I have a number of requirements for a projection screen, the main 2 being: I figured to obtain the multiple aspect ratios, I would employ a variable masking design. The screen would be fixed width and the masking would reduce the screen's vertical dimension to allow for any aspect ratio from 1.3 (standard TV) to 1.78 (widescreen) to 2.35 (wide movies).

My original design specified custom sized screen material with a black border. The screen would be lowered to it's lowest position with it's black borders providing the lower and side masks. A piece of velvet would would provide the top mask. To increase the ratio (decrease the vertical dimension), the top velvet would be lowered to whatever position was necessary. When the velvet is lowered to its lowest position, the screen behind it would be raised to further decrease the visible screen height. Since the projector always projects a 1.3 image, the bottom black border on the screen would need to be large to catch any light spill when the screen is slightly raised. The size of the required borders proved to be impossible for the screen manufacturer (Dalite), so I had to rethink this design.

The current design changes a bunch of things around. The screen now has no black borders. The top velvet mask is stationary while viewing, but retracts into the screen enclosure when it's closed. The masking is provided by a large piece of velvet behind the screen, which is visible around the bottom and sides of the borderless screen. Variable aspect ratios are achieved by raising or lowering the screen while the back velvet mask remains in place. All these components are motorized and retract into the enclosure when it's closed.

I don't have many pictures of this part of the project since it was built relatively quickly. I'll be adding more as I install the enclosure and I'll also back-fill with design documents after it's complete.

Here's a picture of the screen mockup we've been using. It has a 74" wide viewable area with 4" borders on the sides. The mockup is made of white and black poster board bought at the local office supply store.

Here's another angle on the mockup. We have the TV in front of it for now but I have used a borrowed projector to watch a movie or two.


I'll eventually provide some mechanical drawings here.


This part of the project relies on a motor controller, the same design as used for the projector lift.

The screen electronics and motors share a 20 amp circuit with the projector lift.


The enclosure is basically a pine box that mounts around the frame. It's primed and painted white to match the walls. I don't have any in progress pictures of its construction, but you'll see it in the installation pictures.


Installation has mostly gone according to plan. However, I've had to make some late design changes (and continue to do so). The main change so far is the change of material for the back mask. The velvet I orginally planned on using has proven to be too finicky to sew and mount correctly. It wasn't performing as well as I hoped, so I'm currently looking for a replacement. I have a couple of leads, so hopefully I'll be back on track soon.

Another problem I'm having is the screen material from Dalite. First of all, don't take anything I say here about the material as criticism of Dalite or their dealers. So far I'm being taken care of and I fully expect the issues to be resolved shortly. In fact, I would consider the treatment of these problems as an endorsement.

Anyway, there's 3 main problems with the screen material.

  1. The first problem is that the screen was damaged during shipping by UPS. The damage is not extreme but has resulted in a number of wrinkles in the material. They may be fixable using a little heat from a hair dryer, but I won't bother because of the 2 other problems. I don't know if you will be able to see it clearly, but here's a picture of one of the wrinkled areas. The pattern repeats about every 8 inches down the entire length of the screen. Each wrinkled area is about 3x4".

  2. The next problem are the minor defects in the surface of the material. The picture shows an area a couple of inches across where it appears a "drip" or "run" in some liquid coating has smeared. This also occurs down the length of the screen in varying degrees. It appears that during the manufacturing of the screen, some machine or nozzle dripped something on the surface and then it was rolled up.

  3. I don't have a picture of the last problem since it's hard to capture. The material is not cut square. After partially unrolling the material on 4x8 sheet of plywood and lining the side of the screen up with a straight-edge clamped to the plywood (and checked for square), the bottom egde of the screen is at least 1/4" out of square across it's 84" width. I would not have expected this and it makes mounting the material on a drum and rolling it up evenly virtually impossible.

I noticed the shipping damage the day the screen arrived and talked to the dealer (AVS) the next day. They indicated that they would replace the screen if my attempts at repairing it failed. I'll be talking to them again and we'll see how things go.

UPDATE! AVS and Dalite have since sent me a new screen and it's much better. I've hung it, as you'll see below. Both companys' service was excellent and I wasn't given any hassles. On with the show.

UPDATE! The back masking material problem has also been solved. I found a crushed velvet-like material that has pretty good light absorbing properties. It's much thinner and has a stiffer backing. I was able to seam two pieces together with heat tape (took a couple of tries). It rolls up much better.

Here's the plywood frame, upside down while I'm wiring it. This is the back. You can see the "hook" that will mate with a similar structure mounted to the wall. This will allow the entire enclosure to be moved left/right to allow for proper alignment with the projector.

Here's the motor controller all wired up. You can see the electrical box, behind which is a hole through the plywood where all the motor wires are run. You can also see the motor start capacitors in the lower right.

Here are the motors. The top motor controls the masking, the bottom the screen. You can also the brake on the screen motor. While not shown here, I had to later mount a brake on the masking motor since the masking weighted so much.

Here's the frame mounted on the wall. You can also see the door mounted and in the open position. The black nylon strap in the middle of door prevents the door from swinging too far back which would prevent the masking from catching and closing the door properly. The wire in the middle is the center channel speaker wire.

Here's a shot of the controller end with the masking and screen mounted. The front masking is not in place but will be hung on the white rod you can see just below the screen drum. You can also see the nylon cord and pulleys that make the front mask retract as the door closes.

Here's the motor end. You can now see the second brake I had to add. Because of the tight fit, I can't mount the brake covers so they're exposed.

Though virtually impossible to see here, this shows the back masking, screen, and front mask in a partially down position.

This is another angle on the previous picture. Still can't see much since the velvet sucks up all the light and kills the contrast.

Now all done except for the enclosure, here's the screen fully retracted.

Here's the mask fully lowered.

Here's the screen lowered to the 2.35 aspect ratio.

Here's the screen lowered to the 1.77 (16x9) apsect ratio.

Here's the screen lowered to the 1.33 (4x3) aspect ratio.

Here's a closeup of the closed door.

Here's the finished product with the center channel speaker mounted.

This part of the project is now complete.