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Forums -> Multiple monitors -> Pushing the speed of light -large CRTs and visual perception.
Obcranor   2008-04-28 00:26
I have been searching for a definitive answer on this issue (on and off) for years.

The Backgroud
I am an unashamed visual pedant. I want wide juicy color gamuts, crisp fine dot pitch and sufficient refresh rates. LCD/Plasma may ship cheap and large but but still my monitor of choice in mid-2008 is the old 21" Sony Trinatron.

The Two Problems
In my preferred multi-monitor array I have four Trinatrons sitting in 'Portrait' orientation. I reorient the image 90degrees but two issues occur.

Problem One
Firstly there is an odd shifting of central image that cycles only a few millimeters left to right every second or so. This phasing occurs on all the monitors so I assume it is not a monitor defect. It occurs also with only one monitor active and degaussed and no surrounding magnetic interference.

Problem Two
There is a relatively precise shadow of images offset in grey 1.0mm to 1.5mm below the correct image. Again degaussed and no interference.

The Questions
I know that these screens push physics to the limit. There are only so many electrons a single beam can emit per scan and phosphor radiate before flicker occurs.
If the screens were in 'landscape' and I was reading left to right the first problem would seem less visually challenging i.e. you read left to right and the line of text phasing up and down would be virtually unnoticeable.
However is this all within design parameters?

The shadow effect confuses me even more. If I shift the screen physically into 'landscape' the shadowing entirely disappears. Is this a nature based magnetic problem?

[As an aside a Computer Scientist friend feels it may be a speed addressing problem at CPU level -something about remapping the orientation however I (perhaps foolishly) think that my Cards are up to it.]

Thank you for reading so far. It seems of all the corners of the Interweb that there are people here that have the real experience to help with this problem.

Southern Hemisphere
4x Dell P1100
4x Ultra high quality signal cables
Power phased on same line
NVIDA GeForce 6600 GT
NVIDA GeForce 7100 GS
AMD Athlon 64x2 Dual
Core Processor 3800+
2.01 GHz, 1.00 GB RAM
Slackmaster K   2008-05-02 06:52
When you say "only one screen active", do you mean the other three are turned off, or just disabled/standby? I had similar problems with monitors in portrait mode, and ended up solving it by separating them with a sheet of metal.

ECarlson   2008-05-04 10:36
Could gravity be playing a part and distorting the mask? Are these monitors designed to be operated in a physical orientation other than bottom down? I once operated a cheap CRT monitor in a non-normal position, and the colors got all messed up on part of the screen and stayed that way, even after putting it into the correct orientation and making the monitor degauss. Fortunately we were getting rid of the monitor (and all CRT monitors) since we finally had LCDs on every desk.

Have you tried good LCD monitors? I wouldn't want to go back to CRTs. And LCDs run fine in any orientation and don't interfere with each other.

- Eric,
summer bell   2010-05-10 18:58
Thanks, very useful and informative for me.

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Forums -> Multiple monitors -> Pushing the speed of light -large CRTs and visual perception.

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