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Discussion Starter · #1 ·
Did you ever improve the horizontal pan or dithering issue of the LT150?



An earlier post suggested that your lt150 would not do 72hz and that you were communication with NEc.


Did they do anything.


Mine wont do it either.


Warren
 

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Mine won't do 72, either. I run it at 60.


The image starts to blur excessively at 72, and is lost completely above that.
 

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Sorry to butt in...


I posted a note a while ago about something I noticed in the service menu. It seemed to list the rates at which the LT150 would run at different resolutions.


I never was able to validate from anyone in the know that this was actually the case. However, based on that, I started running at 1024x576 @ 70Hz and have been quite pleased with the results.


--Les
 

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Les,


Any reason for the 576? Or is that just "where it runs" at 70hz?


How has your image improved with this setting over say.. 1024X768 @ 60hz ?


I always assumed the LT150 was synching if the display was working, and that the higher refresh rates would cause artifacts as the hardware became taxed... Is this not the case?


just curious :)
 

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My LT150 will do 60 through 71.3 but that's as close as I get to 72. Anything above 71.3 it'll turn desktop turns all yellow or brown. It'll sync. again at 73 or higher up to 85. After 85 it shimmers and has artifacts (unsupported according to manual over 85 Hz). Just curious if reducing vertical sync to 48 will work with LT150 as it's still a multiple of 24 instead of 72. At 60 Hz, it works pretty well for me using Radeon VE (OEM) and 7199 drivers with Win98SE. It won't sync at 72 with Geforce2 GTS Pro either. I switch to Radeon for the dual head feature, ATI player, steady sync at 60 Hz (my Geforce2 MSI Starforce 831 jitters very mildly every few seconds at 60 Hz for some reason), and better image. I'm glad I am not the only one that could not sync with LT150 at 72 Hz as it's supposed to be the best for film source DVD (24 FPS X 3).
 

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Quote:
Originally posted by uncledeathmonkey
Les,


Any reason for the 576? Or is that just "where it runs" at 70hz?


How has your image improved with this setting over say.. 1024X768 @ 60hz ?


I always assumed the LT150 was synching if the display was working, and that the higher refresh rates would cause artifacts as the hardware became taxed... Is this not the case?


just curious :)
1024x576 is 1.78 ratio and matches my screen. Otherwise the picture would overrun the screen.


I also run at 1024x768 @ 70Hz when I apply the panamorph.


I thought I saw slight improvement in overall picture quality when I changed to 70Hz from 60Hz.


--Les
 

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Les,


Ah - I see... I have been running 1024X768 @ 70hz as well... but alas no panamorph here...


I suppose the res of the actual display minus letterboxing would be around 576 pixels high... but what's the difference between driving the projector at 1024X576 with no letterboxing as opposed to 1024X768 with letterboxing?


Would the lower vertical res help reduce motion dithering... fewer pixels changing overall and therefore less chance of overrunning the dmd?
 

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Quote:
Originally posted by uncledeathmonkey
Les,


Ah - I see... I have been running 1024X768 @ 70hz as well... but alas no panamorph here...


I suppose the res of the actual display minus letterboxing would be around 576 pixels high... but what's the difference between driving the projector at 1024X576 with no letterboxing as opposed to 1024X768 with letterboxing?


Would the lower vertical res help reduce motion dithering... fewer pixels changing overall and therefore less chance of overrunning the dmd?
The purpose of the 1024x576 res is so that you can use a 16:9 screen.


Jeff
 

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I have that feeling... you know: when my head feels thick... and information does not pass readily thru my own skull...


Ok.. I will ask... since I want to understand...


Assuming we are projecting on a 16:9 screen (and we are); what are *all* the differences between running 1024X768 and 1024X576 into the lt150?


As Les said "1024x576 is 1.78 ratio and matches my screen. Otherwise the picture would overrun the screen."


Ok - assuming the same pixel widths, wouldn't the only difference be that the 768pixel high version would be letterboxed and the 576pixel version would not be letterboxed?? But they both should display the image area of the picture in the same aspect ratio... right?


If this is true the only stuff overunning the 16:9 screen in 576pixel high mode would be the letterbox bars...or am I high?
 

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When watching either a 2.35:1 or a 16:9 film there is zero difference between running the projector at 1024x768 or 1024x576. However if you have a 16:9 screen, when you return to the windows desktop the top and bottom parts of the screen will be cut off if you run at 1024x768. With 1024x576 the only thing you are cutting off is black bars.


Jeff
 

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Aha! Thank you JeffY :D...

(makes sense... I just pulled the screen up and down... till now)


But the more I think about it... It would make sense that the lower vertical rez could reduce lt150 motion dithering a bit; as, unless there is a perfectly clean feed to the projector, noise in the letterbox bars could contribute to load on the dmd switching... (probably only a tiny load, but hey... I hate mothion dithering)
 

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Discussion Starter · #15 ·
How are people setting refresh rates of odd numbers. Windows seemed to allow only certain choices.

I look at power strip but did not understand things like porch, vertical refresh etc.
 
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