Da-Lite Electrol Screen Review
My Da-Lite Tab Tensioned Dual Masking Electrol Screen. Cinema Vision Material. 2.35:1/16:9. Gain 1.3
Introduction
When I had the opportunity to build my own dedicated A/V room I decided to go all out as there wouldn’t be a second chance. So for the screen I turned to an electrically operated dual masking system as both 16:9 and 2.35:1 scope movies were very popular. I had also decided to use a Panamorph lens in order to ensure that I utilised the entire panel pixel array and light output from my projector. It is well known that once a projector is calibrated to meet either REC709 or now REC2020 its light output can be as much as 30% lower than the claimed lumens by the manufacturer. So I did not want to waste any lumens or panel resolution.
16:9 Masking Panels Partially Descended
Screen Material
All my screens up until now had been unity gain matte white as I have always had the luxury of total light control. When I purchased the BenQ W10000 DLP projector, and built my dedicated room, I was concerned that its claimed 1200 lumens, despite the stellar reviews, after its ISF calibration, might be too low for a unity gain screen. So after guidance and a few simple calculations I concluded that I would go with a screen with a modest 1.3 gain, just to be safe. The Da-Lite Cinema Vision material seemed to fit my bill and thanks to my employment I was in a position to buy Da-Lite at trade, despite my preference for a Stewart screen.
After the projectors ISF calibration by Kevin Miller of ISFTV, there was plenty of light output and my screen size and total room light control allowed my to run the projector on low lamp with the iris backed of by about 30%. My concerns about screen gain were clearly miss-placed and I should have gone for unity gain material. You are always wise after the event!
The good news was that despite a modest screen gain of 1.3 the material performed quite well with only minimal hot spotting and few sparkles. Pixels were all quite well defined and the image was nice and sharp with minimal color shift (see later comments).
Installation
The Dual Masking Electrol (now discontinued) may be controlled by either a pair of simple switches, one for the screen and one for the mask, or there are options to enable either IR control or GPI control from either the projector or receiver. This control would automatically raise and lower either the screen and/or mask depending upon the format selected. For simplicity, and cost, I just went with the dual wall mounted switches which were very straightforward to wire up.
Screen and Mask Control Switches
The screen was to be surface mounted on the ceiling as it was to be built down to support sound absorption and final finishes. So there was no need to open up the ceiling to recess it. Nor was that an option, as I did not want to impact the rooms acoustic isolation, which I had spent so much time and effort getting right. The ceiling joists were blocked out to match the three mounting points on the wooden screen box, and using a floor hoist the screen was lifted into position and secured dead central to the room using five carriage bolts.
Marking Out The Ceiling. Screen Positioned on Hoist
Screen Installed. Ceiling Framing In.
Cabling connected, the preset start and stop positions for the screen and mask were slightly adjusted and all was well.
Roller Raise & Lower Adjustment Stops
The 16:9 masking system worked very well being tight up against the screen surface when in place. However, it was made from a shiny black vinyl material instead of matt black, causing it to reflect more light than I would have liked and the left hand side mask was not quite vertical. It tilted in by about 1/4″ at the bottom. This was a manufacturing defect and wasn’t adjustable. Being barely noticeable on the image I decided to ignore it.
Screen Material Change
Unfortunately, the recent purchase of my JVC DLA-RS640 put an end to the exceptable performance of the Cinema Vision screen material (now discontinued). The increased brightenss and slightly softer focussing of this projector significantly increased hot spotting, sparkles and in particular the ‘Window Effect’. All to a level that was really distracting on bright scenes. In particular the very large number of tiny sparkles from the reflective material blurred the pixel edges, making them indistinct and appear even further out of focus.
NOTE: The RS640 has an adjustment for vendor screen material. It alters the light output to better match the screens reflectance characteristics. I initially, inadvertently, choose setting seven that was for Da-Lite Da-Mat not Cinema Vision. To my surprise correcting this to the correct setting, fourteen, slightly improved the black level and the screens performance, for everything BUT the tiny sparkles.
