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Boilermaker
Joined: 21 May 2006
Posts: 527
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| Posted: Sun May 27, 2012 7:54 pm Post subject: |
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I have the space and the time to do it, but can't handle the $ part. I have to redo my HVAC this year and have a few other projects to do also. Maybe next year, and if I do it, I will take many pictures to share.
Bob
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Nashou66
Joined: 12 Jan 2007
Posts: 16171
Location: West Seneca NY
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Boilermaker
Joined: 21 May 2006
Posts: 527
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| Posted: Sun May 27, 2012 8:34 pm Post subject: |
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That's a good idea, but I have a better one. You send me the money, and I'll do it here with 3 XGLC's!
Seriously, that cost isn't that much in equipment as I already have another XGLC with new tubes - It's in finishing the basement!
Bob
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VideoGrabber
Joined: 09 Apr 2006
Posts: 933
Location: Michigan
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| Posted: Tue May 29, 2012 11:15 am Post subject: |
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Boilermaker wrote:
> you can easily double that to 1600 lines even with 8" projectors <
Since I'm not seeing anyone else question this assertion, I have to ask. Really?
I wasn't aware that 8" PJs had that capability. Much less "easily". Scan rate alone (~120 kHz) would preclude that on many 8" PJs, if not the CRT rez itself (though since you're doubling, being able to actually resolve the 1600 lines isn't so much of an issue). While you may be able to push the scanrate that high on many 8" PJs, in my experience bandwidth limitations would result in horizontal rez then suffering significantly (due to maximum beam slew-rates). I.e., BW limits affect the product, and when you push the vertical rez, the horizontal suffers. I wouldn't perceive either of these constraints as a problem with 9" units, but the 8" claim does surprise me.
I haven't been following the blending movement, but it was my impression that they were still doing 1080p. Perhaps many have gone beyond that to 1600p, and I simply am not aware of it?
Craig commented:
> I really like your point here with respect to 4k. I think it is something not understood by folks in the CRT community yet. Upsampling a source such as 1080p to 4k will not add any detail or sharpness. It can only serve to make the pixel pack more dense. <
I'd agree with that.
> CRT essentially has an infinitely dense pixel pack. <
Only on the horizontal axis. The vertical is limited by the raster scan lines. Though I agree that the CRT face itself has no such limitations.
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- Tim
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Boilermaker
Joined: 21 May 2006
Posts: 527
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| Posted: Tue May 29, 2012 1:02 pm Post subject: |
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| Quote: | | I wasn't aware that 8" PJs had that capability. Much less "easily". Scan rate alone (~120 kHz) would preclude that on many 8" PJs, if not the CRT rez itself (though since you're doubling, being able to actually resolve the 1600 lines isn't so much of an issue). While you may be able to push the scanrate that high on many 8" PJs, in my experience bandwidth limitations would result in horizontal rez then suffering significantly (due to maximum beam slew-rates). I.e., BW limits affect the product, and when you push the vertical rez, the horizontal suffers. I wouldn't perceive either of these constraints as a problem with 9" units, but the 8" claim does surprise me. |
Not only can it do it, it is actually much easier to do than running 1080P on a single projector. There are two reasons for this. First, because (in the case of 1920X1600) each projector only "sees" 1064X1600, the bandwidth requirement is substantially lower than 1920X1080. At 1064X800, the video frequency is less than conventional 1080i!!!
Secondly, in a conventional setup when you are watching a 2.40 source, you are using less than 1/2 the height of the tube face available. In a blend, you are using the entire (or as close to the edge as you want to take it) height. Also, you are only recreating 1064 pixels across the width in comparison to 1920. An 8" projector can handle this easily.
| Quote: | | Only on the horizontal axis. The vertical is limited by the raster scan lines. |
Exactly, and since a blend gets to use the entire tube, running just 1080P there are visible scan lines everywhere on the screen.
Try watching a 2.4 movie, and adjust your vertical gain until it fills the tube face and you will see it for yourself.
The projectors are just loafing at these rates which is one reason why the picture looks so good.
Bob
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Boilermaker
Joined: 21 May 2006
Posts: 527
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| Posted: Tue May 29, 2012 1:12 pm Post subject: |
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There is another way to look at all this:
If you took the crt projector that you are now using and multiplied the size of the tube area by a factor of 4, and increased its bandwidth by a factor of 2, you would have the same performance as a blend of two of your projectors.
