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To curve or not

post #1 of 128
Thread Starter 
I've been thinking more about getting a curved screen as of late. In speaking to Stewart about it, only about 1% of the screens they sell right now are curved. However, they expect to see a huge increase in curved sales, possibly getting as high as 20% of their business within the next year or two.

I also understand that Dennis (HT guru) installs a ton of curved screen in higher end rooms.

As I understand it, curved screens work particulary well with scope set ups (another huge trend) and with higher gain screens but if I'm misguided on this, please let me know.

I'm trying to fully understand the benefits and drawbacks of such a set up and that is what I would like to have this thread discuss. Let me start with some comments and questions. I'd really like to hear from those that have a curved screen or have seen one.

The benefits I see with the curved screen are as follows:
-reduced hot spotting with gain screens
- screen curve avoids cross reflection (all projected light is transmitted to the audience)
- looks "cool"
- improves image uniformity

Drawbacks?
-Added cost
-difficulty in figuring out optimal curve radius
- not sure about impact on viewing cone - expand it from the far side but reduce it from the near side?

Miss anything?
post #2 of 128
Your benefits are well stated except that, the curve will also resolve any pincushion resulting from the projector and lens combination. There is not a negative impact on the viewing cone in a residential space unless the room is very significantly wider than the screen.
Quote:


they expect to see a huge increase in curved sales, possibly getting as high as 20%

Durn. I forgot to negotiate a royalty agreement. Nuts.
post #3 of 128
Thread Starter 
Have an update. After speaking to a Stewart product expert, he reminded me that this screen will remove pin cushion effect with an anamorphic lens.

He also said that it effectively widens the viewing angle. I was originally concerned about loss of viewing angle on the near side but it's not a factor because the radius is not high enough to offset the adavantage of the viewer being directly in front of that portion of the screen. You do gain on the far side because of the angle of the screen.

EDIT: didn't see Denis's post before I submitted this

In terms of determining the correct radius, it depnds mostly on your anamorphic lens of choice. So in my case, I will contact Prismsonic to get the info that Stewart will need to determine approriate radius.

Other interesting fact is that the non-masked version of the screen is far less expensive than the cine-curve screen so give up hope if you saw that $18k quote. Further, given the structure of the screen, lace and gromut, it will likely be relatively easy to wedge in some masking. BTW, the screen border with this method of fixing the screen to the frame is 6". This screen must look realy cool!
post #4 of 128
What about Torus screens? I would like to consider a 2.35 or 2.05 screen in my new room but my projector is a CRT and I will be going the torus route. When a scope screen is masked down for 1.78 or 1.85 material doesn't it affect the hotspotting and color shifting?
post #5 of 128
Thread Starter 
Quote:
Originally Posted by GScott View Post

What about Torus screens? I would like to consider a 2.35 or 2.05 screen in my new room but my projector is a CRT and I will be going the torus route. When a scope screen is masked down for 1.78 or 1.85 material doesn't it affect the hotspotting and color shifting?

Hi GScott, I'm still learning about all of this and I am not familiar with the Torus screen. Who makes it?

I'm not sure about the answer to your second question. Hopefully others will pipe in on it.
post #6 of 128
The Torus screen is a DIY screen that usually uses 3.1gain material that is around 5$ per square foot. It is best suited for CRT's because of the high gain. The Torus is curved with there being about a 9" depth difference from the center to any corner. The Torus is usually a near air tight curved "box" with a fan sucking air out to stretch the screen, which gets rid of wrinkles. Search "torus" in the CRT projector section or sceen section.
post #7 of 128
Quote:


The Torus screen is a DIY screen that usually uses 3.1gain material that is around 5$ per square foot.

...and can have a serious adverse impact on room acoustics.
post #8 of 128
Dennis,

What makes a torus worse than a standard curved screen? Thanks.

Gary
post #9 of 128
It becomes an acoustical concentrator due to its shape, pointed pretty much right at the prime viewing location. As such it will pick up room reflections and beam them at the viewers location.

Vern
post #10 of 128
Imagine you are projecting onto your DirecTV satellite dish and sitting where the LNB is.
post #11 of 128
Gary:

Vern and Poindexter have it nailed. The effect is very audible and rather ugly.
post #12 of 128
Other than reducing pin cushion, what is /are the advantages of a curved screen ?

