The Ultimate 3D projection system: A Practical Discussion Thread - Page 25 - AVS Forum
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post #721 of 2269 Old 06-06-2011, 02:14 PM
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oh, that is brilliant. I hope that works on my flat black walls.
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post #722 of 2269 Old 06-07-2011, 03:06 AM
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Quote:
Originally Posted by wnielsenbb View Post

oh, that is brilliant. I hope that works on my flat black walls.

Another idea is to make one IR sensor less sensitive: Put a filter on it.
If you aim the remote at the walls, only one projector is triggering menu.
Then you swap menus with normal aiming at the screen:

menu - no menu
no menu - menu

Also, on my projectors, I can choose from two locations on the screen for the menus: center and lower left. Guess what... one is center and one is lower left. So I know which projector is showing menu.

Jack
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post #723 of 2269 Old 06-13-2011, 07:10 AM
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Quote:
Originally Posted by solid_dvd View Post

Could please someone tell me the best way to test that I have the filters in the direction suggested by RBTO and how to work my way up to have the filters at the correct angles? I am losing the little hair I have left on my head over this. Thanks for the info again guys.

The best way to do this is to have someone help you. Turn on both of your projectors and illuminate the screen (has to be a silver screen which preserves polarization). Sit with your head level and glasses on (have to be linear 45/135 polarized glasses). Have your friend place one of the circular filters in front of the projector you will use for your left eye, and temporarily block the other projector output. Close your left eye and have them rotate the filter until you see the least amount of light on the screen (as seen with your right eye). If the circular filter is backwards, you won't be able to do this (null won't happen). Repeat for your right eye projector (close your right eye and obtain the dimmest image possible by rotating the filter on that projector - opposite projector temporarily blocked). Leave the filters in the positions found. You should now see one projector with your right eye and the other with your left eye.
That's it.
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post #724 of 2269 Old 06-13-2011, 10:36 AM
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Quote:
Originally Posted by rdjam View Post

I'll have a big update on this in the next week or so, after I have played with the Black Diamond 3D and Harkness 240 that I have coming in.

rdjam,
Hows the update coming? I'm curious to read your new findings and opinions.
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post #725 of 2269 Old 06-14-2011, 06:28 PM
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As of now is using two optoma 3dxl's the only way to send a left and right signals from blurays to left and right projectors?
Also what is this Dolby 3D sync generator?
http://item.mobileweb.ebay.com/viewi...d=300544508452
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post #726 of 2269 Old 06-14-2011, 08:44 PM
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Yes, as far as I know. No idea that that sync generator is.
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post #727 of 2269 Old 06-14-2011, 08:49 PM
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Those are wheel controllers, you could see them here: In pairs




Best darn Dolby I have ever seen on a 80 foot wide IMAX in Galveston at the DCI symposium.
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post #728 of 2269 Old 06-14-2011, 11:42 PM
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Quote:
Originally Posted by curtishd View Post

As of now is using two optoma 3dxl's the only way to send a left and right signals from blurays to left and right projectors?
Also what is this Dolby 3D sync generator?
http://item.mobileweb.ebay.com/viewi...d=300544508452

A few people have the cypress demultiplexor (CH-322). It works, from what we can tell.
http://www.avsforum.com/avs-vb/showthread.php?t=1313893

There's another one, I think... can't remember what that one is called.
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post #729 of 2269 Old 06-15-2011, 03:08 AM
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Quote:
Originally Posted by CINERAMAX View Post

Those are wheel controllers, you could see them here: In pairs

Best darn Dolby I have ever seen on a 80 foot wide IMAX in Galveston at the DCI symposium.

Wouldn't static filters be better with two projectors?? Either inside or outside. You get 7-10% more light and definitely get rid of sequential issues.

Jack
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post #730 of 2269 Old 06-15-2011, 04:50 PM - Thread Starter
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Oh woe is me....

I now have two new 3D projection screens (the Harkness, and the SI BD II 3D 2.70)

...but one of my JVC projectors decided to take this opportunity to die last week...

