CurtPalme.com Home Theater Forum

[CasetheCorvetteman]

[CasetheCorvetteman]

http://forums.prosoundweb.com/index.php?topic=137029.0

[Spanky Ham]

I have seen a couple of high end rear pro screens and they do block ambient light better than a FP screen. What the percentage difference is I have no idea. The problem is an excellent DNP rear pro is expensive.

I should also add if you were doing a blend then it would be easier on a rear pro as long as you aren't ceiling mounting the pjs.

[benareeno]

well...since installation could be no more difficult, and image quality is up for debate...it still makes a hell of a lot of sense to get the projector out of the room. It's loud, it's distracting, it's ugly...I could hit my head on it...the list goes on.

Since you can get 9500 lc's for a grand...a few extra bucks on a screen would be easy to take.

I wonder why Widescreen review did not one but both of their crt projector installs as rear projection. It's almost as if it might be...the best it can be

[benareeno]

and from that link above...I read things like this:

Generally speaking it's the contrast, not the total brightness that matters for image quality (including readability). Many rear projection surfaces are somewhat better than a matte front screen at dealing with ambient light on the viewing side of the screen yielding a better contrast ratio.

so, your link is there to prove my point, I guess? thanks....

and other things like:

Rear projection also has the advantage of keeping the projector out of sight lines and foot traffic

and then this:

Where rear projection, perhaps combined with a short throw lens, may have an advantage is in making it easier to keep ambient light off the screen. In an outdoor application it is often easier to create a projection 'room' behind a screen than to try to control the light coming from the audience side.

This speaks directly to my point that rear projection is far more functional in ambient light. This is not a point for debate...it is fact.

If I turn a small light on in my theater, the screen is almost blank...if I did that with a rear projection crt, it would be no problem.

Arguments on this forum are great...but, it's really hard to argue facts. Rear projection allows more ambient light to be in the room where the people are. That is not a debatable point...front projection sucks at this. Unless it's a light cannon.

as I mention, a simple googling of rear projection ambient light will show scads of confirmation of this.

from one screen manufacturer:

Benefits of dnp front projection screens
Easy to install
No dedicated projection room required
Space-effective design
Cost-effective solution
Enhanced mobility of screen and projector

Benefits of dnp rear projection screens
Enhanced contrast and image brightness
Suitable for high brightness applications
No shadows from the presenter/viewers cast onto the screen
Projection equipment is hidden behind the screen
Noise-free operation


hmmmm....enhanced contrast AND image brightness. That seems like something most people would want. And suitable for high brightness applications means that it works well in ambient light.

If you want me to list all other screen manufacturers, I will....but, rear projection works a lot better in ambient light. That's obvious.

[ecrabb]

You're not really surprised that a manufacturer selling an expensive product has a bullet list of advantages of that product, are you?

No, Benareeno - it isn't "a fact" that rear projection is better at contrast and brightness than front projection. You're reading marketing verbiage and copying and pasting it without understanding any of the physics.

Just like with front projection, you can make a rear-projection image completely washed out and unwatchable. Just like with front projection, it depends on the type of surface. If you're using a pure diffusion surface, the rear-projection image will wash out and look like crap just like the front projection. The ambient light is diffused just as well as the projected image.

Where you get great gains with rear-projection and ambient light rejection (and therefore contrast) is with either high-gain surfaces (via lenticular or fresnel lenses) which simply overpowers ambient light with projected light (just like a high-gain front-projection screen), or with special screen surfaces with engineered geometries to absorb ambient light from the viewer side, but pass and diffuse projected light from the back side. An example is Vikuiti by 3M.

So, rear projection itself isn't inherently better than front projection when it comes to contrast and ambient light rejection; it's certain types of rear-projection surfaces that are better. Of course, those surfaces come with inherent drawbacks of their own. If you don't believe me, look up the cost on a Vikuiti-based screen, and then we'll talk. No free lunches, pal.

For the DIY'er that doesn't have a deep pocket, that leaves only a couple of options for rear-projection:
1) High gain, which you'll have to accomplish with a fresnel or lenticular screen, most likely salvaged from an RPTV, which will clearly limit you on screen size, and will have a narrow viewing cone (remember that from the old RPTVs?)
2) A traditional diffusion material (like frosted glass or lexan), which is much more affordable, but has no ambient light rejection properties whatsoever, so is negligibly better than a 1.1 or 1.2-gain front projection screen.

Sorry. That's just the facts.

RP is indeed excellent for getting the projector out of the room, which if you need to have a large, noisy CRT, is especially useful. My JVC hangs about five feet from my head, so I have no need for RP, nor could I justify the expense if I did.

SC

[ecrabb]

Oh, it's also very hard to get uniformity right with RP. A good old 1.0 gain front screen is about is good as it gets, and it's all downhill from there. RP... Not so good. That, cost, and the space the RP setup requires are the answers to your question about why more setups aren't RP-based.

SC

[benareeno]

You're wrong...rp can be a reference for screen uniformity. Perfect for edge blending...etc.

