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best modifications Barco 808s

Discussion in 'Projectors, Screens & Video Processors' started by condor, Oct 26, 2005.

  1. condor

    condor
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    Hi all I was looking into replacing the glycol in my red and green tubes or going the 144 lenses way to improve the colours. I have a computer background, so modding things is what I do on my htpc, now I want to extend it to my pj.

    This got me thinking of the best ways of modifying my projector until I can get enough money for one of the nine crts.

    So, here I am wanting to know what people have done to modify their projectors and what were the best and most cost effective modifications.
    Most likely a lot of people are waiting for the right time to upgrade, like myself, whilst I am waiting I also want to get the best out of my PJ.

    I know a lot of people may think that it would be simpler to just get a top end pj but for myself thats not possible at the moment, nor I assume for a lot of people.

    The things that I most want to improve is the colour, that modification for me would be either the glycol or hd 144 route.

    The other thing that interests me is the contrast ratio. This projector is quoted as having 20000 to 1, where as most nines are 30000 to 1. What I would like to know is can a 8 crt match this or is that sort of contrast ratio only the area of 9 crts like the 1209 and such.

    Any thoughts ideas would be great, happy modding.
     
  2. Mad Mr H

    Mad Mr H
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    Just 144 lenses might not be right.

    You should look at colour corrected colour filtered 144's

    145, HD6 , HD8 are all available as above BUT most dont come with both options as the norm.
     
  3. Gary Lightfoot

    Gary Lightfoot
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    Contrast is just the relationship between the blackest black and whitest white (ideally when calibrated), so if you set any CRT for total black-out, you could have infinity contrast provided the light output for black was nil (zero lumens divided into 50 lumens or 100 lumens is infinity). You simply generate a full white field, take a measurement, then a full black field, take a measurment, then divide the black into the white and that is your full on/off Contrats Ratio.

    Having a very high CR due to a black level setting that allows total fade to black may actually be hiding image detail since much of the dark grey shadow detail is being displayed as black, so although the figures are impressive, you could actually be seeing less detail than a machine with considerably less CR.

    If you want to set the black level (brightness) and white level (contrast) correctly, you should use a test disk. It will allow your DVD player to send out the correct analogue voltages that represent black and white, and you can then set your display to show them correctly. Avia is a good disk for NTSC and DVE for PAL, though I prefer a German disk for generating PAL test patterns.

    If you set the CRT for good shadow detail, you may not get a complete blackout but have a slight glow on the screen, and the CR may only be around 10000:1. Don't wory though, as you will be seeing all the detail and have more than enough to display the contrast range that is available from the source (which is considerably less than 20000:1 or 30000:1).

    Gary.
     
  4. Mad Mr H

    Mad Mr H
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    Which German Disk do you prefer?

    I am NOT a fan of the AVIA disk - in fact I really hate it!

    Sorry,

    I find it so bad to navigate.

    I hate the opening chat....

    And it does not seem to have a cross hatch patten or from memory 4:3 16:9 etc size check patterns.....

    my opinions but there you go....
     
  5. condor

    condor
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    interesting stuff here, from what I can gather I take it then that the 30,000 to one contrast ratio for a barco 9 crt or marquee is just a marketing gimmick, or is it something that is would provide a visual improvement over 20,000 to 1 ratio 8 crt pjs. Apart from the ability to go to higher resolutions I assume the 9 crts must have other advantages over even a good 8 crt and I had always assumed that was where the contrast ratio came into it, a 9 crt should be able to hold the fine detail or is the contrast ratio working against it?.

    I am running of a HTPC not a dvd player scaler route, but I will have a look at the test disks all the same.
     
  6. Gary Lightfoot

    Gary Lightfoot
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    MMH,

    I find Avia easy to navigate as I know the main test patterns by heart and can go straight to each one from my HTPC, by-passing the main intro etc. The only thing that may be a drawback for CRT calibration is that it doesn't have any patterns that pass BTB or WTW if you want to set-up for that. It does contain some cross-patterns but I don't know if they're the ones you mean. For PAL I use the Peter Finzell test disk which is easy to follow despite being in German. It doesn't contain the video sequences used to test for deinterlacing etc like DVE does but it does contain some newer patterns since I bought it (it's been updated).

    Condor,

    You can achieve any CR value you like if you are unable to measure the black level and so get 0.0000 lumens on the meter. CRTs can also produce brighter spot white than full white, so a full white field will be considerably dimmer than a much smaller spot white (like a star in space), and that is where you may see much higher lumen figures quoted (like 1200 instead of 250). Some proffessionaly calibrated CRTs only measure around the 8500:1 mark due to a black level set for detail. The available contrast from a source may be as little as 1000:1 or as much as 4000:1, though the movie camera recording the images to film (or digital medium) is the limiting factor. The only time I would think a CRT may have trouble with contrast is if the black level is set too low, so crushing shadow detail into black (custom gamma curves can be useful if you want TFTB and good shadow detail), or if there is a mixed scene with both bright and dark images in the frame at the same time - the bright parts will bleed into the dark parts and reduce the intra-scene contrast (called ANSI contrast). This is down to the light scatter within the tubes and is also a factor of the room environment (the darker the walls the better). Perhaps a softer, less resolved image would blend some detail more and make it look less visible but I haven't studied this yet.

    9" CRT will probably be sharper, brighter and capable of higher resolutions as you've already said. They may also have superior contrast modulation so can do full field white very well indeed, whereas some struggle and the colour change across the screen is more noticable. The G90 and Marquee looked excellent when I saw them, and only the ANSI was an issue IMHO. I'm sure they must have better quality electronic components so will look more 'transparent' than lesser models, though there are people on this forum far more knowledgable than I in that department. SOme have better convergance ability and the Marquee 9500 I saw even had it's own camera for set-up so you can see why they cost more. Having said that, CRT must be the best bang for buck these days and can be picked up for very good prices now.

    I use HTPC myself and think it's the best source in the most part. It will take a more expensive solution of DVD player and scaler to match it IMHO.

    Gary.
     
  7. Mad Mr H

    Mad Mr H
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    Ah,

    The Peter Finzell disks.......

    The Guy I bought my colourimeter from........

    Funny story there......

    I buy this colourimeter from a guy....
    He says I'll out on of my dvd's in with it for you
    I say "thank you" but think......god, I have so many test disks but hey I can always stick it in the microwave for fun.
    Colourimeter arrives
    DVD arrives....
    Oh!
    by "one of mine" he really meant "one of mine", turns out it was from Peter Finzell and he sent me the test write up colourimeter and one of his own sealed DVD's

    So Peter if your reading this - lesson learnt, Thank you.

    I will try and sound more impressed next time.....

    So the rest of you

    GO AND BUY IT!
     

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