Geez... talk about timing

OK - so as soon as I get it out to JVC and back, I'll finally be able to finish all the work in this thread and enjoy!

Sorry everyone!

Ahh... F1 in full HD 3D with
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post #731 of 2269 Old 06-15-2011, 04:55 PM - Thread Starter
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Quote:
Originally Posted by xhonzi View Post

rdjam,
Hows the update coming? I'm curious to read your new findings and opinions.

Sadly, see above...

But we'll get thru it!

Ahh... F1 in full HD 3D with
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post #732 of 2269 Old 06-15-2011, 05:05 PM - Thread Starter
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Quote:
Originally Posted by curtishd View Post

As of now is using two optoma 3dxl's the only way to send a left and right signals from blurays to left and right projectors?

There are a couple of ways, but the nice thing with the 3DXL is that it can output 24p per channel for Bluray 3D - others convert each channel to 60p I believe.

The 3DXL also has very good compatibility with most 3D formats.

Ahh... F1 in full HD 3D with
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post #733 of 2269 Old 06-15-2011, 06:37 PM
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I see the new Vutec Silverstar 3D can be bought curved. That would be a really awesome screen I imagine. One funky thing is they have both passive and active versions. Not sure how the active one would be different than my regular silverstar, which is amazing for active already.
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post #734 of 2269 Old 06-16-2011, 10:09 AM
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Quote:
Originally Posted by rdjam View Post

Oh woe is me....

I now have two new 3D projection screens (the Harkness, and the SI BD II 3D 2.70)

...but one of my JVC projectors decided to take this opportunity to die last week...

Geez... talk about timing

OK - so as soon as I get it out to JVC and back, I'll finally be able to finish all the work in this thread and enjoy!

Sorry everyone!

That is a real shame. Looking forward to the results when you get it back from JVC
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post #735 of 2269 Old 06-16-2011, 10:18 AM
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Quote:
Originally Posted by rdjam View Post

Oh woe is me....

I now have two new 3D projection screens (the Harkness, and the SI BD II 3D 2.70)

...but one of my JVC projectors decided to take this opportunity to die last week...

Ouch! That sucks. I mean...

I am sorry for your loss. My condolences to the widow.
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post #736 of 2269 Old 06-16-2011, 07:25 PM
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I am getting closer and closer to actually doing this but I have yet another question: when doing Dolby 3D when placing the filter in front of each projector can I simply just put the filter in the light path or must it be placed at the same angle as the light path? Basically if the projector is ceiling mounted and by using the lense shift to adjust screen placement must the filter also be rotated/manipulated?
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post #737 of 2269 Old 06-17-2011, 12:25 AM
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Quote:
Originally Posted by curtishd View Post

I am getting closer and closer to actually doing this but I have yet another question: when doing Dolby 3D when placing the filter in front of each projector can I simply just put the filter in the light path or must it be placed at the same angle as the light path? Basically if the projector is ceiling mounted and by using the lense shift to adjust screen placement must the filter also be rotated/manipulated?

Just give a little tilt so filter is perpendicular to light path, as prescribed here.
Rotation has no effect.
Also it is best if you have long throw as projection cone is narrower (Unfortunately for me, I have a poor 1.5:1 throw but still love my setup ).
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post #738 of 2269 Old 06-17-2011, 12:51 AM
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I am going to chime in with my experience with the glasses as filters. I've been keeping quite as I wanted to give all my energy and time to the setup and pm'ing Jack-bauer

Hopefully I am going to share my experiences soon with also spectrometric scans of the glasses which I did at work.

@curtishd, I am using glasses as filters and my projectors are currently at 4 meters for a 100" diagonal screen. I dont have any problems luckily because of the longer throw of my projector and the distance. I cut slices of PVC pipe (~2cm deep) and mounted the glasses in and I can turn them that way. But as jack said, angle of the glasses dont affect the picture much. I am going to upload a picture when i get home.
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post #739 of 2269 Old 06-17-2011, 06:59 AM
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Some quick and dirty way of making lens holders


We were discussing with jack the possibility of putting the filters after the lamp. My projector seems to have some space which would accommodate the filters. a rail system can be also made which would let the filter go in and out.




