Sunday, April 19, 2015

Tributaries 4K UHDMI Cable Review - Part 2

As mentioned in Part 1 of this series, it is best to begin at the beginning and test the tester. Saying this another way, make sure that the assumptions you make about your system are valid and that things haven't changed to which you are unaware. In particular, it is a good idea for you to test your own TV with a simple video image that shows you if your set is properly adjusted. The standard test images I used are 1080p test image or a 4K test image (NOTE: these are high-quality PNG-format pictures, not videos).

In Part 2 of this series, I will test the following four cables manufactured by the Tributaries Cable Company of Orlando, Florida, on my Samsung F8000 65" 1080p LED TV:
  • UHD HDMI (UHD-010b), 1-meter length, MSRP $35
  • UHD Slim (UHDS-010b), 1-meter length, MSRP $65
  • UHD Slim Active (UHDS-020b), 2-meter length, MSRP $85
  • UHD Pro (UHDP-010b), 1-meter length, MSRP $80
My current (reference) cables are the 1-meter Series 8 Tributaries HDMI and I have been very pleased with their performance. With time I have grown familiar with the characteristics of these reference cables and I look forward to observing any changes these wider-bandwidth cables may make in the 1080p signal world. Unfortunately, I do not currently own a 4K television so I cannot test their true potential. However, I will report on any improvements noticed in the 1K format. I suspect that - if anywhere - I may observe improvements in 3-D images. But we shall see...

To be consistent, I used my tripod-mounted FUJI S1500 digital camera to photograph the video image on the screen. The object is to use this same image and display it through each of the HDMI cables taking identical exposure images. Then, I will use PaintShop Pro to arithmetically subtract the information between the two images (the Reference Series 8 and the cable under test) and show you the results. What differences there are will be shown as non-black features in the Difference image. Exposure value for all images was ASA64, 1 second, F/5; no other adjustments. Source files for each image is 3648x2736 pixels and 4Mb in size (JPG format). All images were taken at 3:00AM to eliminate any ambient lighting changes.

Now there is some error introduced to the source images due to JPG compression. However if there is a compression error introduced by the camera, a test between two pictures of the same image of the same cable through the same camera with the same exposure should reveal what errors are introduced. Below are two such pictures taken through the Series 8 cable.

This type of test is called a NULL test and it takes into account all forms of change regardless of the source. In other words, what the Difference image shows are the things that have changed between the two images and nothing else. So theoretically the mathematical difference between two pictures of the reference image should be a completely black image (no difference) and in fact it is. This verifies that the software is working as anticipated and the assumption that the JPG compression adds no comparative errors is correct (i.e., identical amount of compression error introduced).

So the testing strategy is sound. Now let's see the difference between the Series 8 HDMI cable and the UHD-010b cable.

Viola! Herein is evidence of subtle differences between these two cables. This is not rocket science folks, just simple computer wizardry. For those naysayers who claim that there are no differences between cables, here is indisputable proof that there are indeed differences. Although the differences are minor, there are differences since the NULL (Difference) image is no longer completely black. What these differences are or how they impact an image remains to be seen, but that is not the object of this test. This test just points out differences and nothing else.

Now let's see what this same process reveals when comparing the Series 8 HDMI cable and the UHDS-010b cable.

My oh my. To me it is evident that there are even more differences here. This is very interesting. So let's see what the next cable looks like compared to the Series 8: the UHDS-020b.

Fascinating. To me, it appears that there are more differences measured between the Series 8 and the UHDS-10b than between the Series 8 and the UHDS-20b. But let us continue and see what happens with the last comparison to the Series 8: the UHDP-10b.

Again there are measured differences between cables and it looks like the cable that shows the most differences is the UHDS-010b, the UHDS-20b measuring second, the UHDP-10b third, and the UHD-10b last.

I could go on and analyze the differences between these four cables themselves but I will not since it is clear that one cable shows more differences than the other three.

Now this is what the data tells me about image differences but it tells me nothing about the image quality or color accuracy. For that, a different set of testing is required - subjective - and these tests will be covered in Part 3 of this series.

Yours for higher fidelity,

Philip Rastocny

I do not use ads in this blog to help support my efforts. If you like what you are reading, please remember to reciprocate by purchasing one of my eBooks or through a PayPal donation, My newest title is called Where, oh Where did the Star of Bethlehem Go? It’s an astronomer’s look at what this celestial object may have been, who the "Wise Men" were, and where they came from. Written in an investigative journalism style (like that of the Discovery Channel), it targets one star that has never been considered before and builds a solid case for its candidacy.

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