projection calculator from projector central*, you can search your projector model and then click on 'Throw Dist' in projector's specifications, on the right hand side of the page. You can see how it looks using my projector, and old HITACHI CP-X345 in the picture.

So, at this moment we have an idea of the following:
- A good estimation of the amount of light in the room from last step.
- The size of the room, the options to place the projector and where do you want to sit.

So, you know the parameters and now you can use the projection calculator to find the optimum values:
1- First select the primary use, in my case will be video games and movies, so I select video games.
2- The values show that I need lower amount of light (2 fc) and the website gives me the recommended seating at the actual throw distance.
3- Using the first slider at the bottom, in my case I select 4.5m (14' 9'') due to the size of the room and where I can place the projector. That gives me recommended seating values between 3.6 and 6m (12' 7'' to 19' 9'').
4- Select the aspect ratio and the mounting. In my case I choose 16:9 and floor, respectively. So now I can see that the bottom of my picture should be 5cm (2") higher than the center of my projector lenses, this is called the vertical offset.

Please, spend some time in this step and tweak all the parameters and get used to play with the calculator, this is definitely the most important step because you can see and compare what you will have at the end. Play with different projectors if you are choosing a new one or different positions if you are trying to find the best place for yours.

As a recommendation, I would suggest you not to rely on enhancements that your project may have as the zoom to increase the size of the screen, the keystone, etc. This are very useful tools that can be used once you have placed the projector. First try to get everything without touching anything, specially the keystone: The keystone is used to get the perfect square image if the projector is not completely flat but it degrades digital image. If your image is not perfectly squared, try to move the mount until it is and do not use the keystone if you can.

A couple of more optional things you probably want to be aware:
Sound and noise: You should not hear the projector, new ones have quite silent fans but just be careful if you put the projector behind your head.
Cables: You will have several of them, plan ahead were they will be placed.

*I'm not affiliate with projector central in any way, I just find their calculator useful.

Step 3: Finally, Place the Projector

Ok, you made it! At this time:

- You should have played enough with the calculator with different projectors to choose the one that suits you better. You only need to get the chosen one!


- You have a good idea of where it has to be placed, so you can start to move the furniture. The last step will be play with the configuration of the projector to get the best quality possible. If you have followed this instructable it shouldn't be so difficult and you just need to tweak a couple of parameters.

As an example, you can see in the first picture how my screen looks from where I sit to watch movies. It is just below the ceiling and the projected image looks squared. In the second picture you can see how I place it below the couch using an old desk and a small bedside table. The zoom is at minimum and I didn't use the keystone, I just corrected the brightness and the contrast.

Share your comments and thoughts!! Everyone is welcome!!



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