[mavromatis]

I posted this also in the Screens forum, sorry for the cross post but I know you guys will have the answer quicker...


Which of these Steward Screens would you perfer if you had a choice? A 16x9 110" with vert masking or a 4:3 with Horz Masking? Would you do Perf screen at this size? or would you just put the Center channel below or above the screen?


The projector is a brand new XG85...


EMSN110W - Vert Electronic Masking Velux trim w/Studio Tec 130

EMSNH120-VAR - Horz Electronic Mask Velux trim w/Studio Tec 130


Thanks,

Danny

 

[thebland]

110" wide or diagonal?


remember a perforated screen will cut brightness ~ 10% over same material non-perforated screen.


If your screen is 110" wide get a digital projector.


If 110" DIAGONAL (96" width) a perforated screen in a total light controlled room should be fine.


Consider having the screen at a 2.4 (Cinemascope) aspect with vertical masking to allow for all other various aspect ratios (2.35, 1.85, 1.78, etc).


(the above is my configuration)


Jeff

 

[mavromatis]

It will be 96" wide ... 110" diag.


So a perf would give me good results? It's about $1000 more for that material... is it worth it?


Danny

 

[Bill Lucas]

I wouldn't say a perforated screen will give you good results at that screen size. A non-perforated screen would be preferable. Good luck.

 

[thebland]

Total light control, a perforated screen would be fine.


Remember, your next projector (after the XG) will be digital and brightness galore. You will enjoy it more on a perforated screen.


Jeff

 

[Ted White]

Personally I am not a fan of perforated screens, but then again, I'm a CRT guy. With a perf screen, as mentioned before, you lose 10% of the light.


Critics of perf screens will offer that they are prone to "hotspotting", etc.


Look, in a perfect environment a standard screen would be used for video. Forget about audio for a moment. No one would ever put in a perf screen for a video improvement.


Perf screens were manufactured to meet a THX standard. I went through this decision process myself, and concluded that I would not use a perf, despite the fact that I'll be using an extremely high end sound system. Personally, I see the perf as a video sacrifice.


Ted

 

[mavromatis]

Ted,


Your thoughts are close to mine... I really don't want a perf screen due to cost and loss of light/video res. I am going to place the center channel directly below the screen.


Now the question is 16x9 horz or vert mask or 4:3 horz or vert mask.


Thanks.

 

[thebland]

Danny,



Yes, a 10% loss of light is significant for CRt. It is a terrible achilles heal.


That said, there have been numerous studies commisioned by Hollywood and Universities that, briefly, confirm that when a the subtended viewing angles are a certain percentage (I can't recall the exact figure off hand), the viewer is drawn into the movie to the point where auditory and visual acuity is muted & therefore sonic and visual cues are less significant.


Hollywood has known this for years. Hollywood uses perforated screens.


In English, a larger screen will have some visual trade-offs but when properly seated and theater properly designed a better movie experience is obtained.


The larger the screen the more can enjoy such an experience!


Bigger is better in this respect.


Jeff

 

[wm]

Ah, well, my ten cents worth...


I don't believe you lose 10% with a perf screen, I think it's more like 8%. And personally, I love having the sound come from directly where the action is. I think it was worth the extra $1k, and I paid it.


William

 

[AVB]

I've had a perfed screen and when I did an upgrade of my front speakers I also went to a non-perfed screen. The video improvement was there be it 8, 10 or 15% and I really didn't notice the difference in sound location in moving my center to the bottom of the screen. In my case tilting the center so that the tweeter pooints directly at my head yeilded the best results.

 

[Cardguy]

I am leaning to a non-perf screen. I have had a soffit built on top of where my screen will go. Soffit depth is 11 inches. I Left an opening in the soffit for my center speaker. Projector will be a G11 projecting at 22ft. Will I have problems with light on the soffit? How should I finish the soffit?? Thanks for any Ideas or prev. experience...Chuck

 

[jkv]

I have a Stewart MicroPerf screen with a gain of 2.0. I have never seen any hotspotting at all, but I use a dwin hd700 projector; this has 7" tubes so that may explain why I don't have hot spots. The center is lined up directly with the tweeters on my fronts, which is lined up (more or less) to the average 'ear height' of the members of my family.


My HT room is small (14x17x8) and I have complete control of the light.

 

[thebland]

My soon to be built theater is featuring a Stewart Micro-perf at 123" wide (2.35 aspect).


The projector is a JVC G150HT D'ILA


With brightness galore why not go perforated and put the voices where they coming from........the screen.



Remember a floor mounted center will have early reflections from the floor (carpet or not) interfering with dialogue intelligence, not to mention those seated in the second row craining their necks forward to get good sound.


Jeff

 

[Ted White]

My Opinion here:


I've heard the arguments for years. None are new. My conclusion is there is no "best answer". The scenario is different for each person.


CRT owners put up with CRT because of their belief (and mine) that CRT produces a better picture. Most CRT owners want to squeeze every lumen out of the system, and therefore usually go non-perf. Imagine telling a CRT owner that you were going to reduce the tube output by 10%. Suppose that would go over?


Digital allows more light so perf is more able to be considered.


As far as sound performance, I personally feel that a center speaker mounted under the screen is a better option. That's me. Are you going to get an increase in early reflections having the speaker lower than if placed at front row ear level? Perhaps. But tell an audiophile that we're going to put his $5K center channel behind an "acoustically transparent " screen and he'll emasculate you. Hell, he won't allow speaker cloth. Let's keep in mind that we're talking tweeter location. If the tweeter is under the screen, this puts it 30" to 36" from the floor. Your ear in the first row is what, 48"? That's presumably where you'd place the tweeter behind a perf screen. So what are we talking here for a difference? 12" to 18"?