Bob
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Boilermaker
Joined: 21 May 2006
Posts: 527
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| Posted: Tue May 29, 2012 1:32 pm Post subject: |
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Opps - Almost forgot that there is another advantage. Obviously somewhere in the signal chain you have to do a digital to analog conversion, most likely a Moome input card. Awhile back Craig showed some nice oscillograph's of the performance of several D/A converters and none of them were perfect at high rates. They would all be much better at the lower frequencies that a blend uses.
Bob
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mp20748
Joined: 12 Sep 2006
Posts: 5689
Location: Maryland
TV/Projector: 9500LC Ultra / Super 02 and 03 VIM
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| Posted: Tue May 29, 2012 2:15 pm Post subject: |
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| Boilermaker wrote: | Opps - Almost forgot that there is another advantage. Obviously somewhere in the signal chain you have to do a digital to analog conversion, most likely a Moome input card. Awhile back Craig showed some nice oscillograph's of the performance of several D/A converters and none of them were perfect at high rates. They would all be much better at the lower frequencies that a blend uses.
Bob |
I remember those results, but they were showing the difference between a converter that could not and one that could. The one that could actually 100% resolved the higher rates and that is what most are using today.
Concerning blending. The science is correct in that you'll be using lower scan and bandwidth when doing blending, but because you are also blowing up the image, the lower scan rates will not show the finer detail that's very important for the High Resolution HD signals of today.
So in getting the best image, you'll need to go with higher scan rates, and when going that way, you'll also need higher bandwidth requirements from the projector. and that's why we're seeing higher vertical elements (vertical resolution/vertical refresh) being mentioned. And forget about any large screen projected resolution below 1440X1050P being able to properly deal with the native 1920x1080 HD standard.
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dturco
Joined: 06 Feb 2009
Posts: 3778
Location: Eastern Shore Maryland
TV/Projector: Runco DLP VX-3000i Marquee 9500 parts doner
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| Posted: Tue May 29, 2012 2:32 pm Post subject: |
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| MP wrote: | And forget about any large screen projected resolution below 1440X1050P being able to properly deal with the native 1920x1080 HD standard.
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OK Mike, just so I get this right, each projector needs to run say 1600x1200p to get the true benefit of the Blu ray. So two 8500 Marquees...can still easily do that?
Oh, and on that note, can the 8500 tubes be put in LC chambers from a 9500? Or do they have their own special LC chambers?
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Boilermaker
Joined: 21 May 2006
Posts: 527
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| Posted: Tue May 29, 2012 2:37 pm Post subject: |
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| Quote: | | I remember those results, but they were showing the difference between a converter that could not and one that could. The one that could actually 100% resolved the higher rates and that is what most are using today. |
As I remember it, there was a large difference between the different converters with Moome's latest version being the best by far, but even it had a drop off on the last pulse pattern. When a bandwidth or frequency response is specified as X, it does not mean that the response is flat at that frequency - It means (usually) that it is 3db down at X.
| Quote: | | Concerning blending. The science is correct in that you'll be using lower scan and bandwidth when doing blending, but because you are also blowing up the image, the lower scan rates will not show the finer detail that's very important for the High Resolution HD signals of today. |
Sorry, I don't have the faintest idea of what you are saying - Can you further explain?
| Quote: | | So in getting the best image, you'll need to go with higher scan rates, and when going that way, you'll also need higher bandwidth requirements from the projector. and that's why we're seeing higher vertical elements (vertical resolution/vertical refresh) being mentioned. And forget about any large screen projected resolution below 1440X1050P being able to properly deal with the native 1920x1080 HD standard |
Since I am running a refresh rate of 72, I again don't understand what you are saying?
Bob
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barclay66
Joined: 27 Jun 2011
Posts: 1304
Location: Germany
TV/Projector: Marquee 9500 Ultra
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| Posted: Tue May 29, 2012 2:44 pm Post subject: |
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| dturco wrote: | | Oh, and on that note, can the 8500 tubes be put in LC chambers from a 9500? Or do they have their own special LC chambers? |
They have their own. Although the outer housing seems identical to those of 9'' tubes, the inner one (that part which can be tilted via Scheimpflug bolts) is smaller.