This stewart one is one such example: http://www.stewartfilmscreen.com/residential/materials/rear_projection_screen_materials_felxible/aeroview_70/aeroview_70_residential.html

It would be darn near impossible to do a front projection setup with crt that can deal with ANY ambient light.

You could quite easily do it with a rear screen projection setup and a crt though. Is this up for debate still?

Digitals would be another story altogether. those light cannons and a black screen could likely deal with some ambient light.

The bottom line is, if you have the means to do rp and you have a crt...then do it! It would be ultra cool, and the result could be amazing. To have a nice big image and no projector in the room.

The reason I think it's so great...is that I hate having the projector in the room. Some of you likely love it...I mean, if you have one in your bedroom...then you surely don't mind one in the theater room. I wouldn't have a projector anywhere near a bedroom...and preferably not in the theater room either. But that's just me...I'm ok, you're ok.

[the big E]

I never was one for rear projection due to the marketing hype
The only resion I have rear projection tvs is because no one makes a front projection type tv like Sony did (still looking for one)

[benareeno]

tv's are one thing...but using a crt projector in rear vs front is something entirely different.

[ecrabb]

[benareeno]

and I've never heard any marketing on rear projection...unless you are referring to tv's.

[CasetheCorvetteman]

Benareeno, youre talking about something you clearly have no first hand experience in, and your only real knowledge is bits of information youve selected from websites to suit your side of the argument.

You ARE wrong, Crabb IS right, and that is NOT debatable, its a FACT.

Read ALL the data about the screens on the stewart website, anyone who's got an ounce of knowledge will see quite quickly that your arguement is going to be washed out just like the image on screen.

You will see that the gains for the screens performing in ambient light are VERY low, meaning your little 7" machine wont light it up anyway, and anything with a 1.0 gain says either controlled lighting recomended or controlled lighting required. That alone makes your argument weak as water.

But there is still a way you can win this argument, and that is get on the horn to Stewart and order your 92" Starglas 60 and 2 G90s to light it up, take same pics and PROVE your point.

[benareeno]

what is my argument? Please clarify before you say I'm wrong.

Crt would do better in rp if ambient light is a factor...where is that wrong? Obviously a higher gain screen is required...but, IT IS POSSIBLE! And if done, would allow ambient light in the room...vs any fp screen for a crt.

and ecrab is dead wrong....he says, and I quote "Oh, it's also very hard to get uniformity right with RP" - this is dead wrong. I make no mention of gains...you can get great uniformity with a rear screen with lower gain. So, work on your communication skills before you argue, please...

And of course, if ambient light is a concern, it would need to be higher gain....but, no higher gain screen with a fp crt setup would allow ambient light and not have it ruin the picture. Nothing I have said is wrong...stop trying to argue derivatives of my point. My point is simple...

Obviously...low gain would require light control. THere are various higher gain screens where it would be less of a factor.

And, I don't really even care about ambient light...so, let it go. Go up to your bedroom and make love to your XG.

I dare say you don't know what you're talking about...rp is the bee's knee's.

[CasetheCorvetteman]

No, Crabb is very correct in the statement RE uniformity on rear projection systems.

Lower gain rear pro screens deal with ambient light better in alot of cases. That means your CRT wont drive it for a start, youll need a decent 8" or a 9" to do it properly. Read the specs on the Stewart site again regarding gain and lighting control requirements. You will find that depending on screen type and properties required, higher gain does not equal improved ambient light performance. For what youll use in home cinema, the Starglas would be my pick at a very quick glance, the .6 gain is clearly better for uncontrolled ambient light than the 1.0 gain.

Viewing angles are terrible compared to front projection screens, and when viewing angles are good, something else suffers instead.

Uniformity is generally speaking very good on almost all front types, rear types typically not.

Your argument seems to be you can watch a CRT projector on a rear pro screen with the lights on and not wash it out or reduce contrast ratio, both of which are total horse sh*t and youre only kidding yourself to think it so. Turning on the lights with a high end 42" plasma screen still reduces contrast ratio.

The last rear projection setup i did ( of a total of two ) was around 170" diagonal, using a Mitsubishi 6000 lumen projector worth around $26,000, it was SIGNIFICANTLY better with the lights all totally off, turning them on washed it out abit, uniformity was pretty ordinary, and viewing angle was pretty narrow. I have since replaced that with a 225" 1.1 gain matte white front projection screen and an Epson 5000 lumen LCD projector. Its better in every single way, even with a lessor projector and a bigger screen. It was also way cheaper.

That is my first hand experience, limited as it is with rear projection, but im very interested to hear all about your first hand experience with both front and rear installs.

You can dare say anything you like, you still have zero stated experience, and its quite obvious you dont know what youre talking about.

[benareeno]

it would obviously be better with the lights off...my initial and only statement was simple...a rp setup would HANDLE ambient light better than a fp setup with crt. I will stand by it...you believe the opposite, and are apparently a pro, so...there you go. Your pro opinion just doesn't quite have the pull that would change my opinion though.