Art
post #13 of 128
Thread Starter 
Quote:
Originally Posted by Art Sonneborn View Post

Other than reducing pin cushion, what is /are the advantages of a curved screen ?

Art

Hi Art, added benefits include:

-widens viewing cone - particularly useful for those with a high gain screen

-Reduces/removes hot spotting

-More uniform color

-screen curve avoids cross reflection (all projected light is transmitted to the audience) enhancing perceived contrast especially if screen is close to the wall or walls are light colored

- Looks cool
post #14 of 128
What if the screen is curved only slightly, like in this thread : http://www.avsforum.com/avs-vb/showthread.php?t=541964

Will the sound reflection still be "very audible and rather ugly" -Dennis
post #15 of 128
Thread Starter 
Quote:
Originally Posted by Dennis Erskine View Post

Gary:

Vern and Poindexter have it nailed. The effect is very audible and rather ugly.

So needless to say, Torus is an acoustically reflective hard material - yuk. As it is, I don't even like a regular screen between myself and the diffusors at the front of the room because of the slap echo it creates - although it's a very minor issue in the grand scheme of things.

Dennis or others - any disadvantages?

When going from a 16:9 screen to a scope screen, I loved it and would never go back to 16:9. How about you folks out there that have gone to a curved screen - would you ever go back, why or why not?
post #16 of 128
Thread Starter 
Quote:
Originally Posted by NautikaL View Post

What if the screen is curved only slightly, like in this thread : http://www.avsforum.com/avs-vb/showthread.php?t=541964

Will the sound reflection still be "very audible and rather ugly" -Dennis

I wouldn't do it because from what I undersatnd, the radius of the curve is important to the implementation of an effective curved screen. If you compromise on that, you may not like it plus you have compromised your audio. In terms of audio, I have a curve at the front of my room but it's the opposite of what the Torus is because you want to diffuse the sound not gather it and beam it at the listener.
post #17 of 128
Well I don't have a whole lot of pluses to add, as Dennis and your Stewart contacts seem to have them all listed. But as an owner of a Stewart curved, 2.35:1 screen, I thought I'd tell you the reason I went with it.

I have a CRT projector (9pg extra) and wanted a 9' wide screen. Don Stewart, while encouraging me to go a bit smaller, recommended the curved screen and higher gain material if I was set on a screen that large.

I'm glad I went with the curved/higher gain material and the 9' width. I'm sure that HAD I gone smaller the image would probably have looked even better than it does now (which in my opinion is awsome.) But I've never had anyone, who has seen it, say that it was dim. Far from it, in fact. And this is running it with a only average brightness and contrast levels.

And yes the coolness factor of the curved 2.35 screen is incredible.

So, in conclusion, you might want to add something along the lines of: Larger screen widths can be used, because the curve helps eliminate some of the problems that using a high gain screen can cause. Especially with CRT projection.
post #18 of 128
Ah, I see. The reason I asked is that these seem now ill suited for CRTs and since light output on so many fixed pixel devices didn't seem like an issue I though a flat screen would have done as well. Thanks !

Art
post #19 of 128
Thread Starter 
Quote:
Originally Posted by lawdawg View Post

Well I don't have a whole lot of pluses to add, as Dennis and your Stewart contacts seem to have them all listed. But as an owner of a Stewart curved, 2.35:1 screen, I thought I'd tell you the reason I went with it.

I have a CRT projector (9pg extra) and wanted a 9' wide screen. Don Stewart, while encouraging me to go a bit smaller, recommended the curved screen and higher gain material if I was set on a screen that large.

I'm glad I went with the curved/higher gain material and the 9' width. I'm sure that HAD I gone smaller the image would probably have looked even better than it does now (which in my opinion is awsome.) But I've never had anyone, who has seen it, say that it was dim. Far from it, in fact. And this is running it with a only average brightness and contrast levels.

And yes the coolness factor of the curved 2.35 screen is incredible.

So, in conclusion, you might want to add something along the lines of: Larger screen widths can be used, because the curve helps eliminate some of the problems that using a high gain screen can cause. Especially with CRT projection.

Love your theater and the screen does look very impressive! I'm curious, did you have frame options?