Regards,
barclay66
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Nashou66
Joined: 12 Jan 2007
Posts: 16171
Location: West Seneca NY
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| Posted: Tue May 29, 2012 2:50 pm Post subject: |
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| mp20748 wrote: | | Boilermaker wrote: | Opps - Almost forgot that there is another advantage. Obviously somewhere in the signal chain you have to do a digital to analog conversion, most likely a Moome input card. Awhile back Craig showed some nice oscillograph's of the performance of several D/A converters and none of them were perfect at high rates. They would all be much better at the lower frequencies that a blend uses.
Bob |
I remember those results, but they were showing the difference between a converter that could not and one that could. The one that could actually 100% resolved the higher rates and that is what most are using today.
Concerning blending. The science is correct in that you'll be using lower scan and bandwidth when doing blending, but because you are also blowing up the image, the lower scan rates will not show the finer detail that's very important for the High Resolution HD signals of today.
So in getting the best image, you'll need to go with higher scan rates, and when going that way, you'll also need higher bandwidth requirements from the projector. and that's why we're seeing higher vertical elements (vertical resolution/vertical refresh) being mentioned. And forget about any large screen projected resolution below 1440X1050P being able to properly deal with the native 1920x1080 HD standard. |
WTF are you talking about?
1920x1080 is the same no matter what. be it on One PJ or across two that splits the duty.
I'm off to Toronto so I'll let Bob respond here.
Athanasios
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Tim in Phoenix
Joined: 21 Oct 2006
Posts: 4409
Location: Phoenix
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| Posted: Tue May 29, 2012 3:01 pm Post subject: |
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Guys
For edge blending and displaying 1920 pixels with a 20% overlap, each projector need only resolve 60% of the 1920 pixels or 1152 pixels; a seven inch CRT can manage that.
.
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mp20748
Joined: 12 Sep 2006
Posts: 5689
Location: Maryland
TV/Projector: 9500LC Ultra / Super 02 and 03 VIM
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| Posted: Tue May 29, 2012 3:02 pm Post subject: |
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| Boilermaker wrote: | | Quote: | | I remember those results, but they were showing the difference between a converter that could not and one that could. The one that could actually 100% resolved the higher rates and that is what most are using today. |
As I remember it, there was a large difference between the different converters with Moome's latest version being the best by far, but even it had a drop off on the last pulse pattern. When a bandwidth or frequency response is specified as X, it does not mean that the response is flat at that frequency - It means (usually) that it is 3db down at X. |
Ok, let me go further. Craig's test showed that one performed better, but in order to 100% prove the test, his scope and test leads would need to be confirmed as well as where and how the probes were loaded and attached for the test. FET probes are best for this. The other part of Craig's testing was confirmed here on my setup, where we got to see the one pixel on/off pattern clearly resoled on my screen. He later posted this in another thread.
| Quote: | Concerning blending. The science is correct in that you'll be using lower scan and bandwidth when doing blending, but because you are also blowing up the image, the lower scan rates will not show the finer detail that's very important for the High Resolution HD signals of today.
Sorry, I don't have the faintest idea of what you are saying - Can you further explain? |
If you use computer monitors at the lower resolutions then you would not notice that the finer detail is not there, that is there at 1920X1080 material. When projecting that same resolution on larger screens, you would notice the lost in finer detail. And I know you're going to come back with numbers, but if the numbers proved everything, then we would not be looking at the higher rates that's on the table of every new design. And so that you'll also know, even 1440X1050 is short.
| Quote: | | Concerning blending. The science is correct in that you'll be using lower scan and bandwidth when doing blending, but because you are also blowing up the image, the lower scan rates will not show the finer detail that's very important for the High Resolution HD signals of today. |
Sorry, I don't have the faintest idea of what you are saying - Can you further explain?[/quote]
You would have to see this on a system for yourself to understand this. If you are ever able to play around with these higher resolution systems and be able to change the rates around yourself, it's then that you'll understand that you'll want the higher scan rates and what actually happens when native HD signals broken down.
It's not even a debate in the real world. The higher the scan rate the better the image is resolved. And that has become one of the biggest challenges for CRT projectors in the commercial world. They're are still loved for their low end, but everything today deals with higher resolutions.
| Quote: | So in getting the best image, you'll need to go with higher scan rates, and when going that way, you'll also need higher bandwidth requirements from the projector. and that's why we're seeing higher vertical elements (vertical resolution/vertical refresh) being mentioned. And forget about any large screen projected resolution below 1440X1050P being able to properly deal with the native 1920x1080 HD standard
Since I am running a refresh rate of 72, I again don't understand what you are saying?
