View Full Version : Expensive HDMI cables make no difference - the absolute proof

08-06-2012, 04:38 PM
Whether or not to buy an expensive HDMI cable is one of the most contentious subjects on the internet. On pro the side of buying them are home cinema magazines and audiophile websites, which sing the praises of more expensive cables, heralding how they can do remarkable things, such as boosting flesh tones.

On the other side, you have the sceptics that say HDMI uses digital, so all cables are equal. In fact, James Randi has even extended his $1 million prize for anyone that can prove paranormal activity to include anyone that can prove that expensive HDMI cables make a difference.

We've always been sceptical about the benefits of more expensive cables, but the problem was always proving it in a scientific, repeatable way that removes any argument. Now, we've found the way to do that and can once and for all prove beyond a doubt if expensive cables make any difference.


Whether expensive HDMI cables make a difference is one of the big questions about home cinema, but we've answered it

The only way to answer the question of whether or not expensive cables really make a difference is to test image quality objectively. Subjective testing using a group of people is inherently flawed, as the average person will almost always pick a side when given two options to choose from ? even if they are identical. HDMI cables are no exception to this rule, as we found out when we last tested HDMI cables.

Using identical kit is no guarantee of identical results and subjective testing is inherently flawed

There are other problems, too. Using identical TVs, Blu-ray players and discs still can?t create a level playing field, because of minor differences between the colour casts of each set. Even identical devices have the potential to affect the results of a blind test. When we compared two PlayStation 3 consoles, we noticed a distinct difference in the colour reproduction of a Blu-ray disc - independent of the TV or HDMI cable we used. Unless you colour calibrate each device first, a blind test can?t produce reliable results.


To objectively test HDMI cables we first bought the Digital Foundry TrueHD capture card. This high-quality card allowed us to capture the HDMI output from a device in a RAW uncompressed format with no error correction, using 24-bit RGB. This eliminates any colour cast or error correction from the equation, as we're dealing with raw frames captured.

Next, we used a PC to output the Blu-ray version of Sintel, an open source film produced by the Blender Foundation. The choice of a PC may seem a little strange, and some people would argue that we should have used a Blu-ray player instead. However, we're not interested in the argument of which device produces the best-quality video, but rather if HDMI cables produce different results. To this end, the PC gave us one important advantage: we could screenshot a frame from the film on the PC and compare this to a frame captured on the TrueHD card. If the two were the same, the cable had made absolutely no difference; if the two differed, the cable was affecting quality.

To ensure that we managed to get the same frames at the PC and TrueHD ends, we paused the film and jumped to chapter two. It may seem strange to pause the film, as we weren't capturing motion, but as far as the PC's graphics card, cable and TrueHD card are concerned, pausing has no effect. The PC still has to output at the same rate, but rather than outputting 24 different frames per second for motion, it's outputting 24 identical frames per second.

As an HDMI-certified cable allows for a maximum of 1-bit error in a billion (roughly one pixel incorrect per second), we captured 24 frames of the paused Sintel (one second's worth) and saved them as uncompressed bitmap files that we could then compare to original frame we'd screen-grabbed on the PC. As the TrueHD doesn't apply any correction to the source, a single pixel's difference would be highlighted.

Sintel is an open source Blu-ray film, which we used to test if HDMI cables make any difference at all


Once we had our captured frames, we needed an objective way of comparing the captured frames to the original frame we'd captured on the PC. For this we decided to use two methods. First, we used the ImageMagick Compare command. This takes two images and creates a third picture, highlighting any pixels that are different in red. Next, we created a MD5 hash of each file we captured. An MD5 hash is a unique fingerprint of file: if two files have the same MD5 hash, they're physically and scientifically identical, no argument.

By also creating an MD5 hash of the ImageMagick-created compare files, we could prove that they're all identical, too. In essence, then, we ensured that our captured frames were identical and that our comparison frames were identical.

ImageMagick's Compare command can detect a single pixel error and highlight it.

In both of our verification tests, a single shade of colour in a single pixel will be enough to trigger a difference. To test this level of accuracy, we edited a screenshot in Photoshop, changing the red colour value of a single pixel by one point before running our comparison tools. The red highlight in the comparison image and different MD5 hashes indicate a difference in the two images.


