[BiggerPicture]

I'd like to try installing a 10 ft widescreen ratio rear projection screen to replace my DIY 7ft front projection screen (I have plenty of room, and complete lighting control for blackout conditions....)


I'm using a Sony D50 with internal line doubler, and have plenty of room to back project. My viewing distance is very high (7m) hence the desire to go for a larger 10 foot screen.....


A company called Polivision are offering a very reasonable 2.5 gain flexible rear projection fabric which I intent to install in a newly built wall.


So - here's the question... Is this a good idea? Will I get a good enjoyable picture? and is it better to floor or ceiling mount the projector behind the screen?


Thanks for any help you can give me

Biggerpicture

 

[Ray Cendroski]

Big...


I'm not at all familiar with the capabilities of a G50, but I have a 128" x 72" Vutec 2.5 gain rear screen setup that I'm really happy with. I think the arrangement makes a lot of sense, and offers the fewest compromises if you have the room. You can also get those noisy fans out of the viewing area.


My projector is about 12 feet behind the screen, and I sit about the same distance in front of the screen. My projector lens focus limits my max image size to about 114" x 64".


With a line doubler and anamorphic source material I get a very good image. Scan lines are visible, but certainly not objectionable. Total darkness control is a must. I occassionally use a HTPC with a 1280 x 720 output, especially on non-anamorphic stuff like Titanic, but generally I'm not too wild about the softer image and the control hassles.


I thought it made sense to install the largest screen I could fit. Hopefully down the road, as projector technology improves, I'll find something to fill the whole screen. Right now I just ignore the unused portion.


Don't count on picking up a lot of extra brightness range by going up to a 2.5 gain screen. The good news is that my image brightness doesn't drop much to either side of center.


I like the table top mounting position arrangement. It makes it easy to get into the projector for tweaking and the like. I have my projector dead center behind the screen center. The back of the projector is tilted up so there is no keystone offset required. That is, there is a square image on the crt raster.


Ray

 

[bryan_chow]

That should be a great setup. If you have the room, rear projector is the best option. I've always wanted to walk up to my screen without blocking the picture...


Only thing is that you might want to go with more than doubling, with a D50 and a large screen.


Bryan

 

[KFung]

I don't have any experience with the fabric you are looking for, but I should warn you that you may experience visible hotspotting with a 10' (diagonal?) screen if you use such a high gain.


You would want to mount your projector as close to the centre as possible or at an angle so that the projector points directly at the audience through the centre of the screen. This should maximize brightness and even out hotspotting so it won't show as much. You might also consider a rigid diffusion screen with a fresnel lens, this will also help reduce hotspotting, however it can be quite costly. If you used a rigid diffusion with a fresnel lens you would centre mount your projector. An even more costly option is a full fresnel/lenticular screen like the Stewart Microwave. However, it is generally not recommended for critical viewing.


I can't say how noticeable you might find the hotspotting, but it will be there to some degree whether it is visible or not (this is unavoidable with any gain screen).


Regards,


Kam Fung