Ideal Mount Height for the BenQ TH671ST Projector on 16x9 screen?

[kirkemg]

Projector central is a huge help but I can't seem to get the last piece which is how far from the ceiling it needs to mounted. Relevant stats below

Par2Pro Stealth Image Size:
183" W
103" T

Ceiling is 11'3"

PC has it being placed about 11'6" away from the screen.

How far beneath the ceiling should the BenQ TH671ST Projector be placed to get the top of the image correctly placed?

Thanks!

[Cruisin1966]

Let me see if I understand all these numbers.

Ceiling is 135"
Top of Image is 103"
Projector is a -3" vertical offset

Center of projector lense should be at 100", or 38" from the ceiling

[kirkemg]

I messed it up. Top of the image is 107.5"

[spaz]

This is from the BenQ site.

[Cruisin1966]

Hmmm, does that mean I misunderstand the vertical offset? If I put it on the other side, 3" above the 103" mark, it would be approximately 32" from the ceiling.

[sgp2204]

Hmmm, does that mean I misunderstand the vertical offset? If I put it on the other side, 3" above the 103" mark, it would be approximately 32" from the ceiling.

I believe that is correct. If you click on the info button, it says, "The Vertical Offset number shown is the distance the projector is sitting above or below the bottom of the image. It is measured from the center of the lens to the bottom of the image." I'm not 100% sure, but for what it's worth, I've never seen a number with a + sign for vertical offset. I think the - sign indicates inches below the screen for a bottom mount, which means, in theory, it should change to a + sign when you switch to a ceiling mount to indicate inches above the screen (but it obviously doesn't). Like I said, I'm not 100% positive, but that's the way I understand it.

[Cruisin1966]

Here's an example of a projector with a "+" vertical offset: https://www.projectorcentral.com/Ric...ulator-pro.htm

[GungHoGolf]

You don't really need to worry about exact height with the TH671ST, as it has very flexible and smooth vertical keystone adjustment with no image degradation if you point it up or down slightly from its ideal height with no keystone (which is 3" above the top of your image). Most screen enclosures have a straight top to them, which means you have to mount the projector low enough to not have its light beam cut off by the extended top of the enclosure - centering the lens with the top of the image is the easiest way to accomplish that.

Otherwise, if you have an angled top to the enclosure, you can mount up to 3-4 feet higher than the top of the image and still get a very good image with the keystone adjustment. It's one of the many reasons the TH671ST makes a good projector for golf sim use; I go into all the reasons at https://store.gunghogolf.com/BenQ-TH...NEW-p265749740.

[GungHoGolf]

The TH685 has a much longer throw, making it less suitable for golf sim use (will probably have shadows of player on screen at the distance it needs to be mounted back from the screen).

[RIGolfGuy16]

Ron - I have the 671ST with 12' ceilings and running 16:9 ratio. I'm trying to get the projector out of the way as much as I can. Are you saying that will the keystone adjustment, I could raise the projector so it sits 1' higher than it should (i.e. 15" vs. 2") without distorting the image? Viewable screen size is 142x80

[GungHoGolf]

RIGolfGuy16 That's correct - as long as there's no top on your screen enclosure that will cut off the beam of light when the projector is raised. The TH671ST can easily be up to 3-4 feet higher than the top of the screen while allowing a squared-up image with no visible keystone effects. Note however: when dialing in extreme keystone, it can change the throw ratio - typically the projector needs to be further back for the same size screen when a lot of keystone is used. So get up on a ladder and test its position prior to installing the mount in the ceiling.

[RIGolfGuy16]

GungHoGolf This is awesome. Thank you very much. Side note, do you have any thoughts on a decently priced laser? Hate the flicker w/ the FLIR cameras.

[GungHoGolf]

Laser projectors will cause the flicker in the recorded video of the screen too. To avoid that flicker, you have to go with a 3LCD-type projector like the home cinema offerings from Epson, but they max out at WUXGA resolution (1,200 vertical pixels vs 2,160).