This method of testing not only determines the number of errors transmitted by a particular cable, it will also indicate if colours change at all when switching between cables - an idea frequently used to explain why certain cables are ?better? than others in high-end home cinema reviews. Basically, if the cable does anything at all, the captured frame will be different from the frame screencaptured on the PC.

We looked at a range of cables, from the bargain basement cables that come bundled with Blu-ray players and TVs, to incredibly expensive high-end ones with huge feature lists covering the packaging. There was a vast difference in terms of price, ranging from ?5 to an eye-watering ?150, which could easily confuse anyone looking for a new cable.


The list of cables that we used for our testing


After methodically testing each cable, our comprehensive results revealed the truth. We couldn?t find a single error in any of the frames of video we captured using our tests, regardless of the cable we used. Even allowing for a single error per billion bits, none of our captured frames contained as much as a single pixel out of order by a single colour shade.

This image is the ImageMagick Compare-created image. If there were any errors, the pixels would be highlighted in red

The MD5 hash values backed up our findings ? the captured frames were identical to the original ones. As verification, the MD5 hash of the ImageMagick Compare files were also identical. For reference, here are the MD5 hash values generated.

The MD5 hash proves that the captured files are all identical

We had to force an error by reversing a uni-directional cable, which generated several incorrect pixels. Because our capture card doesn?t apply any error correction, these pixels simply failed to render.

Comparing our captured images to one another also proves that individual cables have no impact on colour reproduction. Because each capture was identical, with no differentiation between the colours of individual pixels, there can be no question that the final picture displayed on a TV is unaffected by your choice of HDMI cable. With no active circuitry inside them, HDMI cables don?t know what format the data it transmits will get re-encoded into when it reaches its destination, so there?s no way it could adjust colour values, improve skin tone or create better black response.

More expensive cables may have been engineered to eliminate timing jitter or reduce binary errors, but we didn't get any errors with our Lindy 10m cable, which costs less than the Atlas 1m cable. What's clear from our tests is that we got no errors on any of the cables, and more expensive cables did not improve image quality at all. Given our results, we'd definitely buy cheaper HDMI-certified cables.


Source (http://www.expertreviews.co.uk/home-entertainment/1292371/expensive-hdmi-cables-make-no-difference-the-absolute-proof/3)

08-06-2012, 05:09 PM
Got me 2 from ebay for 2 pounds each,best cables i ever had ;-)

08-06-2012, 05:41 PM
Im going into Comet at the wekend and let the reatil assistant tell all the cr@p about how these cables are better than these and then show them the article pmsl

There has only ever been one difference i have seen with a more expensive cable and that was a scart lead that i got free with a tv once i know it should have been ?100 and i got it for nothing and that did make a difference but thats on scart. HDMI ive always gone for the cheap ones and never had a complaint about them

08-06-2012, 08:57 PM
I have to admit i love letting sales guy try to flog me the most expensive cable they sell pmsl nice post Pejazzle, got mine for about ?5 if i remember.I did read the more expensive ones i.e ?5/10 have better breading around the connections so there is not so much stress on the plastic molding.But as for the picture no difference

08-06-2012, 11:37 PM
I have had this same argument in Comet, because they do love to push their Monster-ously pricy cables! ;)
Though you actually have no hope of winning the argument when comparing them to a salesman's monthly sales bonus or commission!

There can be differences in quality of manufacture though, especially with reference to how the ends are attached and the way in which cables are screened. While that wont affect what passes through the cables, it can make a difference as to how long they last and if they are affected by outside electrical interference?
Given that most of your HDMI cables will stay attached for the longest periods, without you using them as skipping ropes and that most users don't actually live in a power generating station, :rolleyes: there is absolutely no way the huge prices on some named brand cables can be justified!
Which begs the question why are these blatant scams allowed to go on?
Trading standards need to wake up, do their jobs and protect the public from being exploited in this way! :mad:

A very useful and informative post Pejazzle! :thumbup2:

08-06-2012, 11:53 PM
i mind when i was buying my 3 d tv the guy was trying to sell me 40 quid hdmi cables ,i let him go on and on about them then i stopped him and said i have the very same cables and i got them for 10 quid for 2 ,well he didnt believe so i said if i can prove it what would he give me,he said if i bought the same cables hed give me a camera ,so i jumped into my car and came back with them and recipt ,got a nice new camera from them roflmao

09-06-2012, 12:41 AM
YAAAY that's the kind of post I like to read, you stick it to da maan nao bro! :appl:
Respect to him that he kept his end of the bargain though! ;)

Vagelis Georgariou
09-06-2012, 12:58 AM
Got me 2 from ebay for 2 pounds each,best cables i ever had ;-)
Fantastic, I too bought the cheapos from
ebay but they work perfectly!

