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Discussion Starter · #1 ·
Hi all I am getting ready to move back to the states and have a Theater being built. I currently have an unmodified Vidikron Vision One and am looking at the potential of getting another CRT to double stack. I have heard I can get a E-home 9500LC from places like Hi-Rez. Questions to follow:


1. what is benifit in double stacking 9inch CRTs?

2. Do they have to be of the same make: i.e. can I double stack a Vision one with a Barco 1209?

3. Best scaler to use for both picture quality and to drive both CRTs at the same time

4.max screen size for great picture quality for a single 9inch CRT and then for a double stack configuration.



thanks for the help,

Jim
 

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Quote:
Originally Posted by Jim Parys
Hi all I am getting ready to move back to the states and have a Theater being built. I currently have an unmodified Vidikron Vision One and am looking at the potential of getting another CRT to double stack. I have heard I can get a E-home 9500LC from places like Hi-Rez. Questions to follow:


1. what is benifit in double stacking 9inch CRTs?

2. Do they have to be of the same make: i.e. can I double stack a Vision one with a Barco 1209?

3. Best scaler to use for both picture quality and to drive both CRTs at the same time

4.max screen size for great picture quality for a single 9inch CRT and then for a double stack configuration.



thanks for the help,

Jim
I've never done a 9" stack but I successfully stacked (2) 8" projectors and here is how I would answer your questions.


1. Superior contrast and brightness with a good opportunity for smaller spot size and less tube wear.

2. The better matched they are the more successful your outcome likely will be.

3. I don't know about scalers but I can definately tell you from first hand experience a computer video card will not provide enough RGB drive without some bufffering to the video. You can double up on the H and V sync signals but you can not double up the RGB. Fortunately, a good extron interface box solves this problem inexpensively. And since you can bufffer the levels inexpensively with an interface box, the scaler probably is not even relevant (as far as single vs stack) IMO.

4. I'm not really sure but most peoples preference is probably around 9-10' for the single 9" and 10-12' for double.
 

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From what I understand your best performance will come from two identical CRT projectors, and that includes the fact that the hours on the tubes should be close. The game is to be able to drive two projectors at a reasonable levels to illuminate a large screen while not overdriving the tubes. If you want a really crispy picture you really need relativly good tubes on two machines.


Somewhere a long time ago I read that you should also reverse the tube order on one of the projectors to minimize color shift although I can't imagine in practice that it's too necessary.


A far simpler approach to getting a larger image is to build yourself a torus with a 3.0 gain screen and a 9" LC machine.


R-S
 

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Guys!


Side stacking gives a stunning image but works the H Linearity and Geometry section pretty hard; if side stacking you would want a screen of 111" to 120" width; this is nice and punchy; smaller make prove difficult to align the machines. In Marquees it is desirable to use matching main software levels of v3.3 or higher or alignment will be very tough to achieve. Each intended source or resolution needs a test grid from it or equal to it from a generator source (HDTV for example at 1080i) or homogenize all sources thru a scaler to one resolution. An RGB DA like Extron's ADA2/300HV will split your scaler output nicely. The other technique we hope to bring to market is an affordable edge-blend solution, which will make better use of the phosphor area of the tube faces; see the blend thread that was here recently.
 

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Quote:
Originally Posted by Jim Parys
Hi all I am getting ready to move back to the states and have a Theater being built. I currently have an unmodified Vidikron Vision One and am looking at the potential of getting another CRT to double stack. I have heard I can get a E-home 9500LC from places like Hi-Rez. Questions to follow:


1. what is benifit in double stacking 9inch CRTs?

2. Do they have to be of the same make: i.e. can I double stack a Vision one with a Barco 1209?

3. Best scaler to use for both picture quality and to drive both CRTs at the same time

4.max screen size for great picture quality for a single 9inch CRT and then for a double stack configuration.



thanks for the help,

Jim



Jim,

Double stacks are twice as bright, this translates into more color saturation and better apparent CR . If the PJs are the same it theoretically adds to stability. For 9" CRTs there is still no better overall scaler than the venerable Faroudja 5000.With it you can do 960p for DVD sources and very good HD deinterlacing running 1080p 60Hz.


With moderate gain ( about 1.6 to 1.7) as I have ,11' wide is about as big as you can reasonably go and not lose gray scale tracking and still have a nice light output.


