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perisoft
Joined: 29 Aug 2007
Posts: 2920
Location: Ithaca, NY
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| Posted: Tue Mar 11, 2008 7:45 pm Post subject: A strange idea to improve PQ |
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Everybody seems to agree that long analog cable runs are the bane of CRTdom. People make special amplifiers, DVI->RGB converters to put on the PJ itself, etc.
So, being an uber-budget, do-crazy-stuff kinda guy, I thought: What if I mount the damned computer right under the PJ so I've only got a three-inch cable from the VGA out to the BNC on the PJ? Presumably I'd get the same benefit as I would using a DVI->RGB converter. True? And does anybody have any screenshots of, say, an 8" PJ set up well and running some sufficiently high resolution to compare?
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Person99
Joined: 09 Mar 2006
Posts: 4899
Location: Flower Mound, TX
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| Posted: Tue Mar 11, 2008 8:14 pm Post subject: Re: A strange idea to improve PQ |
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| perisoft wrote: | | Everybody seems to agree that long analog cable runs are the bane of CRTdom. |
I don't, my run to the PJ is analog with high quality cable because it is more resilient.
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Dave
A train station is where the train stops. A bus station is where the bus stops. On my desk, I have a work station....
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ecrabb
Forum Moderator
Joined: 13 Mar 2006
Posts: 15909
Location: Utah
TV/Projector: JVC RS40, Epson 5010
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| Posted: Tue Mar 11, 2008 8:34 pm Post subject: |
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Exactly. Long analog runs are only bad if the analog runs are bad. If you have good enough cables and equipment, analog runs can be REALLY long. I worked on an install with Barco 909's driven from an Extron switcher through heavy Extron RG-6 RGB snakes... probably 75-100 feet. Source was SGI Onyx RE video cards running at 1600x1200/60hz and edge-blended, projecting probably an 8x10-foot image - with excellent picture quality.
It's all about using good equipment and cabling.
SC
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MikeEby
Joined: 24 Jun 2007
Posts: 5237
Location: Osceola, Indiana
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| Posted: Thu Mar 13, 2008 12:32 am Post subject: |
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Here was my solution to keeping my cables short.
I had limited space and wanted to maximize my seating capacity so I built a soffit to hold my gear that is accessible in the third row. The projector is also recessed in the same soffit making the hush box appear not as massive. Under the sheet rock is a steel frames lagged to the ceiling.
A nice benefit was very short cables (4 feet), I often wonder if this is one reason I am able to run push my refresh and resolution harder than most and not see a huge amount of softness in the image.
Mike
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Doing HD since the last century!
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Zebu Fellenz
Joined: 21 Dec 2006
Posts: 2567
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| Posted: Thu Mar 13, 2008 12:48 am Post subject: |
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Mike,
That looks really nice, what case are you using for you HTPC? (it looks like the one I have)
Erik
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MikeEby
Joined: 24 Jun 2007
Posts: 5237
Location: Osceola, Indiana
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| Posted: Thu Mar 13, 2008 1:06 am Post subject: |
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| Zebu Fellenz wrote: | Mike,
That looks really nice, what case are you using for you HTPC? (it looks like the one I have)
Erik |
Thanks!
The HTPC is the far unit mounted to the left of the projector. It’s an older Antec rack mount server case. The audio processor is a "new to me" Atlantic Technology P-2000 pre/pro that came out of Art Sonneborn’s theater I have a rack mount kit for it also but I am not using in right now. I figure if it was ever good enough for Art, it would certainly be good enough for me for quite some time. 
I am very impressed with the analog outputs on Asus Maxums audio card. I don't have much of an ear for audio though but it definitely sounds better than SPDIF.
Mike
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Zebu Fellenz
Joined: 21 Dec 2006
Posts: 2567
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| Posted: Thu Mar 13, 2008 1:32 am Post subject: |
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My case is an Athena Power 4U rackmount case. I think it makes a nice HTPC case and will fit into my eventual rack nicely.
Erik
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Spanky Ham
Joined: 22 Mar 2006
Posts: 5643
Location: Comedy Central
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| Posted: Thu Mar 13, 2008 3:33 am Post subject: Re: A strange idea to improve PQ |
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| perisoft wrote: | Everybody seems to agree that long analog cable runs are the bane of CRTdom. People make special amplifiers, DVI->RGB converters to put on the PJ itself, etc.
