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Topic: Need help understanding the "numbers"..
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Joined: Jul 13, 2017
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View the Projection Calculator for the BenQ MX570 BenQ MX570
First Ship Date: 5/2/2015
$457
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Newbie here, trying to sift through options for a garage golf sim build and trying to understand a few aspects of the technical numbers. Taking the following projector BenQ MX570..

My screen size will be @ 108" high by 132" (9ftx11ft). So, I guess that makes my "diagonal" roughly 170" or just over 14 ft. This shape (as I understand it) would be closest to a 4:3 aspect ratio, which puts me needing XGA/SXGA. (hope I correct so far). I want to hang projector from ceiling at a distance of 8-9 feet back from screen. So my calculated throw ratio would be @ .72 to .82 So here is my question....this unit lists a throw ratio of 1.51 - 1.97, which is not enough of a "short throw" that I THINK I need. However, this unit shows a throw distance of 7.9 ft to 30.2 ft and a screen size of 60.2 inches to 300 inches. This is confusing the hell out of me. The throw ratio specs suggest this unit wouldn't fit my needs, but the throw distance/screen sizes DO suggest it would work. What am I not understanding here?! Will this unit fill a 170 inch diagonal 4:3 screen from 8-9 feet or not?!

ANY help or explanations that can be offered by you experts here would be massively appreciated. I don't want to buy the wrong dang unit for my needs. Thanks in advance for your guidance and assistance.

Jim


BenQ MX570
Brightness: 3,200 lumens
Lamp Life: 4,500 hours
Resolution: 1024x768 (XGA)
Contrast: 13,000:1
User Rating: Rate this Projector
L?×?W?×?H: 8.7" × 11.1" × 3.7"
Speakers: 10.0 W Mono
Throw Distance: 7.9' – 30.2'
Throw Ratio (std lens): 1.51 – 1.97
3D Projector: PC 3D Ready
Aspect Ratio: 4:3
Audible Noise: 33 dB
Warranty: 3 years
Technology: DLP
Weight: 4.2 lbs
Volume: 358.60 in³
Screen Size: 60.2" – 300.0"
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Also, in regarding the unit's "screen size" capabilities is says 60.2" to 300". Does this refer to the diagonal length of the image it can project onto a screen OR the width of the image it can project?

Thanks
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Screen size is the diagonal. So, 60-300" is the diagonal range.

The throw distance (range) is the range that the projector lens to screen may sit. It has nothing to do with the size you will get, but just the distance the projector will sit. To me, it is a completely useless set of numbers.

The throw ratio is the one that matters. It's the only one that matters.

It is a ratio of throw distance to image width. So, with a 100" wide image, and a throw ratio of 1.51 to 1.8 you would have a throw distance of 151" to 180" available to fill that 100" width.

The reality is that you are working with a 180" diagonal. That's the true 4:3 aspect ratio of a 108" tall screen. You will have a 108"x144" image from a 4:3 projector.

So, your image width WILL be 144". You may also run into issues with the image falling off the edge of your 132" wide screen. I'm not sure if software corrects for this or not. There is nothing the projector can do to correct this issue for you.

So, you want the projector about 8' lens to screen from a 180" diagonal. Now you use the 'Projector Database' function...

http://www.projectorcentral.com/projectors.cfm?g=1&hide=0&st=1&r=&br=&c=&w=&ar=4%3A3&db=&zr=&wt=<g=&ll=&mfg=&p=200&p=2500&wr=&dt=&t=&pjl=0&pjw=0&pjh=0&td=8&is=180&i=d&tr=&tr2=&oop=2&sort=%24&sz=15

Only a couple will do it from 8'. Change it to 9'...

http://www.projectorcentral.com/projectors.cfm?g=1&hide=0&st=1&r=&br=&c=&w=&ar=4%3A3&db=&zr=&wt=<g=&ll=&mfg=&p=200&p=2500&wr=&dt=&t=&pjl=0&pjw=0&pjh=0&td=9&is=180&i=d&tr=&tr2=&oop=2&sort=%24&sz=15

You get more results, but the price goes up and you need a specialty lens.

This is a pretty short throw distance to a pretty large screen size, so you aren't going to get many results. But, if you can get the Viewsonic from the first link, you may be fine.

http://www.projectorcentral.com/ViewSonic-PJD6381.htm

Keep in mind that 4:3 is basically dead. Most projectors are going to end up as 16:9 or 16:10 models when you need to replace it in the future. Then you will need something that can still fill that 108" height from the same distance.

I wanted to add... Once you know the throw distance from 8' is about .7, then you can create a range of throw distances you can use as the search criteria. Call it .65 to .9...

http://www.projectorcentral.com/projectors.cfm?g=1&hide=0&st=1&r=&br=&c=&w=&ar=4%3A3&db=&zr=&wt=<g=&ll=&mfg=&p=200&p=2500&wr=&dt=&t=&pjl=0&pjw=0&pjh=0&td=&is=&i=d&tr=.65&tr2=.9&oop=2&sort=%24&sz=15

Now you get a more extensive list of models. Some with absolutely no zoom at all.

Unfortunately, one of the considerations you must have is that 180" diagonal screen size.

So, while this model looks great:
http://www.projectorcentral.com/InFocus-IN124STx.htm

It can only focus up to a 120" diagonal, not the 180" you need.

So, you will need to check the potential screen sizes to ensure it works with your setup.

No, not a lot of choices, and none of them are going to be really cheap models. That projector is just too close for the typical projection setup and too large.
[Edited by AV_Integrated on Jul 14, 2017 at 6:45 AM]
AV Integrated - Theater, whole house audio, and technology consultation during the build and installation process in the Washington, DC metropolitan area.
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thank you for your detailed reply / explanation. I will review it several times to digest the info that is there. (no easy task for me, lol) I'm sure I'll have a follow up question of two and hopefully you can impart more wisdom.

One quick question you can probably answer...when using the calculator, I usually pick "video game" and "ceiling mount". The stats will list the number (in inches) from the distance of middle of the lense to the top of the projected image. When there is NO option to choose floor or ceiling mount and NO measurement by the lense.....what exactly does that mean?? Can those models not be ceiling mounted??