Couldnt you buy 2 cheap LCD or DLP projectors (ones with good brightness) and fix them to a platform and synchronise their images to give you twice the lumens?

For example buy 2 BenQ MP6100 projectors for $700 each giving you 3000 lumens each your display would be 6000 lumens, which is equivalent to a much higher cost projector.

I bet you could easily view that in plenty of ambient light!

At first appearance, you would think you are doubling your lumens, but it doesn't exactly work out that way. I know I've read the calculations here somewhere but I'd have to search to find them. It is something that has been done, you just don't get double the lumens.

Someone will chime in with the info before I can find it again.

Lining thme up is the hard part. They don't have geometry controls like CRTs have. Then, of course, your lamp replacement price would double too and they aren't exactly cheap.

Or you could get a 2.0 gain screen and ge the same effect without having to pay for two projectors and two lamps. :D
Better yet, build a 3.0-4.0 gain torus and get the effect of having 3 or 4 projectors. :D

I have a torus. I'm not sure what the gain is, but it's high. Really high. :)

Although, thinking about it now, two projectors would allow projecting onto a darker screen for higher contrast and better blacks in ambient light and rooms wit light colored walls. So, it depends on the screen you use.

i think heat would be the biggest issue. unless you celing mount one and table mount the other, one would be breathing the exhuast of the other

Get a dalite high power screen instead

Get a dalite high power screen instead

I have to agree. I have a big HP and a big torus (for the CRT) and they seem to be about equal in brightness.

Dave

What you are talking about can be done but if your goal is ambient light viewing and your screen size is anywhere around a normal size one 3000 lumen projector will provide the horsepower to tolerate a good amount of ambient light given the right screen.

First off you have to know if the ambient level you are thinking is very severely bright even two 3000 lumen projectors isn’t going to cut it. If by a lot of ambient you mean you would like to sit and watch a bright image and still have enough light to read the newspaper then that is completely possible.

As strange as this is going to sound you don’t need all those lumens to see the brightest parts of the image on the screen. What you will need the high lumens for is to see the darkest parts of the image. And the reason that sounds so strange is making the darkest part of the image doesn’t require many lumens.

Now that I have your head spinning….. :eek: :D

The high lumens is needed to overpower a darker screen to what some call (reject ambient light) I don’t care for that term at least in this mode of dealing with ambient light. the screens darkness has to be matched to the projectors brightness that has to be matched to the amount of ambient you hope to deal with. All three have to be matched to your expectations of PQ under this level of lighting.

There is a added benefit to such a setup and that is after you have it and you start diminishing the ambient level you will be treated to a outstandingly impressive PQ that will be maintaining almost all the projectors rated contrast resolution.

Unless you are thinking a very huge screen or a very bright room you won’t be needing that much horsepower. As to the suggestions of a higher gain screen. That is and isn’t at the same time the same as more lumens when dealing with ambient.

There are links below in my signature if you want more info on gray screens and high ambient. The one labeled fun read is about what you posted to.

A major negative is that you will also be adding to the noise level. Not doubling since we hear logarithmically but still a lot more noise.

I personally find my single Z5 too loud and it is considered a quiet projector. The fan noise from two cheapies would likely be insufferable during even remotely quiet sections of films.

Cheers

A major negative is that you will also be adding to the noise level. Not doubling since we hear logarithmically but still a lot more noise.

I personally find my single Z5 too loud and it is considered a quiet projector. The fan noise from two cheapies would likely be insufferable during even remotely quiet sections of films.

Cheers

It could be said likewise we see logarithmically also because our eyes adjust aperture over a range of 23 f-stops. All this extra light and noise and heat from two projectors wont have the same result on the screen one may think when you hear a number like 6000 lumens. What will happen is our eyes will compensate for the brighter image and higher ambient and you will just be seeing in a comfortable range in your vision. That’s the reason a plasma TV looks ok just like a projector with one tenth the brightness in a dark room looks ok.

Great comments, thanks guys.
Judging from your comments I guess I actually want contrast not lumens.

Some projectors have a "blackboard" display mode to project onto black screens.
Can you really get a good picture projecting onto black, or very dark grey?