CurtPalme.com Home Theater Forum

[Melifluonze]

Ok, so maybe I'm crazy... I'm thinking of doing passive 3D with 2 9500LC projectors (and running them in parallel for 2D)

Aside from the 3D processor, there shouldn't be anything too crazy about the setup, right?

Anyone done this? Passive 3D with CRT? It HAS to be crazy good, right???

What did you use?

- Melifluonze

[stridsvognen]

Did you finish considering what it takes to make this possible.?

Type of filters/ screen.. Processors. and so on. Time/ money.. And the quality compared with a 3D DLP projector.

Not to mention how complex it will be if you also like good 2D.

Ill think you need to go all in for 3D with P22 green tubes, and that messes up the grayscale/ gamme, and light output

Making good 2D imposible.

I think my setup with a 500 hour Marquee 9553LC Ultra, i was not able to push more than 6-7 FL with a messed up grayscale on a 100" 16:9 screen.

Where it today with a p19 LCP green will do 14-16fl with a good grayscale.

How much light will you need to compensate for the glases and filters.?

[Melifluonze]

Cool, thanks for the response. Kind of still working it out. Digital is easy. This is torture, but far more interesting... and I think the results will be the ultimate! No ghosting (aside from filter issues), no weird video modes, no shutter glasses and emitters...

Ok, so Curt has the right processor on this site: dual projector, passive 3D, with 2 HDMI outputs. This allows BOTH projectors to output standard 60 Hz 1080p at max brightness, without trying to run at 120 Hz at a lower resolution or something. No special phosphor needed, no timing adjustments between shutter glasses and projector, no possibility of artifacts due to slow phosphor or incorrect timing, no multiple video timing settings (each with different geometry calibration) for 2D vs. 3D.

http://www.curtpalme.com/3DEvolver.shtm

Guys are running shutter 3D with CRT, which is effectively 1/2 the light per eye, plus shutter glasses attenuation. Passive, with 2 projectors, should result in better brightness!

I'm not worried about the filters. This stuff is mass produced plastic. The glasses (vs shutter) are hugely inexpensive and practically disposable. Great for kids...

http://www.polarization.com/polarshop/

(No, I am not associated with, nor am I promoting the above business... it's an example...)

2D Is no issue. No fast phosphorr needed. Greyscale is good in both 2D and 3D modes. This is a "standard" projector stacking. Once stacked for 2D, works for 3D, assuming your video timing is the same in both modes. That means you need to post process the video with the same scaler(s) you use for 2D.

I see it as the ultimate. No offense, but DLP doesn't do it for me. I see rainbows with the cheap ones, stray light issues, flicker, and pixels. I can't stand pixels. If I went digital, I'd get another DiLA and run dual digital projectors for the same reasons; no emitters and cheap, light glasses! Gives you great brightness without all the BS. But I still see pixels...

The issues I see are that you might want a second scaler/processor (one for each projector) and you need the somewhat expensive passive 3D processor to feed the scalers and projectors. Yeah, that's $$.

The biggest issue I see is that you'd need 2 screens. A silver screen for 3D, and a white screen for 2D, if you wanted the perfect calibration. Since it's nearly impossibke to get the screens in exactly the same place unless you physically swap them, you'd have a focus problem, or you'd be doing set-up (screen swapping) to watch the different formats.

Sooo... aside from the additional scaler and screen thing, I'm still excited! (And yeah, probably not playing with a full deck...) While we're at it, how about those anamorphic lenses to allow you to use the entire tube face for a brighter and better resolved 16x9 raster??? I'm kidding, but not about the passive 3D.

-Melifluonze

[Nashou66]

I think you should just use the shutter glasses. It is how Barco did there stereo optic Simulators. But Barco also had a filter that dropped down in front of the lenses.

I think Noos in Germany played with filters in front of his CRT.

I know there was some one with Pics.

I attached a Barco brochure. go to page 8 I think.

[Melifluonze]

Rough crowd...

Shutter glasses for 8 people + emitter = about $1300... easily pays for the second scaler...

I'm not reading anything good about CRT 3D with shutters:

- need the right phosphor on green
- bad greyscale
- 720p at 120 HZ
- all sorts of timing issues, artifacts, ghosting, etc...

That seems like a compromise... dark images at a lower resolution with set-up problems...

Where's the adventure?

Who has done 3D with a 9500LC or equivalent, and is completely satisfied with the result?

[stridsvognen]

[Nashou66]

[garyfritz]

No, he wouldn't need P43's. You need P43's if you use shutters and you have to swap quickly from left- to right-eye image. With two separate polarized projectors, he's just displaying continuous left on one, right on the other -- basically the same as a non-3D projector.

The polarizer is going to cut down the light, but the stacked projectors would make up for some of that. According to this post by somebody who seems to know what he's talking about, polarizers only transmit about 25% of the light -- near 0% in the "wrong" axis, and about 50% in the "right" axis. So if that's right, even with stacked projectors (adding 25% + 25% to get 50% brightness) you'd only get about the same light to your eye as a 50/50 shutter setup.

[Melifluonze]

But... it would be sooo smooooothhh... and at full resolution...

So, I've found film that is 99.9% efficient (0.1% non-polarized light), and transmissive to 38%. Transmission through two parallel filters is about 30% (i.e. through the glasses, which are parallel polarization). So at your eyes, you'd get about 60% of the total brightness of one equivalent projector...

But... but... you're drawing the full raster at 60 Hz. Are you effectively brighter due to more surface area being drawn on the phosphor, or is it equivalent because you are scanning faster? Bet there's something there...

And, with shutter glasses, perhaps since you are drawing twice as fast, you might only have the shutter glasses transmission to worry about with active glasses, since each re-draw of the raster should be of equivalent brightness to the last...

That means that running the passive setup at 720p @120 Hz would give you more brightness? (And burn your tubes out faster?)

I still believe that the stability and higher resolution would be a winner... The 1/2 equivalent light output is a bummer though... I was so hoping someone actually did it...

I'm impressed with 3D at the theater... I don't see why it has to be so different at home... Maybe 2 4K digital projectors would work... $$$

[jeffslife]

Go man Go !

[CasetheCorvetteman]

You wont need P43 even with just one projector and shutter glasses.