Originally Posted by rtart
I did something like this years ago with a CRT PJ when screens were transitioning from 4:3 to 16:9. I needed to mask the top and bottom of a 4:3 screen to 'show' the 16:9 area. I used a drapery motor to run it and a set of pulleys to raise a velvet-wrapped foam panel on the bottom. To make the longer width (120"), I found some aluminum U-channel that fit nicely over a 1/2" foam insulation board, and it was strong enough, while being light, too. A little duct tape to hold it in place, and then velvet wrap. For the top mask, I used a round aluminum pipe placed in a sleeve sewn into the top velvet fabric panel. Gravity helped it go down, and the drapery motor would easily pull it up. Took some trial and error and engineering to make it all work, but it would mask to 16:9 and 2.35:1, or any other constant-width ratio. Drapery motor (Somfy?) had built-in programmable stops, and an IR sensor, so my Philips Pronto would run it all easily.
Later on, as most TV became HD/16:9, it became kind of redundant and didn't get moved very often. I later went to an AT screen, with a fixed 16:9 ratio, so I retired the system. In my 'bat cave' HT, the few 2.35:1 ratio movies show some empty screen, but my JVC is dark enough that its really not noticeable.
So, your idea CAN be done, but it's not easy, and I'm not sure that with today's content that I would recommend the effort. However, it was really cool!
Hmmmm...aluminum U-Channel. I hadn't thought about that. I like that idea. good way to make a crisp line too. I'll have to see if my Lowes or HD have any U-Channel that will fit well over 1/2 or 3/4" foam boards.
99% of what I watch in my HT are Blu Ray movies. A huge portion of those are either 2.35:1, 2.39:1 or 2.40:1 (unless in real applications, they are all basically the same) and I have the black bars. Some of the older Disney/Pixar Movies were 1.78:1 I think. I recently added some velvet panels to the side walls about 6' out from front wall and covered the tops and sides of my LCR speakers in Velvet. Since I did that, the Black Bars on the screen are now MUCH darker than before, but can still be seen during a movie. It's definitely something I want to do. Oh, and I have a budget friendly PJ, so the bars aren't as dark as something like a JVC PJ
I found a person on a Klipsch Forum while googling Masking who used 3/4" foam board, and drilled holes into the edges with Dowels to connect the two pieces for a longer than 8' length. He then recessed some Rare Earth Magnets into the foam on each end. I'm not sure what he connected it to, but I'm thinking maybe wood blocks just thicker than depth of screen with a piece of metal attached to it and wrapped in Velvet and then attach magnetically. But if too strong, I'm afraid when I remove for a different formatted movie, I may break it.
What did you use to cut your Foam?