LL
LL
LL
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post #740 of 2269 Old 06-17-2011, 10:46 AM
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It is REALLY hot in there. You don't want your lenses in there, and you really don't want to mess with that airflow to the bulb.
I am pretty suprised the glasses make acceptable filters. The glasses are designed to filter the 12fl coming off the screen, not the 800 lumen coming from the projector.
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post #741 of 2269 Old 06-17-2011, 11:06 AM
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Quote:
Originally Posted by wnielsenbb View Post

It is REALLY hot in there. You don't want your lenses in there, and you really don't want to mess with that airflow to the bulb.
I am pretty suprised the glasses make acceptable filters. The glasses are designed to filter the 12fl coming off the screen, not the 800 lumen coming from the projector.

...and still it works very very well... outside the projector for the moment, but still getting all the 800 lumens.

And because they are vacuum deposited glass and not organic, I suspect they can withstand high temperatures (*). Exactly the same manufacturing process as the IR dichroic filter which is touching (almost) the lamp.

But I agree, air flow may be an issue. Any temp sensor efendy?

Also, if the dolby filter could be put after the IR filter....

(*) Of course we are talking about glass glasses here, not the plastic ones.

EDIT: It looks like your IR filter is inside the lamp (front lens looks angled....). Am I wrong?

Jack
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post #742 of 2269 Old 06-19-2011, 02:49 AM
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Quote:


It is REALLY hot in there. You don't want your lenses in there, and you really don't want to mess with that airflow to the bulb.
I am pretty suprised the glasses make acceptable filters. The glasses are designed to filter the 12fl coming off the screen, not the 800 lumen coming from the projector.

yeah it's pretty hot there. I was a little bit worried that the lens would crack but being inorganic, it would withstand, no?
there is around 3.5mm gap between the front of the lamp and fresnel lens(?) and thickness of the filter is 2.5mm. I am not sure this 3.5mm is critical for air flow. lamp appears to have its own cooling/air circulation internally (guessing based on the gridded window on top, or is it a passage to exterior for fumes in case of a blow up on the lamp?). as for the slit, it's very large (2cm?) so adding 2.5mm wouldnt affect the air flow imo.

but as said, it's a little bit risky to try I guess but my motto in research is "high risk - high impact research", that's why I cant publish many papers

Quote:


But I agree, air flow may be an issue. Any temp sensor efendy?

I didnt see one but I need to look more closely.

Quote:


Also, if the dolby filter could be put after the IR filter....
EDIT: It looks like your IR filter is inside the lamp (front lens looks angled....). Am I wrong?

That glass on the front of the lamp is in concave shape but I dont know anything about ir filters except the fact that they make projector-based multi-touch tables possible.

Can it be placed after fresnel lens? would this approach make it more dangerous for the lamp as the reflected light would be focused/concentrated back by the fresnel lens?

I cant open up my projector as it still has got another 3 years of warranty. but as jack said, lenses work pretty good externally. so I would stick to that at the moment
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post #743 of 2269 Old 06-21-2011, 01:56 AM
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Quote:
Originally Posted by jack-bauer View Post

...Of course we are talking about glass glasses here, not the plastic ones.

But plewacka seems to use the plastic ones as filters for the projectors with success:
http://www.avsforum.com/avs-vb/showthread.php?t=1325342
Quote:


5. Take 1 pair of the Dolby 3D glasses, and Remove the Lenses as Carefully as Possible...
8. ... place one of the flattened lenses in front of the projectors light path and mount it using tape or whatever.

That is the good thing with inorganic filters :
- organic filters (polarizers) absorb unwanted light => they heat and die slowly....
- inorganic filters (infitec/dolby) reflect unwanted light => they don't heat and never die

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post #744 of 2269 Old 06-21-2011, 08:32 AM
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Polarizing filters, which are based on organic compounds, are affected by heat, but more so by the actual light which can have violet and ultraviolet components. These cause bleaching of organic materials. On my projector which has a rated 4000 lumen output, very little heat exists in the output beam, but it's the shear intensity of the light which is dangerous to filters over time.