You installed some huge light cannon in some industrial install...or some weirdo's overdone HT and now you're the forum expert on all things ht?

I will take Gary Rebers' G90 in RP or Runco 1101 in RP as a reference for rear projection with crt as the best it can be, he has done and been involved in 2 rp installs in his own house for god's sakes, let alone the countless ht's he has seen over the years...to me RP is the ultimate installation of a display. Short of running a complete bat cave with FP, it's just a lot more practical for several reasons...not everyone wants to watch movies in a dark room at all times...how about a hockey game with some ambient light? I would find that very fun...let alone the dark room movie viewing, which would likely not require a bat cave for best contrast.

So, if you are willing to concede that each could achieve equivalent pic quality with a crt...then the practicality of RP would seriously trump FP...especially with a crt behemoth.

If you're bent on the fact that RP is inferior due to your extensive install credentials, then so be it. We can end it there.

[CasetheCorvetteman]

He may have, but YOU have not. Youre using a hear-say reference. You have no real experience, but you about it on the internet. You claim all kinds of things that you have never seen or attempted first hand, tell Kal your theory on rear pro and ambient light is fact and not debatable, tell Crabb he is wrong when he was correct, and you base every bit of your argument on nothing more than hear-say rather than first hand fact or experience.

You will still need a totally dark room for reference quality images. Any amount of ambient light, no matter how small, will have an impact on contrast ratio.

In the 2 instances i have set up rear projection, neither one handled ambient light well at all. They both looked nothing short of terrible with lights on. Lights off they were both great images, but as good as front projected with considerably cheaper equipment? Nope. My own eyes told me that, not the internet. The larger unit was installed twice, first time by the company that sells and leases them, second time by me. The company owner claims to have more than 25 years in projection setup and installation, so id think he knew what he was doing.

At no point did i claim 80-100 installs as extensive, nor did i claim to be the final word on it, so there is no need to be a sore loser about it but anyway

[Spanky Ham]

Well I Have seen some good rear pro screens and Ben is correct that a good rp handles ambient light better than fp. I have seen the dnp rps and they are better than a fp screen. As crabb said they are expensive.Be prepared to drop a couple of grand. starglas is nice but I would take a dnp instead. I might alos mention that there fp screens are nice as well. If I had the money then i would probably grab a supernova.

http://www.dnp-screens.com/DNP08/Products/Front-projection/Screen-materials.aspx

Oh and if you want to see these screens then I will hold your hand and walk you over to the dnp booth. 8 days and I have already completed one leg of the trip.

[benareeno]

Boom goes the dynamite!! Spanky makes a brave entrance to the thread and disagrees with the resident expert.

You have seen 2 installs...it doesn't make you an expert or an authority. You clearly think you are both...but, I doubt it very much.

Spanky seems to be in my court...are you going to try and crap all over him too?

Please restate the argument as I'm sure it is now lost...I don't want to continue until it is clearly restated.

I will state my point again...

An rp screen could deal better with ambient light with a crt install. That is all I said...I never said it would be reference video, it would have amazing uniformity. I made a simple statement, and I still think it's true. So does Spanky. Although, if reference video is what you're after, I think rp could deliver it...but then ambient light would have to be controlled, which is quite obvious.

Now, it comes down to 2 people who have seen rp installations....I will side with Spanky on this one.

And, I would say it again...I think rp is the best it can be. More expensive, I would grant you that...but, with a good screen, it doesn't get any better. And the practicality gains are huge.

[benareeno]

I don't want to discredit you as a know nothing, as you are trying to do to me. But, Gary Reber is far from a know nothing, and he agrees with me.

I emailed Gary to ask him a few questions...ambient light is better dealt with by an RP setup. He also thinks RP is the best it can be...which I also agree with. I consider it the ultimate installation. For pic quality, and huge advantages in practicality.

here is the email on ambient light in the same terms I stated it, his reply is "absolutely" :

On Tue, Sep 17, 2013 at 11:25 AM, Ben Hanrahan <benareeno@hotmail.com> wrote:
Gary,

I really appreciate your reply! I have been reading your reference systems for what seems like 20 years. It's one of my favourite parts of the magazine.

Would you say that ambient light is more easily dealt with in a rp setup?

Thanks again Gary!

Ben

Gary Reber (editorgary@widescreenreview.com)Add to contacts 3:25 PM
To: Ben Hanrahan
Picture of Gary Reber

Absolutely!


and my previous email to Gary is where he still feels RP is the best it can be:

Date: Tue, 17 Sep 2013 11:03:41 -0700
Subject: Re: rear projection with crt, or digital
From: editorgary@widescreenreview.com
To: benareeno@hotmail.com

Ben,

My main reference system is rear projection; has been for the past 22 years. This is the best possible picture quality for black level I believe to be attain, though it requires physical space to accomplish even with a dual first surface mirror system such as the one I use. See the credits in the Blu-ray Disc section of the magazine for the equipment I use.


I'm with Gary...RP is the best it can be for home theater, for many reasons.