why am i seeing a difference? - AVS Forum
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post #1 of 16 Old 06-02-2012, 10:03 AM - Thread Starter
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I have been (for a long time) one of the guys with the mindset of "HDMI cables are HDMI cables. They pass 1s and 0s. As long as all of the data gets to the display, all is well". I may be changing my thoughts around this, after some more practical research, and some discussion here and with peers.

For the sake of argument, unless specifics are needed, I will leave out brand names.

I set up 2 very common, mid prices panels next to each other. Same settings, same viewing environment. The source is a very common, acceptable performance BR player with 2 HDMI outputs. Cable A (6') retails for $25, and cable B (1m) retails for $95. Content is "Ironman 2". If you are familiar with the movie, specifically this scene:

http://www.dailymotion.com/video/xcr...day_shortfilms

Overall there were 3 things that stood out to me.

1) Flesh tones. Cable B showed more detail in color, and overall had a deeper look. I paused the scene on a specific shot with Gwyneth Paltrow's face very clear and centered in the frame. There is some rosey-ness on her cheek bones (you could tell she had makeup on), but her cheeks look normal. Cable A showed none of that detail. Similar details could easily bee seen in Mickey Rourke's face. Cable a looked flat, while cable B showed a deeper flesh tone.

2) Color saturation/color detail. Mickey Rourke is wearing a bright orange suit in that scene. Cable B showed a nice, deep, detailed orange. Cable A again was flat in detail, and was also a less saturated orange. It was almost as if it was a lighter shade. The depth in the blue race car was also obviously different, cable B showing better saturation.

3) Distortion in motion. Cable A was phenomenally more distorted as the cars were racing around. It was as if cable A couldn't keep up.

I performed my observations using 2 different settings on the panels. My first observation was done using the factory "standard" picture mode. The second observation was as close to calibrated as I could get, as I did not have my gear on site. Picture mode "movie", color space "custom", color temp "normal", sharpness 0, pic size "screen fit", all enhancements and extra processing "off". (Some of you can probably guess the panel at this point!)

The differences that I observed were the same, whether I had the panels set to "standard" or "movie" (with my respective tweaks)

Here where my mind starts to question everything. am I seeing a difference in :

1) the cables?
2) the panels?
3) the HDMI outputs?

My next set of tests would be to hook up my gear (VP403, C6, Calman 4.6) and take some color measurements.

Thoughts?
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post #2 of 16 Old 06-02-2012, 10:15 AM
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So why didn't you just unplug cable A and B at the displays and switch them.. ??? If the image issue follows switch a and b at that player.. if the image follow then it is your cables if not you should be able to figure it out..
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post #3 of 16 Old 06-02-2012, 10:20 AM - Thread Starter
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GENIUS QUESTION!!!

That would have been too easy and obvious! Any other overthinkers here? (As i raise my hand slowly...)
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post #4 of 16 Old 06-02-2012, 10:22 AM
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Don't expect two displays of the same make and model, with the same menu settings values, to perform identically:
'Sharing display menu settings?'
http://www.avsforum.com/avs-vb/showthread.php?t=1055906
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post #5 of 16 Old 06-02-2012, 10:33 PM
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This may sound foreign as a concept, however...

Have you tried "listening" to HDMI cable differences that connect a Blu-ray player or Apple TV to a Surround Processor?

There is a high(er) end brand of cables that starts with "A" that make a decided difference in that regard, especially only with their entry level cable. Depending on associated equipment, mid to upper level cables make a profound difference, especially on Music Video Discs (like Rush "Snakes and Arrows" as an example).

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post #6 of 16 Old 06-03-2012, 05:31 AM
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Does the Blu-Ray player have identical outputs on both HDMI's. I know on some, the processing was only on HDMI 1 and 2 was basically for sound. I would second swapping each cable on 1 display for a truly A-B comparison.
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post #7 of 16 Old 06-03-2012, 06:06 AM
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Until the basic trouble shooting process is followed to isolate the location of what is causing the differences we will never really know.
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post #8 of 16 Old 06-03-2012, 02:08 PM
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With HDMI cables, cable quality is essentially irrelevant once you are above the point where the cable is actually capable of transmitting the full bandwidth signal without any loss.

For example, some very long cables (over 15ft or so) and/or some older cables cannot handle 1080p60 or 3D very well. It's very obvious when this is the case, because you will either not get a picture at all, experience picture drop-outs or hand shaking issues, or have bright spots show up in dark areas of the picture. If it's really bad, you may get digital noise showing up in the image more frequently than that. Best just to put up an all black image and see if it's stable or if you have bright spots showing up though.

Once you have a cable that is competent, spending any more won't get you any other improvements. It might be a nicer looking cable, or more flexible and easier to route, but it won't make a bit of difference to the image.

The things you're describing simply can't be caused by using a better cable.
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post #9 of 16 Old 06-03-2012, 02:26 PM
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As others have pointed to, you're most likely seeing a difference between the displays, and are perfectly illustrating why sharing display settings doesn't work. In order to perform a better comparison, you'd have to calibrate both displays first (as you suggested). Then you could eliminate them as a variable - at which point you'd see that the type of HDMI cable you use doesn't make a lick of difference. It will either work, or it won't.

There are 10 types of people: those who understand binary, and those who don't.