As this projector is pseudo 4K, the physical pixel size remains the same as for HD, but with e-shift the effective pixel size is reduced so I wanted a screen with a smooth surface finish and no sparkles., After a few calculations, I quickly concluded that with the increased lumens I could return to a unity gain screen. The industry standard for such a screen would be the Stewart StudioTek 100. However, installing a whole new electric screen system or a fixed screen wasn’t in my future. So for second best I opted to go with Da-LIte Da-Mat. (None of the Da-Lite HD materials are available for this screen.)
This is a unity gain screen material with a reasonably smooth surface and a viewing angle of 120 degrees. I ordered a sample to test just too make sure that it fixed the unpleasant effects created by the Cinema Vision material, and that it was not going to be significantly less reflective. Upon holding the new material up against the old screen and turning off the screen material correction, it was immediately obvious that this was an excellent performer. Its reflectance was virtually indistinguishable from the Cinema Vision. All the annoying issues disappeared. Pixels were better delineated and focussed, and best of all, the whites were even whiter. Showing that the old screen was actually adding a slight green hue to the image. The two screen surfaces were very different. The Cinema Vision being quite rough, almost sandy in nature, while the Da-Mat was much smoother. Not as smooth as the StudioTek 100 sample that I would have preferred, but for now, the best I could do. Generally speaking it is preferable to have a very smooth screen surface for HD, and in particular 4K and higher. This prevents a screens uneven surface, the dimensions of which might be approaching a significant percentage of the size of the pixel, causing its distortion.
Screen Roller Swap Out
The new roller assembly, sans motor, arrived, and with the removal of two nuts, a retaining clip and disconnecting five wires the old roller assembly easily came out. Taking care to insert the existing motor assembly into the new roller assembly in its correct orientation with respect to the new rollers seem and mount the other bearing assembly into the rollers opposite end, my daughter and I quickly installed the new roller. I said quickly, that wasn’t quite true. The roller assembly was heavier than I expected, and a little difficult to handle as you can only hold the outside 2.5″ of the roller. Taking care not to touch or damage the screen material. It was all a bit of a struggle as I was unable to remove the screen box bottom access panel. However, with a few choice words and phrases we eventually got it in place and fastened in.
Da-Lite Da-Mat Roller and Material Unpacked and Ready to Install
Re-wired, I quickly checked the new rollers stop positions. I was very relieved to find that they were still spot on, so needed no adjustment.
Viewing Results
Well, it was all definitely worth the expense and effort. The irritating screen artifacts; sparkles, window effect, hot spotting and a slight ripple in the screen coating have all disappeared, and to be honest, the screen actually looked brighter. This is probably because of its uniform brightness. The HD and 4K images are now much closer to what I was expecting when I installed the new projector. Bright, clear, lots of detail with great really white highlights and the deepest blacks I have ever seen. Some 4K camera shots almost taking on the appearance of really high quality photographs.
The other issue I will now have to address is to color the rear quadratic diffuser black. Being made from white wood (see the bottom two images here), it is reflecting a small amount of light back to the screen and having a discernible impact on blacks when a large area of the screen is fairly bright. For now I have draped black hessian over it as a “stop gap” measure. So I now have my next project for my room. It just never stops!
UPDATE: I purchased 1″ wide artists black masking tape and covered the bottom of each well of the quadratic cells. A painstakingly awful job. It was not quite as effective as the black hessian that reflected virtually no light, but it kept the “look” of the diffuser, a room feature.
Rear Quadratic Diffuser After Black Out Treatment
I still have some concerns regrading the projectors technical performance, but that is a different story, and I have decided to wait until after the ISF calibration before raising that flag up the pole yet again with JVC. My first attempt didn’t go very well.
Reasonably happy at last. Just waiting for my ISF calibration in September.
For more information on selecting your screen click here.
For more on Da-Lite screens click here.
For more on home theater Stewart screens click here.
For more on the Dual Masking Electrol (discontinued) click here.
