CurtPalme.com Home Theater Forum

kb · Joined: 17 Sep 2008 Posts: 8

My wife needed a bigger dining room and bedroom upstairs. I just got a 16x32 foundation poured. Thus, I now find myself with a space of that size in the basement approved by said wife for use as a theater (8 foot ceiling, but you take what you can get).

The stairway into the space from outside resulted in some space at one end presenting the need for a closet/stairway. This led me to think that it would be really nice if I could hide the projector in the same closet at the extreme rear of the theater area. If i make the closet roughly 8 or 1o feet wide, that leaves me with around 22-24 feet from projector to screen.

Some resulting questions:
1) can I get lenses for either a Barco 1208 or an NEC 75 to accomodate that distance to a maximum 8 foot by 16 foot screen potential (actually, the 8 foot is assuming ceiling to floor but i would really need to reduce a foot or two to get it above the floor - suggestions in that regard?) - I would prefer the Barcos - they seem to stay converged a lot better and I have 2 so will have backup/spares.
2) how much affect on brightness would this have (I assume there is a decrease with longer throw distance)

3) what would you do if you suddenly found yourself with 16x32 feet of space you could use for a theater...

Thanks,
kb

**AnalogRocks** · Posted: Mon Nov 10, 2008 6:23 pm Post subject:

16 feet! No not with CRT. You would neeed two 9" projecors blended side by side to do that. Even then it may get a bit dim.

You'll need to mount your projector much closer to the screen and think 8 foot wide. Maybe 9 but it'll start getting dim.

If you want to hide something back there maybe stuff your equipment in there. Build a hushbox on the celing for the projector.

jask · Joined: 17 Mar 2006 Posts: 10187 Location: kamloops BC

with 32 feet you could even do rear projection and keep the ceiling clean..

kb · Joined: 17 Sep 2008 Posts: 8

Rear projection is a GREAT idea - but, is there a way to avoid the severe light attenuation (is there such a thing as a non-negative gain rear project screen)? Would possibly also need a mirror (more attenuation?) or cut at least 10 feet of the room out (was only thinking around 5 originally). What would be the minimum room length recommended with 15+ feet of width?

I know that Glass Mountain Optics has a coated acrylic rear project panel they use on simulators that actually has positive gain, but would certainly be cost prohibitive for home use. Is there anything similar in a consumer market?

Thanks for the idea - well worth some thought. This room (and it's dimensions) came on me so fast I hadn't even done any out of the box thinking - who would have ever thought rear projection would be an option at home...

kb

Person99 · Joined: 09 Mar 2006 Posts: 4899 Location: Flower Mound, TX

Some basics: if you want a great image, neither of these PJs should be used on a 16:9 screen much larger than 90" wide (84" is really best). If you want a "watchable" image you can go to about 96" wide. Anything more than that and you are getting in to crap looking image.

The only reason for huge screens is multiple rows of seating. So, the first question: how many rows do you want? You'll need about a 90-96 inch wide for 2 rows and much wider for 3 rows. For one row, you could go with an 84" wide screen and have a great picture.

jask is onto something with the rear pro. After seeing Phil's 84" wide G70 rear pro set up several times, I can say rear pro is the way to go. You could put in a false wall creating a 19-20 foot deep theater room and a 12-13 foot deep projection room. This also has the advantage of giving you a place to put your subs. Subs sound the best when you are about 20 feet or so away from them. Most of us do not have the luxury of putting them this far away (my subs sound killer on the far side of the room outside of the theater--smooth and full bodied), but you would in the "projection room". If you want rear pro contact Phil Smith and see what material he used because it looked great (as an aside, one university did a study of rear pro vs. front pro and the "look" of rear pro was preferred by the majority. One last benefit is that your theater is really quiet.

Now, if you want a 10 foot or more wide scope screen, I'd say get rid of the CRTs and do a digital CIH set up. I'd still do a false wall to make a room that was 16x24 which would still give you some distance for the subs and a place to put the equipment rack.

Person99 · Joined: 09 Mar 2006 Posts: 4899 Location: Flower Mound, TX

kb · Joined: 17 Sep 2008 Posts: 8

I would like as many rows as is possible. I was planning on at least 3 with some 'overflow' capability (on bean bags/folding chairs) when the kids have a big party or something. I really only care about one seat - mine, right in the center sweet spot Wink

.

I have been using a screen 100 inches wide for the last 10 years and have been quite happy with it (not sure if your numbers are diagonal or not - i just happen t know mine is 100 wide since I measured it the other day). I had planned to go bigger in the new room maximizing the aspect ratio with the space provided and coming up from the floor a couple of feet (or less).

I actually have 2 1208s (I would need to get Curt to do some repair work to get them both running though). I have considered the possibilty of pairing them up but don't know if my wife would tolerate what i am sure would be a daily convergence/tweaking 'nightmare' - hard enough to keep one converged, cant imagine what it would be like to keep two simultaneously on top of each other. Is this really practical?

Do you have a link to the study about rear projection proving to be prefered over front? isn't it inherently softer and dimmer?

I am not quite ready to leave CRT yet. Some of the new LCOS stuff is pretty close, but I still like CRT much better (some people like chocolate better than vanilla - one is certainly not actually 'better' than the other, just differences in preference). I doubt I will buy any new CRTs, but as long as i can keep what i have running, i plan to use them. I figure about the time they are all dead (2 1208s, 2 800s and a 75), light valve devices will have evolved to where i would buy one. Most notecable light valve dislikes for me are pixelation/screen door - which is being diminished by resolution increases (smaller pixels result in less noticable artifacts), motion blur (swimming pixels make me crazy) and to some extent black level (although this is not a big issue in my mind - in a few seconds, your brain seems to establish what 'black' is and regardless of it actually being grey, it does not seem to bother me too much). I have seen LED stimulated DLP that is promising - currently pretty dim and the colors dont seem 'vivid'. Laser stimulated DLP has a 'shimmer' to it that is even more distracting than motion blur. All of this is of course just my own personal preference - certainly NO intent whatsoever to initiate any sort of debate on the subject of light valve vs. CRT here - just wanted to establish that I fully intend to stay with CRT on this current project.

You all have provided some great stimulus for thought. I will begin search for information on rear projection - very intriguing idea...

Thanks!!
kb

Person99 · Joined: 09 Mar 2006 Posts: 4899 Location: Flower Mound, TX

kb · Joined: 17 Sep 2008 Posts: 8

Sorry for the confusion on light valves. I was using 'light valve' per the common definition with which I am familiar such that it characterizes all typcial non-CRT projectors from LCD to GLV:

googled "define:Light Valve Projector" to get:
"Definitions of Light Valve Projector on the Web:
A projector that uses an imaging system that either blocks or reflects light such as LCD, LCoS or DLP.
www.optoma.co.uk/glossary.aspx"

Your comments on your projector certainly carry some value since you characterize yourself as a previous "CRT zealot". It's been a year since I have seen a consumer (i.e. affordable) LCoS (a Sony SXRD (LCOS) on display at Frys for about $3k (my first Barco 800 cost me that plus a drive from Salt Lake to Sacramento, so certainly feasible).

I have some $15k Christies at work that i have taken home to test against the CRTs and even my wife and kids wouldn't watch it.

Do you know of a place near Salt Lake where I could see a system like yours in action? How does it compare to the Sony SXRD with which I am familiar (and impressed - the first non-CRT that has ever caught my attention at all).

thanks,
kb