Cliff and Ryan saw me picture mute one PJ and see the difference in the image which is by no means subtle.


In my case, to have the clean look I wanted ,a toroidal screen was out since they can't use acoustically transparent screen materials for optimum speaker placement, not to mention the more limited viewing cone.


When you are back in the country give me a call if you would like to see what one of these looks like.


Art
 

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Quote:
Originally Posted by Art Sonneborn
Double stacks are twice as bright, this translates into more color saturation and better apparent CR .
How come you get more color saturation? :confused:
 

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Quote:
Originally Posted by Art Sonneborn
In my case, to have the clean look I wanted ,a toroidal screen was out since they can't use acoustically transparent screen materials for optimum speaker placement, not to mention the more limited viewing cone.


Art
I think a couple of people will have something to say about the limited viewing cone.


I am starting to wonder if the use of an acoustically transparent screen could be done in a Torus. Most say that their fans are pulling to much air. So, could one get enough fan power to suction the screen into a Torus? Just thinking hypothetically, so don't ream me a new one.:)


Jim,

Although they don't make them anymore, Vutec made an UHG screen that would have given you more than enough brightness. That is according to Chuchuf and Wireless.


Ericglo
 

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Quote:
Originally Posted by Ericglo
I am starting to wonder if the use of an acoustically transparent screen could be done in a Torus. Most say that their fans are pulling to much air. So, could one get enough fan power to suction the screen into a Torus? Just thinking hypothetically, so don't ream me a new one.:)
I think you'd need more powerful fans but it may be possible. It depends on how much air you can draw through a screen (how much of the total area is actually missing due to the microperf). In addition you'd have to place your speaker (s) INSIDE the low pressure enclosure.


Worth an experiment I guess...
 

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Having stacked a pair of Xtras, unless your a pro like Ken W (my hat's off to you) - I would build a torus.


It's hard to get them aligned, and it's hard to keep them there.


I did an over-under stack and as the one on the ceiling warmed up with the room the pair would move a tiny bit.


Unless you get them EXACTLY lined up you lose resolution as one smears the other.


A torus would be easier.
 

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Quote:
Originally Posted by raoul
I think you'd need more powerful fans but it may be possible. It depends on how much air you can draw through a screen (how much of the total area is actually missing due to the microperf). In addition you'd have to place your speaker (s) INSIDE the low pressure enclosure.


Worth an experiment I guess...


I guess I need to stop into Vutec and pic up a sample.


Ericglo
 

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Quote:
Originally Posted by htpcfan
How come you get more color saturation? :confused:
You have twice as much color coming to the screen especially if the tubes are putting out a color mix other than black or white. For example, if you are showing a blue sky there will be 2 blue crts (as opposed to just 1) putting out a huge amount of blue saturation during the same time all the green and red tubes are resting with no output. Then the next scene when you show a grass scene the 2 green tubes are going strong but nothing out of the others.


So that helps to bring the colors out much bettter.


.
 

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Discussion Starter · #14 ·
Thanks for the information guys. I am worried about the potential drift and having to have the reconverged often. However the increase in picture potential is applealing. How often (on avaerage if there is such a thing) would reconvergence need to take place? Would you if budget really was not an issue double stack or just go with a newer 3 chip dark chip 3 or 1080p DLP?


thx
 

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Quote:
Originally Posted by Jim Parys
Thanks for the information guys. I am worried about the potential drift and having to have the reconverged often. However the increase in picture potential is applealing. How often (on avaerage if there is such a thing) would reconvergence need to take place? Would you if budget really was not an issue double stack or just go with a newer 3 chip dark chip 3 or 1080p DLP?


thx
There is no cheap 1080p DLP, but there is a lot of interest in the new Sim pj. At $20k, it is about double what a 9500 with a Torus set up and calibrated from Chuchuf would be.


Ericglo
 

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Discussion Starter · #16 ·
Ok - what exactly is a "Torus set up" I have seen a lot of reference to it but not sure what it is?
 

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Quote:
Originally Posted by Jim Parys
Ok - what exactly is a "Torus set up" I have seen a lot of reference to it but not sure what it is?
You'll find the answer here.
 

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Quote:
Originally Posted by Jim Parys
Ok - what exactly is a "Torus set up" I have seen a lot of reference to it but not sure what it is?
Is my sig line link not showing up on your computer? Maybe I need to make it a different color.


Ericglo
 
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