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Dene Wilby
Computer to onstage projectors
on Apr 30, 2010 at 11:58:45 am

Hi

I work for a band and i'm in the process of setting up a computer based system to replace our DVD system.

With the old system I had 3 DVD players fed to 3 projectors on stage via composite cable.

I'm setting up a system using GrandVJ sent to a Matrox TripleHead2Go.

Am I OK to run long VGA cable to the stage without degradation of quality? These are only 1,000 max capacity venues, nothing too big. I'm thinking 50 to 60m should do the job at most places and if not, i'll run it from the side of the stage.

Is there degradation over that length? I've read conflicting reports. Surely, whatever I get will be better quality than what I have been using? Right?

What kind of degradation (if any) should I expect?

Thanks for any advice you can throw my way.

Cheers

Dene



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Walter Soyka
Re: Computer to onstage projectors
on Apr 30, 2010 at 6:55:21 pm

That strikes me as quite a long run for VGA cable.

You might look into Cat-5e VGA extenders for runs like that. Side bonus -- Cat-5e cable is cheaper, thinner, lighter, and easier to work with than VGA cable.

Walter Soyka
Principal & Designer at Keen Live
Motion Graphics, Widescreen Events, Presentation Design, and Consulting
RenderBreak Blog - What I'm thinking when my workstation's thinking
Creative Cow Forum Host: Live & Stage Events


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Dene Wilby
Re: Computer to onstage projectors
on Apr 30, 2010 at 7:19:52 pm

hmmm, would I need one of those extenders for each of the 3 outputs of the matrox card?

when I look into that I see that they are also good for about 50 metres. What would the benefits be, apart from having lighter, more manageable cable?

thanks

Dene



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Walter Soyka
Re: Computer to onstage projectors
on Apr 30, 2010 at 7:33:12 pm

There's no such thing as an absolute cable length limit for VGA -- it depends on the resolution and refresh rate, the graphics card driving it, and the quality of the cable itself. I wouldn't attempt more than 15 or 20 meters with HD15 VGA cable.

For an analog run of that length, most events would use a DA (or line driver) with 5-wire coaxial cable with BNC connectors instead of HD15.

The Cat5 extenders actually work across the whole distance. Some companies have units that can go significantly farther than 50m.

Walter Soyka
Principal & Designer at Keen Live
Motion Graphics, Widescreen Events, Presentation Design, and Consulting
RenderBreak Blog - What I'm thinking when my workstation's thinking
Creative Cow Forum Host: Live & Stage Events


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Dene Wilby
Re: Computer to onstage projectors
on Apr 30, 2010 at 7:43:35 pm

Hi,

I appreciate your advice but i don't do this on a professional level so excuse my ignorance:

>For an analog run of that length, most events would use a DA (or line driver) with 5-wire coaxial cable >with BNC connectors instead of HD15.

So what do I need for this? I have HD15 outputs on the Matrox card and HD15 inputs on the Projectors.

I just need to find an affordable (to us) solution that we can use for 3 shows in a row (in different venues). Why would you not use a 50m HD15 to HD15? What are the downfalls?

Sorry, i'm just trying to understand this final piece of the puzzle.

I'd probably be outputting at 800x600 by the way.

Dene



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Walter Soyka
Re: Computer to onstage projectors
on Apr 30, 2010 at 7:50:43 pm

You'd need 6 VGA/RGBHV fan-out cables, 3 long RGBHV cables, and 3 RGBHV DA's to place by the Matrox devices to act as signal amplifiers. You may also need 3 humbuckers by the projectors to eliminate electrical hum.

If you only need it for 3 gigs in a row, it might be cheaper and easier to rent the Cat5 extenders from a local staging company.

Walter Soyka
Principal & Designer at Keen Live
Motion Graphics, Widescreen Events, Presentation Design, and Consulting
RenderBreak Blog - What I'm thinking when my workstation's thinking
Creative Cow Forum Host: Live & Stage Events


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Dene Wilby
Re: Computer to onstage projectors
on Apr 30, 2010 at 7:53:59 pm

Thanks for the advice, I will look more into this. Also, the advice about the loss of signal over long lengths is very important, thanks for making me understand that.

We do about 10 to 15 shows a year so we need to own the correct equipment really. We've been using some real 'makeshift' gear over the past 6 years and need to take it up a level.

