HIGH POWER a Review! Part 1 - Page 4

I'm guessing you have stadium seating if you're pj is ceiling mounted, yet only 2 feet over your head while seated?

And I'd definitely go 133" if you're sitting 18 feet back.

No, it's just an average-size basement.... The projector is ceiling mounted,
but I adjusted it to the lowest position.(about 18" to 20" from the ceiling)

But I like your idea better! I wonder if I can remodel my basement and add
stadium seating....

Actually, to me that would be the way to do high power. Instead of putting the pj on a shelf, put the people on stadium seating. I don't think it's that difficult or expensive. I just can't do it in my room.

Tryg - A previous post asked a question which I don't see ever getting answered. You state the PJ is 8' above the floor, the screen is 3' above the floor, and you sit 28' back (assuming eyes about 3.5' above the floor). Is that really the type of setup you want for a retro-reflective screen?

I'm looking at getting a Pan AX100 with the following setup:

Room 11.5' by 15' with 10' ceiling
Eyes are 12' from the screen and 3.5' above the floor
Projector will be 14' from screen and 8' above the floor
Screen will be between 100" and 120" diagonally with the bottom at least 4' above the floor

I guess since your eyes are above the bottom of your screen then the retro is helping (think I just answered my own question) whereas my setup has my eyes beneath the bottom of the screen. Does this mean I would be better served with an angular reflective surface? What would you recommend here? I would like a non-fixed screen and prefer image quality over an electric motor for raising and lowering.

Thanks,
Lin

P.S. Great post by the way - extremely helpful to those of us choosing a new screen.

I know this is off-topic but you are correct. It's both cheap and easy. It cost me about $$350 for materials and carpeting. The real expense was the additional row of Berklines($1800). You can save $$$ though as some folks just put an additional couch or a couple of Lazyboy's on their riser

It works great in tryg's setup because of how far back the seating and pj are from the screen. The further back you can go from the screen with a ceiling mounted pj and the HP the better. It lessens the angle of incidence by going that route. The shorter the throw and the higher the mount, the less optimal the results will be.

Okay, thanks. So using THIS calculator and using these numbers.



B = 28' back from screen
A = 4.5' down from lense to center of screen (I'm guessing - don't know your screen height)
X= about 9 degrees.

So you are only off axis by 9 degrees and the screen works for you. According to this graph you are realizing a gain of around 2, I guess.



Is this correct? I wonder what the maximum angle would be before brightness lessens below that of a standard screen? twelve degrees?

My setup would leave a 17 degree angle which looks like it would be too much.

Thanks,

Marshall

Millerwill: My system is a very similar setup so the High Gain looks like the screen to go with. Just got a quote from Jason and once I sell a pair of MLs Vista speakers I have for sale I will be moving over to this screen. My projector is about 3 feet above my head and I am about 16 feet back, middle of screen is about 1-2 feet up if I am sitting in middle of couch. I will be using a 16X9 92" screen...

Marshall - Thanks for the calculator - that's a big help! Looks like I'd be ~17 degrees off axis vertically for my first row (primary row) given the setup I was planning. HP is definitely not going to work in my setup. Looks like I need to take a serious look at a Silverstar in person.

Marshall thank you very much for that calculator. It confirmed me what Tryg told me this morning and I now can't wait for my RS1. I should be able to get gain around 2.3 and that should be plenty for me to enjoy a bright picture.

Will the gain increase if screen is slightly tilted backward (on top) to reduce the angle? Then worry about correcting the keystone problems! I don't need to do this for my setup but just curious how it works for these screens as I read how lot of HD81 owners like to tilt their projector and screen to get the screens closer to ceiling because of HD81 offset limitation.

If I understand retro-reflectivity correctly, the microspheres on the surface of this screen reflect light back along the axis of projection, whatever that angle happens to be. I don't think there's any way to get around placing the projector close to eye level, if the aim is to maximize gain.

HP might not work, but I'd wait to hear a couple of things...

1 is the calculator I posted the correct way to find the angle..

2 Are we interpreting the gain chart correctly.

I'm also curious what Tryg's angle is and his estimation of the gain...

Ditto - I'm just really torn on what to do for the screen. The Silverstar worries me with the "sparklies" and I'm afraid a ~ 1.4 gain screen isn't going to be enough for the wife and I considering this is going to be our primary TV/Movie room with lots of hours logged on the RS1. New bulbs are going to be a killer if we don't go higher gain I'm afraid...

In the calculator above, isn't "A" correctly measured as the distance from the lens of the projector to the level of a seated viewers' eyes, and not necessarily the center of the screen ( unless a viewer's eyes are exactly perpendicular to this point? ) If the term "retro-reflective" refers to a literal phenomenon, then in a "High Power" application, the greatest quantity of light is reflected back along the axis of projection, or area within close proximity to the point of origin, ie: the lens.

Bill - I'm pretty sure mine is a Model B. I found a good deal somewhere (can't remember) on a 96" square screen. I only pull it down enough for what I need. This gives me a 110" diagonal. I also used black felt to mask the wall around the screen.

