CurtPalme.com Home Theater Forum

[rule76]

I am strongly considering rear projection for my setup. My basement is wine bottle shaped and figure I can put the projector into the "neck" of my basement. I've been here and avs. Clarence is one that I could see was on both forums.

I am getting some samples of the "stickyscreen" looks like a goo system. Really excited about the crt. I had a sony 1052, didn't know what I was doing and got rid of it. Some 5 or 6 years ago. Now my curiosity is again piqued. I had a dlp projector Mitsubishi hc 1500. Easy to mount, easy to adjust seemed to work just fine on my wilson art. Problem was the rainbow. I'd reach for popcorn and unicorns and glitter seemed to be upon me.

Now 6 years later we are buying a house and I have dedicated space. I won't have the sound proofing, columns and masking systems as the others but I appreciate a good picture.

So. Most of what I read was in archives. With the current rear projection peeps. What are you using (screen and projector) and what would you recommend (ceiling, floor or center mounted, gain, brand of screen) I'm all ears and appreciate any information.

I'm looking to get an ampro 4600. If that doesnt work out, the nec if I for sure go with rear projecton or the Barco 808x. I like 1080p for future proof but 720p will work fine for my application. I will be using a pc. So scalers and the such I won't have to fool with.

[spitz]

I'm running a retrographics 808s, one mirror, and a diffusion screen of unknown make and model that I got out of a control center in Ohio. Here are some nuggets I'll pass along:

1 - I originally had HD117 lenses on my projector. It was great because of the short throw and they are super sharp, however, that also meant I had big light falloff problems in the corners because the angle the light hit my screen was really steep. I replaced them with HD18's off a G70 and got longer throw and color correction. Things looked much better after that, although not as sharp as the HD117's.

2 - My screen has a glossy viewing surface. Just like all the new TV's, if there is any light in the room, it acts like a mirror and gets a bit annoying after awhile. If you can, get something with an anti-reflective or matte coating on the front.

Other than that, the rear setup is great. No noise and my kid can't fool with my projector!

-Matt

[rule76]

I received my stickyscreen sample however the gain is listed pretty high. 3 and 6. I don't have a projector yet either. Moving into a house at the end of this month and am chomping at the bit. Looking at an ampro 4300, maybe an xg 85. I ruled out nec and sony previously because of sound but I am now open again.

[Phil Smith]

I think high gain on RP is due to the screen not dispersing the light enough, which means it will hot spot really bad.

In the youtube demo, you can see the holographic clear screen horribly hot spotting. They avoid straight shots where the projector is shooting through the screen directly at the camera. The rare occasions the projector is directly behind the screen (look at the top right of the screen starting at the 35 second mark) it hot spots so bad it looks like there's a flashlight behind the screen.

The gray screen looks a lot better. At about 49 seconds the camera drops (you can see the projector disappear behind the screen) to a somewhat direct view. I don't really see any hot spotting at all, which is pretty amazing.

It's hard to tell for sure from a crappy demo video, but that gray screen looks pretty darn good.

[benareeno]

I would opt for something closer to a unity gain...

high gain rp is based on people who are watching in a well lit room...hopefully you won't be doing that very often.

I have always wondered why rp setups are not more mainstream...the projector noise is behind the screen...where it should be!

[rule76]

I thought the same thing with the holographic. I was like when am I going to see this straight on! The grey was a lot better.

As far as gain. I am not sure what the gain should be for rp. Is it the same as fp? I've read where some have stated that the gains are generally reported higher than what is metered. So I am hoping the grey will be less than the 3 that is stated and still be a good solution.

[Phil Smith]

Like benareeno said unity gain would be best. Not sure they make that though.

Because light has to pass through a RP screen, it's a completely different animal from a FP screen. Light bounces off FP. It's irregular surface scatters the light in all directions. Light passes through RP and is *bent* in different directions. My guess is RP isn't as efficient a FP, but on the plus side, ambient light in the viewing room also passes through the screen, making ambient light less of an issue.

I really liked my RP setup. It's the only thing about my house I miss: http://www.dallas-music.com/House/HT.html

Back to hot spotting: AVS member soapsuds has/had a RP setup that used a Draper Ciniflex screen, which I think is supposed to be pretty good stuff. Here's identical screen shots from different angles. It wasn't his intent, but these screen shots clearly show hot spotting. Notice how much the scene changes with the different viewpoints. It's much brighter on the side where the photo was taken.

[rule76]

I have noticed the hotspotting in rp setups. Your setup on avs is one of two setups that brought me to consider rp. My seating area will only be about as wide as your old house in Dallas. So there may be hot spotting from the sides but that just means you aren't in a chair. Thanks guys for the input. I really do appreciate it. Phil do you think ceiling or shelf mounted is the way to go?

[Phil Smith]

I ceiling mounted mine because my garage was my projection room and I still wanted to be able to use it as a garage. It sounds like you have the perfect setup for RP. If you don't need the projection room for anything else, you should definitely shelf mount your PJ. Elevate the rear of the PJ so the tubes are shooting straight at the screen (the tubes are level). Make your shelf/table at a height that puts the tubes centered on the screen. This will completely eliminate keystone on the green tube and only require a little on your red and blue tubes to compensate for toe-in. This lack of keystone will be easier on the convergence circuitry, which should make it run cooler and make your convergence setup more stable (less drift). You can also use more of the tube face, which should make the picture brighter and sharper.

The only negative about RP is very few people have RP setups (as you can tell by the response to this thread), so you're kinda on your own. Matt has had his RP for a while and knows what he's doing. You can always contact one or both of us if you have any questions.