So, being an uber-budget, do-crazy-stuff kinda guy, I thought: What if I mount the damned computer right under the PJ so I've only got a three-inch cable from the VGA out to the BNC on the PJ? Presumably I'd get the same benefit as I would using a DVI->RGB converter. True? And does anybody have any screenshots of, say, an 8" PJ set up well and running some sufficiently high resolution to compare? |
I took some pics of the differences between a three foot and twenty foot Monoprice premium component cables. The differences were exactly zero. The pics aren't worth posting.
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MikeEby
Joined: 24 Jun 2007
Posts: 5237
Location: Osceola, Indiana
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| Posted: Thu Mar 13, 2008 4:31 am Post subject: Re: A strange idea to improve PQ |
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| Spanky Ham wrote: | | I took some pics of the differences between a three foot and twenty foot Monoprice premium component cables. The differences were exactly zero. The pics aren't worth posting. |
What resolution and refresh rate were you running? The higher the bandwidth requirements the higher the demands on cabling. I think most people would agree Monoprice cables are good quality cables.
Mike
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kschmit2
Joined: 09 Mar 2006
Posts: 1141
Location: Heidelberg, Germany
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| Posted: Thu Mar 13, 2008 8:56 am Post subject: |
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Mike,
that's a very elegant solution.
Kai
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Ile
Joined: 09 Mar 2006
Posts: 1491
Location: Jyväskylä, Finland
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| Posted: Thu Mar 13, 2008 12:45 pm Post subject: |
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I don't see any difference between 1 meter and 13 meter DIY Belden 1505A cables+Neutric rear twist bnc's with 1080p72. My video card have MP1.4+bnc's though.
I don't see any benefit to use DVI with pc, it just limit pixel clock to 165MHz.
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ecrabb
Forum Moderator
Joined: 13 Mar 2006
Posts: 15909
Location: Utah
TV/Projector: JVC RS40, Epson 5010
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| Posted: Thu Mar 13, 2008 2:48 pm Post subject: |
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I remember a year or two ago on a lark, Scott (tse) did some high-res/bandwidth tests using a couple 25-foot (or was it 2 50-ft?) lengths of cheap RG6 from Rat Shack. I think it even had the screw-on RF couplers! Anyway, IIRC, he found little to no difference between the cobbled-up Rat Shack cable and good cable. The lesson was that as long as you were using good (or at least decent) cabling and that nothing was deficient, even cheap cable works just fine.
SC
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Curt Palme
CRT Tech
Joined: 08 Mar 2006
Posts: 24396
Location: Langley, BC
TV/Projector: All of them!
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| Posted: Thu Mar 13, 2008 3:14 pm Post subject: |
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Mike, that room ROCKS!
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JustGreg
Joined: 07 Mar 2006
Posts: 3098
Location: Kenosha, WI
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| Posted: Thu Mar 13, 2008 3:52 pm Post subject: |
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| Curt Palme wrote: | | Mike, that room ROCKS! |
I second that! Wow! It makes mine look like a train station waiting area. 
Greg
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Person99
Joined: 09 Mar 2006
Posts: 4899
Location: Flower Mound, TX
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| Posted: Thu Mar 13, 2008 10:36 pm Post subject: |
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| MikeEby wrote: |
A nice benefit was very short cables (4 feet), I often wonder if this is one reason I am able to run push my refresh and resolution harder than most and not see a huge amount of softness in the image.
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I tested 3 foot belden 1694a against 25 foot belden 1694a. You could tell absolutely no difference. The same as spanky with component cables.
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Dave
A train station is where the train stops. A bus station is where the bus stops. On my desk, I have a work station....
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MikeEby
Joined: 24 Jun 2007
Posts: 5237
Location: Osceola, Indiana
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| Posted: Fri Mar 14, 2008 3:17 am Post subject: |
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| Person99 wrote: | | MikeEby wrote: |
A nice benefit was very short cables (4 feet), I often wonder if this is one reason I am able to run push my refresh and resolution harder than most and not see a huge amount of softness in the image.
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I tested 3 foot belden 1694a against 25 foot belden 1694a. You could tell absolutely no difference. The same as spanky with component cables. |
Intesting guess it doesn't do anything for PQ but I still like just standing up in the 3rd row to pop in a disk.
Just did some of my first screen shots from "No Country For Old Men"
Mike
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