I finally got around to playing with the High Power screen sample that Da-Lite
sent me a while ago. This thing is ridiculously BRIGHT! I taped in the center
and turned on my Panasonic AX100. In all modes(Cinema1/2, Normal, Vivid),
there's just a big bright square in the center where the sample is located.
I even tried to turn the lamp down to Eco mode and it was still very bright.

Next, I tried sitting in various locations to judge how narrow the viewing angle
was. Not too bad... The far left/right seats will see a little less brightness,
due to the angles... but still very bright.

My old InFocus(few years old, with old bulb) DLP projector will probably look
bright on the High Power screen... maybe I'll drag it out of the basement and
try it tomorrow.

One thing that I noticed was that the High Power sample sheet looked almost
beigh in sunlight.(compared to a sheet of 98-brightness printer paper)

Cool, I can't wait to get my sample and try it out.

I was just thinking.... if I get enough of these 6" x 6" High Power screen samples,
I can just put together a free screen. At first I thought there might be a
problem with the lines where the samples join, but I did a test by cutting up
the sample in half. I tape them together on the wall, and from nearly 20 feet
away, I cannot see the seam at all.

Just kidding, I don't want to be a cheapskate. (not until I'm about 82 years old, anyway)

The Carada BW should be figured at 1.1 gain if you are ceiling mounting the PJ. The one sample I have does not meet their 1.4 gain rating with the PJ ceiling mounted. The BW has the best color and brightness uniformity I have measured. It causes virtually no color shift in the image. The image on a BW screen will benefit from making the surfaces in your HT dark colored and/or non-reflective. Because of its superb uniformity charectoristics it throws a lot of light onto the walls, ceiling and floor. This light will create some washout in the image if it is reflected back by light colored walls etc. If the RS1 matches its 700 lumen estimate, a 122"D (9' X 5') BW screen would yield 17 fL of screen brightness. Low bulb power would start you off at about 12-13 fL.

The SS is somewhere near 3.0 gain. Its an entirely different type of screen. Choose a screen size and gain that yields proper screen brightness. The BW and SS could not both be in contention at the same screen size because one would be almost 3 times brighter than the other.

The HP is only about 1.0 gain when used with a ceiling mounted PJ and thus you sacrifice its main advantage, high gain.

The Vutec Pearl Bright is rated at 1.8 gain and is relatively cheap. If I recall correctly I measured it at 1.6 gain. It has superior color uniformity compared to some of the other high gain screens. Of course it hot spots like almost all high gain screens, however the importance of brightness uniformity is greatly exagerated by many, IMO. It is much more important to achieve proper screen brightness. I agree with Tryg on this. If you need high gain, then use high gain. Don't choose to have an image that is too dim (or too bright). A caveat about the Pearl Bright. I have only measured a 2' by 2' sample of this screen. It measures out very well compared to comparable materials. I have not seen an image on a Pearl Bright screen. You would want to see one for yourself before selecting this material. It has a bit of a salmon color to it in normal room light.

Glenn

This is the 'great unknown' for me, "proper screen brightness". My room is not a dark-walled, totally light-controlled situation; there is not significant external light, but surfaces are light-colored (though not white).

A lot of people say you should go for ~30 ftL on a new lamp (and some even a lot more, but I consider them the fringe), while you and others say that 12-15 ftL is right for a new lamp. Is this because your recommendation is for the ideal dark-walled, etc. HT? Do you have a 'rule of thumb' for the room I described above, which I think is typical of many AVS'ers.

Bill, I've always been under the impression that you want around 12ftl from the screen when the lamp hits it's half-life.

This is what I've always heard, but then there are some forum members who have HP with ceiling mount and still say they get a significant boost in brightness.

I received my Da-Lite sample today, but only 2 little 6"x6" samples which will make it tough to judge. I think Tryg should get a big piece of scrap HP from Da-Lite and then charge us $10 to rent it for a few days and then send it along to the next person in line.

You could just look in the "for sale area" for someone selling a small used HP screen for cheap and just cut it up into 2'x3' pieces and sell them off.

But who in their right mind would ever sell a High Power screen, unless of course, only to buy a bigger one, right?

I think we have all been avoiding buying the largest HP screen because it has a seam 6 ft down the screen.

Your test brings up an interesting question. Can the seam be seen in the largest HP screen or aa in your test, does that seam disappear when video is projected on to it.

If the seam disappears, then much larger HP screens can be built and used in home theaters. Anybody have any information on the seam on the largest HP screen?

My PJ's fixed offset is .16 times the screen height. The lens of the PJ is 9.5 inches above the top of the screen. From this position I measure the HP at about 1.0 gain at the center of the screen, the same as with the Firehawk in the same configuration. If someone ceiling mounts a PJ so that the lens is lower than the top of the screen, they will likely measure a higher gain.

Another difference is that I am measuring the light coming off the screen with an instrument. I am not looking at an image and estimating the gain.

glenned,
Thanks for the response. That helps as my pj will be mounted about the same height above the screen like yours. My wife will be so happy to hear that I'm not upgrading our screen. When she saw those Da-Lite samples come in the mail yesterday, she said, "I'm going to get online and tell your friends at AVS that you're not allowed to go there anymore because of all the upgrades."