Regarding the psychacoustic issues of speaker (tweeter) placement vs. localization, I tend to agree that as long as the vocals (center channel) are close to the screen, your mind fills in any tiny gap pretty darned effectively unless you're not watching the movie. I've tested moving the center channel al over the place for guests, even moving it without their knowedge during intermission. So is someone going to "crane" their neck in the second row? Maybe if the overall acoustics of the room are deplorable, but in most instances, everyone will be awed by the overall presentation.


Understand that because someone else chooses a screen type (or amp, projector, cables) that 's not YOUR choice doesn't invalidate your choice. I think we lose track of the real issue because we wind up defending what we've sunk $$ into.


Ted

 

[M NEWMAN]

Very well said, Ted (gee, that rhymes!). I'd like to throw my $.02 too. I have extensively evaluated perfed screen centers vs non perfed, mounted above and below screen, and I can pretty much guarantee the following. Both options are a compromise, but more importantly, both options are an AUDIO compromise, while only ONE is a video compromise. Let me explain.... The perfed option is the video compromise - self explanatory and 'nuff said. Perfed screens do offer a "little" better placement of the center channel, but this gain is offset by the following: very distinct timbre change, slightly reduced treble/midrange (that acoustically transparent claim is bunk - should be called "fairly transparent"), and noticeable off axis response dropoff (meaning the center seats have the best sound - the people off to the sides get less). Non-perfed situations merely flip/flop the compromises But as Ted so clearly stated, the psycho-acoustic effect of proper aiming of the center to the listening area, combined with the visual directioning of the image do a good job of "fooling" your mind into locating the sound at the image, instead of a little below or above it. My opinion is, of course, purley subjective analysis, (as is everyone elses') but I thought you might like to hear the parts that no one ever seems to mention.

My suggestion, go non-perf. By the way, there are several manufacturers that go to great lenghts to minimize floor/wall boundry interactions to "fix" just this type of problem. (Snell is an example).

 

[David600]

Bigger is better but closer is better and CRT is the ideal projection device for that, much better than DLP and LCD and it's not just the pixelisation visible on digital projector, it's their "problem" with optical natural depth.


So, we could say that sitting at 3meters from a 4meters wide curved high gain screen with a CRT is much better than sitting 6meters from a 6meters screen with a dlp or lcd.


Now, to perf or not ? I think it should decided inside a "visual" package:

CRT + microperforations + curve screen + high gain (2.0 for instance or go with the ultimate being the TORUS) + horns speakers ( MUCH better to go through a perforated screen, require less equalization boost).


Here's a shot of CAD , a French HT installer, the screen is 3.5m wide, 16:9, microperforated with some gain and all reviews say it looks truely awesome with the Christie 8" CRT that projects on it.

100% light control is present of course.
http://us.f1.yahoofs.com/users/a7a09...K3fM8AMF7Mi6OG

The curving allows higher gain and thus EASILY compensates the loss due to the perforations. As for the front left and right speakers, up until that screen size or 4Meters, leave them on the sides of the screen, not behind. It's better for a wite stereo effect but should be estimated as per the horizontal diffusion angle of the speakers of course.

(An alternative would be only a perforated zone where the center channel will be placed. I heard some people have experimented that.)

hey, here's another one:
http://us.f1.yahoofs.com/users/a7a09...K3fM8ABRlE_oCO

a 2.35:1 , 3.75meter wide. nice isn't it ? G70, QSC DCA amps, DAS cinema speakers ( horns, 100db sensitivity ). So, in those two cases, professional speakers were used ( CAD manufactures its own pro speakers, which are high sensitivity also, horns etc). A must when using perforated screens.

 

[Ted White]

David,


That's interesting! Let me ask, have you noticed any sort of off-axis distortions? I haven't seen one myself, but a real guru (who shall remain nameless) told me that the geometry off axis is very disturbing on a curved screen.


Have you seen this?


Ted

 

[David600]

 http://photos.yahoo.com/bc/huntforpr...heater&.view=t ( enter your yahoo ID to access it )



Hi Ted


first, I notice the link to the photos don't work now but I rebooted my PC a few minutes ago so maybe that's the reason. Maybe on your side it works. anyway, hereabove is the link to my yahoo photos album and the 2 shots I posted are on the second page of the album.


Now, do you speak about the sound being distorted off axis or the image ? I imagine the image. I must admit I never had the chance to experience such curved screens but the reviews in the French HT press of these systems were stunning, praising the reduction in any visible hot spot, a much more immersive impact and the better spread of the brightness on the screen, especially the sides, which is normal. No complaints at all. Now, these screens are SLIGHTLY curved : for these 3.5meters+ screens, the radius used is of 15meters in length. the dept thus is of a few centimeters, not much but enough to allow excellent immersion, higher gain, better brigthness uniformity. The only drawbacks is a small reduction in allowed seats per row ( say, 6 instead of 7 per rows for such large screens, to give an idea ).


best

David

Brussels

 

[Ted White]

Thank you David.


Yes, I was referring to the image being compromised off-axis.


I really need to see one of these things and judge for myself.


Ted

 

[Jay Wilson]

hey Mike, Haven't we been here before? Seems like I remember you and I having this same conversation with someone else! BTW, I love the shots of the CEDIA winner. Awesome!