Dolby filters are made by depositing thin layers of inorganic material on a substrate (traditionally, an expensive process) which filter light frequencies though interference effects. While the inorganic materials are mostly free from bleaching effects, heating can change the thickness (and hence the spacing) of the thin layers, and will "detune" a dichroic filter. Dichroic (multilayer interference) filters also have a problem with off angle light passage. If the light is off axis (not going straight through), the layers appear thicker and result in detuning of the filter. When placed in front of a lens that has a wide dispersion angle, the efficiency of the filter is decreased which Jack has mentioned earlier in his posts.

I guess my point is that both polarizers and Dolby (dichroic) filters have their advantages and disadvantages. Ideally, the Dolby approach should be better than the polarizer take, but as has been pointed out in this thread, the Dolby system has its drawbacks also (color shifts and need for a collimated beam going through the filters).

Those folks who want to locate dichroic filters inside their projectors have the right idea, but keep in mind that the glass substrate type (don't even consider plastic substrates) will shatter if they are subjected to too much heat (near the light source itself), and that would leave a pile of glass shards in your projector that need removal. Likewise, if the filter runs hot, it may shift its characteristics enough to introduce additional color shift in the image and degraded performance.

In any case, with a dichroic filter, all of the light should be going through the filter as much on axis as possible to get the best use of the filter.
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post #745 of 2269 Old 06-21-2011, 09:02 AM
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Thank you RBTO. Very informative post.

I think I can live with replacing the filters (as I use lenses from the glasses) if "detuning" happens.

I can place the filters on axis as much as I can. but this makes me worry if the light reflected back from the filter would harm the LCD panels. Filters never heat up so there is no heating problem as you said but what about other factors you've mentioned?
Is the light reflected back from the lenses condensed (focused/concentrated?) or in the same shape (same intensity)?
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post #746 of 2269 Old 06-21-2011, 09:29 AM
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I did a quick test. I shone iphone4's light through one of the lenses with a little angle and took a picture. with a little angle, light is reflected away from the axis at a degree which, i think, would be enough to pass by the lcds without deteriorating the projected image. does this sound right?


LL
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post #747 of 2269 Old 06-21-2011, 08:48 PM
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Quote:
Originally Posted by efendy View Post

I think I can live with replacing the filters (as I use lenses from the glasses) if "detuning" happens.

I can place the filters on axis as much as I can. but this makes me worry if the light reflected back from the filter would harm the LCD panels. Filters never heat up so there is no heating problem as you said but what about other factors you've mentioned?

Detuning will happen if a dichroic filter is heated, but the filter returns to normal when it cools.

Correct me if I'm wrong, but I think you're planning to use your filters in front of the projection lens. If that's the case, you shouldn't have any problems with light being reflected back into the LCD panels nor problems with the filters detuning due to heat. The reflected light would be a small portion of the light normally handled by the LCD panels, and shouldn't cause any LCD failure (though you might encounter some lens flaring issues - specular reflections in the projected image). If you're projecting a fairly narrow beam (long throw to screen), filter tilt (off axis effects) most likely won't be of concern. I think Jack mentioned that he had some issues because he was projecting a wide beam to a nearby screen (short throw). The portion of the beam going to the screen extremes would be tilted relative to the filter in that case, and the bandpass of the filter would change for those rays. How much this affects the image would be a matter of testing it. If you are projecting to a further placed screen, most of the light will be on-axis and not tilted relative to the filter, so you should be ok. As you posted, testing is the best way to check things out.
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post #748 of 2269 Old 06-22-2011, 12:38 AM
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Quote:
Originally Posted by RBTO View Post

Detuning will happen if a dichroic filter is heated, but the filter returns to normal when it cools.