09-06-2012, 01:01 AM
Im glad being cheap paid off! I bought cheap, never had any problem

09-06-2012, 01:36 AM
But I've brought cheapo ones from ebay and they have been rubbish, loss of sound and picture cutting out. Replaced with expensive one from currys and works a treat. So obviously not all the same.

09-06-2012, 08:31 AM
But I've brought cheapo ones from ebay and they have been rubbish, loss of sound and picture cutting out. Replaced with expensive one from currys and works a treat. So obviously not all the same.
There is a saying you get what you pay for mate, while maybe not strictly true in this case if you spend a couple of quid on something made in the far east it is not going to be that good uunfortunately there is always some one ready to rip you off

09-06-2012, 11:04 AM
Got from here as feedback was 100% http://tinyurl.com/ctoa8cf

09-06-2012, 01:33 PM
free p+p as well worth it

09-06-2012, 02:32 PM
People should remember though that the latest version HDMI cables are 1.4, which have audio feedback capability built in. That is optimized for 3D playback.
You still don't have to buy expensive ones, but if you are looking to buy new HDMI cables you really should get the latest versions. The older 1.3 b cables are very cheap for that reason, with the 1.4 costing very little more!

11-06-2012, 11:34 PM
I started off buying the slightly more expensive HDMI cables and as time went by I tried some of the cheaper ones and to tell you the truth I could not tell the difference.

All I make sure now is that they are they latest version ie 1.4 and look for free P&P on Amazon.

17-07-2012, 01:15 AM
I must admit when buying my first HDMI cable I was a little unsure. Still, I opted for the cheapest one and can honestly say I've never had a problem with it. ?7 Tesco's own.

20-07-2012, 01:15 AM
One thing I've noticed while working in retail is that customers have this idea of perceived value'. The store sells HDMI cables of various types, some around ?5, some around ?15 and others in excess of ?40. We find that the ?15 cables are picked more often as customers think the ?5 ones are too cheap and the others are too expensive (I think this is called the 'Goldilocks Effect') and very few customers ask about the difference in quality - a sign of the times where people are more reticent to spend more than they have to, perhaps?

10-09-2012, 01:05 AM
Thank you so much for this, I have been debating myself wether to by an expensive HDMI cable or not and I'm so glad I didn't now. Il be sticking with my ?3 HDMI cables from tesco from now on

19-09-2012, 12:00 AM
I've always used ?1 HDMI cables, never had a problem so far.

19-09-2012, 12:36 AM
quality speed and shielding come to mind with cheaper cables,if you buy a tv worth ?2000 would you use a ?1 cable,picture quality suffers i will never use those inferior ones that come with boxes as you can see the grainy side with them,and another thing that gets over looked is the old coaxial cable used and not updated.

22-09-2012, 02:00 AM
IMO I've always found, the cheaper cables to be fine. The main difference between the expensive ones is the shielding provided (apparantly). Even if that were the case, you would need a significant amount of Electromagnetic Interference (EMI) for it to actually have any benefit. I usually have a plethora of power (as well as other) cables around my HDMI cable. The fact that data is transmitted digitally means that if interference were to occur, it would alter the digital data and have a similar effect to a bad freeview connection. Digital transmission is basically all or nothing. I'd suggest as others have said, getting an up to date (or recent) version hdmi cable and get it cheap.

I'm glad someone has finally taken the time to debunk this annoying falsehood created by marketing and sales. It's painful to see that people fall into this trap and buy the expensive cables. I can't really blame the sales people as they are given an incentive to help meet their quota set by their employers to sell it. I blame the companies for cashing in on misinformation.

Unless you have several irons, heaters, or vacuum cleaners (or something else that has a huge power usage) practically touching your cable, there shouldn't be a difference (as stated by the OP).