The reason I ask is that the Stewart guy I was talking to said that they normally suggest securing screen with lace and gommat which results in a 6 inch border. Your border looks closer to 3 inches.
post #20 of 128
Thanks for the kind words.

My frame is just a little over 1.5 inches. The back of the frame, and front of the screen material has, for lack of a better term, buttons. They are spaced about ever 4 inches. Very secure and keeps the screen very tight.
post #21 of 128
Thread Starter 
Quote:
Originally Posted by Art Sonneborn View Post

Ah, I see. The reason I asked is that these seem now ill suited for CRTs and since light output on so many fixed pixel devices didn't seem like an issue I though a flat screen would have done as well. Thanks !

Art

Art, I have two primary motivations to go curved

First, I want reduce/remove hot spotting. On a 120" wide sope screen, Ruby is not bright enough and I don't want to go with a DLP 720p 3 chipper so I need a 1.5 gain screen. I hate hot spotting so I don't think this high gain screen would be a realistic option for me without the curve.

Second, to have more of the light from the projector come back to viewers and not bounce off of the sidewalls. I don't want to paint my walls black and so I view this as the next best thing to increased perceived contrast.

The pin cushion benefit is only minor because I use a long throw. The other benfits are "icing on the cake".
post #22 of 128
the biggest disadvantage for some of us is it requires a fixed screen; many of us must use a motorized roll-up

ken
post #23 of 128
Quote:


effective curved screen. If you compromise on that, you may not like it plus you have compromised your audio.

I haven't compromised the audio with a curved 2.35:1 screen. Due to the width of the screen and the required subtended speaker angles for a good sound stage, the speakers are behind an acoustically transparent screen. That acoustical transparency doesn't allow the screen to act as a 'lens' nor contribute to slap echo in the room.

Note as well. A torus is like a segment of a sphere. The curved Stewart screens are like a segment of a cylinder.
post #24 of 128
Does anyone else see the irony in a curved screen....

for years we all screamed for flat screens as all CRT manufacturers could produce was curved (albeit the other way!) screens.

now.. with 2.35:1 in the home the tables have turned and its curve time!
post #25 of 128
Quote:


now.. with 2.35:1 in the home the tables have turned and its curve time!

Nah. We went from convex, to flat, to concave.
post #26 of 128
Thread Starter 
Here is the reponse I got from Prismsonic regarding the question of appropriate radius using their anamorphic lens:

[i]"This really depends on so many things that it is impossible to say any number. However, I have experience of curved screens. I made one from the painted mdf plate. From that I can say that you don't need to have an exact radius, in order to get a good result."[i]

Hmmm, not exactly the response I was hoping for.

Dennis, I'm assuming that you will disagree with the above statement but please confirm. I would assume that the correct radius is needed to fix pin cushion. Is the correct curve radius also a function of screen gain?
post #27 of 128
Quote:
Originally Posted by Dennis Erskine View Post

...and can have a serious adverse impact on room acoustics.

I imagine a curved screen could impact acoustics too. I think you need to compensate for either, less so for a curved screen than the torus, however the torus does add a huge improvement in image quality, especially with CRT.

It is always surprising to me that we haven't placed speakers behind a Torus yet. I don't think it'd be that hard to maintain the vaccuum w/ an acoustically transparent screen.
post #28 of 128
Quote:


I imagine a curved screen could impact acoustics too.

Nope. I use an acoustically transparent screen. A 2.35:1 will require all the speakers be behind the screen if you have the view angles correct.

Torus cannot have an acoustically transparent screen due to the vacuum required.
post #29 of 128
Quote:


I made one from the painted mdf plate.

I would find that disconcerting. If one's business is high quality optics for projection systems, I'd be really nervous when a home made screen is what they are using.
post #30 of 128
Quote:
Originally Posted by kenliles View Post

the biggest disadvantage for some of us is it requires a fixed screen; many of us must use a motorized roll-up

ken

It also makes it difficult for masking systems and impossible for 4-way masking systems.

I had to make the choice between curved and masking and I chose masking instead. Since I was running a low gain screen, the hot spotting wasn't an issue, nor was the viewing cone problems, as the .95 gain Screen Research screen was actually brighter at the edges than a flat Stewart 1.3 gain screen.

While I see a few posts from one person that the curved screen "looks cool" I think that the 2.35:1 screens look cool period and don't need a curve to put them in the cool clique.
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