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post #10 of 16 Old 06-03-2012, 02:29 PM
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^^^ agreed. As long as you are using Certified High Speed HDMI cables, you can take them out of the equation.
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post #11 of 16 Old 06-03-2012, 02:45 PM
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A great read on so-called "speed certifications" on HDMI cables:

http://www.bluejeanscable.com/articl...s.htm?hdmidept

There are 10 types of people: those who understand binary, and those who don't.

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post #12 of 16 Old 06-03-2012, 04:25 PM
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Part of it has to do with the HDMI cable's part are the displays. As stated above the panels are going to have some variation's in them, sadly no two displays are going to be the same unless ISFccc calibration is done on the pro level. However the cable is also to blame, now when you start looking at high high end cables there truely is not a real difference. But when you look at the mid/higher end cables to the entry level one must stop and think ok $50.00 for a 6' or $25 for a 6'. Hmmm my guess is the quality and materials used are different, some cables are solid runs and some have solder points reducing the speed and quality in which the video is being delivered. Which do you think has the solder points.................
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post #13 of 16 Old 06-03-2012, 04:39 PM
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Quote:
Originally Posted by Hatedsalesman172 View Post

Part of it has to do with the HDMI cable's part are the displays. As stated above the panels are going to have some variation's in them, sadly no two displays are going to be the same unless ISFccc calibration is done on the pro level. However the cable is also to blame, now when you start looking at high high end cables there truely is not a real difference. But when you look at the mid/higher end cables to the entry level one must stop and think ok $50.00 for a 6' or $25 for a 6'. Hmmm my guess is the quality and materials used are different, some cables are solid runs and some have solder points reducing the speed and quality in which the video is being delivered. Which do you think has the solder points.................

That may be true but reliable companies like Monoprice, MediaBridge, BlueJeans etc offer excellent certified High Speed HDMI cables for a fraction of the cost of a comparable length cable of the "M" variety. Of course if you buy off of eBay or elsewhere, there's no telling what you're getting. High price doesn't necessarily mean better quality.
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post #14 of 16 Old 06-03-2012, 05:08 PM
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Quote:
Originally Posted by Otto Pylot View Post

That may be true but reliable companies like Monoprice, MediaBridge, BlueJeans etc offer excellent certified High Speed HDMI cables for a fraction of the cost of a comparable length cable of the "M" variety. Of course if you buy off of eBay or elsewhere, there's no telling what you're getting. High price doesn't necessarily mean better quality.

No I mean that is true, i'm not saying buy the most expensive hdmi and I'm not saying buy the "M" lable either but spend a little more than $25.00 on an HDMI cable to get a better quality product is all. I dont agree with "M" lable pricing and speed ratings becuase the truth is even 3D is no where close to needing 17gbps 10-14 tops will be more than enough for the next 5-10yrs or so.
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post #15 of 16 Old 06-04-2012, 02:22 AM
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Quote:
Originally Posted by Hatedsalesman172 View Post

Part of it has to do with the HDMI cable's part are the displays. As stated above the panels are going to have some variation's in them, sadly no two displays are going to be the same unless ISFccc calibration is done on the pro level. However the cable is also to blame, now when you start looking at high high end cables there truely is not a real difference. But when you look at the mid/higher end cables to the entry level one must stop and think ok $50.00 for a 6' or $25 for a 6'. Hmmm my guess is the quality and materials used are different, some cables are solid runs and some have solder points reducing the speed and quality in which the video is being delivered. Which do you think has the solder points.................

Quote:
Originally Posted by Hatedsalesman172 View Post

No I mean that is true, i'm not saying buy the most expensive hdmi and I'm not saying buy the "M" lable either but spend a little more than $25.00 on an HDMI cable to get a better quality product is all. I dont agree with "M" lable pricing and speed ratings becuase the truth is even 3D is no where close to needing 17gbps 10-14 tops will be more than enough for the next 5-10yrs or so.

Sure, you'll see a difference in manufacturing techniques, but either an HDMI cable is going to work or it isn't. There's no shades of grey in terms of image quality with digital cables. The important thing is length (as you see on BJC) - in fact BJC only sells their cheaper cables in shorter lengths because those cables have been shown (in testing) to not work at longer lengths.

There's very little room for snake oil and smoke and mirrors with HDMI cables - as long as the company you're buying from guarantees their cables and has a good return policy, you're not gaining anything by spending $50 over $25.

There are 10 types of people: those who understand binary, and those who don't.

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post #16 of 16 Old 06-04-2012, 07:47 AM
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Quote:
Originally Posted by Hatedsalesman172 View Post

No I mean that is true, i'm not saying buy the most expensive hdmi and I'm not saying buy the "M" lable either but spend a little more than $25.00 on an HDMI cable to get a better quality product is all. I dont agree with "M" lable pricing and speed ratings becuase the truth is even 3D is no where close to needing 17gbps 10-14 tops will be more than enough for the next 5-10yrs or so.

The parts might be better, but the performance won't be. With how HDMI is designed, either you get an image that is identical to any other working cable, or you get no image or a horribly distorted image. Since the packets sent over HDMI are actually dependent on the packets that came before (in a method to reduce errors), you don't get a situation where one pixel would be slightly off by a single value, such as if you had an analog cable where one was perhaps causing the waveform to come in at a slightly lower voltage than another cable.

I buy the nicer HDMI cables from Blue Jeans, but because I find they're more physically durable and not nearly as heavy as Monoprice stuff often is. With how often I swap them around being more flexible and durable is worth the extra money to me. If I was never moving them around, I'd just get Monoprice and be done with it.

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