Bob |
I agree, 72hz is perfect for non-3D systems. perfect for blending. But I can't imaging any H/V scan rate you could use on a large screen display that would properly resolve a true HD image and do so on an NEC giving it's limited bandwidth performance. Again, you're going to need to do at least 1440X1050P resolution.
Last edited by mp20748 on Tue May 29, 2012 3:07 pm; edited 1 time in total
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mp20748
Joined: 12 Sep 2006
Posts: 5689
Location: Maryland
TV/Projector: 9500LC Ultra / Super 02 and 03 VIM
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| Posted: Tue May 29, 2012 3:07 pm Post subject: |
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| Nashou66 wrote: |
WTF are you talking about?
1920x1080 is the same no matter what. be it on One PJ or across two that splits the duty.
I'm off to Toronto so I'll let Bob respond here.
Athanasios |
Thanks!
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Boilermaker
Joined: 21 May 2006
Posts: 527
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| Posted: Tue May 29, 2012 3:10 pm Post subject: |
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| Quote: | | OK Mike, just so I get this right, each projector needs to run say 1600x1200p to get the true benefit of the Blu ray. |
Nothing could be further from the truth. If you run 1600 wide nothing is gained and you lose two things. First the ratio of 3200/1920 is 1.66666... Hardly a nice easy algorithm, but one that will for sure create artifacts.
In my blend, and Nash's we run 1064 to each projector. Not a single pixel is created as they are original from each side of the original signal. 2 X 1064 is 2128 which creates a blend zone that is 208 pixels wide. The net result is 1920 with absolutely no manipulation or loss.
The second loss is that 1600 requires 50% more bandwidth which will have a negative effect on picture quality.
Bob
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Tim in Phoenix
Joined: 21 Oct 2006
Posts: 4409
Location: Phoenix
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| Posted: Tue May 29, 2012 3:11 pm Post subject: |
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Guys
Who said anything about lower scan rates? You still want 1080p; the requirement for 1920 is reduced.
.
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mp20748
Joined: 12 Sep 2006
Posts: 5689
Location: Maryland
TV/Projector: 9500LC Ultra / Super 02 and 03 VIM
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| Posted: Tue May 29, 2012 3:13 pm Post subject: |
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| Tim in Phoenix wrote: | Guys
For edge blending and displaying 1920 pixels with a 20% overlap, each projector need only resolve 60% of the 1920 pixels or 1152 pixels; a seven inch CRT can manage that.
. |
You're right Tim. But 1151X1050 when going at 72hz, the bandwidth requirements are far beyond what any 7" projector will do, with only the 8" Marquee almost having enough bandwidth to properly display the finer detail.
The discussion deals primarily with Bandwidth requirements.
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mp20748
Joined: 12 Sep 2006
Posts: 5689
Location: Maryland
TV/Projector: 9500LC Ultra / Super 02 and 03 VIM
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| Posted: Tue May 29, 2012 3:19 pm Post subject: |
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| Boilermaker wrote: |
The second loss is that 1600 requires 50% more bandwidth which will have a negative effect on picture quality.
Bob |
So that deals with the higher scan rates that was previously mentioned in this thread and was somehow said it was OK
| VideoGrabber wrote: | Boilermaker wrote:
> you can easily double that to 1600 lines even with 8" projectors <
Since I'm not seeing anyone else question this assertion, I have to ask. Really? |
And since the topic was on higher scan rates and such, I'm only saying that you will need higher bandwidth for CRT, and that there's also a reason why the INDUSTRY has and are moving to higher resolutions.
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Boilermaker
Joined: 21 May 2006
Posts: 527
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| Posted: Tue May 29, 2012 3:23 pm Post subject: |
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| Quote: | | If you are ever able to play around with these higher resolution systems and be able to change the rates around yourself, it's then that you'll understand that you'll want the higher scan rates and what actually happens when native HD signals broken down. |
????????????? I give up!
| Quote: | | Who said anything about lower scan rates? You still want 1080p; the requirement for 1920 is reduced |
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Exactly! Thanks Tim. Nuff said.
Bob
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