Correct me if I'm wrong, but I think you're planning to use your filters in front of the projection lens. If that's the case, you shouldn't have any problems with light being reflected back into the LCD panels nor problems with the filters detuning due to heat. The reflected light would be a small portion of the light normally handled by the LCD panels, and shouldn't cause any LCD failure (though you might encounter some lens flaring issues - specular reflections in the projected image). If you're projecting a fairly narrow beam (long throw to screen), filter tilt (off axis effects) most likely won't be of concern. I think Jack mentioned that he had some issues because he was projecting a wide beam to a nearby screen (short throw). The portion of the beam going to the screen extremes would be tilted relative to the filter in that case, and the bandpass of the filter would change for those rays. How much this affects the image would be a matter of testing it. If you are projecting to a further placed screen, most of the light will be on-axis and not tilted relative to the filter, so you should be ok. As you posted, testing is the best way to check things out.

Thank you for your comments RBTO. I also came to the same conclusion through a different way though:
http://www.mtbs3d.com/phpBB/viewtopi...12986&start=41
Do you agree?

Jack
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post #749 of 2269 Old 06-22-2011, 02:34 AM
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Quote:
Originally Posted by RBTO View Post

Detuning will happen if a dichroic filter is heated, but the filter returns to normal when it cools.

Correct me if I'm wrong, but I think you're planning to use your filters in front of the projection lens. If that's the case, you shouldn't have any problems with light being reflected back into the LCD panels nor problems with the filters detuning due to heat. The reflected light would be a small portion of the light normally handled by the LCD panels, and shouldn't cause any LCD failure (though you might encounter some lens flaring issues - specular reflections in the projected image). If you're projecting a fairly narrow beam (long throw to screen), filter tilt (off axis effects) most likely won't be of concern. I think Jack mentioned that he had some issues because he was projecting a wide beam to a nearby screen (short throw). The portion of the beam going to the screen extremes would be tilted relative to the filter in that case, and the bandpass of the filter would change for those rays. How much this affects the image would be a matter of testing it. If you are projecting to a further placed screen, most of the light will be on-axis and not tilted relative to the filter, so you should be ok. As you posted, testing is the best way to check things out.

Yes, at the moment my plan is to use the filters outside of the projector. Even though it should be safe for the LCDs for the reasons you said (as far as I know, even they are inorganic LCDs panasonic introduced in that year) I'll try to use the lenses tilted in case. My throw ratio is at around 1.7 to 1.8 so, as you said, i should be fine even though I am at the border of what infitec suggests for throw ratio. I'll do some more visual experiments with the projector to see how tilted lenses affect the picture in my case.
thank you
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post #750 of 2269 Old 06-22-2011, 06:39 AM
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About filters.

External:
The curvature of the lens from the glasses looks to suit your setup perfectly efendy:

When taking measurements, I am getting a 1.875 throw ratio. Flat filters are not necessary for you actually.

Internal:
I went to see my optician yesterday and talked with him about the filters. If the filters are tempered, they could whistand a couple of hundred degreesC but precaution has to be taken for cutting. He has means to see whether the flat filters are tempered glass or not. He also said that cutting them is no problem and would do it complimentary for me if I decide to go that way.

@RBTO: You are right about glass thermal expansion, but this is peanuts. A 100°C increase means a 0.00085 linear expansion factor. This is equivalent to an incident beam angle of 0.05 degrees.

Glasses:
I also asked him if glasses can be added an inside ar coating. He is going to see with his provider. Hopefully I will have an answer in a couple of days.

In the meantime, I created my own custom glasses with Dolby plastic filters over my prescription glasses (Fortunately, I had a spare pair to play with):



Plastic lenses have been taken from the pair I have been complaining about because of the bad frame/branch design. I was surprised to see that those were so thin. Thickness is about 0.2 mm.

That's the best dolby glasses I have tested so far. Very comfortable and light. Still, some reflections remain on the external sides but that's much better than wearing two pairs on top of each other. Of course, they are fragile but I dont allow anybody else to wear them .
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Reply Digital Hi-End Projectors - $3,000+ USD MSRP

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