Dene



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Walter Soyka
Re: Computer to onstage projectors
on Apr 30, 2010 at 7:45:32 pm

I forgot to mention this before -- one of the biggest problems of trying to extend VGA too far isn't just loss of picture quality (like you may have seen with long composite runs), but an absolute loss of picture. The projector may not be able to keep a lock on the sync signal if it's too weak, and if it lost sync, it would drop the image entirely.

Walter Soyka
Principal & Designer at Keen Live
Motion Graphics, Widescreen Events, Presentation Design, and Consulting
RenderBreak Blog - What I'm thinking when my workstation's thinking
Creative Cow Forum Host: Live & Stage Events


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Thomas Leong
Re: Computer to onstage projectors
on May 1, 2010 at 3:16:13 am

I've used 100m HD-15 to HD-15 for b&w Stage Teleprompters, and did not notice any degradation such ghosting or loss of signal. So 50-60m should be fine in my view.

But VGA Extenders are far lighter. Besides with the right tools in the bag, one can make up an RJ-45 quickly when required, versus HD-15. And if you are too tired after the gig, you can dump the CAT-5 cables without a second thought. Lately I've been using the ATEN VGA Extender VE-150 which is supposed to handle up to 150m. I've only taken it up to 100m though. They are about one of the cheapest on the market, bought at less then US$200 a set. Only thing is you need a power source at both ends. At the Local (source) end, the unit has a HD-15 monitor out which is convenient.



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Dene Wilby
Re: Computer to onstage projectors
on May 1, 2010 at 11:14:23 am

Thomas and Walter

Thanks guys, this thread has helped me tremendously. I sincerely appreciate you directing me to VGA extenders, that is definitely the last piece of the puzzle. Do these look like good units?

http://www.maplin.co.uk/module.aspx?moduleno=45472

If so, i've setup the new system for less than £1,500 which is just great and like Thomas says, Cat5e is pretty much 'disposable'.

Cheers

Dene



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Thomas Leong
Re: Computer to onstage projectors
on May 1, 2010 at 2:57:44 pm

Dene,

The Maplin units look good. Cheaper than my Taiwan-made ATEN by about half! Good find.

Thomas



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Dene Wilby
Re: Computer to onstage projectors
on May 9, 2010 at 4:09:36 pm

OK, i've got my hardware and software setup and it's working great via the Matrox triplehead2go to 3 VGA monitors.

I now just need to get the VGA Extenders and CAT5e to the 3 projectors.

Would this stuff be OK for this job?

http://www.tmb.com/Pdf/ProPlexCAT5esnake-LTR-web.pdf

Am I right in thinking that the 4 channel would suit my purpose leaving 1 spare?

Dene



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Thomas Leong
Re: Computer to onstage projectors
on May 10, 2010 at 4:29:41 pm

I use the std cheapo stuff, but this one looks good. Pro! Not so easily disposable though.

One thing to be aware of is "how far apart are your projectors, relative to each other?" The snake would have to split from either the left/right projector or from the centre projector.



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Joel Servetz
Re: Computer to onstage projectors
on May 1, 2010 at 12:41:42 pm

The vga to cat-5 extender is a very good idea for long runs. I have done literally hundreds of events involving multiple long (100' - 150') vga runs to projectors and monitors using Extron VGA-DAs which are capable of runs of up to 250'. Long (100' or more) VGA cables are thick and heavy and prone to failure from mis-handling so treat them with care and have plenty of backups.

Joel Servetz
RGB Media Services, LLC
Sarasota, Fl
videobyjoel@aol.com


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Robert Lubiran
Re: Computer to onstage projectors
on Jun 24, 2010 at 7:41:44 am

Great day! We bought a datavideo switcher SE-800 for our Church Media, a decklink card and CG-100 Character Generator. Everything works fine. Projecting it through an LCD Projector (Sanyo PDG-DXT10L). We also used a 30 meters RGB cable from decklink (Installed to a PC) going to LCD projector. We noticed the delay of the Video on the our LCD and the actual video on stage. Is there a solution for this? How can we synchronize the video in the LCD and the actual stage performance? Is there any gadget to solve this problem or is it natural?

Thanks for the help.
It is appreciated!


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